-uniform vec4 PREFIX(samples)[(R + 1) * (R + 1)];
+// Implicit uniforms:
+// uniform vec4 PREFIX(samples)[(R + 1) * (R + 1)];
vec4 FUNCNAME(vec2 tc) {
// The full matrix has five different symmetry cases, that look like this:
//
- // D * * C * * D
- // * D * C * D *
- // * * D C D * *
+ // D D D C D D D
+ // D D D C D D D
+ // D D D C D D D
// B B B A B B B
- // * * D C D * *
- // * D * C * D *
- // D * * C * * D
+ // D D D C D D D
+ // D D D C D D D
+ // D D D C D D D
//
// We only store the lower-right part of the matrix:
//
- // A B B
- // C D *
- // C * D
+ // A B B B
+ // C D D D
+ // C D D D
+ // C D D D
// Case A: Top-left sample has no symmetry.
vec4 sum = PREFIX(samples)[0].z * INPUT(tc);
sum += sample.z * (INPUT(tc - sample.xy) + INPUT(tc + sample.xy));
}
- // Case D: Diagonal samples have four-way symmetry.
- for (int xy = 1; xy <= R; ++xy) {
- vec4 sample = PREFIX(samples)[xy * (R + 1) + xy];
-
- vec4 local_sum = INPUT(tc - sample.xy) + INPUT(tc + sample.xy);
- sample.y = -sample.y;
- local_sum += INPUT(tc - sample.xy) + INPUT(tc + sample.xy);
-
- sum += sample.z * local_sum;
- }
-
- // Case *: All other samples have eight-way symmetry.
+ // Case D: All other samples have four-way symmetry.
+ // (Actually we have eight-way, but since we are using normalized
+ // coordinates, we can't just flip x and y.)
for (int y = 1; y <= R; ++y) {
- for (int x = y + 1; x <= R; ++x) {
+ for (int x = 1; x <= R; ++x) {
vec4 sample = PREFIX(samples)[y * (R + 1) + x];
vec2 mirror_sample = vec2(sample.x, -sample.y);
vec4 local_sum = INPUT(tc - sample.xy) + INPUT(tc + sample.xy);
local_sum += INPUT(tc - mirror_sample.xy) + INPUT(tc + mirror_sample.xy);
-
- sample.xy = sample.yx;
- mirror_sample.xy = mirror_sample.yx;
-
- local_sum += INPUT(tc - sample.xy) + INPUT(tc + sample.xy);
- local_sum += INPUT(tc - mirror_sample.xy) + INPUT(tc + mirror_sample.xy);
-
sum += sample.z * local_sum;
}
}
return sum;
}
+
+#undef R