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

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