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/*****
* bezierpatch.h
* Authors: John C. Bowman and Jesse Frohlich
*
* Render Bezier patches and triangles.
*****/
#ifndef BEZIERPATCH_H
#define BEZIERPATCH_H
#include "drawelement.h"
namespace camp {
#ifdef HAVE_GL
extern const double Fuzz4;
struct BezierPatch
{
vertexBuffer data;
bool transparent;
bool color;
double epsilon;
double Epsilon;
double res2;
double Res2; // Reduced resolution for Bezier triangles flatness test.
typedef GLuint (vertexBuffer::*vertexFunction)(const triple &v,
const triple& n);
vertexFunction pvertex;
bool Onscreen;
void init(double res);
triple normal(triple left3, triple left2, triple left1, triple middle,
triple right1, triple right2, triple right3) {
triple rp=right1-middle;
triple lp=left1-middle;
triple n=triple(rp.gety()*lp.getz()-rp.getz()*lp.gety(),
rp.getz()*lp.getx()-rp.getx()*lp.getz(),
rp.getx()*lp.gety()-rp.gety()*lp.getx());
if(abs2(n) > epsilon)
return unit(n);
triple lpp=bezierPP(middle,left1,left2);
triple rpp=bezierPP(middle,right1,right2);
n=cross(rpp,lp)+cross(rp,lpp);
if(abs2(n) > epsilon)
return unit(n);
triple lppp=bezierPPP(middle,left1,left2,left3);
triple rppp=bezierPPP(middle,right1,right2,right3);
return unit(9.0*cross(rpp,lpp)+
3.0*(cross(rp,lppp)+cross(rppp,lp)+
cross(rppp,lpp)+cross(rpp,lppp))+
cross(rppp,lppp));
}
triple derivative(triple p0, triple p1, triple p2, triple p3) {
triple lp=p1-p0;
if(abs2(lp) > epsilon)
return lp;
triple lpp=bezierPP(p0,p1,p2);
if(abs2(lpp) > epsilon)
return lpp;
return bezierPPP(p0,p1,p2,p3);
}
virtual double Distance(const triple *p) {
triple p0=p[0];
triple p3=p[3];
triple p12=p[12];
triple p15=p[15];
// Check the flatness of a Bezier patch.
double d=Distance2(p15,p0,normal(p3,p[2],p[1],p0,p[4],p[8],p12));
// Determine how straight the edges are.
d=max(d,Straightness(p0,p[1],p[2],p3));
d=max(d,Straightness(p0,p[4],p[8],p12));
d=max(d,Straightness(p3,p[7],p[11],p15));
d=max(d,Straightness(p12,p[13],p[14],p15));
// Determine how straight the interior control curves are.
d=max(d,Straightness(p[4],p[5],p[6],p[7]));
d=max(d,Straightness(p[8],p[9],p[10],p[11]));
d=max(d,Straightness(p[1],p[5],p[9],p[13]));
return max(d,Straightness(p[2],p[6],p[10],p[14]));
}
struct Split3 {
triple m0,m2,m3,m4,m5;
Split3() {}
Split3(triple z0, triple c0, triple c1, triple z1) {
m0=0.5*(z0+c0);
triple m1=0.5*(c0+c1);
m2=0.5*(c1+z1);
m3=0.5*(m0+m1);
m4=0.5*(m1+m2);
m5=0.5*(m3+m4);
}
};
// Approximate bounds by bounding box of control polyhedron.
bool offscreen(size_t n, const triple *v) {
if(bbox2(n,v).offscreen()) {
Onscreen=false;
return true;
}
return false;
}
virtual void render(const triple *p, bool straight, GLfloat *c0=NULL);
void render(const triple *p,
GLuint I0, GLuint I1, GLuint I2, GLuint I3,
triple P0, triple P1, triple P2, triple P3,
bool flat0, bool flat1, bool flat2, bool flat3,
GLfloat *C0=NULL, GLfloat *C1=NULL, GLfloat *C2=NULL,
GLfloat *C3=NULL);
void append() {
if(transparent)
transparentData.Append(data);
else {
if(color)
colorData.Append(data);
else
materialData.append(data);
}
}
void queue(const triple *g, bool straight, double ratio, bool Transparent,
GLfloat *colors=NULL) {
data.clear();
Onscreen=true;
transparent=Transparent;
color=colors;
init(pixel*ratio);
render(g,straight,colors);
}
};
struct BezierTriangle : public BezierPatch {
public:
BezierTriangle() : BezierPatch() {}
double Distance(const triple *p) {
triple p0=p[0];
triple p6=p[6];
triple p9=p[9];
// Check how far the internal point is from the centroid of the vertices.
double d=abs2((p0+p6+p9)*third-p[4]);
// Determine how straight the edges are.
d=max(d,Straightness(p0,p[1],p[3],p6));
d=max(d,Straightness(p0,p[2],p[5],p9));
return max(d,Straightness(p6,p[7],p[8],p9));
}
void render(const triple *p, bool straight, GLfloat *c0=NULL);
void render(const triple *p,
GLuint I0, GLuint I1, GLuint I2,
triple P0, triple P1, triple P2,
bool flat0, bool flat1, bool flat2,
GLfloat *C0=NULL, GLfloat *C1=NULL, GLfloat *C2=NULL);
};
struct Triangles : public BezierPatch {
public:
Triangles() : BezierPatch() {}
void queue(size_t nP, const triple* P, size_t nN, const triple* N,
size_t nC, const prc::RGBAColour* C, size_t nI,
const uint32_t (*PI)[3], const uint32_t (*NI)[3],
const uint32_t (*CI)[3], bool transparent);
void append() {
if(transparent)
transparentData.Append(data);
else
triangleData.Append(data);
}
};
extern void sortTriangles();
#endif
} //namespace camp
#endif
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