%--------------------------------------------
%
% Package pgfplots, library for higher order patch plots.
% It contains advanced patch plots like quadratic triangles,
% biquadratic quadrilaterals, coons patches and others.
% The basic implementation for patches supports already line, triangle
% and rectangle (=2 triangles) patches.
%
% Copyright 2007/2008/2009 by Christian Feuersänger.
%
% This program is free software: you can redistribute it and/or modify
% it under the terms of the GNU General Public License as published by
% the Free Software Foundation, either version 3 of the License, or
% (at your option) any later version.
%
% This program is distributed in the hope that it will be useful,
% but WITHOUT ANY WARRANTY; without even the implied warranty of
% MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
% GNU General Public License for more details.
%
% You should have received a copy of the GNU General Public License
% along with this program. If not, see .
%
%--------------------------------------------
% NOTES:
% In general, a Bezier spline C:[0,1] -> \R of order n fulfills
% C'(0) = n ( P_1 - P_0 ),
% C'(1) = n ( P_n - P_{n-1} ).
% For n=3 and given P_0 and P_3, I can directly compute P_1 and P_2 once I know
% the derivatives at t=0 and t=1.
%
%
%
%--------------------------------------------------
% 4-point Lagrange interpolation on {0,1/3,2/3,1}:
% C(x) =
% a * (1/3 - x)/(1/3) * (2/3-x)/(2/3) * (1-x) +
% b * (0 - x)/(0 - 1/3) * (2/3-x)/(2/3-1/3) * (1-x)/(1-1/3) +
% c * (0 - x)/(0 - 2/3) * (1/3-x)/(1/3-2/3) * (1-x)/(1-2/3) +
% d * (0 - x)/(0 - 1) * (1/3-x)/(1/3-1) * (2/3-x) /(2/3-1)
%
%
% Derivative:
%
% (-9*c + 2*d + 72*c*x - 18*d*x - 81*c*x^2 + 27*d*x^2 +
% a*(-11 + 36*x - 27*x^2) + 9*b*(2 - 10*x + 9*x^2))/2
%
% bezier control points are
% P1 = (-5*a)/6 + 3*b - (3*c)/2 + d/3
% = -0.833333 a + 3. b - 1.5 c + 0.333333 d
%
% P2 = 0.333333 (0.5 (2. a - 9. b + 18. c - 11. d) + 3. d)
% = 0.333333 a - 1.5 b + 3. c - 0.833333 d
%--------------------------------------------------
% A quadratic spline in the ordering
%
%
%
% where is the function value at the left end of the spline
% segmment, the function value at the right end, and
% the function value in the middle of the spline segment.
\pgfplotsdeclarepatchclass{quadratic spline}{%
get dimension=\def\pgfplotsretval{1},
supports global path=\def\pgfplotsretval{1},
new=\def\pgfplotspatchclass@qspline@no{A},
set next vertex={%
% EXPECTED ORDERING: first 2 corners, then 1 mid nodes
% (interpolatory).
% defines \pgfplotspatchclass@qspline@A ... \pgfplotspatchclass@qspline@C (3 points)
\expandafter\edef\csname pgfplotspatchclass@qspline@\pgfplotspatchclass@qspline@no\endcsname{#1}%
\if C\pgfplotspatchclass@qspline@no
\def\pgfplotspatchclass@qspline@no{A}%
\pgfplotspatchready
\else
\expandafter\let\expandafter\pgfplotspatchclass@qspline@no\csname pgfpptchindexnext@\pgfplotspatchclass@qspline@no\endcsname
\fi
},
if current point can be first last={%
\pgfplots@loc@tmptrue
\if A\pgfplotspatchclass@qspline@no
% Ah - the current point is the 'C' point, i.e. the
% control point (we have advanced the '@no' counter)
\pgfplots@loc@tmpfalse
\fi
\ifpgfplots@loc@tmp
#1\relax%
\else
#2\relax
\fi
},
sample in unit cube={%
\def\pgfplotspatchclassx{0}%
\def\pgfplotspatchclassy{0}%
#1%
\def\pgfplotspatchclassx{1}%
\def\pgfplotspatchclassy{0}%
#1%
\def\pgfplotspatchclassx{0.5}%
\def\pgfplotspatchclassy{0}%
#1%
\pgfplotspatchready
},%
first vertex=\expandafter\pgfplotspatchvertex\pgfplotspatchclass@qspline@A\endvertex,
foreach vertex={%
\expandafter\pgfplotspatchvertex\pgfplotspatchclass@qspline@A\endvertex #1%
\expandafter\pgfplotspatchvertex\pgfplotspatchclass@qspline@B\endvertex #1%
\expandafter\pgfplotspatchvertex\pgfplotspatchclass@qspline@C\endvertex #1%
},
fill path={%
\begingroup
% Draw the patch boundary using a bezier curves.
%
% Since I have lagrange points to describe the patch (i.e.
% points the patch passes through), I have to convert the
% lagrange representation to bezier.
%
% Furthermore, I convert to *cubic* bezier since pdf only
% supports cubic curves.
%
% See the docs for 'biquadratic::fill path' for more details,
% in does the same.
\def\pgfplots@edge{%
\ifx\pgfplotspatchclass@qspline@A\PA
\pgfplotsplothandlermesh@pathmoveto{\expandafter\pgfplotspointpatchvertex\PA\endvertex}%
\fi
\pgfpathcurveto {%
\pgfpointadd
{\pgfqpointscale{1.333333}{\expandafter\pgfplotspointpatchvertex\PB\endvertex}}%
{\pgfqpointscale{-0.333333}{\expandafter\pgfplotspointpatchvertex\PC\endvertex}}%
}{%
\pgfpointadd
{\pgfqpointscale{1.333333}{\expandafter\pgfplotspointpatchvertex\PB\endvertex}}%
{\pgfqpointscale{-0.333333}{\expandafter\pgfplotspointpatchvertex\PA\endvertex}}%
}{%
\expandafter\pgfplotspointpatchvertex\PC\endvertex
}%
}%
\let\PA=\pgfplotspatchclass@qspline@A
\let\PB=\pgfplotspatchclass@qspline@C
\let\PC=\pgfplotspatchclass@qspline@B
\pgfplots@edge
\pgfplotsplothandlermesh@setlastpoint{\expandafter\pgfplotspointpatchvertex\PC\endvertex}%
\endgroup
},
triangulate class=\def\pgfplotsretval{line},
triangulate={%
\let\pgfplotsplothandlermesh@patchclass@=\pgfplotsplothandlermesh@patchclass
\def\pgfplotsplothandlermesh@patchclass{line}%
\pgfplotspatchclass{\pgfplotsplothandlermesh@patchclass}{new}%
\expandafter\pgfplotsplothandlermesh@setnextvertex\expandafter{\pgfplotspatchclass@qspline@A}%
\expandafter\pgfplotsplothandlermesh@setnextvertex\expandafter{\pgfplotspatchclass@qspline@C}%
\expandafter\pgfplotsplothandlermesh@setnextvertex\expandafter{\pgfplotspatchclass@qspline@C}%
\expandafter\pgfplotsplothandlermesh@setnextvertex\expandafter{\pgfplotspatchclass@qspline@B}%
\let\pgfplotsplothandlermesh@patchclass=\pgfplotsplothandlermesh@patchclass@
},%
recursive refine@={%
\pgfplotspatchclass{\pgfplotspatchclassname}{new}%
\pgfplotspatchvertexaccumstart
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@qspline@A\times{0.375}%
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@qspline@B\times{-0.125}%
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@qspline@C\times{0.75}%
\pgfplotspatchvertexfinish\pgfplotspatchclass@qspline@AC
%
\expandafter\pgfplotsplothandlermesh@setnextvertex\expandafter{\pgfplotspatchclass@qspline@A}%
\expandafter\pgfplotsplothandlermesh@setnextvertex\expandafter{\pgfplotspatchclass@qspline@C}%
\expandafter\pgfplotsplothandlermesh@setnextvertex\expandafter{\pgfplotspatchclass@qspline@AC}%
#1%
%
\pgfplotspatchvertexaccumstart
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@qspline@A\times{-0.125}%
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@qspline@B\times{0.375}%
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@qspline@C\times{0.75}%
\pgfplotspatchvertexfinish\pgfplotspatchclass@qspline@CB
%
\expandafter\pgfplotsplothandlermesh@setnextvertex\expandafter{\pgfplotspatchclass@qspline@C}%
\expandafter\pgfplotsplothandlermesh@setnextvertex\expandafter{\pgfplotspatchclass@qspline@B}%
\expandafter\pgfplotsplothandlermesh@setnextvertex\expandafter{\pgfplotspatchclass@qspline@CB}%
#1%
%
},%
get pdf shading type=0,
get num vertices=\def\pgfplotsretval{3},
}%
\pgfplotsdeclarepatchclass{cubic spline}{%
get dimension=\def\pgfplotsretval{1},
supports global path=\def\pgfplotsretval{1},
new=\def\pgfplotspatchclass@cspline@no{A},
set next vertex={%
% EXPECTED ORDERING: first 2 corners, then 1 mid nodes
% (interpolatory).
% defines \pgfplotspatchclass@cspline@A ... \pgfplotspatchclass@cspline@D (4 points)
\expandafter\edef\csname pgfplotspatchclass@cspline@\pgfplotspatchclass@cspline@no\endcsname{#1}%
\if D\pgfplotspatchclass@cspline@no
\def\pgfplotspatchclass@cspline@no{A}%
\pgfplotspatchready
\else
\expandafter\let\expandafter\pgfplotspatchclass@cspline@no\csname pgfpptchindexnext@\pgfplotspatchclass@cspline@no\endcsname
\fi
},
if current point can be first last={%
\pgfplots@loc@tmpfalse
\if B\pgfplotspatchclass@cspline@no
% Ah - the current point is the 'A' point (we have
% advanced the '@no' counter)
\pgfplots@loc@tmptrue
\fi
\if C\pgfplotspatchclass@cspline@no
% Ah - the current point is the 'B' point (we have
% advanced the '@no' counter)
\pgfplots@loc@tmptrue
\fi
\ifpgfplots@loc@tmp
#1\relax%
\else
#2\relax
\fi
},
sample in unit cube={%
\def\pgfplotspatchclassx{0}%
\def\pgfplotspatchclassy{0}%
#1%
\def\pgfplotspatchclassx{1}%
\def\pgfplotspatchclassy{0}%
#1%
\def\pgfplotspatchclassx{0.3333333}%
\def\pgfplotspatchclassy{0}%
#1%
\def\pgfplotspatchclassx{0.6666666}%
\def\pgfplotspatchclassy{0}%
#1%
\pgfplotspatchready
},%
first vertex=\expandafter\pgfplotspatchvertex\pgfplotspatchclass@cspline@A\endvertex,
foreach vertex={%
\expandafter\pgfplotspatchvertex\pgfplotspatchclass@cspline@A\endvertex #1%
\expandafter\pgfplotspatchvertex\pgfplotspatchclass@cspline@B\endvertex #1%
\expandafter\pgfplotspatchvertex\pgfplotspatchclass@cspline@C\endvertex #1%
\expandafter\pgfplotspatchvertex\pgfplotspatchclass@cspline@D\endvertex #1%
},
fill path={%
% Draw the patch boundary using a bezier curve.
\pgfplotsplothandlermesh@pathmoveto{\expandafter\pgfplotspointpatchvertex\pgfplotspatchclass@cspline@A\endvertex}%
\pgfplotspathcubicfrominterpolation
{\pgfplotspatchclass@cspline@A}%
{\pgfplotspatchclass@cspline@C}%
{\pgfplotspatchclass@cspline@D}%
{\pgfplotspatchclass@cspline@B}%
\pgfplotsplothandlermesh@setlastpoint{\expandafter\pgfplotspointpatchvertex\pgfplotspatchclass@cspline@B\endvertex}%
},
triangulate class=\def\pgfplotsretval{line},
triangulate={%
\let\pgfplotsplothandlermesh@patchclass@=\pgfplotsplothandlermesh@patchclass
\def\pgfplotsplothandlermesh@patchclass{line}%
\pgfplotspatchclass{\pgfplotsplothandlermesh@patchclass}{new}%
\expandafter\pgfplotsplothandlermesh@setnextvertex\expandafter{\pgfplotspatchclass@cspline@A}%
\expandafter\pgfplotsplothandlermesh@setnextvertex\expandafter{\pgfplotspatchclass@cspline@C}%
\expandafter\pgfplotsplothandlermesh@setnextvertex\expandafter{\pgfplotspatchclass@cspline@C}%
\expandafter\pgfplotsplothandlermesh@setnextvertex\expandafter{\pgfplotspatchclass@cspline@D}%
\expandafter\pgfplotsplothandlermesh@setnextvertex\expandafter{\pgfplotspatchclass@cspline@D}%
\expandafter\pgfplotsplothandlermesh@setnextvertex\expandafter{\pgfplotspatchclass@cspline@B}%
\let\pgfplotsplothandlermesh@patchclass=\pgfplotsplothandlermesh@patchclass@
},%
recursive refine@={%
% The 4-point lagrangian interpolation formular is shown on
% the top of this page. What I do here is simply to evaluate
% C(i*1/9) for i =0,...,9:
% 0
% 0.493827 A +0.740741 C -0.296296 D +0.0617284 B
% 0.17284 A +1.03704 C -0.259259 D +0.0493827 B
% 1/3
% -0.0617284 A +0.740741 C +0.37037 D -0.0493827 B
% -0.0493827 A +0.37037 C +0.740741 D -0.0617284 B
% 2/3
% 0.0493827 A -0.259259 C +1.03704 D +0.17284 B
% 0.0617284 A -0.296296 C +0.740741 D +0.493827 B
% 1
\pgfplotspatchclass{\pgfplotspatchclassname}{new}%
\pgfplotspatchvertexaccumstart
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@cspline@A\times{0.493827}%
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@cspline@B\times{0.0617284}%
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@cspline@C\times{0.740741}%
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@cspline@D\times{-0.296296}%
\pgfplotspatchvertexfinish\pgfplotspatchclass@cspline@AA
%
\pgfplotspatchvertexaccumstart
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@cspline@A\times{0.17284}%
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@cspline@B\times{0.0493827}%
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@cspline@C\times{1.03704}%
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@cspline@D\times{-0.259259}%
\pgfplotspatchvertexfinish\pgfplotspatchclass@cspline@AB
%
\expandafter\pgfplotsplothandlermesh@setnextvertex\expandafter{\pgfplotspatchclass@cspline@A}%
\expandafter\pgfplotsplothandlermesh@setnextvertex\expandafter{\pgfplotspatchclass@cspline@C}%
\expandafter\pgfplotsplothandlermesh@setnextvertex\expandafter{\pgfplotspatchclass@cspline@AA}%
\expandafter\pgfplotsplothandlermesh@setnextvertex\expandafter{\pgfplotspatchclass@cspline@AB}%
#1%
%
%
\pgfplotspatchvertexaccumstart
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@cspline@A\times{-0.0617284}%
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@cspline@B\times{-0.0493827}%
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@cspline@C\times{0.740741}%
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@cspline@D\times{0.37037}%
\pgfplotspatchvertexfinish\pgfplotspatchclass@cspline@AA
%
\pgfplotspatchvertexaccumstart
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@cspline@A\times{-0.0493827}%
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@cspline@B\times{-0.0617284}%
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@cspline@C\times{0.37037}%
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@cspline@D\times{0.740741}%
\pgfplotspatchvertexfinish\pgfplotspatchclass@cspline@AB
%
\expandafter\pgfplotsplothandlermesh@setnextvertex\expandafter{\pgfplotspatchclass@cspline@C}%
\expandafter\pgfplotsplothandlermesh@setnextvertex\expandafter{\pgfplotspatchclass@cspline@D}%
\expandafter\pgfplotsplothandlermesh@setnextvertex\expandafter{\pgfplotspatchclass@cspline@AA}%
\expandafter\pgfplotsplothandlermesh@setnextvertex\expandafter{\pgfplotspatchclass@cspline@AB}%
#1%
%
%
\pgfplotspatchvertexaccumstart
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@cspline@A\times{0.0493827}%
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@cspline@B\times{0.17284}%
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@cspline@C\times{-0.259259}%
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@cspline@D\times{+1.03704}%
\pgfplotspatchvertexfinish\pgfplotspatchclass@cspline@AA
%
\pgfplotspatchvertexaccumstart
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@cspline@A\times{0.0617284}%
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@cspline@B\times{0.493827}%
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@cspline@C\times{-0.296296}%
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@cspline@D\times{0.740741}%
\pgfplotspatchvertexfinish\pgfplotspatchclass@cspline@AB
%
\expandafter\pgfplotsplothandlermesh@setnextvertex\expandafter{\pgfplotspatchclass@cspline@D}%
\expandafter\pgfplotsplothandlermesh@setnextvertex\expandafter{\pgfplotspatchclass@cspline@B}%
\expandafter\pgfplotsplothandlermesh@setnextvertex\expandafter{\pgfplotspatchclass@cspline@AA}%
\expandafter\pgfplotsplothandlermesh@setnextvertex\expandafter{\pgfplotspatchclass@cspline@AB}%
#1%
},
get pdf shading type=0,
get num vertices=\def\pgfplotsretval{4},
}%
\def\pgfplotspathcubicfrominterpolation#1#2#3#4{%
% switch basis from lagrange to bezier (see formular on top of
% this file)
\pgfpathcurveto {%
\begingroup
\pgfplotspatchvertexaccumstart
\expandafter\pgfplotspatchvertexaddXY#1\times{-0.833333}%
\expandafter\pgfplotspatchvertexaddXY#2\times{3}%
\expandafter\pgfplotspatchvertexaddXY#3\times{-1.5}%
\expandafter\pgfplotspatchvertexaddXY#4\times{0.3333333}%
\pgfplotspatchvertexfinish\pgfplots@loc@TMPa
\expandafter\pgfplotspointpatchvertex\pgfplots@loc@TMPa\endvertex
\endgroup
}{%
\begingroup
\pgfplotspatchvertexaccumstart
\expandafter\pgfplotspatchvertexaddXY#1\times{0.333333}%
\expandafter\pgfplotspatchvertexaddXY#2\times{-1.5}%
\expandafter\pgfplotspatchvertexaddXY#3\times{3}%
\expandafter\pgfplotspatchvertexaddXY#4\times{-0.833333}%
\pgfplotspatchvertexfinish\pgfplots@loc@TMPa
\expandafter\pgfplotspointpatchvertex\pgfplots@loc@TMPa\endvertex
\endgroup
}{%
\expandafter\pgfplotspointpatchvertex#4\endvertex
}%
}%
% This is JUST a curveto operation! Nothing special.
