shaders/blitblur.fs

   1 out vec4 FragColor;
   2 uniform sampler2D uTexMain;
   3 uniform sampler2D uTexMotion;
   4 uniform float uBlurStrength;
   5 uniform vec2 uOverrideDir;
   6 uniform float uTime;
   7 uniform float uGlitchStrength;
   8
   9 in vec2 aUv;
  10
  11 vec2 rand_hash22( vec2 p ){
  12    vec3 p3 = fract(vec3(p.xyx) * 213.8976123);
  13    p3 += dot(p3, p3.yzx+19.19);
  14    return fract(vec2((p3.x + p3.y)*p3.z, (p3.x+p3.z)*p3.y));
  15 }
  16
  17 const int NOISE_LOOP = 3;
  18 vec3 digital_noise( uvec3 iuv ){
  19    iuv *=uvec3(8,2524,7552);
  20    for( int i=0; i<NOISE_LOOP; i++ )
  21       iuv += (iuv.yzx<<2) ^ (iuv.yxz)+iuv.z;
  22    return vec3(iuv)*(1.0/float(0xffffffffU));
  23 }
  24
  25 void main(){
  26    vec2 vuv = aUv;
  27
  28    if( uGlitchStrength > 0.0 ){
  29       uvec3 p = uvec3( gl_FragCoord.xy, uint(uTime*30.0) );
  30       vec2 g = digital_noise(p).xy;
  31       vuv = aUv + g.xy*uGlitchStrength - uGlitchStrength*0.5;
  32    }
  33
  34    vec2 vrand = rand_hash22( vuv ) * 2.0 - vec2(1.0);
  35    vec2 vrand1 = rand_hash22( vrand ) * 2.0 - vec2(1.0);
  36
  37    vec2 vdir = texture( uTexMotion, vuv ).xy * uBlurStrength + uOverrideDir;
  38
  39    vec4 vcolour0 = texture( uTexMain, vuv + vdir*vrand.x );
  40    vec4 vcolour1 = texture( uTexMain, vuv + vdir*vrand.y );
  41    vec4 vcolour2 = texture( uTexMain, vuv + vdir*vrand1.x );
  42    vec4 vcolour3 = texture( uTexMain, vuv + vdir*vrand1.y );
  43
  44    FragColor = ( vcolour0 + vcolour1 + vcolour2 + vcolour3 ) * 0.25;
  45 }