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

   1 // Implicit uniforms:
   2 // uniform vec2 PREFIX(offset);
   3 // uniform vec2 PREFIX(scale);
   4 //
   5 // uniform vec2 PREFIX(normalized_coords_to_texels);
   6 // uniform vec2 PREFIX(offset_bottomleft);
   7 // uniform vec2 PREFIX(offset_topright);
   8
   9 vec4 FUNCNAME(vec2 tc) {
  10         tc -= PREFIX(offset);
  11         tc *= PREFIX(scale);
  12
  13         vec2 tc_texels = tc * PREFIX(normalized_coords_to_texels);
  14         vec2 coverage_bottomleft = clamp(tc_texels + PREFIX(offset_bottomleft), 0.0f, 1.0f);
  15         vec2 coverage_topright = clamp(PREFIX(offset_topright) - tc_texels, 0.0f, 1.0f);
  16         vec2 coverage_both = coverage_bottomleft * coverage_topright;
  17         float coverage = coverage_both.x * coverage_both.y;
  18
  19         if (coverage <= 0.0f) {
  20                 // Short-circuit in case the underlying function is expensive to call.
  21                 return PREFIX(border_color);
  22         } else {
  23                 return mix(PREFIX(border_color), INPUT(tc), coverage);
  24         }
  25 }