\pgfplotsdeclarepatchclass{bezier spline}{%
get dimension=\def\pgfplotsretval{1},
supports global path=\def\pgfplotsretval{1},
new=\def\pgfplotspatchclass@cspline@no{A},
set next vertex={%
% EXPECTED ORDERING: first 2 corners, then 2 control points
% (NOT interpolatory).
% defines \pgfplotspatchclass@cspline@A ... \pgfplotspatchclass@cspline@D (4 points)
\expandafter\edef\csname pgfplotspatchclass@cspline@\pgfplotspatchclass@cspline@no\endcsname{#1}%
\if D\pgfplotspatchclass@cspline@no
\def\pgfplotspatchclass@cspline@no{A}%
\pgfplotspatchready
\else
\expandafter\let\expandafter\pgfplotspatchclass@cspline@no\csname pgfpptchindexnext@\pgfplotspatchclass@cspline@no\endcsname
\fi
},
if current point can be first last={%
\pgfplots@loc@tmpfalse
\if B\pgfplotspatchclass@cspline@no
% Ah - the current point is the 'A' point (we have
% advanced the '@no' counter)
\pgfplots@loc@tmptrue
\fi
\if C\pgfplotspatchclass@cspline@no
% Ah - the current point is the 'B' point (we have
% advanced the '@no' counter)
\pgfplots@loc@tmptrue
\fi
\ifpgfplots@loc@tmp
#1\relax%
\else
#2\relax
\fi
},
first vertex=\expandafter\pgfplotspatchvertex\pgfplotspatchclass@cspline@A\endvertex,
foreach vertex={%
\expandafter\pgfplotspatchvertex\pgfplotspatchclass@cspline@A\endvertex #1%
\expandafter\pgfplotspatchvertex\pgfplotspatchclass@cspline@B\endvertex #1%
\expandafter\pgfplotspatchvertex\pgfplotspatchclass@cspline@C\endvertex #1%
\expandafter\pgfplotspatchvertex\pgfplotspatchclass@cspline@D\endvertex #1%
},
fill path={%
% Draw the patch boundary using a bezier curve.
\pgfplotsplothandlermesh@pathmoveto{\expandafter\pgfplotspointpatchvertex\pgfplotspatchclass@cspline@A\endvertex}%
\pgfpathcurveto {
\expandafter\pgfplotspointpatchvertex\pgfplotspatchclass@cspline@C\endvertex
}{
\expandafter\pgfplotspointpatchvertex\pgfplotspatchclass@cspline@D\endvertex
}{%
\expandafter\pgfplotspointpatchvertex\pgfplotspatchclass@cspline@B\endvertex
}%
\pgfplotsplothandlermesh@setlastpoint{\expandafter\pgfplotspointpatchvertex\pgfplotspatchclass@cspline@B\endvertex}%
},
triangulate class=\def\pgfplotsretval{line},
triangulate={%
\let\pgfplotsplothandlermesh@patchclass@=\pgfplotsplothandlermesh@patchclass
\def\pgfplotsplothandlermesh@patchclass{line}%
\pgfplotspatchclass{\pgfplotsplothandlermesh@patchclass}{new}%
% XXX : very poor quality ...
\expandafter\pgfplotsplothandlermesh@setnextvertex\expandafter{\pgfplotspatchclass@cspline@A}%
\expandafter\pgfplotsplothandlermesh@setnextvertex\expandafter{\pgfplotspatchclass@cspline@B}%
\let\pgfplotsplothandlermesh@patchclass=\pgfplotsplothandlermesh@patchclass@
},%
get pdf shading type=0,
get num vertices=\def\pgfplotsretval{4},
}%
% make a linearized sequence around the edge of the quad.triangle.
% note the ordering: first 3 corners, then 3 mid nodes:
\def\pgfplots@qtri@next@A{D}%
\def\pgfplots@qtri@next@B{E}%
\def\pgfplots@qtri@next@C{F}%
\def\pgfplots@qtri@next@D{B}%
\def\pgfplots@qtri@next@E{C}%
\def\pgfplots@qtri@next@F{A}%
\def\pgfplots@qtri@rnext@A{F}%
\def\pgfplots@qtri@rnext@B{D}%
\def\pgfplots@qtri@rnext@C{E}%
\def\pgfplots@qtri@rnext@D{A}%
\def\pgfplots@qtri@rnext@E{B}%
\def\pgfplots@qtri@rnext@F{C}%
\def\pgfplotspatchclass@qtri@recursiverefine@newnames{%
\let\pgfplotspatchclass@qtri@A@=\pgfplotspatchclass@qtri@A%
\let\pgfplotspatchclass@qtri@B@=\pgfplotspatchclass@qtri@B%
\let\pgfplotspatchclass@qtri@C@=\pgfplotspatchclass@qtri@C%
\let\pgfplotspatchclass@qtri@D@=\pgfplotspatchclass@qtri@D%
\let\pgfplotspatchclass@qtri@E@=\pgfplotspatchclass@qtri@E%
\let\pgfplotspatchclass@qtri@F@=\pgfplotspatchclass@qtri@F%
}%
% A 3-point interpolatory patch which draws quadratic polynomial
% splines (functions f(x), x 1d).
\pgfplotsdeclarepatchclass{triangle quadr}{%
uses view depth=\def\pgfplotsretval{1},% used by the shader: we reorder corners.
new=\def\pgfplotspatchclass@qtri@no{A}\let\pgfplotspatchclass@qtrie@AB\relax,
set next vertex={%
% EXPECTED ORDERING: first 3 corners, then 3 mid nodes.
% defines \pgfplotspatchclass@qtri@A ... \pgfplotspatchclass@qtri@F (6 points)
\expandafter\edef\csname pgfplotspatchclass@qtri@\pgfplotspatchclass@qtri@no\endcsname{#1}%
\if F\pgfplotspatchclass@qtri@no
\def\pgfplotspatchclass@qtri@no{A}%
\pgfplotspatchready
\else
\expandafter\let\expandafter\pgfplotspatchclass@qtri@no\csname pgfpptchindexnext@\pgfplotspatchclass@qtri@no\endcsname
\fi
},
sample in unit cube={%
\def\pgfplotspatchclassx{0}%
\def\pgfplotspatchclassy{0}%
#1%
\def\pgfplotspatchclassx{1}%
\def\pgfplotspatchclassy{0}%
#1%
\def\pgfplotspatchclassx{0}%
\def\pgfplotspatchclassy{1}%
#1%
%
\def\pgfplotspatchclassx{0.5}%
\def\pgfplotspatchclassy{0}%
#1%
\def\pgfplotspatchclassx{0.5}%
\def\pgfplotspatchclassy{0.5}%
#1%
\def\pgfplotspatchclassx{0}%
\def\pgfplotspatchclassy{0.5}%
#1%
\pgfplotspatchready
%
%
\def\pgfplotspatchclassx{0}%
\def\pgfplotspatchclassy{1}%
#1%
\def\pgfplotspatchclassx{1}%
\def\pgfplotspatchclassy{0}%
#1%
\def\pgfplotspatchclassx{1}%
\def\pgfplotspatchclassy{1}%
#1%
%
\def\pgfplotspatchclassx{0.5}%
\def\pgfplotspatchclassy{0.5}%
#1%
\def\pgfplotspatchclassx{1}%
\def\pgfplotspatchclassy{0.5}%
#1%
\def\pgfplotspatchclassx{0.5}%
\def\pgfplotspatchclassy{1}%
#1%
\pgfplotspatchready
},%
first vertex=\expandafter\pgfplotspatchvertex\pgfplotspatchclass@qtri@A\endvertex,
foreach vertex={%
\expandafter\pgfplotspatchvertex\pgfplotspatchclass@qtri@A\endvertex #1%
\expandafter\pgfplotspatchvertex\pgfplotspatchclass@qtri@B\endvertex #1%
\expandafter\pgfplotspatchvertex\pgfplotspatchclass@qtri@C\endvertex #1%
\expandafter\pgfplotspatchvertex\pgfplotspatchclass@qtri@D\endvertex #1%
\expandafter\pgfplotspatchvertex\pgfplotspatchclass@qtri@E\endvertex #1%
\expandafter\pgfplotspatchvertex\pgfplotspatchclass@qtri@F\endvertex #1%
},
foreach cdata vertex={%
\expandafter\pgfplotspatchvertex\pgfplotspatchclass@qtri@A\endvertex #1%
\expandafter\pgfplotspatchvertex\pgfplotspatchclass@qtri@B\endvertex #1%
\expandafter\pgfplotspatchvertex\pgfplotspatchclass@qtri@C\endvertex #1%
},
fill path={%
\begingroup
% Draw the patch boundary using three bezier curves.
%
% Since I have lagrange points to describe the patch (i.e.
% points the patch passes through), I have to convert the
% lagrange representation to bezier.
%
% Furthermore, I convert to *cubic* bezier since pdf only
% supports cubic curves.
%
% See the docs for 'biquadratic::fill path' for more details,
% in does the same.
\def\pgfplots@edge{%
\ifx\pgfplotspatchclass@qtri@A\PA
\pgfpathmoveto{\expandafter\pgfplotspointpatchvertex\PA\endvertex}%
\fi
\pgfpathcurveto {%
\pgfpointadd
{\pgfqpointscale{1.333333}{\expandafter\pgfplotspointpatchvertex\PB\endvertex}}%
{\pgfqpointscale{-0.333333}{\expandafter\pgfplotspointpatchvertex\PC\endvertex}}%
}{%
\pgfpointadd
{\pgfqpointscale{1.333333}{\expandafter\pgfplotspointpatchvertex\PB\endvertex}}%
{\pgfqpointscale{-0.333333}{\expandafter\pgfplotspointpatchvertex\PA\endvertex}}%
}{%
\expandafter\pgfplotspointpatchvertex\PC\endvertex
}%
}%
\let\PA=\pgfplotspatchclass@qtri@A
\let\PB=\pgfplotspatchclass@qtri@D
\let\PC=\pgfplotspatchclass@qtri@B
\pgfplots@edge
%
\let\PA=\pgfplotspatchclass@qtri@B
\let\PB=\pgfplotspatchclass@qtri@E
\let\PC=\pgfplotspatchclass@qtri@C
\pgfplots@edge
%
\let\PA=\pgfplotspatchclass@qtri@C
\let\PB=\pgfplotspatchclass@qtri@F
\let\PC=\pgfplotspatchclass@qtri@A
\pgfplots@edge
\endgroup
\pgfpathclose
},
%--------------------------------------------------
% stroke path={%
% \ifx\pgfplotspatchclass@qtrie@AB\relax
% \pgfpathmoveto{\expandafter\pgfplotspointpatchvertex\pgfplotspatchclass@qtri@A\endvertex}%
% \pgfpathlineto{\expandafter\pgfplotspointpatchvertex\pgfplotspatchclass@qtri@B\endvertex}%
% \pgfpathlineto{\expandafter\pgfplotspointpatchvertex\pgfplotspatchclass@qtri@C\endvertex}%
% \pgfpathclose
% \else
% \if1\pgfplotspatchclass@qtrie@AB
% \pgfpathmoveto{\expandafter\pgfplotspointpatchvertex\pgfplotspatchclass@qtri@A\endvertex}%
% \pgfpathlineto{\expandafter\pgfplotspointpatchvertex\pgfplotspatchclass@qtri@B\endvertex}%
% \fi
% \if1\pgfplotspatchclass@qtrie@BC
% \pgfpathmoveto{\expandafter\pgfplotspointpatchvertex\pgfplotspatchclass@qtri@B\endvertex}%
% \pgfpathlineto{\expandafter\pgfplotspointpatchvertex\pgfplotspatchclass@qtri@C\endvertex}%
% \fi
% \if1\pgfplotspatchclass@qtrie@CA
% \pgfpathmoveto{\expandafter\pgfplotspointpatchvertex\pgfplotspatchclass@qtri@C\endvertex}%
% \pgfpathlineto{\expandafter\pgfplotspointpatchvertex\pgfplotspatchclass@qtri@A\endvertex}%
% \fi
% \fi
% },
%--------------------------------------------------
stream to shader={%
% create a degenerate coons patch:
\begingroup
%\message{EDGE INIT^^J}%
% this defines \Pcur and \Pnextseq :
\pgfplotspatchclass@tri@to@coonspatch@findshadingsequence@for@depth
%
\pgfutil@namelet{Pstart}{pgfplotspatchclass@qtri@\Pcur}%
%
% see the docus for "fill path" about these 1.33333 and -0.33333 factors
\def\pgfplots@coonsedge{%
%\message{EDGE \Pcur^^J}%
\expandafter\let\expandafter\PA\csname pgfplotspatchclass@qtri@\Pcur\endcsname
\edef\Pcur{\csname pgfplots@qtri@\Pnextseq next@\Pcur\endcsname}%
%\message{---> \Pcur^^J}%
\expandafter\let\expandafter\PB\csname pgfplotspatchclass@qtri@\Pcur\endcsname
\edef\Pcur{\csname pgfplots@qtri@\Pnextseq next@\Pcur\endcsname}%
%\message{---> \Pcur^^J}%
\expandafter\let\expandafter\PC\csname pgfplotspatchclass@qtri@\Pcur\endcsname
\ifx\PA\Pstart
\expandafter\pgfplotspatchvertex\PA\endvertex
\let\pgfplots@current@point@meta=\pgfplotspatchvertexmeta
\pgfplotsaxisvisphasetransformpointmeta
\pgfplotslibrarysurfstreamcoord{\pgfqpoint\pgfplotspatchvertexx\pgfplotspatchvertexy}{\pgfplotspointmetatransformed}%
% degenerate: the "edge" \PA -- \PA collabses into one
% point.
% Per construction, the "edge" is the FOREGROUND.
