- float offset, total_weight;
- combine_two_samples(w1, w2, &offset, &total_weight);
+ float offset, total_weight, sum_sq_error;
+ combine_two_samples(w1, w2, &offset, &total_weight, &sum_sq_error);
+
+ // If the interpolation error is larger than that of about sqrt(2) of
+ // a level at 8-bit precision, don't combine. (You'd think 1.0 was enough,
+ // but since the artifacts are not really random, they can get quite
+ // visible. On the other hand, going to 0.25f, I can see no change at
+ // all with 8-bit output, so it would not seem to be worth it.)
+ if (sum_sq_error > 0.5f / (256.0f * 256.0f)) {
+ continue;
+ }