git.sesse.net Git - movit/blob - vignette_effect.frag

   1 // A simple, circular vignette, with a cos² falloff.
   2
   3 uniform float PREFIX(pihalf_div_radius);
   4 uniform vec2 PREFIX(aspect_correction);
   5
   6 vec4 FUNCNAME(vec2 tc) {
   7         vec4 x = INPUT(tc);
   8
   9         const float pihalf = 0.5 * 3.14159265358979324;
  10
  11         vec2 normalized_pos = (tc - PREFIX(center)) * PREFIX(aspect_correction);
  12         float dist = (length(normalized_pos) - PREFIX(inner_radius)) * PREFIX(pihalf_div_radius);
  13         float linear_falloff = clamp(dist, 0.0, pihalf);
  14         float falloff = cos(linear_falloff) * cos(linear_falloff);
  15         x.rgb *= vec3(falloff);
  16
  17         return x;
  18 }