%\message{STREAMING COLLAPSED EDGE AT START POINT^^J}%
\pgfplotslibrarysurfstreamcoord{\pgfqpoint\pgfplotspatchvertexx\pgfplotspatchvertexy}{\pgfplotspointmetatransformed}%
\pgfplotslibrarysurfstreamcoord{\pgfqpoint\pgfplotspatchvertexx\pgfplotspatchvertexy}{\pgfplotspointmetatransformed}%
\pgfplotslibrarysurfstreamcoord{\pgfqpoint\pgfplotspatchvertexx\pgfplotspatchvertexy}{\pgfplotspointmetatransformed}%
\fi
\pgfplotslibrarysurfstreamcoord{%
\pgfpointadd
{\pgfqpointscale{1.333333}{\expandafter\pgfplotspointpatchvertex\PB\endvertex}}%
{\pgfqpointscale{-0.333333}{\expandafter\pgfplotspointpatchvertex\PC\endvertex}}%
}{}%
\pgfplotslibrarysurfstreamcoord{%
\pgfpointadd
{\pgfqpointscale{1.333333}{\expandafter\pgfplotspointpatchvertex\PB\endvertex}}%
{\pgfqpointscale{-0.333333}{\expandafter\pgfplotspointpatchvertex\PA\endvertex}}%
}{}%
\ifx\PC\Pstart
\else
\expandafter\pgfplotspatchvertex\PC\endvertex
\let\pgfplots@current@point@meta=\pgfplotspatchvertexmeta
\pgfplotsaxisvisphasetransformpointmeta
\pgfplotslibrarysurfstreamcoord{\pgfqpoint\pgfplotspatchvertexx\pgfplotspatchvertexy}{\pgfplotspointmetatransformed}%
\fi
}%
\pgfplots@coonsedge
%
\pgfplots@coonsedge
%
\pgfplots@coonsedge
%
%
\endgroup
},%
triangulate={%
\let\pgfplotsplothandlermesh@patchclass@=\pgfplotsplothandlermesh@patchclass
\def\pgfplotsplothandlermesh@patchclass{triangle}%
\pgfplotspatchclass{\pgfplotsplothandlermesh@patchclass}{new}%
\pgfplotspatchclass{\pgfplotsplothandlermesh@patchclass}{set edge visible}01%
\pgfplotspatchclass{\pgfplotsplothandlermesh@patchclass}{set edge visible}11%
\pgfplotspatchclass{\pgfplotsplothandlermesh@patchclass}{set edge visible}20%
% Ok. Now create 4 triangles. The ordering is not arbitrary
% (unless z buffer=sort is in effect). Let's assume that the
% AB edge is BACKGROUND and the CD edge is FOREGROUND. Then
% this sequence here should have approximately the same depth
% ordering:
\expandafter\pgfplotsplothandlermesh@setnextvertex\expandafter{\pgfplotspatchclass@qtri@F}%
\expandafter\pgfplotsplothandlermesh@setnextvertex\expandafter{\pgfplotspatchclass@qtri@A}%
\expandafter\pgfplotsplothandlermesh@setnextvertex\expandafter{\pgfplotspatchclass@qtri@D}%
%
\pgfplotspatchclass{\pgfplotsplothandlermesh@patchclass}{set edge visible}00%
\pgfplotspatchclass{\pgfplotsplothandlermesh@patchclass}{set edge visible}10%
\expandafter\pgfplotsplothandlermesh@setnextvertex\expandafter{\pgfplotspatchclass@qtri@F}%
\expandafter\pgfplotsplothandlermesh@setnextvertex\expandafter{\pgfplotspatchclass@qtri@D}%
\expandafter\pgfplotsplothandlermesh@setnextvertex\expandafter{\pgfplotspatchclass@qtri@E}%
%
\pgfplotspatchclass{\pgfplotsplothandlermesh@patchclass}{set edge visible}01%
\pgfplotspatchclass{\pgfplotsplothandlermesh@patchclass}{set edge visible}11%
\expandafter\pgfplotsplothandlermesh@setnextvertex\expandafter{\pgfplotspatchclass@qtri@D}%
\expandafter\pgfplotsplothandlermesh@setnextvertex\expandafter{\pgfplotspatchclass@qtri@B}%
\expandafter\pgfplotsplothandlermesh@setnextvertex\expandafter{\pgfplotspatchclass@qtri@E}%
%
\expandafter\pgfplotsplothandlermesh@setnextvertex\expandafter{\pgfplotspatchclass@qtri@E}%
\expandafter\pgfplotsplothandlermesh@setnextvertex\expandafter{\pgfplotspatchclass@qtri@C}%
\expandafter\pgfplotsplothandlermesh@setnextvertex\expandafter{\pgfplotspatchclass@qtri@F}%
\let\pgfplotsplothandlermesh@patchclass=\pgfplotsplothandlermesh@patchclass@
},%
set edge visible={%
\ifcase#1
\edef\pgfplotspatchclass@qtrie@AB{#2}%
\or
\edef\pgfplotspatchclass@qtrie@BC{#2}%
\or
\edef\pgfplotspatchclass@qtrie@CA{#2}%
\fi
},
serialize except vertices={%
\ifx\pgfplotspatchclass@qtrie@AB\relax
\let\pgfplotsretval\pgfutil@empty%
\else
\edef\pgfplotsretval{%
\noexpand\def\noexpand\pgfplotspatchclass@qtrie@AB{\pgfplotspatchclass@qtrie@AB}%
\noexpand\def\noexpand\pgfplotspatchclass@qtrie@BC{\pgfplotspatchclass@qtrie@BC}%
\noexpand\def\noexpand\pgfplotspatchclass@qtrie@CA{\pgfplotspatchclass@qtrie@CA}%
}%
\fi
},%
deserialize except vertices=%
\let\pgfplotspatchclass@qtrie@AB\relax
#1,
recursive refine@={%
\pgfplotspatchclass@qtri@recursiverefine@newnames
%
\pgfplotspatchclass{\pgfplotspatchclassname}{new}%
%--------------------------------------------------
% \pgfplotspatchclass{\pgfplotspatchclassname}{set edge visible}01%
% \pgfplotspatchclass{\pgfplotspatchclassname}{set edge visible}11%
% \pgfplotspatchclass{\pgfplotspatchclassname}{set edge visible}20%
%--------------------------------------------------
% The ordering is not arbitrary
% (unless z buffer=sort is in effect). Let's assume that the
% AB edge is BACKGROUND and the CD edge is FOREGROUND. Then
% this sequence here should have approximately the same depth
% ordering:
%
% I used the reference triangle and shape functions as listed in
% http://www.colorado.edu/engineering/CAS/courses.d/IFEM.d/
\pgfplotspatchvertexaccumstart
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@qtri@A\times{0.375}%
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@qtri@B\times{-0.125}%
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@qtri@D\times{0.75}%
\pgfplotspatchvertexfinish\pgfplotspatchclass@qtri@AD
%
\pgfplotspatchvertexaccumstart
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@qtri@B\times{-.125}%
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@qtri@C\times{-.125}%
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@qtri@D\times{0.5}%
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@qtri@E\times{0.25}%
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@qtri@F\times{0.5}%
\pgfplotspatchvertexfinish\pgfplotspatchclass@qtri@DF
%
\pgfplotspatchvertexaccumstart
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@qtri@A\times{0.375}%
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@qtri@C\times{-0.125}%
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@qtri@F\times{0.75}%
\pgfplotspatchvertexfinish\pgfplotspatchclass@qtri@AF
%
\expandafter\pgfplotsplothandlermesh@setnextvertex\expandafter{\pgfplotspatchclass@qtri@F@}%
\expandafter\pgfplotsplothandlermesh@setnextvertex\expandafter{\pgfplotspatchclass@qtri@A@}%
\expandafter\pgfplotsplothandlermesh@setnextvertex\expandafter{\pgfplotspatchclass@qtri@D@}%
\expandafter\pgfplotsplothandlermesh@setnextvertex\expandafter{\pgfplotspatchclass@qtri@AF}%
\expandafter\pgfplotsplothandlermesh@setnextvertex\expandafter{\pgfplotspatchclass@qtri@AD}%
\expandafter\pgfplotsplothandlermesh@setnextvertex\expandafter{\pgfplotspatchclass@qtri@DF}%
%
#1\pgfplotspatchclass@qtri@recursiverefine@newnames
%
%
%
\pgfplotspatchvertexaccumstart
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@qtri@B\times{-.125}%
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@qtri@C\times{-.125}%
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@qtri@D\times{0.5}%
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@qtri@E\times{0.25}%
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@qtri@F\times{0.5}%
\pgfplotspatchvertexfinish\pgfplotspatchclass@qtri@DF
%
\pgfplotspatchvertexaccumstart
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@qtri@A\times{-.125}%
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@qtri@C\times{-.125}%
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@qtri@D\times{0.5}%
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@qtri@E\times{0.5}%
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@qtri@F\times{0.25}%
\pgfplotspatchvertexfinish\pgfplotspatchclass@qtri@DE
%
\pgfplotspatchvertexaccumstart
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@qtri@A\times{-.125}%
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@qtri@B\times{-.125}%
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@qtri@D\times{0.25}%
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@qtri@E\times{0.5}%
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@qtri@F\times{0.5}%
\pgfplotspatchvertexfinish\pgfplotspatchclass@qtri@EF
%
%
%--------------------------------------------------
% \pgfplotspatchclass{\pgfplotspatchclassname}{set edge visible}00%
% \pgfplotspatchclass{\pgfplotspatchclassname}{set edge visible}10%
%--------------------------------------------------
\expandafter\pgfplotsplothandlermesh@setnextvertex\expandafter{\pgfplotspatchclass@qtri@F@}%
\expandafter\pgfplotsplothandlermesh@setnextvertex\expandafter{\pgfplotspatchclass@qtri@D@}%
\expandafter\pgfplotsplothandlermesh@setnextvertex\expandafter{\pgfplotspatchclass@qtri@E@}%
\expandafter\pgfplotsplothandlermesh@setnextvertex\expandafter{\pgfplotspatchclass@qtri@DF}%
\expandafter\pgfplotsplothandlermesh@setnextvertex\expandafter{\pgfplotspatchclass@qtri@DE}%
\expandafter\pgfplotsplothandlermesh@setnextvertex\expandafter{\pgfplotspatchclass@qtri@EF}%
% %
% %--------------------------------------------------
% % \pgfplotspatchclass{\pgfplotspatchclassname}{set edge visible}01%
% % \pgfplotspatchclass{\pgfplotspatchclassname}{set edge visible}11%
% %--------------------------------------------------
#1\pgfplotspatchclass@qtri@recursiverefine@newnames
%
%
\pgfplotspatchvertexaccumstart
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@qtri@A\times{-0.125}%
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@qtri@B\times{0.375}%
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@qtri@D\times{0.75}%
\pgfplotspatchvertexfinish\pgfplotspatchclass@qtri@DB
%
\pgfplotspatchvertexaccumstart
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@qtri@A\times{-.125}%
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@qtri@C\times{-.125}%
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@qtri@D\times{0.5}%
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@qtri@E\times{0.5}%
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@qtri@F\times{0.25}%
\pgfplotspatchvertexfinish\pgfplotspatchclass@qtri@DE
%
%
\pgfplotspatchvertexaccumstart
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@qtri@B\times{0.375}%
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@qtri@C\times{-0.125}%
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@qtri@E\times{0.75}%
\pgfplotspatchvertexfinish\pgfplotspatchclass@qtri@BE
%
\expandafter\pgfplotsplothandlermesh@setnextvertex\expandafter{\pgfplotspatchclass@qtri@D@}%
\expandafter\pgfplotsplothandlermesh@setnextvertex\expandafter{\pgfplotspatchclass@qtri@B@}%
\expandafter\pgfplotsplothandlermesh@setnextvertex\expandafter{\pgfplotspatchclass@qtri@E@}%
\expandafter\pgfplotsplothandlermesh@setnextvertex\expandafter{\pgfplotspatchclass@qtri@DB}%
\expandafter\pgfplotsplothandlermesh@setnextvertex\expandafter{\pgfplotspatchclass@qtri@BE}%
\expandafter\pgfplotsplothandlermesh@setnextvertex\expandafter{\pgfplotspatchclass@qtri@DE}%
%
#1\pgfplotspatchclass@qtri@recursiverefine@newnames
%
\pgfplotspatchvertexaccumstart
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@qtri@B\times{-0.125}%
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@qtri@C\times{0.375}%
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@qtri@E\times{0.75}%
\pgfplotspatchvertexfinish\pgfplotspatchclass@qtri@EC
%
\pgfplotspatchvertexaccumstart
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@qtri@A\times{-.125}%
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@qtri@B\times{-.125}%
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@qtri@D\times{0.25}%
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@qtri@E\times{0.5}%
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@qtri@F\times{0.5}%
\pgfplotspatchvertexfinish\pgfplotspatchclass@qtri@EF
%
%
\pgfplotspatchvertexaccumstart
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@qtri@A\times{-0.125}%
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@qtri@C\times{0.375}%
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@qtri@F\times{0.75}%
\pgfplotspatchvertexfinish\pgfplotspatchclass@qtri@CF
%
\expandafter\pgfplotsplothandlermesh@setnextvertex\expandafter{\pgfplotspatchclass@qtri@E@}%
\expandafter\pgfplotsplothandlermesh@setnextvertex\expandafter{\pgfplotspatchclass@qtri@C@}%
\expandafter\pgfplotsplothandlermesh@setnextvertex\expandafter{\pgfplotspatchclass@qtri@F@}%
\expandafter\pgfplotsplothandlermesh@setnextvertex\expandafter{\pgfplotspatchclass@qtri@EC}%
\expandafter\pgfplotsplothandlermesh@setnextvertex\expandafter{\pgfplotspatchclass@qtri@CF}%
\expandafter\pgfplotsplothandlermesh@setnextvertex\expandafter{\pgfplotspatchclass@qtri@EF}%
%
#1%
%
},%
get pdf shading type=6,
get num vertices=\def\pgfplotsretval{6},
get num cdata vertices=\def\pgfplotsretval{3},
}%
% see
% \pgfplotspatchclass@rect@to@coonspatch@findshadingsequence@for@depth
% and its documentation.
%
% POSTCONDITION:
% \Pcur and \Pnextseq are defined.
\def\pgfplotspatchclass@tri@to@coonspatch@findshadingsequence@for@depth{%
\def\Pcur{A}%
\def\Pnextseq{}%
%
\expandafter\pgfplotspatchvertex\pgfplotspatchclass@qtri@A\endvertex
\ifx\pgfplotspatchvertexdepth\pgfutil@empty
\else
% ah. We have view depth. Use it!
% The idea here is as follows.
% According to pdf standard, the COONS Shading is
% generated in the unit cube and then mapped to the
% shading. If u,v in [0,1] are the coordinates in the unit
% cube, pixel values for v=1 overwrite values for v=0.
% If pixel values have the same v, u=1 overwrites u=0.
% In other words, the loop is
% for v= 0 to Nv
% for u = 0 to Nu
% shade pixel for (u,v)
%
% BB-------CC <--v=1
% | |
% | |
% | |
% AA-------DD <--v=0
% | |
% u=0 u=1
%
%
% IDEA: re-order the sequence of vertices such that z
% buffering is obtained.
%
% APPROACH:
% the edge BB--CC collapses into just one point, namely
% the FOREGROUND point (i.e. it is drawn on top of
% everything else).
%
% The AA point is the second nearest foreground point.
% The sequence is chosen such that AA,BB is the first
% edge.
%
% What is to do (besides determining the vertices for AA
% and BB)? Well, make sure, that we can arrange them in
% the desired order. This involves a periodic "next vertex"
% algorithm which might either go forward
% or backward.
%
% sort according to depth.
% To do so, prepare macros \PA,\PB,\PC for use in
% \pgfplotsutilsortthree. FORMAT:
% \PA={pt }
\edef\PA{\pgfplotspatchvertexdepth pt A}%
\expandafter\pgfplotspatchvertex\pgfplotspatchclass@qtri@B\endvertex
\edef\PB{\pgfplotspatchvertexdepth pt B}%
\expandafter\pgfplotspatchvertex\pgfplotspatchclass@qtri@C\endvertex
\edef\PC{\pgfplotspatchvertexdepth pt C}%
\pgfplotsutilsortthree\PA\PB\PC
\def\toCHAR##1pt ##2{##2}% get original index
%
\edef\Pcur{\expandafter\toCHAR\PB}%%
\edef\Pnext{\csname pgfplots@qtri@next@\Pcur\endcsname}%
\edef\Pnext{\csname pgfplots@qtri@next@\Pnext\endcsname}%
\if\Pnext\PA
% ok, next(next(AA)) = BB.
% that means we have to advance forward.
\def\Pnextseq{}%
\else
% well, since we have a triangle, there only remains
% the backwards direction.
\def\Pnextseq{r}%
\fi
%\message{FOREGROUND VERTEX = \PA.^^J}%
%\message{SECOND NEAREST VERTEX = \PB.^^J}%
\fi
}
\def\pgfplotspatchclass@tri@to@coonspatch@findshadingsequence@for@depth@no@op{%
\def\Pcur{A}%
\def\Pnextseq{}%
}
% bilinear is the same as 'rectangle', but it uses a different shader.
\pgfplotsdeclarepatchclass{bilinear}{%
allow matrix=\def\pgfplotsretval{1},
new=\def\pgfplotspatchclass@rect@no{0},
set next vertex={%
\ifcase\pgfplotspatchclass@rect@no\relax
\edef\pgfplotspatchclass@rect@A{#1}%
\def\pgfplotspatchclass@rect@no{1}%
\or
\edef\pgfplotspatchclass@rect@B{#1}%
\def\pgfplotspatchclass@rect@no{2}%
\or
\edef\pgfplotspatchclass@rect@C{#1}%
\def\pgfplotspatchclass@rect@no{3}%
\or
\edef\pgfplotspatchclass@rect@D{#1}%
\def\pgfplotspatchclass@rect@no{0}%
\pgfplotspatchready%
\fi
},
sample in unit cube={%
\def\pgfplotspatchclassx{0}%
\def\pgfplotspatchclassy{0}%
#1%
\def\pgfplotspatchclassx{1}%
\def\pgfplotspatchclassy{0}%
#1%
\def\pgfplotspatchclassx{1}%
\def\pgfplotspatchclassy{1}%
#1%
\def\pgfplotspatchclassx{0}%
\def\pgfplotspatchclassy{1}%
#1%
\pgfplotspatchready
},%
first vertex=\expandafter\pgfplotspatchvertex\pgfplotspatchclass@rect@A\endvertex,
first vertex before z buffer=\pgfplotspatchclass@rect@first@before@z@buffer,
foreach vertex={%
\expandafter\pgfplotspatchvertex\pgfplotspatchclass@rect@A\endvertex #1%
\expandafter\pgfplotspatchvertex\pgfplotspatchclass@rect@B\endvertex #1%
\expandafter\pgfplotspatchvertex\pgfplotspatchclass@rect@C\endvertex #1%
\expandafter\pgfplotspatchvertex\pgfplotspatchclass@rect@D\endvertex #1%
},
stream to shader={%
% create a coons patch:
\begingroup
\pgfplotspatchclass@rect@to@coonspatch@findshadingsequence@for@depth
{pgfplotspatchclass@rect@}{\Pcur}{\Pnextseq}%
%
\pgfutil@namelet{Pstart}{pgfplotspatchclass@rect@\Pcur}%
\def\pgfplots@coonsedge{%
%\message{EDGE \Pcur^^J}%
\expandafter\let\expandafter\PA\csname pgfplotspatchclass@rect@\Pcur\endcsname
\edef\Pcur{\csname pgfplots@rect@\Pnextseq next@\Pcur\endcsname}%
%\message{---> \Pcur^^J}%
\expandafter\let\expandafter\PB\csname pgfplotspatchclass@rect@\Pcur\endcsname
\ifx\PA\Pstart
\expandafter\pgfplotspatchvertex\PA\endvertex
\let\pgfplots@current@point@meta=\pgfplotspatchvertexmeta
\pgfplotsaxisvisphasetransformpointmeta
\pgfplotslibrarysurfstreamcoord{\pgfqpoint\pgfplotspatchvertexx\pgfplotspatchvertexy}{\pgfplotspointmetatransformed}%
\fi
%
% CONTROL POINT A+1/3(B-A)
\pgfplotslibrarysurfstreamcoord{%
\pgfpointadd
{\pgfqpointscale{0.6666666}{\expandafter\pgfplotspointpatchvertex\PA\endvertex}}%
{\pgfqpointscale{0.3333333}{\expandafter\pgfplotspointpatchvertex\PB\endvertex}}%
}{}%
% CONTROL POINT A+2/3(B-A)
\pgfplotslibrarysurfstreamcoord{%
