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diff --git a/Master/texmf-dist/doc/generic/pst-solides3d/doc-src/par-eclairageponctuel-en.tex b/Master/texmf-dist/doc/generic/pst-solides3d/doc-src/par-eclairageponctuel-en.tex new file mode 100644 index 00000000000..4b73bbad211 --- /dev/null +++ b/Master/texmf-dist/doc/generic/pst-solides3d/doc-src/par-eclairageponctuel-en.tex @@ -0,0 +1,144 @@ +\newpage +\section{Lighting by a point light source} + +Two parameters, the first one positions the \Index{light source}, the second one sets the \Index{light intensity}: +\begin{itemize} + \item \Lkeyword{lightsrc}=20 30 50 in Cartesian coordinates, or +\texttt{\Lkeyword{lightsrc}=\Lkeyval{viewpoint}} to put the light source at the view point. + \item \texttt{\Lkeyword{lightintensity}=2} (default value). +\end{itemize} +\begin{center} +\newcommand\LIGHTSRC[3]{% +\pstVerb{ + /xLIGHTSRC #1 def + /yLIGHTSRC #2 def + /zLIGHTSRC #3 def + /RADIUS 4 def + /THETA yLIGHTSRC xLIGHTSRC atan def + /DISTANCE xLIGHTSRC dup mul yLIGHTSRC dup mul add zLIGHTSRC dup mul add sqrt def + /PHI zLIGHTSRC DISTANCE div arcsin def + /ALPHA RADIUS DISTANCE div arccos def + /OH ALPHA cos RADIUS mul def + /radius_cone ALPHA sin RADIUS mul def + /Hauteur_cone DISTANCE OH sub def + /X_C xLIGHTSRC OH mul DISTANCE div def + /Y_C yLIGHTSRC OH mul DISTANCE div def + /Z_C zLIGHTSRC OH mul DISTANCE div def + /rotX_axe_cone PHI 90 sub def + /rotZ_axe_cone THETA 90 sub def + } +\psset{Decran=50,viewpoint=50 10 15} +\psSolid[object=sphere,r=RADIUS,fillcolor=blue,ngrid=18 36, + lightsrc=xLIGHTSRC yLIGHTSRC zLIGHTSRC](0,0,0) +\psPoint(xLIGHTSRC,yLIGHTSRC,zLIGHTSRC){LS} +\psset{lightsrc=} +\psSolid[object=cone,r=radius_cone,h=Hauteur_cone,fillcolor=yellow!50, + ngrid=1 36,RotX=rotX_axe_cone,RotZ=rotZ_axe_cone,opacity=0.5, + linecolor=yellow](X_C,Y_C,Z_C) +\psdot(LS)} + +\begin{pspicture}(-2,-2.5)(5,5) +\psset{unit=0.5} +\LIGHTSRC{0}{8}{8} +\uput[45](LS){Light Source} +\axesIIID(4,4,4)(6,6,6) +\end{pspicture} +\begin{pspicture}(-4,-2.5)(5,2.5) +\psset{unit=0.5} +\LIGHTSRC{2}{-5}{0} +\uput[l](LS){Light Source} +\axesIIID(4,4,4)(6,6,6) +\end{pspicture} + +\begin{pspicture}(-1,-2.5)(9,2.5) +\psset{unit=0.5} +\LIGHTSRC{0}{20}{0} +\uput[r](LS){Light Source} +\axesIIID(4,4,4)(6,6,6) +\end{pspicture} +\end{center} + +As you can see, the intersecting \Index{plane} (section of the sphere with the cone of +\Index{light}) divides the object into two half spaces: the first half space +(the one on the side of the \Index{light source}) is illuminated and the other half space is the shadow region referring to this light source position. + +Now it is clear, that if the view point is setup with the same coordiates as the light source, the object is illuminated uniquely. + +\encadre{In order to get some shadow regions to appear in the graphic---which emphasises the 3D character---we would suggest choosing the light source and the view point differently.} + +\newpage +Here follow a few examples: + +\begin{pspicture}(-3,-2)(3,3) +\psset{unit=0.3} +\psset{Decran=1e3, + viewpoint=500 0 1000, + lightsrc=10 20 30,mode=3} +\psSolid[object=sphere,r=5,fillcolor=blue](0,0,8) +\rput(0,-3.5){\texttt{lightsrc=10 20 30}} +\end{pspicture} +\begin{pspicture}(-3,-2)(3,3) +\psset{unit=0.3} +\psset{Decran=1e3, + viewpoint=500 0 1000, + lightsrc=-10 -20 30,mode=3} +\psSolid[object=sphere,r=5,fillcolor=blue](0,0,8) +\rput(0,-3.5){\texttt{lightsrc=-10 -20 30}} +\end{pspicture} +\begin{pspicture}(-3,-2)(3,3) +\psset{unit=0.3} +\psset{Decran=1e3, + viewpoint=500 0 1000, + lightsrc=30 -20 30,mode=3} +\psSolid[object=sphere,r=5,fillcolor=blue](0,0,8) +\rput(0,-3.5){\texttt{lightsrc=30 -20 30}} +\end{pspicture} + +When the option \verb+[lightsrc=value1 value2 value3]+ +is not specified, the object is uniformly illuminated. + +\begin{center} + \begin{pspicture}(-6,-2)(6,2) +%\psframe(-6,-4)(6,4) +\psset{viewpoint=50 50 30 rtp2xyz,Decran=40,unit=0.6} +\psSolid[object=datfile,file=./tore1836,deactivatecolor] + %\psSolid[r1=3.5,r0=1,object=tore,ngrid=18 36,fillcolor={[rgb]{.372 .62 .628}}]% + \axesIIID(0,4.5,0)(6,6,4) + \end{pspicture} +\end{center} + + + +Here are some examples, where we always keep the same object, the same view point, the same light +source coordinates and just vary the \Lkeyword{lightintensity} value: + +\begin{pspicture}(-3,-2)(3,3) +\psset{unit=0.3} +\psset{Decran=1e3, + viewpoint=500 0 1000, + lightsrc=-10 -20 30,mode=4,lightintensity=1} +\psSolid[object=sphere,r=5,fillcolor=green](0,0,8) +\rput(0,-3.5){\texttt{lightintensity=2}} +\end{pspicture} +\begin{pspicture}(-3,-2)(3,3) +\psset{unit=0.3} +\psset{Decran=1e3, + viewpoint=500 0 1000, + lightsrc=-10 -20 30,mode=4,lightintensity=3} +\psSolid[object=sphere,r=5,fillcolor=green](0,0,8) +\rput(0,-3.5){\texttt{lightintensity=3}} +\end{pspicture} +\begin{pspicture}(-3,-2)(3,3) +\psset{unit=0.3} +\psset{Decran=1e3, + viewpoint=500 0 1000, + lightsrc=-10 -20 30,mode=4,lightintensity=8} +\psSolid[object=sphere,r=5,fillcolor=green](0,0,8) +\rput(0,-3.5){\texttt{lightintensity=8}} +\end{pspicture} + +Here we can see, that by increasing the \Lkeyword{lightintensity} value, the shading nuances of the solid are decreasing. + + + +\endinput |