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 .orig_file = "../shaders/blit.vs",
  11 .static_src =
  12 "layout (location=0) in vec2 a_co;\n"
  13 "out vec2 aUv;\n"
  14 "\n"
  15 "void main()\n"
  16 "{\n"
  17 "   gl_Position = vec4(a_co*2.0-1.0,0.0,1.0);\n"
  18 "   aUv = a_co;\n"
  19 "}\n"
  20 ""},
  21    .fs =
  22 {
  23 .orig_file = "../shaders/blit.fs",
  24 .static_src =
  25 "out vec4 FragColor;\n"
  26 "uniform sampler2D uTexMain;\n"
  27 "\n"
  28 "in vec2 aUv;\n"
  29 "\n"
  30 "float kPi = 3.14159265358979;\n"
  31 "\n"
  32 "vec2 fisheye_distort(vec2 xy)\n"
  33 "{\n"
  34 "   float aperture = 1350.0;\n"
  35 "   float apertureHalf = 0.5 * aperture * (kPi / 180.0);\n"
  36 "   float maxFactor = sin(apertureHalf);\n"
  37 "\n"
  38 "   vec2 uv;\n"
  39 "   float d = length(xy);\n"
  40 "   if(d < (2.0-maxFactor))\n"
  41 "   {\n"
  42 "      d = length(xy * maxFactor);\n"
  43 "      float z = sqrt(1.0 - d * d);\n"
  44 "      float r = atan(d, z) / kPi;\n"
  45 "      float phi = atan(xy.y, xy.x);\n"
  46 "\n"
  47 "      uv.x = r * cos(phi) + 0.5;\n"
  48 "      uv.y = r * sin(phi) + 0.5;\n"
  49 "   }\n"
  50 "   else\n"
  51 "   {\n"
  52 "      uv = 0.5*xy + 0.5;\n"
  53 "   }\n"
  54 "   \n"
  55 "   return uv;\n"
  56 "}\n"
  57 "\n"
  58 "\n"
  59 "void main()\n"
  60 "{\n"
  61 "   vec2 vwarp = 2.0*aUv - 1.0;\n"
  62 "   vwarp = fisheye_distort( vwarp );\n"
  63 "\n"
  64 "   FragColor = texture( uTexMain, aUv );\n"
  65 "}\n"
  66 ""},
  67 };
  68
  69 static GLuint _uniform_blit_uTexMain;
  70 static void shader_blit_uTexMain(int i){
  71    glUniform1i( _uniform_blit_uTexMain, i );
  72 }
  73 static void shader_blit_register(void){
  74    vg_shader_register( &_shader_blit );
  75 }
  76 static void shader_blit_use(void){ glUseProgram(_shader_blit.id); }
  77 static void shader_blit_link(void){
  78    _uniform_blit_uTexMain = glGetUniformLocation( _shader_blit.id, "uTexMain" );
  79 }
  80 #endif /* SHADER_blit_H */