\pgfpointadd
{\pgfqpointscale{0.3333333}{\expandafter\pgfplotspointpatchvertex\PA\endvertex}}%
{\pgfqpointscale{0.6666666}{\expandafter\pgfplotspointpatchvertex\PB\endvertex}}%
}{}%
\ifx\PB\Pstart
\else
\expandafter\pgfplotspatchvertex\PB\endvertex
\let\pgfplots@current@point@meta=\pgfplotspatchvertexmeta
\pgfplotsaxisvisphasetransformpointmeta
\pgfplotslibrarysurfstreamcoord{\pgfqpoint\pgfplotspatchvertexx\pgfplotspatchvertexy}{\pgfplotspointmetatransformed}%
\fi
}%
%
\pgfplots@coonsedge
%
\pgfplots@coonsedge
%
\pgfplots@coonsedge
%
\pgfplots@coonsedge
%
\endgroup
},%
fill path={%
\pgfpathmoveto{\expandafter\pgfplotspointpatchvertex\pgfplotspatchclass@rect@A\endvertex}%
\pgfpathlineto{\expandafter\pgfplotspointpatchvertex\pgfplotspatchclass@rect@B\endvertex}%
\pgfpathlineto{\expandafter\pgfplotspointpatchvertex\pgfplotspatchclass@rect@C\endvertex}%
\pgfpathlineto{\expandafter\pgfplotspointpatchvertex\pgfplotspatchclass@rect@D\endvertex}%
\pgfpathclose
},
triangulate={%
\pgfplotscoordmath{meta}{parsenumber}{0.25}%
\let\pgfplots@loc@scale=\pgfmathresult
%
\pgfplotspatchvertexaccumstart
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@rect@A\endvertex\times{0.25}%
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@rect@B\endvertex\times{0.25}%
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@rect@C\endvertex\times{0.25}%
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@rect@D\endvertex\times{0.25}%
\pgfplotspatchvertexfinish\pgfplotspatchclass@rect@M
%
\let\pgfplotsplothandlermesh@patchclass@=\pgfplotsplothandlermesh@patchclass
\def\pgfplotsplothandlermesh@patchclass{triangle}%
\pgfplotspatchclass{\pgfplotsplothandlermesh@patchclass}{new}%
\pgfplotspatchclass{\pgfplotsplothandlermesh@patchclass}{set edge visible}01%
\pgfplotspatchclass{\pgfplotsplothandlermesh@patchclass}{set edge visible}10%
\pgfplotspatchclass{\pgfplotsplothandlermesh@patchclass}{set edge visible}20%
% Ok. Now create 4 triangles. The ordering is not arbitrary
% (unless z buffer=sort is in effect). Let's assume that the
% AB edge is BACKGROUND and the CD edge is FOREGROUND. Then
% this sequence here should have approximately the same depth
% ordering:
\expandafter\pgfplotsplothandlermesh@setnextvertex\expandafter{\pgfplotspatchclass@rect@A}%
\expandafter\pgfplotsplothandlermesh@setnextvertex\expandafter{\pgfplotspatchclass@rect@B}%
\expandafter\pgfplotsplothandlermesh@setnextvertex\expandafter{\pgfplotspatchclass@rect@M}%
%
\expandafter\pgfplotsplothandlermesh@setnextvertex\expandafter{\pgfplotspatchclass@rect@B}%
\expandafter\pgfplotsplothandlermesh@setnextvertex\expandafter{\pgfplotspatchclass@rect@C}%
\expandafter\pgfplotsplothandlermesh@setnextvertex\expandafter{\pgfplotspatchclass@rect@M}%
%
\expandafter\pgfplotsplothandlermesh@setnextvertex\expandafter{\pgfplotspatchclass@rect@D}%
\expandafter\pgfplotsplothandlermesh@setnextvertex\expandafter{\pgfplotspatchclass@rect@A}%
\expandafter\pgfplotsplothandlermesh@setnextvertex\expandafter{\pgfplotspatchclass@rect@M}%
%
\expandafter\pgfplotsplothandlermesh@setnextvertex\expandafter{\pgfplotspatchclass@rect@C}%
\expandafter\pgfplotsplothandlermesh@setnextvertex\expandafter{\pgfplotspatchclass@rect@D}%
\expandafter\pgfplotsplothandlermesh@setnextvertex\expandafter{\pgfplotspatchclass@rect@M}%
\let\pgfplotsplothandlermesh@patchclass=\pgfplotsplothandlermesh@patchclass@
},%
recursive refine@={%
\pgfplotspatchclass@rect@refine@{#1}%
},%
serialize except vertices=\let\pgfplotsretval\pgfutil@empty,%
deserialize except vertices=,
get pdf shading type=6,
get num vertices=\def\pgfplotsretval{4},
}%
\pgfplotsdeclarepatchclass{rectangle}{%
recursive refine@={%
\pgfplotspatchclass@rect@refine@{#1}%
},%
}
\def\pgfplotspatchclass@rect@refine@#1{%
\pgfplotspatchclass@rect@recursiverefine@newnames
%
\pgfplotspatchclass{\pgfplotspatchclassname}{new}%
%--------------------------------------------------
% \pgfplotspatchclass{\pgfplotspatchclassname}{set edge visible}01%
% \pgfplotspatchclass{\pgfplotspatchclassname}{set edge visible}11%
% \pgfplotspatchclass{\pgfplotspatchclassname}{set edge visible}20%
%--------------------------------------------------
% The ordering is not arbitrary
% (unless z buffer=sort is in effect). Let's assume that the
% AB edge is BACKGROUND and the CD edge is FOREGROUND. Then
% this sequence here should have approximately the same depth
% ordering:
%
\pgfplotspatchvertexaccumstart
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@rect@A\times{0.25}%
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@rect@B\times{0.25}%
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@rect@C\times{0.25}%
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@rect@D\times{0.25}%
\pgfplotspatchvertexfinish\pgfplotspatchclass@rect@M
%
\expandafter\pgfplotspatchclass@rect@refine@@\expandafter{\pgfplotspatchclass@rect@M}{#1}%
}
\def\pgfplotspatchclass@rect@refine@@#1#2{%
\pgfplotspatchvertexaccumstart
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@rect@A\times{0.5}%
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@rect@B\times{0.5}%
\pgfplotspatchvertexfinish\pgfplotspatchclass@rect@AB
%
\pgfplotspatchvertexaccumstart
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@rect@A\times{0.5}%
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@rect@D\times{0.5}%
\pgfplotspatchvertexfinish\pgfplotspatchclass@rect@DA
%
\expandafter\pgfplotsplothandlermesh@setnextvertex\expandafter{\pgfplotspatchclass@rect@A@}%
\expandafter\pgfplotsplothandlermesh@setnextvertex\expandafter{\pgfplotspatchclass@rect@AB}%
\pgfplotsplothandlermesh@setnextvertex{#1}%
\expandafter\pgfplotsplothandlermesh@setnextvertex\expandafter{\pgfplotspatchclass@rect@DA}%
#2\pgfplotspatchclass@rect@recursiverefine@newnames
%
%
\pgfplotspatchvertexaccumstart
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@rect@A\times{0.5}%
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@rect@B\times{0.5}%
\pgfplotspatchvertexfinish\pgfplotspatchclass@rect@AB
%
\pgfplotspatchvertexaccumstart
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@rect@B\times{0.5}%
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@rect@C\times{0.5}%
\pgfplotspatchvertexfinish\pgfplotspatchclass@rect@BC
%
\expandafter\pgfplotsplothandlermesh@setnextvertex\expandafter{\pgfplotspatchclass@rect@AB}%
\expandafter\pgfplotsplothandlermesh@setnextvertex\expandafter{\pgfplotspatchclass@rect@B@}%
\expandafter\pgfplotsplothandlermesh@setnextvertex\expandafter{\pgfplotspatchclass@rect@BC}%
\pgfplotsplothandlermesh@setnextvertex{#1}%
#2\pgfplotspatchclass@rect@recursiverefine@newnames
%
%
%
\pgfplotspatchvertexaccumstart
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@rect@C\times{0.5}%
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@rect@D\times{0.5}%
\pgfplotspatchvertexfinish\pgfplotspatchclass@rect@CD
%
\pgfplotspatchvertexaccumstart
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@rect@B\times{0.5}%
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@rect@C\times{0.5}%
\pgfplotspatchvertexfinish\pgfplotspatchclass@rect@BC
%
\expandafter\pgfplotsplothandlermesh@setnextvertex\expandafter{\pgfplotspatchclass@rect@BC}%
\expandafter\pgfplotsplothandlermesh@setnextvertex\expandafter{\pgfplotspatchclass@rect@C@}%
\expandafter\pgfplotsplothandlermesh@setnextvertex\expandafter{\pgfplotspatchclass@rect@CD}%
\pgfplotsplothandlermesh@setnextvertex{#1}%
#2\pgfplotspatchclass@rect@recursiverefine@newnames
%
%
%
\pgfplotspatchvertexaccumstart
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@rect@C\times{0.5}%
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@rect@D\times{0.5}%
\pgfplotspatchvertexfinish\pgfplotspatchclass@rect@CD
%
\pgfplotspatchvertexaccumstart
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@rect@D\times{0.5}%
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@rect@A\times{0.5}%
\pgfplotspatchvertexfinish\pgfplotspatchclass@rect@DA
%
\expandafter\pgfplotsplothandlermesh@setnextvertex\expandafter{\pgfplotspatchclass@rect@CD}%
\expandafter\pgfplotsplothandlermesh@setnextvertex\expandafter{\pgfplotspatchclass@rect@D@}%
\expandafter\pgfplotsplothandlermesh@setnextvertex\expandafter{\pgfplotspatchclass@rect@DA}%
\pgfplotsplothandlermesh@setnextvertex{#1}%
#2\pgfplotspatchclass@rect@recursiverefine@newnames
%
}%
\def\pgfplotspatchclass@rect@recursiverefine@newnames{%
\let\pgfplotspatchclass@rect@A@=\pgfplotspatchclass@rect@A%
\let\pgfplotspatchclass@rect@B@=\pgfplotspatchclass@rect@B%
\let\pgfplotspatchclass@rect@C@=\pgfplotspatchclass@rect@C%
\let\pgfplotspatchclass@rect@D@=\pgfplotspatchclass@rect@D%
}%
% An arbitrary poligy specified in the sequence
% D <-- C
% | ^
% v |
% A --> B
%
\pgfkeyssetvalue{/pgfplots/vertex count}{0}%
\pgfplotsdeclarepatchclass{polygon}{%
new=\def\pgfplotspatchclass@poly@no{0},
set next vertex={%
\pgfplotspatchclass@poly@checkcount
\expandafter\edef\csname pgfplotspatchclass@poly@\pgfplotspatchclass@poly@no\endcsname{#1}%
\pgfplotsutil@advancestringcounter\pgfplotspatchclass@poly@no
\ifnum\pgfplotspatchclass@poly@no=\pgfkeysvalueof{/pgfplots/vertex count} %
\def\pgfplotspatchclass@poly@no{0}%
\pgfplotspatchready%
\fi
},
first vertex=\expandafter\expandafter\expandafter\pgfplotspatchvertex\csname pgfplotspatchclass@poly@0\endcsname\endvertex,
foreach vertex={%
\pgfplotspatchclass@poly@foreach@loop{0}{#1}%
},
init pdf shading={%
\pgfplots@error{Sorry, patch type=polygon does not support shadings}%
},
serialize except vertices=\let\pgfplotsretval\pgfutil@empty,%
deserialize except vertices=,
get pdf shading type=4,
get num vertices=\def\pgfplotsretval{\pgfkeysvalueof{/pgfplots/vertex count}},
}%
\def\pgfplotspatchclass@poly@checkcount{%
\ifnum\pgfkeysvalueof{/pgfplots/vertex count}>0
\else
\pgfplots@error{Sorry, 'patch type=polygon' *requires* that 'vertex count=' is set (note: it is allowed if multiple vertices have the same coordinates).}%
\fi
}%
\long\def\pgfplotspatchclass@poly@foreach@loop#1#2{%
\ifnum#1<\pgfkeysvalueof{/pgfplots/vertex count} %
\expandafter\expandafter\expandafter\pgfplotspatchvertex\csname pgfplotspatchclass@poly@#1\endcsname\endvertex #2%
\begingroup
\c@pgf@counta=#1 %
\advance\c@pgf@counta by1 %
\t@pgfplots@toka={#2}%
\xdef\pgfplots@glob@TMPc{\noexpand\pgfplotspatchclass@poly@foreach@loop{\the\c@pgf@counta}{\the\t@pgfplots@toka}}%
\endgroup
\else
\gdef\pgfplots@glob@TMPc{}%
\fi
\pgfplots@glob@TMPc
}%
\def\pgfplots@biquad@next@A{E}
\def\pgfplots@biquad@next@B{F}
\def\pgfplots@biquad@next@C{G}
\def\pgfplots@biquad@next@D{H}
\def\pgfplots@biquad@next@E{B}
\def\pgfplots@biquad@next@F{C}
\def\pgfplots@biquad@next@G{D}
\def\pgfplots@biquad@next@H{A}
\def\pgfplots@biquad@rnext@A{H}
\def\pgfplots@biquad@rnext@B{E}
\def\pgfplots@biquad@rnext@C{F}
\def\pgfplots@biquad@rnext@D{G}
\def\pgfplots@biquad@rnext@E{A}
\def\pgfplots@biquad@rnext@F{B}
\def\pgfplots@biquad@rnext@G{C}
\def\pgfplots@biquad@rnext@H{D}
\def\pgfplotspatchclass@biquad@recursiverefine@newnames{%
\let\pgfplotspatchclass@biquad@A@=\pgfplotspatchclass@biquad@A%
\let\pgfplotspatchclass@biquad@B@=\pgfplotspatchclass@biquad@B%
\let\pgfplotspatchclass@biquad@C@=\pgfplotspatchclass@biquad@C%
\let\pgfplotspatchclass@biquad@D@=\pgfplotspatchclass@biquad@D%
\let\pgfplotspatchclass@biquad@E@=\pgfplotspatchclass@biquad@E%
\let\pgfplotspatchclass@biquad@F@=\pgfplotspatchclass@biquad@F%
\let\pgfplotspatchclass@biquad@G@=\pgfplotspatchclass@biquad@G%
\let\pgfplotspatchclass@biquad@H@=\pgfplotspatchclass@biquad@H%
\let\pgfplotspatchclass@biquad@I@=\pgfplotspatchclass@biquad@I%
}%
% mathematica shape functions parameterized in
% (xi,eta) in [-1,1]x[-1,1]:
%f[xi_, eta_] =
% a*1/4*(1 - xi) (1 - eta) xi*eta +
% b 1/4 (-1 - xi) (1 - eta) xi*eta +
% c* 1/4 (-1 - xi) (-1 - eta) xi*eta +
% d *1/4 (1 - xi) (-1 - eta) xi*eta +
% e * 1/2 (xi^2 - 1) (1 - eta) eta +
% f*1/2 (-1 - xi) (eta^2 - 1) xi +
% g* -1/2 (1 - xi^2) (-1 - eta) eta +
% h* -1/2 (1 - xi) (1 - eta^2) xi +
% i*(1 - xi^2) (1 - eta^2)
% here, a,b,...,i are the 9 nodes.
\pgfplotsdeclarepatchclass{biquadratic}{%
new=\def\pgfplotspatchclass@biquad@no{A}\let\pgfplotspatchclass@biquade@AB\relax,
set next vertex={%
% defines \pgfplotspatchclass@biquad@A ... \pgfplotspatchclass@biquad@I (9 points)
\expandafter\edef\csname pgfplotspatchclass@biquad@\pgfplotspatchclass@biquad@no\endcsname{#1}%
\if I\pgfplotspatchclass@biquad@no
\def\pgfplotspatchclass@biquad@no{A}%
\pgfplotspatchready
\else
\expandafter\let\expandafter\pgfplotspatchclass@biquad@no\csname pgfpptchindexnext@\pgfplotspatchclass@biquad@no\endcsname
\fi
},
sample in unit cube={%
\def\pgfplotspatchclassx{0}%
\def\pgfplotspatchclassy{0}%
#1%
\def\pgfplotspatchclassx{1}%
\def\pgfplotspatchclassy{0}%
#1%
\def\pgfplotspatchclassx{1}%
\def\pgfplotspatchclassy{1}%
#1%
\def\pgfplotspatchclassx{0}%
\def\pgfplotspatchclassy{1}%
#1%
\def\pgfplotspatchclassx{0.5}%
\def\pgfplotspatchclassy{0}%
#1%
\def\pgfplotspatchclassx{1}%
\def\pgfplotspatchclassy{0.5}%
#1%
\def\pgfplotspatchclassx{0.5}%
\def\pgfplotspatchclassy{1}%
#1%
\def\pgfplotspatchclassx{0}%
\def\pgfplotspatchclassy{0.5}%
#1%
\def\pgfplotspatchclassx{0.5}%
\def\pgfplotspatchclassy{0.5}%
#1%
\pgfplotspatchready
},%
first vertex=\expandafter\pgfplotspatchvertex\pgfplotspatchclass@biquad@A\endvertex,
foreach vertex={%
\expandafter\pgfplotspatchvertex\pgfplotspatchclass@biquad@A\endvertex #1%
\expandafter\pgfplotspatchvertex\pgfplotspatchclass@biquad@B\endvertex #1%
\expandafter\pgfplotspatchvertex\pgfplotspatchclass@biquad@C\endvertex #1%
\expandafter\pgfplotspatchvertex\pgfplotspatchclass@biquad@D\endvertex #1%
\expandafter\pgfplotspatchvertex\pgfplotspatchclass@biquad@E\endvertex #1%
\expandafter\pgfplotspatchvertex\pgfplotspatchclass@biquad@F\endvertex #1%
\expandafter\pgfplotspatchvertex\pgfplotspatchclass@biquad@G\endvertex #1%
\expandafter\pgfplotspatchvertex\pgfplotspatchclass@biquad@H\endvertex #1%
\expandafter\pgfplotspatchvertex\pgfplotspatchclass@biquad@I\endvertex #1%
},
foreach cdata vertex={%
\expandafter\pgfplotspatchvertex\pgfplotspatchclass@biquad@A\endvertex #1%
\expandafter\pgfplotspatchvertex\pgfplotspatchclass@biquad@B\endvertex #1%
\expandafter\pgfplotspatchvertex\pgfplotspatchclass@biquad@C\endvertex #1%
\expandafter\pgfplotspatchvertex\pgfplotspatchclass@biquad@D\endvertex #1%
},
fill path={%
\begingroup
% Visualize the patch boundary using four bezier curves.
%
% This involves a change from Lagrange to bezier
% representation of the boundary curves.
%
% Furthermore, pdf supports only **cubic** bezier curves. What
% I am doing here is
% a) change of basis from 3-point lagrange ---> 3 point quadratic bezier
% b) expression 3 point quadratic bezier ----> 4 point cubic bezier
%
% INPUT:
% 3 langrange points (i.e. the patch passes through them)
% \PA,\PB,\PC (start,middle,end)
%
% OUTPUT:
% \PA,bezier control 1, bezier control 2, \PC.
%
\def\pgfplots@edge{%
\ifx\pgfplotspatchclass@biquad@A\PA
\pgfpathmoveto{\expandafter\pgfplotspointpatchvertex\PA\endvertex}%
\fi
\pgfpathcurveto {%
\pgfpointadd
{\pgfqpointscale{1.333333}{\expandafter\pgfplotspointpatchvertex\PB\endvertex}}%
{\pgfqpointscale{-0.333333}{\expandafter\pgfplotspointpatchvertex\PC\endvertex}}%
}{%
\pgfpointadd
{\pgfqpointscale{1.333333}{\expandafter\pgfplotspointpatchvertex\PB\endvertex}}%
{\pgfqpointscale{-0.333333}{\expandafter\pgfplotspointpatchvertex\PA\endvertex}}%
}{%
\expandafter\pgfplotspointpatchvertex\PC\endvertex
}%
}%
\let\PA=\pgfplotspatchclass@biquad@A
\let\PB=\pgfplotspatchclass@biquad@E
\let\PC=\pgfplotspatchclass@biquad@B
\pgfplots@edge
%
\let\PA=\pgfplotspatchclass@biquad@B
\let\PB=\pgfplotspatchclass@biquad@F
\let\PC=\pgfplotspatchclass@biquad@C
\pgfplots@edge
%
\let\PA=\pgfplotspatchclass@biquad@C
\let\PB=\pgfplotspatchclass@biquad@G
\let\PC=\pgfplotspatchclass@biquad@D
\pgfplots@edge
%
\let\PA=\pgfplotspatchclass@biquad@D
\let\PB=\pgfplotspatchclass@biquad@H
\let\PC=\pgfplotspatchclass@biquad@A
\pgfplots@edge
\endgroup
\pgfpathclose
},
%--------------------------------------------------
% stroke path={%
% \ifx\pgfplotspatchclass@biquade@AB\relax
% \pgfpathmoveto{\expandafter\pgfplotspointpatchvertex\pgfplotspatchclass@biquad@A\endvertex}%
% \pgfpathlineto{\expandafter\pgfplotspointpatchvertex\pgfplotspatchclass@biquad@B\endvertex}%
% \pgfpathlineto{\expandafter\pgfplotspointpatchvertex\pgfplotspatchclass@biquad@C\endvertex}%
% \pgfpathclose
% \else
% \if1\pgfplotspatchclass@biquade@AB
% \pgfpathmoveto{\expandafter\pgfplotspointpatchvertex\pgfplotspatchclass@biquad@A\endvertex}%
% \pgfpathlineto{\expandafter\pgfplotspointpatchvertex\pgfplotspatchclass@biquad@B\endvertex}%
% \fi
% \if1\pgfplotspatchclass@biquade@BC
% \pgfpathmoveto{\expandafter\pgfplotspointpatchvertex\pgfplotspatchclass@biquad@B\endvertex}%
% \pgfpathlineto{\expandafter\pgfplotspointpatchvertex\pgfplotspatchclass@biquad@C\endvertex}%
% \fi
% \if1\pgfplotspatchclass@biquade@CA
% \pgfpathmoveto{\expandafter\pgfplotspointpatchvertex\pgfplotspatchclass@biquad@C\endvertex}%
% \pgfpathlineto{\expandafter\pgfplotspointpatchvertex\pgfplotspatchclass@biquad@A\endvertex}%
% \fi
% \fi
% },
%--------------------------------------------------
stream to shader={%
\begingroup
%
% An early version of this shader used Coons patch shadings
% (which provides coordinates only for the 9 boundary
% vertices, not for the inner vertices). That is a little bit
% simpler than what you see in the following lines of code: a
% transformation to a tensor bezier shading.
