1 uniform vec2 PREFIX(offset);
2 uniform vec2 PREFIX(scale);
4 uniform vec2 PREFIX(normalized_coords_to_texels);
5 uniform vec2 PREFIX(offset_bottomleft);
6 uniform vec2 PREFIX(offset_topright);
8 vec4 FUNCNAME(vec2 tc) {
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;
18 if (coverage <= 0.0f) {
19 // Short-circuit in case the underlying function is expensive to call.
20 return PREFIX(border_color);
22 return mix(PREFIX(border_color), INPUT(tc), coverage);