shaders/blit.h

   1 #ifndef SHADER_blit_H
   2 #define SHADER_blit_H
   3 static void shader_blit_link(void);
   4 static void shader_blit_register(void);
   5 static struct vg_shader _shader_blit = {
   6    .name = "blit",
   7    .link = shader_blit_link,
   8    .vs =
   9 {
  10 .static_src =
  11 "layout (location=0) in vec2 a_co;\n"
  12 "out vec2 aUv;\n"
  13 "\n"
  14 "void main()\n"
  15 "{\n"
  16 "   gl_Position = vec4(a_co*2.0-1.0,0.0,1.0);\n"
  17 "   aUv = a_co;\n"
  18 "}\n"
  19 ""},
  20    .fs =
  21 {
  22 .static_src =
  23 "out vec4 FragColor;\n"
  24 "uniform sampler2D uTexMain;\n"
  25 "\n"
  26 "in vec2 aUv;\n"
  27 "\n"
  28 "float kPi = 3.14159265358979;\n"
  29 "\n"
  30 "vec2 fisheye_distort(vec2 xy)\n"
  31 "{\n"
  32 "   float aperture = 1350.0;\n"
  33 "   float apertureHalf = 0.5 * aperture * (kPi / 180.0);\n"
  34 "   float maxFactor = sin(apertureHalf);\n"
  35 "\n"
  36 "   vec2 uv;\n"
  37 "   float d = length(xy);\n"
  38 "   if(d < (2.0-maxFactor))\n"
  39 "   {\n"
  40 "      d = length(xy * maxFactor);\n"
  41 "      float z = sqrt(1.0 - d * d);\n"
  42 "      float r = atan(d, z) / kPi;\n"
  43 "      float phi = atan(xy.y, xy.x);\n"
  44 "\n"
  45 "      uv.x = r * cos(phi) + 0.5;\n"
  46 "      uv.y = r * sin(phi) + 0.5;\n"
  47 "   }\n"
  48 "   else\n"
  49 "   {\n"
  50 "      uv = 0.5*xy + 0.5;\n"
  51 "   }\n"
  52 "   \n"
  53 "   return uv;\n"
  54 "}\n"
  55 "\n"
  56 "\n"
  57 "void main()\n"
  58 "{\n"
  59 "   vec2 vwarp = 2.0*aUv - 1.0;\n"
  60 "   vwarp = fisheye_distort( vwarp );\n"
  61 "\n"
  62 "   FragColor = texture( uTexMain, aUv );\n"
  63 "}\n"
  64 ""},
  65 };
  66
  67 static GLuint _uniform_blit_uTexMain;
  68 static void shader_blit_uTexMain(int i){
  69    glUniform1i(_uniform_blit_uTexMain,i);
  70 }
  71 static void shader_blit_register(void){
  72    vg_shader_register( &_shader_blit );
  73 }
  74 static void shader_blit_use(void){ glUseProgram(_shader_blit.id); }
  75 static void shader_blit_link(void){
  76    _uniform_blit_uTexMain = glGetUniformLocation( _shader_blit.id, "uTexMain" );
  77 }
  78 #endif /* SHADER_blit_H */