%
% What we need is to map the 3x3 data from lagrangrian
% (interpolation) representation to 4x4 cubic bezier - and
% handle the four INNER nodes correctly.
%
% The algorithm to convert from 1d curves with 3 point langrange to 4 point
% bezier is well-known and relatively simple. Fortunately, the
% extension to 3x3 -> 4x4 can be boiled down to a successive
% application of the 1d algorithm - applied to horizontal and
% vertical lines in the data matrizes.
%
% NOTE: the algorithm in the following lines results in
% EXACTLY THE SAME four cubic boundary curves as the approach
% in 'fill path'. The only difference is that it also does the
% right thing for the inner node.
%
% STEP 1: ensure that the patch's coordinates are streamed in
% a sequence which is compatible with the DEPTH of the
% corners.
%
% we use
% \pgfplotspatchclass@rect@to@coonspatch@findshadingsequence@for@depth
% which works for bilinear, biquadratic, and bicubic
\pgfplotspatchclass@rect@to@coonspatch@findshadingsequence@for@depth
{pgfplotspatchclass@biquad@}{\Pcur}{\Pnextseq}%
%
% STEP 2:
% now, translate the result into our matrix form.
% This means to (a) identify the FIRST point which needs to be
% streamed (it is stored in \Pcur as 'A', 'B', 'C', or 'D')
% and (b) keep in mind that we have to take care of the
% sequence in which points are streamed ("forward" means to
% rotate the matrix elements and "backward" means to transpose
% the "forward" result).
%
% This can be seen as conversion from the "linearized"
% numbering to matrix indexing - while respecting the "start
% point".
%
% INPUT:
%
% D G C
% H I F
% A E B
%
\if A\Pcur
% Ah - the point "A" needs to be streamed as first.
%
% Well, this is simple: take the matrix as-is!
% simply copy 1:1
%
% i.e. convert
% D G C
% H I F
% A E B
%
% to
%
% AC BC CC
% AB BB CB
% AA BA CA
\let\P@AA=\pgfplotspatchclass@biquad@A
\let\P@BA=\pgfplotspatchclass@biquad@E
\let\P@CA=\pgfplotspatchclass@biquad@B
\let\P@AB=\pgfplotspatchclass@biquad@H
\let\P@BB=\pgfplotspatchclass@biquad@I
\let\P@CB=\pgfplotspatchclass@biquad@F
\let\P@AC=\pgfplotspatchclass@biquad@D
\let\P@BC=\pgfplotspatchclass@biquad@G
\let\P@CC=\pgfplotspatchclass@biquad@C
\fi
\if B\Pcur
% the "B" point needs to be streamed as first.
%
% i.e. reorder
% D G C
% H I F
% A E B
%
% to
% A H D AC BC CC
% E I G =: AB BB CB
% B F C AA BA CA
%
\let\P@AA=\pgfplotspatchclass@biquad@B
\let\P@BA=\pgfplotspatchclass@biquad@F
\let\P@CA=\pgfplotspatchclass@biquad@C
\let\P@AB=\pgfplotspatchclass@biquad@E
\let\P@BB=\pgfplotspatchclass@biquad@I
\let\P@CB=\pgfplotspatchclass@biquad@G
\let\P@AC=\pgfplotspatchclass@biquad@A
\let\P@BC=\pgfplotspatchclass@biquad@H
\let\P@CC=\pgfplotspatchclass@biquad@D
\fi
\if C\Pcur
% the "C" point needs to be streamed as first.
%
% i.e. reorder
% D G C
% H I F
% A E B
%
% to
% B E A AC BC CC
% F I H =: AB BB CB
% C G D AA BA CA
%
\let\P@AA=\pgfplotspatchclass@biquad@C
\let\P@BA=\pgfplotspatchclass@biquad@G
\let\P@CA=\pgfplotspatchclass@biquad@D
\let\P@AB=\pgfplotspatchclass@biquad@F
\let\P@BB=\pgfplotspatchclass@biquad@I
\let\P@CB=\pgfplotspatchclass@biquad@H
\let\P@AC=\pgfplotspatchclass@biquad@B
\let\P@BC=\pgfplotspatchclass@biquad@E
\let\P@CC=\pgfplotspatchclass@biquad@A
\fi
\if D\Pcur
% the "D" point needs to be streamed as first.
%
% i.e. reorder
% D G C
% H I F
% A E B
%
% to
% C F B AC BC CC
% G I E =: AB BB CB
% D H A AA BA CA
%
\let\P@AA=\pgfplotspatchclass@biquad@D
\let\P@BA=\pgfplotspatchclass@biquad@H
\let\P@CA=\pgfplotspatchclass@biquad@A
\let\P@AB=\pgfplotspatchclass@biquad@G
\let\P@BB=\pgfplotspatchclass@biquad@I
\let\P@CB=\pgfplotspatchclass@biquad@E
\let\P@AC=\pgfplotspatchclass@biquad@C
\let\P@BC=\pgfplotspatchclass@biquad@F
\let\P@CC=\pgfplotspatchclass@biquad@B
\fi
\ifx\Pnextseq\pgfutil@empty
\else
% reverse the ordering. This means to transpose the
% matrix:
\pgfplotspatchclass@biquad@transpose
\fi
%
%
% Step: convert to tensor bezier representation.
%
% Converting a 2d tensor product lagrangian interpoland to a
% 2d tensor product bezier interpoland can be achieved by
% means of 1d algorithms along LINES in the matrix.
%
% The underlying proof for this is related to the tensor
% product form: the U and V coordinates are orthogonal to each
% other, so we can redistribute all intermediate results. (I
% do not have the real proof, so this hand-waving argument has
% to be enough). I verified its results experimentally.
%
% Note that the underlying 1d operation is the same as for
% 'patch type=quadratic spline' . We only need to apply it to all
% lines in U direction and afterwards to all lines in V
% direction.
%
\def\pgfplotspatchvertexaddXY@expanded##1\times{%
\edef\pgfplots@loc@TMPa{##1}%
\expandafter\pgfplotspatchvertexaddXY\pgfplots@loc@TMPa\times
}%
%
% this macro operates on \pgfplots@line{[ABC]} and defines
% \pgfplots@line{[ABCD]} (i.e. one dimension more!)
\def\pgfplots@apply@to@line{%
\pgfplotspatchvertexaccumstart
\pgfplotspatchvertexaddXY@expanded\pgfplots@line{B}\times{1.333333}%
\pgfplotspatchvertexaddXY@expanded\pgfplots@line{C}\times{-0.333333}%
\pgfplotspatchvertexfinish\pgfplots@controlpoint@A
%
\pgfplotspatchvertexaccumstart
\pgfplotspatchvertexaddXY@expanded\pgfplots@line{A}\times{-0.333333}%
\pgfplotspatchvertexaddXY@expanded\pgfplots@line{B}\times{1.333333}%
\pgfplotspatchvertexfinish\pgfplots@controlpoint@B
%
% ... we output 4 points (cubic!).
% A= left endpoint (untouched)
% B= first control
% C= second control
% D= right endpoint (untouched, is formerly called 'C')
\edef\pgfplots@loc@TMPa{\pgfplots@line{C}}%
\expandafter\expandafter\expandafter\let\pgfplots@line{B}=\pgfplots@controlpoint@A
\expandafter\expandafter\expandafter\let\pgfplots@line{C}=\pgfplots@controlpoint@B
\expandafter\expandafter\expandafter\let\pgfplots@line{D}=\pgfplots@loc@TMPa
}%
%
\def\pgfplots@line##1{\csname P@##1A\endcsname}%
\pgfplots@apply@to@line
%
\def\pgfplots@line##1{\csname P@##1B\endcsname}%
\pgfplots@apply@to@line
%
\def\pgfplots@line##1{\csname P@##1C\endcsname}%
\pgfplots@apply@to@line
%
% Now, we have a 3x4 matrix.
%
%
\def\pgfplots@line##1{\csname P@A##1\endcsname}%
\pgfplots@apply@to@line
%
\def\pgfplots@line##1{\csname P@B##1\endcsname}%
\pgfplots@apply@to@line
%
\def\pgfplots@line##1{\csname P@C##1\endcsname}%
\pgfplots@apply@to@line
%
\def\pgfplots@line##1{\csname P@D##1\endcsname}%
\pgfplots@apply@to@line
%
% OK. The tensor product representation is READY.
%
% in particular, we have a 4x4 matrix right now:
%
\pgfplotsplothandlermesh@shade@cubic@tensor
\endgroup
},%
triangulate={%
\let\pgfplotsplothandlermesh@patchclass@=\pgfplotsplothandlermesh@patchclass
\def\pgfplotsplothandlermesh@patchclass{triangle}%
\pgfplotspatchclass{\pgfplotsplothandlermesh@patchclass}{new}%
\pgfplotspatchclass{\pgfplotsplothandlermesh@patchclass}{set edge visible}01%
\pgfplotspatchclass{\pgfplotsplothandlermesh@patchclass}{set edge visible}10%
\pgfplotspatchclass{\pgfplotsplothandlermesh@patchclass}{set edge visible}20%
% Ok. Now create 4 triangles. The ordering is not arbitrary
% (unless z buffer=sort is in effect). Let's assume that the
% AB edge is BACKGROUND and the CD edge is FOREGROUND. Then
% this sequence here should have approximately the same depth
% ordering:
\expandafter\pgfplotsplothandlermesh@setnextvertex\expandafter{\pgfplotspatchclass@biquad@A}%
\expandafter\pgfplotsplothandlermesh@setnextvertex\expandafter{\pgfplotspatchclass@biquad@E}%
\expandafter\pgfplotsplothandlermesh@setnextvertex\expandafter{\pgfplotspatchclass@biquad@I}%
%
\expandafter\pgfplotsplothandlermesh@setnextvertex\expandafter{\pgfplotspatchclass@biquad@H}%
\expandafter\pgfplotsplothandlermesh@setnextvertex\expandafter{\pgfplotspatchclass@biquad@A}%
\expandafter\pgfplotsplothandlermesh@setnextvertex\expandafter{\pgfplotspatchclass@biquad@I}%
%
\expandafter\pgfplotsplothandlermesh@setnextvertex\expandafter{\pgfplotspatchclass@biquad@E}%
\expandafter\pgfplotsplothandlermesh@setnextvertex\expandafter{\pgfplotspatchclass@biquad@B}%
\expandafter\pgfplotsplothandlermesh@setnextvertex\expandafter{\pgfplotspatchclass@biquad@I}%
%
\expandafter\pgfplotsplothandlermesh@setnextvertex\expandafter{\pgfplotspatchclass@biquad@B}%
\expandafter\pgfplotsplothandlermesh@setnextvertex\expandafter{\pgfplotspatchclass@biquad@F}%
\expandafter\pgfplotsplothandlermesh@setnextvertex\expandafter{\pgfplotspatchclass@biquad@I}%
%
\expandafter\pgfplotsplothandlermesh@setnextvertex\expandafter{\pgfplotspatchclass@biquad@D}%
\expandafter\pgfplotsplothandlermesh@setnextvertex\expandafter{\pgfplotspatchclass@biquad@H}%
\expandafter\pgfplotsplothandlermesh@setnextvertex\expandafter{\pgfplotspatchclass@biquad@I}%
%
\expandafter\pgfplotsplothandlermesh@setnextvertex\expandafter{\pgfplotspatchclass@biquad@D}%
\expandafter\pgfplotsplothandlermesh@setnextvertex\expandafter{\pgfplotspatchclass@biquad@G}%
\expandafter\pgfplotsplothandlermesh@setnextvertex\expandafter{\pgfplotspatchclass@biquad@I}%
%
\expandafter\pgfplotsplothandlermesh@setnextvertex\expandafter{\pgfplotspatchclass@biquad@G}%
\expandafter\pgfplotsplothandlermesh@setnextvertex\expandafter{\pgfplotspatchclass@biquad@C}%
\expandafter\pgfplotsplothandlermesh@setnextvertex\expandafter{\pgfplotspatchclass@biquad@I}%
%
\expandafter\pgfplotsplothandlermesh@setnextvertex\expandafter{\pgfplotspatchclass@biquad@C}%
\expandafter\pgfplotsplothandlermesh@setnextvertex\expandafter{\pgfplotspatchclass@biquad@F}%
\expandafter\pgfplotsplothandlermesh@setnextvertex\expandafter{\pgfplotspatchclass@biquad@I}%
\let\pgfplotsplothandlermesh@patchclass=\pgfplotsplothandlermesh@patchclass@
},%
%--------------------------------------------------
% set edge visible={%
% \ifcase#1
% \edef\pgfplotspatchclass@biquade@AB{#2}%
% \or
% \edef\pgfplotspatchclass@biquade@BC{#2}%
% \or
% \edef\pgfplotspatchclass@biquade@CA{#2}%
% \fi
% },
%--------------------------------------------------
serialize except vertices={%
\ifx\pgfplotspatchclass@biquade@AB\relax
\let\pgfplotsretval\pgfutil@empty%
\else
\edef\pgfplotsretval{%
\noexpand\def\noexpand\pgfplotspatchclass@biquade@AB{\pgfplotspatchclass@biquade@AB}%
\noexpand\def\noexpand\pgfplotspatchclass@biquade@BC{\pgfplotspatchclass@biquade@BC}%
\noexpand\def\noexpand\pgfplotspatchclass@biquade@CA{\pgfplotspatchclass@biquade@CA}%
}%
\fi
},%
deserialize except vertices=%
\let\pgfplotspatchclass@biquade@AB\relax
#1,
recursive refine@={%
\pgfplotspatchclass@biquad@recursiverefine@newnames
%
\pgfplotspatchclass{\pgfplotspatchclassname}{new}%
%--------------------------------------------------
% \pgfplotspatchclass{\pgfplotspatchclassname}{set edge visible}01%
% \pgfplotspatchclass{\pgfplotspatchclassname}{set edge visible}11%
% \pgfplotspatchclass{\pgfplotspatchclassname}{set edge visible}20%
%--------------------------------------------------
% The ordering is not arbitrary
% (unless z buffer=sort is in effect). Let's assume that the
% AB edge is BACKGROUND and the CD edge is FOREGROUND. Then
% this sequence here should have approximately the same depth
% ordering:
%
% I used the reference triangle and shape functions as listed in
% http://www.colorado.edu/engineering/CAS/courses.d/IFEM.d/,
% see above for the definition of f[xi,eta]
%
% N[{f[-1/2, -1], f[0, -1/2], f[-1/2, 0], f[-1, -1/2], f[-1/2, -1/2]}]
% {0.375` a - 0.125` b + 0.75` e,
% 0.375` e - 0.125` g + 0.75` i,
% -0.125` f + 0.375` h + 0.75` i,
% 0.375` a - 0.125` d + 0.75` h,
% 0.140625` a - 0.046875` b + 0.015625` c - 0.046875` d +
% 0.28125` e - 0.09375` f - 0.09375` g + 0.28125` h +
% 0.5625` i}
%--------------------------------------------------
\pgfplotspatchvertexaccumstart
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@biquad@A\times{0.375}%
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@biquad@B\times{-0.125}%
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@biquad@E\times{0.75}%
\pgfplotspatchvertexfinish\pgfplotspatchclass@biquad@AE
%
\pgfplotspatchvertexaccumstart
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@biquad@E\times{0.375}%
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@biquad@G\times{-0.125}%
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@biquad@I\times{0.75}%
\pgfplotspatchvertexfinish\pgfplotspatchclass@biquad@EI
%
\pgfplotspatchvertexaccumstart
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@biquad@F\times{-0.125}%
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@biquad@H\times{0.375}%
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@biquad@I\times{0.75}%
\pgfplotspatchvertexfinish\pgfplotspatchclass@biquad@HI
%
\pgfplotspatchvertexaccumstart
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@biquad@A\times{0.375}%
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@biquad@D\times{-0.125}%
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@biquad@H\times{0.75}%
\pgfplotspatchvertexfinish\pgfplotspatchclass@biquad@AH
%
\pgfplotspatchvertexaccumstart
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@biquad@A\times{0.140625}%
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@biquad@B\times{-0.046875}%
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@biquad@C\times{0.015625}%
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@biquad@D\times{-0.046875}%
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@biquad@E\times{0.28125}%
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@biquad@F\times{-0.09375}%
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@biquad@G\times{-0.09375}%
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@biquad@H\times{0.28125}%
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@biquad@I\times{0.5625}%
\pgfplotspatchvertexfinish\pgfplotspatchclass@biquad@AEIH
%
\expandafter\pgfplotsplothandlermesh@setnextvertex\expandafter{\pgfplotspatchclass@biquad@A@}%
\expandafter\pgfplotsplothandlermesh@setnextvertex\expandafter{\pgfplotspatchclass@biquad@E@}%
\expandafter\pgfplotsplothandlermesh@setnextvertex\expandafter{\pgfplotspatchclass@biquad@I@}%
\expandafter\pgfplotsplothandlermesh@setnextvertex\expandafter{\pgfplotspatchclass@biquad@H@}%
\expandafter\pgfplotsplothandlermesh@setnextvertex\expandafter{\pgfplotspatchclass@biquad@AE}%
\expandafter\pgfplotsplothandlermesh@setnextvertex\expandafter{\pgfplotspatchclass@biquad@EI}%
\expandafter\pgfplotsplothandlermesh@setnextvertex\expandafter{\pgfplotspatchclass@biquad@HI}%
\expandafter\pgfplotsplothandlermesh@setnextvertex\expandafter{\pgfplotspatchclass@biquad@AH}%
\expandafter\pgfplotsplothandlermesh@setnextvertex\expandafter{\pgfplotspatchclass@biquad@AEIH}%
%
#1\pgfplotspatchclass@biquad@recursiverefine@newnames
%
% N[{f[1/2, -1], f[1, -1/2], f[1/2, 0], f[1/2, -1/2]}]
% {-0.125` a + 0.375` b + 0.75` e,
% 0.375` b - 0.125` c + 0.75` f,
% 0.375` f - 0.125` h + 0.75` i,
% -0.046875 a + 0.140625 b - 0.046875 c + 0.015625 d + 0.28125 e + 0.28125 f - 0.09375 g - 0.09375 h + 0.5625 i}
\pgfplotspatchvertexaccumstart
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@biquad@A\times{-0.125}%
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@biquad@B\times{0.375}%
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@biquad@E\times{0.75}%
\pgfplotspatchvertexfinish\pgfplotspatchclass@biquad@EB
%
\pgfplotspatchvertexaccumstart
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@biquad@B\times{0.375}%
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@biquad@C\times{-0.125}%
