shaders/blit.fs

   1 out vec4 FragColor;
   2 uniform sampler2D uTexMain;
   3
   4 in vec2 aUv;
   5
   6 float kPi = 3.14159265358979;
   7
   8 vec2 fisheye_distort(vec2 xy)
   9 {
  10    float aperture = 1350.0;
  11    float apertureHalf = 0.5 * aperture * (kPi / 180.0);
  12    float maxFactor = sin(apertureHalf);
  13
  14    vec2 uv;
  15    float d = length(xy);
  16    if(d < (2.0-maxFactor))
  17    {
  18       d = length(xy * maxFactor);
  19       float z = sqrt(1.0 - d * d);
  20       float r = atan(d, z) / kPi;
  21       float phi = atan(xy.y, xy.x);
  22
  23       uv.x = r * cos(phi) + 0.5;
  24       uv.y = r * sin(phi) + 0.5;
  25    }
  26    else
  27    {
  28       uv = 0.5*xy + 0.5;
  29    }
  30
  31    return uv;
  32 }
  33
  34
  35 void main()
  36 {
  37    vec2 vwarp = 2.0*aUv - 1.0;
  38    vwarp = fisheye_distort( vwarp );
  39
  40    FragColor = texture( uTexMain, aUv );
  41 }