Quartz Composer / GLSL Shader / BokehなFragment Shaderを生成するコード

参考

THE ART-LOG OF MARTINS UPITIS: a GLSL depth of field filter with bokeh

GLSL depth of field with bokeh v2.4 (update)

コード
参考のコード他をよくわからないまま弄くり回していました．
とりあえずサンプリングする点を求めるのにコードにしたのでそれをメモしておきます．

#include <stdio.h>
#include <stdlib.h>
double *cross(double *p, double *q) {
 double *r;
 r= (double *)malloc(3*sizeof(double));
 r[0]= p[1]*q[2]-p[2]*q[1];
 r[1]=-p[0]*q[2]+p[2]*q[0];
 r[2]= p[0]*q[1]-p[1]*q[0];
 return r;
}
double *sub(double *p, double *q) {
 double *r;
 r= (double *)malloc(3*sizeof(double));
 r[0]= p[0]-q[0];
 r[1]= p[1]-q[1];
 r[2]= p[2]-q[2];
 return r;
}
int isinCircle(double *q) {
 return (q[0]*q[0]+q[1]*q[1]<0.25)?1:0;
}
int isin6(double *q)
{
 double p[6][3]= {
     { 0.0, 0.50, 0.},
     { 0.5, 0.25, 0.},
     { 0.5,-0.25, 0.},
     { 0.0,-0.50, 0.},
     {-0.5,-0.25, 0.},
     {-0.5, 0.25, 0.}};
 double *r;
 int i, c= 0;

 for(i= 0; i<5; i++) {
  r= cross(sub(p[i], q), sub(p[i+1], q)); 
  c+= r[2]<0?0:1;
 }
 r= cross(sub(p[5], q), sub(p[0], q)); 
 c+= r[2]<0?0:1;

 return (c==0)?1:0;
}
int main(int argc, char* argv[]) {

 double q[3]= {0., 0., 0.};
 int j,k,c= 0;
 int r= 5;
 
 printf("uniform sampler2D RenderedTexture;\nuniform sampler2D DepthTexture;\n");
 printf("const float blurclamp = 1.;\nconst float bias = 10.;\nuniform float focus;\n");
 printf("uniform float pixelsWide;\nuniform float pixelsHigh;\n");
 printf("vec2 texcel = vec2(1./pixelsWide, 1./pixelsHigh);\n");
 printf("void main()\n{\n");
 printf("\tvec4 depth = texture2D(DepthTexture,gl_TexCoord[0].xy );\n");
 printf("\tfloat factor = ( depth.x - focus );\n");
 printf("\tvec2 dofblur = vec2 (clamp( factor * bias, -blurclamp, blurclamp ));\n");
 printf("\tvec4 col = vec4(0.0);\n");
 
 for(k= -r; k<r; k++) {
  for(j= -r; j<r; j++) {
   q[0]= k/(r*2.);
   q[1]= j/(r*2.);
   if (isin6(q)==1) {
    if (0) {
     printf("\tcol += texture2D(RenderedTexture, gl_TexCoord[0].xy + (vec2(");
     printf("%2d., %2d.", k, j);
     printf(")*texcel) * dofblur);\n");
    }
    else {
     printf("\tcol.r += texture2D(RenderedTexture, gl_TexCoord[0].xy + (vec2(");
     printf("%2d., %2d.", k, j);
     printf(")*texcel) * dofblur*vec2( .000, .50)).r;\n");
     printf("\tcol.g += texture2D(RenderedTexture, gl_TexCoord[0].xy + (vec2(");
     printf("%2d., %2d.", k, j);
     printf(")*texcel) * dofblur*vec2( .866,-.25)).g;\n");
     printf("\tcol.b += texture2D(RenderedTexture, gl_TexCoord[0].xy + (vec2(");
     printf("%2d., %2d.", k, j);
     printf(")*texcel) * dofblur*vec2(-.866,-.25)).b;\n");
    }
    c++;
   }
  }
 }
 
 printf("\tgl_FragColor = col/%d.;\n\tgl_FragColor.a = 1.0;\n}\n", c);
 return 0;
}

結果
こんな感じ．