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@biquad@F\times{0.75}%
\pgfplotspatchvertexfinish\pgfplotspatchclass@biquad@BF
%
\pgfplotspatchvertexaccumstart
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@biquad@F\times{0.375}%
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@biquad@H\times{-0.125}%
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@biquad@I\times{0.75}%
\pgfplotspatchvertexfinish\pgfplotspatchclass@biquad@FI
%
%
\pgfplotspatchvertexaccumstart
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@biquad@E\times{0.375}%
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@biquad@G\times{-0.125}%
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@biquad@I\times{0.75}%
\pgfplotspatchvertexfinish\pgfplotspatchclass@biquad@EI
%
\pgfplotspatchvertexaccumstart
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@biquad@A\times{-0.046875}%
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@biquad@B\times{0.140625}%
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@biquad@C\times{-0.046875}%
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@biquad@D\times{0.015625}%
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@biquad@E\times{0.28125}%
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@biquad@F\times{0.28125}%
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@biquad@G\times{-0.09375}%
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@biquad@H\times{-0.09375}%
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@biquad@I\times{0.5625}%
\pgfplotspatchvertexfinish\pgfplotspatchclass@biquad@EBFI
%
\expandafter\pgfplotsplothandlermesh@setnextvertex\expandafter{\pgfplotspatchclass@biquad@E@}%
\expandafter\pgfplotsplothandlermesh@setnextvertex\expandafter{\pgfplotspatchclass@biquad@B@}%
\expandafter\pgfplotsplothandlermesh@setnextvertex\expandafter{\pgfplotspatchclass@biquad@F@}%
\expandafter\pgfplotsplothandlermesh@setnextvertex\expandafter{\pgfplotspatchclass@biquad@I@}%
\expandafter\pgfplotsplothandlermesh@setnextvertex\expandafter{\pgfplotspatchclass@biquad@EB}%
\expandafter\pgfplotsplothandlermesh@setnextvertex\expandafter{\pgfplotspatchclass@biquad@BF}%
\expandafter\pgfplotsplothandlermesh@setnextvertex\expandafter{\pgfplotspatchclass@biquad@FI}%
\expandafter\pgfplotsplothandlermesh@setnextvertex\expandafter{\pgfplotspatchclass@biquad@EI}%
\expandafter\pgfplotsplothandlermesh@setnextvertex\expandafter{\pgfplotspatchclass@biquad@EBFI}%
%
#1\pgfplotspatchclass@biquad@recursiverefine@newnames
%
%
% N[ {f[1, 1/2], f[1/2, 1], f[0, 1/2], f[1/2, 1/2]}]
% {-0.125` b + 0.375` c + 0.75` f,
% 0.375` c - 0.125` d + 0.75` g,
% -0.125` e + 0.375` g + 0.75` i,
% 0.015625` a - 0.046875` b + 0.140625` c - 0.046875` d - 0.09375` e + 0.28125` f + 0.28125` g - 0.09375` h + 0.5625` i}
\pgfplotspatchvertexaccumstart
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@biquad@B\times{-0.125}%
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@biquad@C\times{0.375}%
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@biquad@F\times{0.75}%
\pgfplotspatchvertexfinish\pgfplotspatchclass@biquad@FC
%
\pgfplotspatchvertexaccumstart
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@biquad@C\times{0.375}%
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@biquad@D\times{-0.125}%
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@biquad@G\times{0.75}%
\pgfplotspatchvertexfinish\pgfplotspatchclass@biquad@CG
%
\pgfplotspatchvertexaccumstart
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@biquad@E\times{-0.125}%
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@biquad@G\times{0.375}%
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@biquad@I\times{0.75}%
\pgfplotspatchvertexfinish\pgfplotspatchclass@biquad@GI
%
\pgfplotspatchvertexaccumstart
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@biquad@F\times{0.375}%
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@biquad@H\times{-0.125}%
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@biquad@I\times{0.75}%
\pgfplotspatchvertexfinish\pgfplotspatchclass@biquad@FI
%
%
%
\pgfplotspatchvertexaccumstart
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@biquad@A\times{0.015625}%
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@biquad@B\times{-0.046875}%
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@biquad@C\times{0.140625}%
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@biquad@D\times{-0.046875}%
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@biquad@E\times{-0.09375}%
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@biquad@F\times{0.28125}%
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@biquad@G\times{0.28125}%
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@biquad@H\times{-0.09375}%
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@biquad@I\times{0.5625}%
\pgfplotspatchvertexfinish\pgfplotspatchclass@biquad@IFCG
%
\expandafter\pgfplotsplothandlermesh@setnextvertex\expandafter{\pgfplotspatchclass@biquad@I@}%
\expandafter\pgfplotsplothandlermesh@setnextvertex\expandafter{\pgfplotspatchclass@biquad@F@}%
\expandafter\pgfplotsplothandlermesh@setnextvertex\expandafter{\pgfplotspatchclass@biquad@C@}%
\expandafter\pgfplotsplothandlermesh@setnextvertex\expandafter{\pgfplotspatchclass@biquad@G@}%
\expandafter\pgfplotsplothandlermesh@setnextvertex\expandafter{\pgfplotspatchclass@biquad@FI}%
\expandafter\pgfplotsplothandlermesh@setnextvertex\expandafter{\pgfplotspatchclass@biquad@FC}%
\expandafter\pgfplotsplothandlermesh@setnextvertex\expandafter{\pgfplotspatchclass@biquad@CG}%
\expandafter\pgfplotsplothandlermesh@setnextvertex\expandafter{\pgfplotspatchclass@biquad@GI}%
\expandafter\pgfplotsplothandlermesh@setnextvertex\expandafter{\pgfplotspatchclass@biquad@IFCG}%
%
#1\pgfplotspatchclass@biquad@recursiverefine@newnames
%
%
% N[{f[-1/2, 1], f[-1, 1/2], f[-1/2, 1/2]}]
% {-0.125 c + 0.375 d + 0.75 g,
% -0.125 a + 0.375 d + 0.75 h,
% -0.046875 a + 0.015625 b - 0.046875 c + 0.140625 d - 0.09375 e - 0.09375 f + 0.28125 g + 0.28125 h + 0.5625 i}
\pgfplotspatchvertexaccumstart
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@biquad@C\times{-0.125}%
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@biquad@D\times{0.375}%
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@biquad@G\times{0.75}%
\pgfplotspatchvertexfinish\pgfplotspatchclass@biquad@GD
%
\pgfplotspatchvertexaccumstart
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@biquad@A\times{-0.125}%
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@biquad@D\times{0.375}%
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@biquad@H\times{0.75}%
\pgfplotspatchvertexfinish\pgfplotspatchclass@biquad@DH
%
\pgfplotspatchvertexaccumstart
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@biquad@E\times{-0.125}%
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@biquad@G\times{0.375}%
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@biquad@I\times{0.75}%
\pgfplotspatchvertexfinish\pgfplotspatchclass@biquad@GI
%
\pgfplotspatchvertexaccumstart
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@biquad@F\times{-0.125}%
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@biquad@H\times{0.375}%
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@biquad@I\times{0.75}%
\pgfplotspatchvertexfinish\pgfplotspatchclass@biquad@HI
%
\pgfplotspatchvertexaccumstart
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@biquad@A\times{-0.046875}%
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@biquad@B\times{0.015625}%
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@biquad@C\times{-0.046875}%
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@biquad@D\times{0.140625}%
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@biquad@E\times{-0.09375}%
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@biquad@F\times{-0.09375}%
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@biquad@G\times{0.28125}%
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@biquad@H\times{0.28125}%
\expandafter\pgfplotspatchvertexadd\pgfplotspatchclass@biquad@I\times{0.5625}%
\pgfplotspatchvertexfinish\pgfplotspatchclass@biquad@HIGD
%
\expandafter\pgfplotsplothandlermesh@setnextvertex\expandafter{\pgfplotspatchclass@biquad@H@}%
\expandafter\pgfplotsplothandlermesh@setnextvertex\expandafter{\pgfplotspatchclass@biquad@I@}%
\expandafter\pgfplotsplothandlermesh@setnextvertex\expandafter{\pgfplotspatchclass@biquad@G@}%
\expandafter\pgfplotsplothandlermesh@setnextvertex\expandafter{\pgfplotspatchclass@biquad@D@}%
\expandafter\pgfplotsplothandlermesh@setnextvertex\expandafter{\pgfplotspatchclass@biquad@HI}%
\expandafter\pgfplotsplothandlermesh@setnextvertex\expandafter{\pgfplotspatchclass@biquad@GI}%
\expandafter\pgfplotsplothandlermesh@setnextvertex\expandafter{\pgfplotspatchclass@biquad@GD}%
\expandafter\pgfplotsplothandlermesh@setnextvertex\expandafter{\pgfplotspatchclass@biquad@DH}%
\expandafter\pgfplotsplothandlermesh@setnextvertex\expandafter{\pgfplotspatchclass@biquad@HIGD}%
%
#1%
%
},%
get pdf shading type*={%
\if1\b@pgfplotsplothandlermesh@enable@fixed@biquadratic
\def\pgfplotsretval{7}%
\else
\def\pgfplotsretval{6}%
\fi
},%
get num vertices=\def\pgfplotsretval{9},
get num cdata vertices=\def\pgfplotsretval{4},
}%
% set this to 0 to revert to an older implementation (which was buggy,
% though)
\def\b@pgfplotsplothandlermesh@enable@fixed@biquadratic{1}%
% see docs in 'biquadratic::stream to shader' for details.
% PRECONDITION: to be used inside of 'stream to shader'.
\def\pgfplotspatchclass@biquad@coonsedge{%
%\message{EDGE \Pcur^^J}%
\expandafter\let\expandafter\PA\csname pgfplotspatchclass@biquad@\Pcur\endcsname
\edef\Pcur{\csname pgfplots@biquad@\Pnextseq next@\Pcur\endcsname}%
\expandafter\let\expandafter\PB\csname pgfplotspatchclass@biquad@\Pcur\endcsname
%\message{---> \Pcur^^J}%
\edef\Pcur{\csname pgfplots@biquad@\Pnextseq next@\Pcur\endcsname}%
\expandafter\let\expandafter\PC\csname pgfplotspatchclass@biquad@\Pcur\endcsname
%\message{---> \Pcur^^J}%
\ifx\PA\Pstart
\expandafter\pgfplotspatchvertex\PA\endvertex
\let\pgfplots@current@point@meta=\pgfplotspatchvertexmeta
\pgfplotsaxisvisphasetransformpointmeta
\pgfplotslibrarysurfstreamcoord{\pgfqpoint\pgfplotspatchvertexx\pgfplotspatchvertexy}{\pgfplotspointmetatransformed}%
\fi
\pgfplotslibrarysurfstreamcoord{%
\pgfpointadd
{\pgfqpointscale{1.333333}{\expandafter\pgfplotspointpatchvertex\PB\endvertex}}%
{\pgfqpointscale{-0.333333}{\expandafter\pgfplotspointpatchvertex\PC\endvertex}}%
}{}%
\pgfplotslibrarysurfstreamcoord{%
\pgfpointadd
{\pgfqpointscale{1.333333}{\expandafter\pgfplotspointpatchvertex\PB\endvertex}}%
{\pgfqpointscale{-0.333333}{\expandafter\pgfplotspointpatchvertex\PA\endvertex}}%
}{}%
\ifx\PC\Pstart
\else
\expandafter\pgfplotspatchvertex\PC\endvertex
\let\pgfplots@current@point@meta=\pgfplotspatchvertexmeta
\pgfplotsaxisvisphasetransformpointmeta
\pgfplotslibrarysurfstreamcoord{\pgfqpoint\pgfplotspatchvertexx\pgfplotspatchvertexy}{\pgfplotspointmetatransformed}%
\fi
}%
\def\pgfplotspatchclass@biquad@innercontrolpoints{%
\begingroup
%
% This here computes the FOUR INNER CONTROL POINTS of a tensor
% cubic bezier patch (Shading Type 7).
%
%
% the following point coordinates have been acquired from
% biquadratic::recursive refine. See above for documentation.
\pgfplotspatchvertexaccumstart
\expandafter\pgfplotspatchvertexaddXY\pgfplotspatchclass@biquad@A\times{0.375}%
\expandafter\pgfplotspatchvertexaddXY\pgfplotspatchclass@biquad@B\times{-0.125}%
\expandafter\pgfplotspatchvertexaddXY\pgfplotspatchclass@biquad@E\times{0.75}%
\pgfplotspatchvertexfinishXY\pgfplotspatchclass@biquad@AE
%
%
\pgfplotspatchvertexaccumstart
\expandafter\pgfplotspatchvertexaddXY\pgfplotspatchclass@biquad@F\times{-0.125}%
\expandafter\pgfplotspatchvertexaddXY\pgfplotspatchclass@biquad@H\times{0.375}%
\expandafter\pgfplotspatchvertexaddXY\pgfplotspatchclass@biquad@I\times{0.75}%
\pgfplotspatchvertexfinishXY\pgfplotspatchclass@biquad@HI
%
\pgfplotspatchvertexaccumstart
\expandafter\pgfplotspatchvertexaddXY\pgfplotspatchclass@biquad@A\times{-0.125}%
\expandafter\pgfplotspatchvertexaddXY\pgfplotspatchclass@biquad@B\times{0.375}%
\expandafter\pgfplotspatchvertexaddXY\pgfplotspatchclass@biquad@E\times{0.75}%
\pgfplotspatchvertexfinishXY\pgfplotspatchclass@biquad@EB
%
\pgfplotspatchvertexaccumstart
\expandafter\pgfplotspatchvertexaddXY\pgfplotspatchclass@biquad@F\times{0.375}%
\expandafter\pgfplotspatchvertexaddXY\pgfplotspatchclass@biquad@H\times{-0.125}%
\expandafter\pgfplotspatchvertexaddXY\pgfplotspatchclass@biquad@I\times{0.75}%
\pgfplotspatchvertexfinishXY\pgfplotspatchclass@biquad@FI
%
\pgfplotspatchvertexaccumstart
\expandafter\pgfplotspatchvertexaddXY\pgfplotspatchclass@biquad@C\times{0.375}%
\expandafter\pgfplotspatchvertexaddXY\pgfplotspatchclass@biquad@D\times{-0.125}%
\expandafter\pgfplotspatchvertexaddXY\pgfplotspatchclass@biquad@G\times{0.75}%
\pgfplotspatchvertexfinishXY\pgfplotspatchclass@biquad@CG
%
\pgfplotspatchvertexaccumstart
\expandafter\pgfplotspatchvertexaddXY\pgfplotspatchclass@biquad@C\times{-0.125}%
\expandafter\pgfplotspatchvertexaddXY\pgfplotspatchclass@biquad@D\times{0.375}%
\expandafter\pgfplotspatchvertexaddXY\pgfplotspatchclass@biquad@G\times{0.75}%
\pgfplotspatchvertexfinishXY\pgfplotspatchclass@biquad@GD
%
%
\let\PA=\pgfplotspatchclass@biquad@AE
\let\PB=\pgfplotspatchclass@biquad@HI
\let\PC=\pgfplotspatchclass@biquad@GD
\pgfplotspatchclass@biquad@innercontrolpoints@PREPARE\pgfplotspatchclass@biquad@@A\pgfplotspatchclass@biquad@@D
%
\let\PA=\pgfplotspatchclass@biquad@EB
\let\PB=\pgfplotspatchclass@biquad@FI
\let\PC=\pgfplotspatchclass@biquad@CG
\pgfplotspatchclass@biquad@innercontrolpoints@PREPARE\pgfplotspatchclass@biquad@@B\pgfplotspatchclass@biquad@@C
%
%
\let\Pcur=\Pstartidx
\pgfplotslibrarysurfstreamcoord{\csname pgfplotspatchclass@biquad@@\Pcur\endcsname}{}%
%
\edef\Pcur{\csname pgfplots@rect@\Pnextseq next@\Pcur\endcsname}%
\pgfplotslibrarysurfstreamcoord{\csname pgfplotspatchclass@biquad@@\Pcur\endcsname}{}%
%
\edef\Pcur{\csname pgfplots@rect@\Pnextseq next@\Pcur\endcsname}%
\pgfplotslibrarysurfstreamcoord{\csname pgfplotspatchclass@biquad@@\Pcur\endcsname}{}%
%
\edef\Pcur{\csname pgfplots@rect@\Pnextseq next@\Pcur\endcsname}%
\pgfplotslibrarysurfstreamcoord{\csname pgfplotspatchclass@biquad@@\Pcur\endcsname}{}%
\endgroup
}%
\def\pgfplotspatchclass@biquad@innercontrolpoints@PREPARE#1#2{%
\pgfpointadd
{\pgfqpointscale{1.333333}{\expandafter\pgfplotspointpatchvertex\PB\endvertex}}%
{\pgfqpointscale{-0.333333}{\expandafter\pgfplotspointpatchvertex\PC\endvertex}}%
\edef#1{\global\pgf@x=\the\pgf@x\space\global\pgf@y=\the\pgf@y\space}%
%
\pgfpointadd
{\pgfqpointscale{1.333333}{\expandafter\pgfplotspointpatchvertex\PB\endvertex}}%
{\pgfqpointscale{-0.333333}{\expandafter\pgfplotspointpatchvertex\PA\endvertex}}%
\edef#2{\global\pgf@x=\the\pgf@x\space\global\pgf@y=\the\pgf@y\space}%
%
\pgfpathcircle{\expandafter\pgfplotspointpatchvertex\PA\endvertex}{1pt}\pgfusepath{fill}%
\pgfpathcircle{\expandafter\pgfplotspointpatchvertex\PB\endvertex}{1pt}\pgfusepath{fill}%
\pgfpathcircle{\expandafter\pgfplotspointpatchvertex\PC\endvertex}{1pt}\pgfusepath{fill}%
\pgfpathmoveto{\expandafter\pgfplotspointpatchvertex\PA\endvertex}%
\pgfpathcurveto{#1}{#2}{\expandafter\pgfplotspointpatchvertex\PC\endvertex}%
\pgfusepath{stroke}%
}
% Direct interface to coons patches (pdf shading type 6).
