Remove some unneeded conversions from ResampleEffect. Speeds up texture generation...

[movit] / resample_effect.cpp

diff --git a/resample_effect.cpp b/resample_effect.cpp
index 9b6d5f3d4d964168d0a4a0f191e8552b1f54217d..ba8a71c0241443c0730a5ce99d68a2fa7c014ad3 100644 (file)
--- a/resample_effect.cpp
+++ b/resample_effect.cpp
@@ -1,7 +1,7 @@
 // Three-lobed Lanczos, the most common choice.
 // Note that if you change this, the accuracy for LANCZOS_TABLE_SIZE
 // needs to be recomputed.
-#define LANCZOS_RADIUS 3.0
+#define LANCZOS_RADIUS 3.0f
 
 #include <epoxy/gl.h>
 #include <assert.h>
@@ -90,7 +90,7 @@ float lanczos_weight_cached(float x)
                return 0.0f;
        }
        float table_pos = x * (LANCZOS_TABLE_SIZE / LANCZOS_RADIUS);
-       int table_pos_int = int(table_pos);  // Truncate towards zero.
+       unsigned table_pos_int = int(table_pos);  // Truncate towards zero.
        float table_pos_frac = table_pos - table_pos_int;
        assert(table_pos < LANCZOS_TABLE_SIZE + 2);
        return lanczos_table[table_pos_int] +
@@ -249,10 +249,10 @@ double compute_sum_sq_error(const Tap<float>* weights, unsigned num_weights,
        // Find the effective range of the bilinear-optimized kernel.
        // Due to rounding of the positions, this is not necessarily the same
        // as the intended range (ie., the range of the original weights).
-       int lower_pos = int(floor(to_fp32(bilinear_weights[0].pos) * size - 0.5));
-       int upper_pos = int(ceil(to_fp32(bilinear_weights[num_bilinear_weights - 1].pos) * size - 0.5)) + 2;
-       lower_pos = min<int>(lower_pos, lrintf(weights[0].pos * size - 0.5));
-       upper_pos = max<int>(upper_pos, lrintf(weights[num_weights - 1].pos * size - 0.5) + 1);
+       int lower_pos = int(floor(to_fp32(bilinear_weights[0].pos) * size - 0.5f));
+       int upper_pos = int(ceil(to_fp32(bilinear_weights[num_bilinear_weights - 1].pos) * size - 0.5f)) + 2;
+       lower_pos = min<int>(lower_pos, lrintf(weights[0].pos * size - 0.5f));
+       upper_pos = max<int>(upper_pos, lrintf(weights[num_weights - 1].pos * size - 0.5f) + 1);
 
        float* effective_weights = new float[upper_pos - lower_pos];
        for (int i = 0; i < upper_pos - lower_pos; ++i) {
@@ -271,7 +271,7 @@ double compute_sum_sq_error(const Tap<float>* weights, unsigned num_weights,
                assert(x0 < upper_pos - lower_pos);
                assert(x1 < upper_pos - lower_pos);
 
-               effective_weights[x0] += to_fp32(bilinear_weights[i].weight) * (1.0 - f);
+               effective_weights[x0] += to_fp32(bilinear_weights[i].weight) * (1.0f - f);
                effective_weights[x1] += to_fp32(bilinear_weights[i].weight) * f;
        }
 
@@ -638,11 +638,12 @@ ScalingWeights calculate_scaling_weights(unsigned src_size, unsigned dst_size, f
                int base_src_y = lrintf(center_src_y);
 
                // Now sample <int_radius> pixels on each side around that point.
+               float inv_src_size = 1.0 / float(src_size);
                for (int i = 0; i < src_samples; ++i) {
                        int src_y = base_src_y + i - int_radius;
                        float weight = lanczos_weight_cached(radius_scaling_factor * (src_y - center_src_y - subpixel_offset));
                        weights[y * src_samples + i].weight = weight * radius_scaling_factor;
-                       weights[y * src_samples + i].pos = (src_y + 0.5) / float(src_size);
+                       weights[y * src_samples + i].pos = (src_y + 0.5f) * inv_src_size;
                }
        }