shaders/trail.fs

   1 layout (location = 0) out vec4 oColour;
   2 in float aAlpha;
   3 uniform vec4 uColour;
   4
   5 #include "motion_vectors_fs.glsl"
   6
   7 void main(){
   8    compute_motion_vectors();
   9
  10    vec2 ssuv = gl_FragCoord.xy;
  11    vec3 vDither = vec3( dot( vec2( 171.0, 231.0 ), ssuv) );
  12    float dither = fract( vDither.g / 71.0 ) - 0.5;
  13
  14    if( aAlpha+dither<0.5 )
  15       discard;
  16
  17    oColour = vec4( uColour.rgb, uColour.a * aAlpha );
  18 }