% See manual and/or pdf reference
\pgfplotsdeclarepatchclass{coons}{%
new=\def\pgfplotspatchclass@coons@no{A},
set next vertex={%
% defines \pgfplotspatchclass@coons@A ... \pgfplotspatchclass@coons@L (12 points)
\expandafter\edef\csname pgfplotspatchclass@coons@\pgfplotspatchclass@coons@no\endcsname{#1}%
\if L\pgfplotspatchclass@coons@no
\def\pgfplotspatchclass@coons@no{A}%
\pgfplotspatchready
\else
\expandafter\let\expandafter\pgfplotspatchclass@coons@no\csname pgfpptchindexnext@\pgfplotspatchclass@coons@no\endcsname
\fi
},
first vertex=\expandafter\pgfplotspatchvertex\pgfplotspatchclass@coons@A\endvertex,
foreach vertex={%
\expandafter\pgfplotspatchvertex\pgfplotspatchclass@coons@A\endvertex #1%
\expandafter\pgfplotspatchvertex\pgfplotspatchclass@coons@B\endvertex #1%
\expandafter\pgfplotspatchvertex\pgfplotspatchclass@coons@C\endvertex #1%
\expandafter\pgfplotspatchvertex\pgfplotspatchclass@coons@D\endvertex #1%
\expandafter\pgfplotspatchvertex\pgfplotspatchclass@coons@E\endvertex #1%
\expandafter\pgfplotspatchvertex\pgfplotspatchclass@coons@F\endvertex #1%
\expandafter\pgfplotspatchvertex\pgfplotspatchclass@coons@G\endvertex #1%
\expandafter\pgfplotspatchvertex\pgfplotspatchclass@coons@H\endvertex #1%
\expandafter\pgfplotspatchvertex\pgfplotspatchclass@coons@I\endvertex #1%
\expandafter\pgfplotspatchvertex\pgfplotspatchclass@coons@J\endvertex #1%
\expandafter\pgfplotspatchvertex\pgfplotspatchclass@coons@K\endvertex #1%
\expandafter\pgfplotspatchvertex\pgfplotspatchclass@coons@L\endvertex #1%
},
foreach cdata vertex={%
% 0, 3, 6, 9
\expandafter\pgfplotspatchvertex\pgfplotspatchclass@coons@A\endvertex #1%
\expandafter\pgfplotspatchvertex\pgfplotspatchclass@coons@D\endvertex #1%
\expandafter\pgfplotspatchvertex\pgfplotspatchclass@coons@G\endvertex #1%
\expandafter\pgfplotspatchvertex\pgfplotspatchclass@coons@J\endvertex #1%
},
fill path={%
\pgfpathmoveto {\expandafter\pgfplotspointpatchvertex\pgfplotspatchclass@coons@A\endvertex}%
\pgfpathcurveto {\expandafter\pgfplotspointpatchvertex\pgfplotspatchclass@coons@B\endvertex}%
{\expandafter\pgfplotspointpatchvertex\pgfplotspatchclass@coons@C\endvertex}%
{\expandafter\pgfplotspointpatchvertex\pgfplotspatchclass@coons@D\endvertex}%
\pgfpathcurveto {\expandafter\pgfplotspointpatchvertex\pgfplotspatchclass@coons@E\endvertex}%
{\expandafter\pgfplotspointpatchvertex\pgfplotspatchclass@coons@F\endvertex}%
{\expandafter\pgfplotspointpatchvertex\pgfplotspatchclass@coons@G\endvertex}%
\pgfpathcurveto {\expandafter\pgfplotspointpatchvertex\pgfplotspatchclass@coons@H\endvertex}%
{\expandafter\pgfplotspointpatchvertex\pgfplotspatchclass@coons@I\endvertex}%
{\expandafter\pgfplotspointpatchvertex\pgfplotspatchclass@coons@J\endvertex}%
\pgfpathcurveto {\expandafter\pgfplotspointpatchvertex\pgfplotspatchclass@coons@K\endvertex}%
{\expandafter\pgfplotspointpatchvertex\pgfplotspatchclass@coons@L\endvertex}%
{\expandafter\pgfplotspointpatchvertex\pgfplotspatchclass@coons@A\endvertex}%
\pgfpathclose
},
serialize except vertices=\let\pgfplotsretval\pgfutil@empty,%
deserialize except vertices=,
get pdf shading type=6,
get num vertices=\def\pgfplotsretval{12},
get num cdata vertices=\def\pgfplotsretval{4},
}%
% Direct interface to tensor product bezier patches (pdf shading type 7).
% See manual and/or pdf reference
\pgfplotsdeclarepatchclass{tensor bezier}{%
new=\def\pgfplotspatchclass@tensor@no{A},
set next vertex={%
% defines \pgfplotspatchclass@tensor@A ... \pgfplotspatchclass@tensor@P (16 points)
\expandafter\edef\csname pgfplotspatchclass@tensor@\pgfplotspatchclass@tensor@no\endcsname{#1}%
\if P\pgfplotspatchclass@tensor@no
\def\pgfplotspatchclass@tensor@no{A}%
\pgfplotspatchready
\else
\expandafter\let\expandafter\pgfplotspatchclass@tensor@no\csname pgfpptchindexnext@\pgfplotspatchclass@tensor@no\endcsname
\fi
},
first vertex=\expandafter\pgfplotspatchvertex\pgfplotspatchclass@tensor@A\endvertex,
foreach vertex={%
\expandafter\pgfplotspatchvertex\pgfplotspatchclass@tensor@A\endvertex #1%
\expandafter\pgfplotspatchvertex\pgfplotspatchclass@tensor@B\endvertex #1%
\expandafter\pgfplotspatchvertex\pgfplotspatchclass@tensor@C\endvertex #1%
\expandafter\pgfplotspatchvertex\pgfplotspatchclass@tensor@D\endvertex #1%
\expandafter\pgfplotspatchvertex\pgfplotspatchclass@tensor@E\endvertex #1%
\expandafter\pgfplotspatchvertex\pgfplotspatchclass@tensor@F\endvertex #1%
\expandafter\pgfplotspatchvertex\pgfplotspatchclass@tensor@G\endvertex #1%
\expandafter\pgfplotspatchvertex\pgfplotspatchclass@tensor@H\endvertex #1%
\expandafter\pgfplotspatchvertex\pgfplotspatchclass@tensor@I\endvertex #1%
\expandafter\pgfplotspatchvertex\pgfplotspatchclass@tensor@J\endvertex #1%
\expandafter\pgfplotspatchvertex\pgfplotspatchclass@tensor@K\endvertex #1%
\expandafter\pgfplotspatchvertex\pgfplotspatchclass@tensor@L\endvertex #1%
\expandafter\pgfplotspatchvertex\pgfplotspatchclass@tensor@M\endvertex #1%
\expandafter\pgfplotspatchvertex\pgfplotspatchclass@tensor@N\endvertex #1%
\expandafter\pgfplotspatchvertex\pgfplotspatchclass@tensor@O\endvertex #1%
\expandafter\pgfplotspatchvertex\pgfplotspatchclass@tensor@P\endvertex #1%
},
foreach cdata vertex={%
% 0, 3, 6, 9
\expandafter\pgfplotspatchvertex\pgfplotspatchclass@tensor@A\endvertex #1%
\expandafter\pgfplotspatchvertex\pgfplotspatchclass@tensor@D\endvertex #1%
\expandafter\pgfplotspatchvertex\pgfplotspatchclass@tensor@G\endvertex #1%
\expandafter\pgfplotspatchvertex\pgfplotspatchclass@tensor@J\endvertex #1%
},
fill path={%
\pgfpathmoveto {\expandafter\pgfplotspointpatchvertex\pgfplotspatchclass@tensor@A\endvertex}%
\pgfpathcurveto {\expandafter\pgfplotspointpatchvertex\pgfplotspatchclass@tensor@B\endvertex}%
{\expandafter\pgfplotspointpatchvertex\pgfplotspatchclass@tensor@C\endvertex}%
{\expandafter\pgfplotspointpatchvertex\pgfplotspatchclass@tensor@D\endvertex}%
\pgfpathcurveto {\expandafter\pgfplotspointpatchvertex\pgfplotspatchclass@tensor@E\endvertex}%
{\expandafter\pgfplotspointpatchvertex\pgfplotspatchclass@tensor@F\endvertex}%
{\expandafter\pgfplotspointpatchvertex\pgfplotspatchclass@tensor@G\endvertex}%
\pgfpathcurveto {\expandafter\pgfplotspointpatchvertex\pgfplotspatchclass@tensor@H\endvertex}%
{\expandafter\pgfplotspointpatchvertex\pgfplotspatchclass@tensor@I\endvertex}%
{\expandafter\pgfplotspointpatchvertex\pgfplotspatchclass@tensor@J\endvertex}%
\pgfpathcurveto {\expandafter\pgfplotspointpatchvertex\pgfplotspatchclass@tensor@K\endvertex}%
{\expandafter\pgfplotspointpatchvertex\pgfplotspatchclass@tensor@L\endvertex}%
{\expandafter\pgfplotspointpatchvertex\pgfplotspatchclass@tensor@A\endvertex}%
\pgfpathclose
},
serialize except vertices=\let\pgfplotsretval\pgfutil@empty,%
deserialize except vertices=,
get pdf shading type=7,
get num vertices=\def\pgfplotsretval{16},
get num cdata vertices=\def\pgfplotsretval{4},
}%
% A bicubic patch with 16 points.
%
% It expects points in the order (i.e. in matrix ordering, row-wise):
%
% AD BD CD DD
% AC BC CC DC
% AB BB CB DB
% AA BA CA DA
%
\pgfplotsdeclarepatchclass{bicubic}{%
new=\def\pgfplotspatchclass@bicubic@row{A}\def\pgfplotspatchclass@bicubic@col{A},
set next vertex={%
% defines \pgfplotspatchclass@bicubic@AA ... \pgfplotspatchclass@bicubic@DD (16 points)
\expandafter\edef\csname pgfplotspatchclass@bicubic@\pgfplotspatchclass@bicubic@row\pgfplotspatchclass@bicubic@col\endcsname{#1}%
\if D\pgfplotspatchclass@bicubic@row
\def\pgfplotspatchclass@bicubic@row{A}%
\if D\pgfplotspatchclass@bicubic@col
\def\pgfplotspatchclass@bicubic@col{A}%
\pgfplotspatchready
\else
\expandafter\let\expandafter\pgfplotspatchclass@bicubic@col\csname pgfpptchindexnext@\pgfplotspatchclass@bicubic@col\endcsname
\fi
\else
\expandafter\let\expandafter\pgfplotspatchclass@bicubic@row\csname pgfpptchindexnext@\pgfplotspatchclass@bicubic@row\endcsname
\fi
},
sample in unit cube={%
\def\pgfplotspatchclassx{0}%
\def\pgfplotspatchclassy{0}%
#1%
\def\pgfplotspatchclassx{0.333333333}%
\def\pgfplotspatchclassy{0}%
#1%
\def\pgfplotspatchclassx{0.666666666}%
\def\pgfplotspatchclassy{0}%
#1%
\def\pgfplotspatchclassx{1}%
\def\pgfplotspatchclassy{0}%
#1%
%
%
\def\pgfplotspatchclassx{0}%
\def\pgfplotspatchclassy{0.333333333}%
#1%
\def\pgfplotspatchclassx{0.333333333}%
\def\pgfplotspatchclassy{0.333333333}%
#1%
\def\pgfplotspatchclassx{0.666666666}%
\def\pgfplotspatchclassy{0.333333333}%
#1%
\def\pgfplotspatchclassx{1}%
\def\pgfplotspatchclassy{0.333333333}%
#1%
%
%
\def\pgfplotspatchclassx{0}%
\def\pgfplotspatchclassy{0.666666666}%
#1%
\def\pgfplotspatchclassx{0.333333333}%
\def\pgfplotspatchclassy{0.666666666}%
#1%
\def\pgfplotspatchclassx{0.666666666}%
\def\pgfplotspatchclassy{0.666666666}%
#1%
\def\pgfplotspatchclassx{1}%
\def\pgfplotspatchclassy{0.666666666}%
#1%
%
%
\def\pgfplotspatchclassx{0}%
\def\pgfplotspatchclassy{1}%
#1%
\def\pgfplotspatchclassx{0.333333333}%
\def\pgfplotspatchclassy{1}%
#1%
\def\pgfplotspatchclassx{0.666666666}%
\def\pgfplotspatchclassy{1}%
#1%
\def\pgfplotspatchclassx{1}%
\def\pgfplotspatchclassy{1}%
#1%
%
%
%
\pgfplotspatchready
},%
first vertex=\expandafter\pgfplotspatchvertex\pgfplotspatchclass@bicubic@AA\endvertex,
foreach vertex={%
\expandafter\pgfplotspatchvertex\pgfplotspatchclass@bicubic@AA\endvertex #1%
\expandafter\pgfplotspatchvertex\pgfplotspatchclass@bicubic@BA\endvertex #1%
\expandafter\pgfplotspatchvertex\pgfplotspatchclass@bicubic@CA\endvertex #1%
\expandafter\pgfplotspatchvertex\pgfplotspatchclass@bicubic@DA\endvertex #1%
\expandafter\pgfplotspatchvertex\pgfplotspatchclass@bicubic@AB\endvertex #1%
\expandafter\pgfplotspatchvertex\pgfplotspatchclass@bicubic@BB\endvertex #1%
\expandafter\pgfplotspatchvertex\pgfplotspatchclass@bicubic@CB\endvertex #1%
\expandafter\pgfplotspatchvertex\pgfplotspatchclass@bicubic@DB\endvertex #1%
\expandafter\pgfplotspatchvertex\pgfplotspatchclass@bicubic@AC\endvertex #1%
\expandafter\pgfplotspatchvertex\pgfplotspatchclass@bicubic@BC\endvertex #1%
\expandafter\pgfplotspatchvertex\pgfplotspatchclass@bicubic@CC\endvertex #1%
\expandafter\pgfplotspatchvertex\pgfplotspatchclass@bicubic@DC\endvertex #1%
\expandafter\pgfplotspatchvertex\pgfplotspatchclass@bicubic@AD\endvertex #1%
\expandafter\pgfplotspatchvertex\pgfplotspatchclass@bicubic@BD\endvertex #1%
\expandafter\pgfplotspatchvertex\pgfplotspatchclass@bicubic@CD\endvertex #1%
\expandafter\pgfplotspatchvertex\pgfplotspatchclass@bicubic@DD\endvertex #1%
},
foreach cdata vertex={%
\expandafter\pgfplotspatchvertex\pgfplotspatchclass@bicubic@AA\endvertex #1%
\expandafter\pgfplotspatchvertex\pgfplotspatchclass@bicubic@DA\endvertex #1%
\expandafter\pgfplotspatchvertex\pgfplotspatchclass@bicubic@DD\endvertex #1%
\expandafter\pgfplotspatchvertex\pgfplotspatchclass@bicubic@AD\endvertex #1%
},
fill path={%
% Visualize the patch boundary using four bezier curves.
%
% This involves a change from Lagrange to bezier
% representation of the boundary curves.
%
\pgfpathmoveto{\expandafter\pgfplotspointpatchvertex\pgfplotspatchclass@bicubic@AA\endvertex}%
\pgfplotspathcubicfrominterpolation
{\pgfplotspatchclass@bicubic@AA}
{\pgfplotspatchclass@bicubic@BA}
{\pgfplotspatchclass@bicubic@CA}
{\pgfplotspatchclass@bicubic@DA}%
\pgfplotspathcubicfrominterpolation
{\pgfplotspatchclass@bicubic@DA}
{\pgfplotspatchclass@bicubic@DB}
{\pgfplotspatchclass@bicubic@DC}
{\pgfplotspatchclass@bicubic@DD}%
\pgfplotspathcubicfrominterpolation
{\pgfplotspatchclass@bicubic@DD}
{\pgfplotspatchclass@bicubic@CD}
{\pgfplotspatchclass@bicubic@BD}
{\pgfplotspatchclass@bicubic@AD}%
\pgfplotspathcubicfrominterpolation
{\pgfplotspatchclass@bicubic@AD}
{\pgfplotspatchclass@bicubic@AC}
{\pgfplotspatchclass@bicubic@AB}
{\pgfplotspatchclass@bicubic@AA}%
\pgfpathclose
},
stream to shader={%
\begingroup
%
% AD BD CD DD
% AC BC CC DC
% AB BB CB DB
% AA BA CA DA
%
% STEP 1: ensure that the patch's coordinates are streamed in
% a sequence which is compatible with the DEPTH of the
% corners.
%
% we use
% \pgfplotspatchclass@rect@to@coonspatch@findshadingsequence@for@depth
% which works for bilinear, biquadratic, and bicubic
%
% define helper macros which are input for
% \pgfplotspatchclass@rect@to@coonspatch@findshadingsequence@for@depth:
\let\pgfplotspatchclass@rect@A=\pgfplotspatchclass@bicubic@AA
\let\pgfplotspatchclass@rect@B=\pgfplotspatchclass@bicubic@DA
\let\pgfplotspatchclass@rect@C=\pgfplotspatchclass@bicubic@DD
\let\pgfplotspatchclass@rect@D=\pgfplotspatchclass@bicubic@AD
\pgfplotspatchclass@rect@to@coonspatch@findshadingsequence@for@depth
{pgfplotspatchclass@rect@}{\Pcur}{\Pnextseq}%
%
%\message{using \Pcur\space(set = \Pnextseq)^^J}%
% now, translate the result into our matrix form.
