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 uniform vec2 PREFIX(flipped_center);
   6
   7 vec4 FUNCNAME(vec2 tc) {
   8         vec4 x = INPUT(tc);
   9
  10         const float pihalf = 0.5 * 3.14159265358979324;
  11
  12         vec2 normalized_pos = (tc - PREFIX(flipped_center)) * PREFIX(aspect_correction);
  13         float dist = (length(normalized_pos) - PREFIX(inner_radius)) * PREFIX(pihalf_div_radius);
  14         float linear_falloff = clamp(dist, 0.0, pihalf);
  15         float falloff = cos(linear_falloff) * cos(linear_falloff);
  16         x.rgb *= vec3(falloff);
  17
  18         return x;
  19 }