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

   1 // A simple, circular vignette, with a cos² falloff.
   2
   3 // Implicit uniforms:
   4 // uniform float PREFIX(pihalf_div_radius);
   5 //
   6 // uniform vec2 PREFIX(aspect_correction);
   7 // uniform vec2 PREFIX(flipped_center);
   8
   9 vec4 FUNCNAME(vec2 tc) {
  10         vec4 x = INPUT(tc);
  11
  12         const float pihalf = 0.5 * 3.14159265358979324;
  13
  14         vec2 normalized_pos = (tc - PREFIX(flipped_center)) * PREFIX(aspect_correction);
  15         float dist = (length(normalized_pos) - PREFIX(inner_radius)) * PREFIX(pihalf_div_radius);
  16         float linear_falloff = clamp(dist, 0.0, pihalf);
  17         float falloff = cos(linear_falloff) * cos(linear_falloff);
  18         x.rgb *= vec3(falloff);
  19
  20         return x;
  21 }