% This means to (a) identify the FIRST point which needs to be
% streamed (it is stored in \Pcur as 'A', 'B', 'C', or 'D')
% and (b) keep in mind that we have to take care of the
% sequence in which points are streamed ("forward" means to
% rotate the matrix elements and "backward" means to transpose
% the "forward" result).
%
\if A\Pcur
% Ah - the point "AA" needs to be streamed as first.
%
% Well, this is simple: take the matrix as-is!
% simply copy 1:1
\let\P@AA=\pgfplotspatchclass@bicubic@AA
\let\P@BA=\pgfplotspatchclass@bicubic@BA
\let\P@CA=\pgfplotspatchclass@bicubic@CA
\let\P@DA=\pgfplotspatchclass@bicubic@DA
\let\P@AB=\pgfplotspatchclass@bicubic@AB
\let\P@BB=\pgfplotspatchclass@bicubic@BB
\let\P@CB=\pgfplotspatchclass@bicubic@CB
\let\P@DB=\pgfplotspatchclass@bicubic@DB
\let\P@AC=\pgfplotspatchclass@bicubic@AC
\let\P@BC=\pgfplotspatchclass@bicubic@BC
\let\P@CC=\pgfplotspatchclass@bicubic@CC
\let\P@DC=\pgfplotspatchclass@bicubic@DC
\let\P@AD=\pgfplotspatchclass@bicubic@AD
\let\P@BD=\pgfplotspatchclass@bicubic@BD
\let\P@CD=\pgfplotspatchclass@bicubic@CD
\let\P@DD=\pgfplotspatchclass@bicubic@DD
\fi
\if B\Pcur
% the "DA" point needs to be streamed as first.
%
% Reorder
% AD BD CD DD
% AC BC CC DC
% AB BB CB DB
% AA BA CA DA
% to
% AA AB AC AD
% BA BB BC BD
% CA CB CC CD
% DA DB DC DD
%
\let\P@AA=\pgfplotspatchclass@bicubic@DA
\let\P@BA=\pgfplotspatchclass@bicubic@DB
\let\P@CA=\pgfplotspatchclass@bicubic@DC
\let\P@DA=\pgfplotspatchclass@bicubic@DD
\let\P@AB=\pgfplotspatchclass@bicubic@CA
\let\P@BB=\pgfplotspatchclass@bicubic@CB
\let\P@CB=\pgfplotspatchclass@bicubic@CC
\let\P@DB=\pgfplotspatchclass@bicubic@CD
\let\P@AC=\pgfplotspatchclass@bicubic@BA
\let\P@BC=\pgfplotspatchclass@bicubic@BB
\let\P@CC=\pgfplotspatchclass@bicubic@BC
\let\P@DC=\pgfplotspatchclass@bicubic@BD
\let\P@AD=\pgfplotspatchclass@bicubic@AA
\let\P@BD=\pgfplotspatchclass@bicubic@AB
\let\P@CD=\pgfplotspatchclass@bicubic@AC
\let\P@DD=\pgfplotspatchclass@bicubic@AD
\fi
\if C\Pcur
% the "DD" point needs to be streamed as first.
%
% Reorder
% AD BD CD DD
% AC BC CC DC
% AB BB CB DB
% AA BA CA DA
% to
% DA CA BA AA
% DB CB BB AB
% DC CC BC AC
% DD CD BD AD
%
\let\P@AA=\pgfplotspatchclass@bicubic@DD
\let\P@BA=\pgfplotspatchclass@bicubic@CD
\let\P@CA=\pgfplotspatchclass@bicubic@BD
\let\P@DA=\pgfplotspatchclass@bicubic@AD
\let\P@AB=\pgfplotspatchclass@bicubic@DC
\let\P@BB=\pgfplotspatchclass@bicubic@CC
\let\P@CB=\pgfplotspatchclass@bicubic@BC
\let\P@DB=\pgfplotspatchclass@bicubic@AC
\let\P@AC=\pgfplotspatchclass@bicubic@DB
\let\P@BC=\pgfplotspatchclass@bicubic@CB
\let\P@CC=\pgfplotspatchclass@bicubic@BB
\let\P@DC=\pgfplotspatchclass@bicubic@AB
\let\P@AD=\pgfplotspatchclass@bicubic@DA
\let\P@BD=\pgfplotspatchclass@bicubic@CA
\let\P@CD=\pgfplotspatchclass@bicubic@BA
\let\P@DD=\pgfplotspatchclass@bicubic@AA
\fi
\if D\Pcur
% the "AD" point needs to be streamed as first.
%
% Reorder
% AD BD CD DD
% AC BC CC DC
% AB BB CB DB
% AA BA CA DA
% to
% DD DC DB DA
% CD CC CB CA
% BD BC BB BA
% AD AC AB AA
%
\let\P@AA=\pgfplotspatchclass@bicubic@AD
\let\P@BA=\pgfplotspatchclass@bicubic@AC
\let\P@CA=\pgfplotspatchclass@bicubic@AB
\let\P@DA=\pgfplotspatchclass@bicubic@AA
\let\P@AB=\pgfplotspatchclass@bicubic@BD
\let\P@BB=\pgfplotspatchclass@bicubic@BC
\let\P@CB=\pgfplotspatchclass@bicubic@BB
\let\P@DB=\pgfplotspatchclass@bicubic@BA
\let\P@AC=\pgfplotspatchclass@bicubic@CD
\let\P@BC=\pgfplotspatchclass@bicubic@CC
\let\P@CC=\pgfplotspatchclass@bicubic@CB
\let\P@DC=\pgfplotspatchclass@bicubic@CA
\let\P@AD=\pgfplotspatchclass@bicubic@DD
\let\P@BD=\pgfplotspatchclass@bicubic@DC
\let\P@CD=\pgfplotspatchclass@bicubic@DB
\let\P@DD=\pgfplotspatchclass@bicubic@DA
\fi
\ifx\Pnextseq\pgfutil@empty
\else
% reverse the ordering. This means to transpose the
% matrix:
\pgfplotspatchclass@bicubic@transpose
\fi
%
% Step: convert to tensor bezier representation.
%
% Converting a 2d tensor product lagrangian interpoland to a
% 2d tensor product bezier interpoland can be achieved by
% means of 1d algorithms along LINES in the matrix.
%
% The underlying proof for this is related to the tensor
% product form: the U and V coordinates are orthogonal to each
% other, so we can redistribute all intermediate results. (I
% do not have the real proof, so this hand-waving argument has
% to be enough). I verified its results experimentally.
%
% Note that the underlying 1d operation is the same as for
% 'patch type=cubic spline' . We only need to apply it to all
% lines in U direction and afterwards to all lines in V
% direction.
%
\def\pgfplotspatchvertexaddXY@expanded##1\times{%
\edef\pgfplots@loc@TMPa{##1}%
\expandafter\pgfplotspatchvertexaddXY\pgfplots@loc@TMPa\times
}%
%
% this macro operates on \pgfplots@line{[ABCD]}, see below:
\def\pgfplots@apply@to@line{%
\pgfplotspatchvertexaccumstart
\pgfplotspatchvertexaddXY@expanded\pgfplots@line{A}\times{-0.833333}%
\pgfplotspatchvertexaddXY@expanded\pgfplots@line{B}\times{3}%
\pgfplotspatchvertexaddXY@expanded\pgfplots@line{C}\times{-1.5}%
\pgfplotspatchvertexaddXY@expanded\pgfplots@line{D}\times{0.3333333}%
\pgfplotspatchvertexfinish\pgfplots@controlpoint@A
%
\pgfplotspatchvertexaccumstart
\pgfplotspatchvertexaddXY@expanded\pgfplots@line{A}\times{0.333333}%
\pgfplotspatchvertexaddXY@expanded\pgfplots@line{B}\times{-1.5}%
\pgfplotspatchvertexaddXY@expanded\pgfplots@line{C}\times{3}%
\pgfplotspatchvertexaddXY@expanded\pgfplots@line{D}\times{-0.833333}%
\pgfplotspatchvertexfinish\pgfplots@controlpoint@B
%
\expandafter\expandafter\expandafter\let\pgfplots@line{B}=\pgfplots@controlpoint@A
\expandafter\expandafter\expandafter\let\pgfplots@line{C}=\pgfplots@controlpoint@B
}%
%
\def\pgfplots@line##1{\csname P@##1A\endcsname}%
\pgfplots@apply@to@line
%
\def\pgfplots@line##1{\csname P@##1B\endcsname}%
\pgfplots@apply@to@line
%
\def\pgfplots@line##1{\csname P@##1C\endcsname}%
\pgfplots@apply@to@line
%
\def\pgfplots@line##1{\csname P@##1D\endcsname}%
\pgfplots@apply@to@line
%
%
\def\pgfplots@line##1{\csname P@A##1\endcsname}%
\pgfplots@apply@to@line
%
\def\pgfplots@line##1{\csname P@B##1\endcsname}%
\pgfplots@apply@to@line
%
\def\pgfplots@line##1{\csname P@C##1\endcsname}%
\pgfplots@apply@to@line
%
\def\pgfplots@line##1{\csname P@D##1\endcsname}%
\pgfplots@apply@to@line
%
% OK. The tensor product representation is READY.
%
\pgfplotsplothandlermesh@shade@cubic@tensor
\endgroup
},
triangulate={%
\let\pgfplotsplothandlermesh@patchclass@=\pgfplotsplothandlermesh@patchclass
\def\pgfplotsplothandlermesh@patchclass{triangle}%
\pgfplotspatchclass{\pgfplotsplothandlermesh@patchclass}{new}%
% Ok. Now create a lot of triangles.
%
% FIXME: The ordering is not arbitrary (unless z buffer=sort is in effect).
%
% ##1: the row index of the cell to be triangulated (either A,B,or C)
% ##2: the col index of the cell to be triangulated (either A,B,or C)
% ##3: the 1. 'set edge visible' value for the first triangle
% ##4: the 2. 'set edge visible' value for the first triangle
% ##5: the 3. 'set edge visible' value for the first triangle
% ##6: the 1. 'set edge visible' value for the second triangle
% ##7: the 2. 'set edge visible' value for the second triangle
% ##8: the 3. 'set edge visible' value for the second triangle
\def\pgfplots@bicubic@triangulate@cell##1##2##3##4##5##6##7##8{%
\pgfplotspatchclass{\pgfplotsplothandlermesh@patchclass}{set edge visible}0##3%
\pgfplotspatchclass{\pgfplotsplothandlermesh@patchclass}{set edge visible}1##4%
\pgfplotspatchclass{\pgfplotsplothandlermesh@patchclass}{set edge visible}2##5%
\pgfplotsplothandlermesh@setnextvertex{\csname pgfplotspatchclass@bicubic@##1##2\endcsname}%
\pgfplotsplothandlermesh@setnextvertex{\csname pgfplotspatchclass@bicubic@\csname pgfpptchindexnext@##1\endcsname##2\endcsname}%
\pgfplotsplothandlermesh@setnextvertex{\csname pgfplotspatchclass@bicubic@\csname pgfpptchindexnext@##1\endcsname \csname pgfpptchindexnext@##2\endcsname\endcsname}%
%
\pgfplotspatchclass{\pgfplotsplothandlermesh@patchclass}{set edge visible}0##6%
\pgfplotspatchclass{\pgfplotsplothandlermesh@patchclass}{set edge visible}1##7%
\pgfplotspatchclass{\pgfplotsplothandlermesh@patchclass}{set edge visible}2##8%
\pgfplotsplothandlermesh@setnextvertex{\csname pgfplotspatchclass@bicubic@##1\csname pgfpptchindexnext@##2\endcsname\endcsname}%
\pgfplotsplothandlermesh@setnextvertex{\csname pgfplotspatchclass@bicubic@##1##2\endcsname}%
\pgfplotsplothandlermesh@setnextvertex{\csname pgfplotspatchclass@bicubic@\csname pgfpptchindexnext@##1\endcsname \csname pgfpptchindexnext@##2\endcsname\endcsname}%
%
}%
%
\pgfplotspatchclass{\pgfplotsplothandlermesh@patchclass}{set edge visible}01%
\pgfplotspatchclass{\pgfplotsplothandlermesh@patchclass}{set edge visible}10%
\pgfplotspatchclass{\pgfplotsplothandlermesh@patchclass}{set edge visible}20%
\pgfplots@bicubic@triangulate@cell AA100 100%
\pgfplots@bicubic@triangulate@cell BA100 000%
\pgfplots@bicubic@triangulate@cell CA110 000%
%
\pgfplots@bicubic@triangulate@cell AB000 100%
\pgfplots@bicubic@triangulate@cell BB000 000%
\pgfplots@bicubic@triangulate@cell CB010 000%
%
\pgfplots@bicubic@triangulate@cell AC000 101%
\pgfplots@bicubic@triangulate@cell BC000 001%
\pgfplots@bicubic@triangulate@cell CC010 001%
\let\pgfplotsplothandlermesh@patchclass=\pgfplotsplothandlermesh@patchclass@
},%
serialize except vertices=\let\pgfplotsretval\pgfutil@empty,%
deserialize except vertices=,
get pdf shading type=7,
get num vertices=\def\pgfplotsretval{16},
get num cdata vertices=\def\pgfplotsretval{4},
}%
% Transpose a bicubic matrix (4x4).
%
% Reorder
% AD BD CD DD
% AC BC CC DC
% AB BB CB DB
% AA BA CA DA
% to
% DA DB DC DD
% CA CB CC CD
% BA BB BC BD
% AA AB AC AD
\def\pgfplotspatchclass@bicubic@transpose{%
\pgfplotsutil@swap\P@AB\P@BA
\pgfplotsutil@swap\P@CA\P@AC
\pgfplotsutil@swap\P@DA\P@AD
\pgfplotsutil@swap\P@CB\P@BC
\pgfplotsutil@swap\P@BD\P@DB
\pgfplotsutil@swap\P@DC\P@CD
}
% Transpose a bicubic matrix (4x4).
%
% Reorder
% AC BC CC
% AB BB CB
% AA BA CA
% to
% CA CB CC
% BA BB BC
% AA AB AC
\def\pgfplotspatchclass@biquad@transpose{%
\pgfplotsutil@swap\P@AB\P@BA
\pgfplotsutil@swap\P@CA\P@AC
\pgfplotsutil@swap\P@CB\P@BC
}
% Expects that a 4x4 matrix in tensor bezier representation where
% A = left end point
% B = first control point
% C = second control point
% D = right end point
%
% and the coordinates are stored in \csname P@[ABCD][ABCD]\endcsname
%
% Streaming starts with \P@AA and is applied rowwise.
\def\pgfplotsplothandlermesh@shade@cubic@tensor{%
% Stream it to the shader. Note that the shader has a
% DIFFERENT ordering; it expects points in the cyclic ordering
%
% AA BA CA DA DB DC DD CD BD AD AC AB BB CB CC BC
%
% note furthermore that only the corners have "point meta" in
% this shading :-(
%
\expandafter\pgfplotspatchvertex\P@AA\endvertex
\let\pgfplots@current@point@meta=\pgfplotspatchvertexmeta
\pgfplotsaxisvisphasetransformpointmeta
\pgfplotslibrarysurfstreamcoord{\pgfqpoint\pgfplotspatchvertexx\pgfplotspatchvertexy}{\pgfplotspointmetatransformed}%
\pgfplotslibrarysurfstreamcoord{\expandafter\pgfplotspointpatchvertex\P@BA\endvertex}{\pgfplotspointmetatransformed}%
\pgfplotslibrarysurfstreamcoord{\expandafter\pgfplotspointpatchvertex\P@CA\endvertex}{\pgfplotspointmetatransformed}%
\expandafter\pgfplotspatchvertex\P@DA\endvertex
\let\pgfplots@current@point@meta=\pgfplotspatchvertexmeta
\pgfplotsaxisvisphasetransformpointmeta
\pgfplotslibrarysurfstreamcoord{\pgfqpoint\pgfplotspatchvertexx\pgfplotspatchvertexy}{\pgfplotspointmetatransformed}%
%
\pgfplotslibrarysurfstreamcoord{\expandafter\pgfplotspointpatchvertex\P@DB\endvertex}{\pgfplotspointmetatransformed}%
\pgfplotslibrarysurfstreamcoord{\expandafter\pgfplotspointpatchvertex\P@DC\endvertex}{\pgfplotspointmetatransformed}%
\expandafter\pgfplotspatchvertex\P@DD\endvertex
\let\pgfplots@current@point@meta=\pgfplotspatchvertexmeta
\pgfplotsaxisvisphasetransformpointmeta
\pgfplotslibrarysurfstreamcoord{\pgfqpoint\pgfplotspatchvertexx\pgfplotspatchvertexy}{\pgfplotspointmetatransformed}%
%
\pgfplotslibrarysurfstreamcoord{\expandafter\pgfplotspointpatchvertex\P@CD\endvertex}{\pgfplotspointmetatransformed}%
\pgfplotslibrarysurfstreamcoord{\expandafter\pgfplotspointpatchvertex\P@BD\endvertex}{\pgfplotspointmetatransformed}%
\expandafter\pgfplotspatchvertex\P@AD\endvertex
\let\pgfplots@current@point@meta=\pgfplotspatchvertexmeta
\pgfplotsaxisvisphasetransformpointmeta
\pgfplotslibrarysurfstreamcoord{\pgfqpoint\pgfplotspatchvertexx\pgfplotspatchvertexy}{\pgfplotspointmetatransformed}%
%
\pgfplotslibrarysurfstreamcoord{\expandafter\pgfplotspointpatchvertex\P@AC\endvertex}{\pgfplotspointmetatransformed}%
\pgfplotslibrarysurfstreamcoord{\expandafter\pgfplotspointpatchvertex\P@AB\endvertex}{\pgfplotspointmetatransformed}%
%
%
\pgfplotspatchclass{\pgfplotspatchclassname}{get pdf shading type}%
\if 7\pgfplotsretval
\pgfplotslibrarysurfstreamcoord{\expandafter\pgfplotspointpatchvertex\P@BB\endvertex}{\pgfplotspointmetatransformed}%
\pgfplotslibrarysurfstreamcoord{\expandafter\pgfplotspointpatchvertex\P@CB\endvertex}{\pgfplotspointmetatransformed}%
\pgfplotslibrarysurfstreamcoord{\expandafter\pgfplotspointpatchvertex\P@CC\endvertex}{\pgfplotspointmetatransformed}%
\pgfplotslibrarysurfstreamcoord{\expandafter\pgfplotspointpatchvertex\P@BC\endvertex}{\pgfplotspointmetatransformed}%
\else
% assume 'get pdf shading type=6' - it does not contain the
% inner vertices.
\fi
}
\endinput