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

   1 // A simple, circular vignette, with a cos² falloff.
   2
   3 uniform float PREFIX(inv_radius);
   4 varying vec2 PREFIX(normalized_pos);
   5
   6 vec4 FUNCNAME(vec2 tc) {
   7         vec4 x = LAST_INPUT(tc);
   8
   9         const float pihalf = 0.5 * 3.14159265358979324;
  10
  11         float dist = (length(PREFIX(normalized_pos)) - PREFIX(inner_radius)) * PREFIX(inv_radius);
  12         float linear_falloff = clamp(dist, 0.0, 1.0) * pihalf;
  13         float falloff = cos(linear_falloff) * cos(linear_falloff);
  14         x.rgb *= vec3(falloff);
  15
  16         return x;
  17 }