lavfi/lut3d: faster tetrahedral interpolation.

Increase performance by fetching only the necessary points.

1097 → 917 decicyles.

libavfilter/vf_lut3d.c

@@ -144,38 +144,44 @@ static inline struct rgbvec interp_tetrahedral(const LUT3DContext *lut3d,
     const int next[] = {NEXT(s->r), NEXT(s->g), NEXT(s->b)};
     const struct rgbvec d = {s->r - prev[0], s->g - prev[1], s->b - prev[2]};
     const struct rgbvec c000 = lut3d->lut[prev[0]][prev[1]][prev[2]];
-    const struct rgbvec c001 = lut3d->lut[prev[0]][prev[1]][next[2]];
-    const struct rgbvec c010 = lut3d->lut[prev[0]][next[1]][prev[2]];
-    const struct rgbvec c011 = lut3d->lut[prev[0]][next[1]][next[2]];
-    const struct rgbvec c100 = lut3d->lut[next[0]][prev[1]][prev[2]];
-    const struct rgbvec c101 = lut3d->lut[next[0]][prev[1]][next[2]];
-    const struct rgbvec c110 = lut3d->lut[next[0]][next[1]][prev[2]];
     const struct rgbvec c111 = lut3d->lut[next[0]][next[1]][next[2]];
     struct rgbvec c;
     if (d.r > d.g) {
         if (d.g > d.b) {
+            const struct rgbvec c100 = lut3d->lut[next[0]][prev[1]][prev[2]];
+            const struct rgbvec c110 = lut3d->lut[next[0]][next[1]][prev[2]];
             c.r = (1-d.r) * c000.r + (d.r-d.g) * c100.r + (d.g-d.b) * c110.r + (d.b) * c111.r;
             c.g = (1-d.r) * c000.g + (d.r-d.g) * c100.g + (d.g-d.b) * c110.g + (d.b) * c111.g;
             c.b = (1-d.r) * c000.b + (d.r-d.g) * c100.b + (d.g-d.b) * c110.b + (d.b) * c111.b;
         } else if (d.r > d.b) {
+            const struct rgbvec c100 = lut3d->lut[next[0]][prev[1]][prev[2]];
+            const struct rgbvec c101 = lut3d->lut[next[0]][prev[1]][next[2]];
             c.r = (1-d.r) * c000.r + (d.r-d.b) * c100.r + (d.b-d.g) * c101.r + (d.g) * c111.r;
             c.g = (1-d.r) * c000.g + (d.r-d.b) * c100.g + (d.b-d.g) * c101.g + (d.g) * c111.g;
             c.b = (1-d.r) * c000.b + (d.r-d.b) * c100.b + (d.b-d.g) * c101.b + (d.g) * c111.b;
         } else {
+            const struct rgbvec c001 = lut3d->lut[prev[0]][prev[1]][next[2]];
+            const struct rgbvec c101 = lut3d->lut[next[0]][prev[1]][next[2]];
             c.r = (1-d.b) * c000.r + (d.b-d.r) * c001.r + (d.r-d.g) * c101.r + (d.g) * c111.r;
             c.g = (1-d.b) * c000.g + (d.b-d.r) * c001.g + (d.r-d.g) * c101.g + (d.g) * c111.g;
             c.b = (1-d.b) * c000.b + (d.b-d.r) * c001.b + (d.r-d.g) * c101.b + (d.g) * c111.b;
         }
     } else {
         if (d.b > d.g) {
+            const struct rgbvec c001 = lut3d->lut[prev[0]][prev[1]][next[2]];
+            const struct rgbvec c011 = lut3d->lut[prev[0]][next[1]][next[2]];
             c.r = (1-d.b) * c000.r + (d.b-d.g) * c001.r + (d.g-d.r) * c011.r + (d.r) * c111.r;
             c.g = (1-d.b) * c000.g + (d.b-d.g) * c001.g + (d.g-d.r) * c011.g + (d.r) * c111.g;
             c.b = (1-d.b) * c000.b + (d.b-d.g) * c001.b + (d.g-d.r) * c011.b + (d.r) * c111.b;
         } else if (d.b > d.r) {
+            const struct rgbvec c010 = lut3d->lut[prev[0]][next[1]][prev[2]];
+            const struct rgbvec c011 = lut3d->lut[prev[0]][next[1]][next[2]];
             c.r = (1-d.g) * c000.r + (d.g-d.b) * c010.r + (d.b-d.r) * c011.r + (d.r) * c111.r;
             c.g = (1-d.g) * c000.g + (d.g-d.b) * c010.g + (d.b-d.r) * c011.g + (d.r) * c111.g;
             c.b = (1-d.g) * c000.b + (d.g-d.b) * c010.b + (d.b-d.r) * c011.b + (d.r) * c111.b;
         } else {
+            const struct rgbvec c010 = lut3d->lut[prev[0]][next[1]][prev[2]];
+            const struct rgbvec c110 = lut3d->lut[next[0]][next[1]][prev[2]];
             c.r = (1-d.g) * c000.r + (d.g-d.r) * c010.r + (d.r-d.b) * c110.r + (d.b) * c111.r;
             c.g = (1-d.g) * c000.g + (d.g-d.r) * c010.g + (d.r-d.b) * c110.g + (d.b) * c111.g;
             c.b = (1-d.g) * c000.b + (d.g-d.r) * c010.b + (d.r-d.b) * c110.b + (d.b) * c111.b;