When combining samples, take fp16 rounding into account.

[movit] / blur_effect.cpp

diff --git a/blur_effect.cpp b/blur_effect.cpp
index 027d25b1113ef83e37f472e5dc561b95251a5484..6e5e843d5ce21b2608b4232716021472e1c65574 100644 (file)
--- a/blur_effect.cpp
+++ b/blur_effect.cpp
@@ -187,18 +187,21 @@ void SingleBlurPassEffect::set_gl_state(GLuint glsl_program_num, const string &p
                unsigned base_pos = i * 2 - 1;
                float w1 = weight[base_pos];
                float w2 = weight[base_pos + 1];
-
-               float offset, total_weight;
-               combine_two_samples(w1, w2, &offset, &total_weight, NULL);
-
+               int size;
                if (direction == HORIZONTAL) {
-                       samples[2 * i + 0] = (base_pos + offset) / (float)width;
+                       size = width;
                } else if (direction == VERTICAL) {
-                       samples[2 * i + 0] = (base_pos + offset) / (float)height;
+                       size = height;
                } else {
                        assert(false);
                }
 
+               float pos1 = base_pos / (float)size;
+               float pos2 = (base_pos + 1) / (float)size;
+               float pos, total_weight;
+               combine_two_samples(w1, w2, pos1, pos2, size, COMBINE_DO_NOT_ROUND, &pos, &total_weight, NULL);
+
+               samples[2 * i + 0] = pos;
                samples[2 * i + 1] = total_weight;
        }