Doesn't actually influence the benchmarks much, but is useful to get 100%
equivalence with the coming compute shader.
// to compute the destination pixel, and how many depend on the scaling factor.
// Thus, the kernel width will vary with how much we scale.
float radius_scaling_factor = min(scaling_factor, 1.0f);
// to compute the destination pixel, and how many depend on the scaling factor.
// Thus, the kernel width will vary with how much we scale.
float radius_scaling_factor = min(scaling_factor, 1.0f);
- int int_radius = lrintf(LANCZOS_RADIUS / radius_scaling_factor);
- int src_samples = int_radius * 2 + 1;
+ const int int_radius = lrintf(LANCZOS_RADIUS / radius_scaling_factor);
+ const int src_samples = int_radius * 2 + 1;
unique_ptr<Tap<float>[]> weights(new Tap<float>[dst_samples * src_samples]);
float subpixel_offset = offset - lrintf(offset); // The part not covered by whole_pixel_offset.
assert(subpixel_offset >= -0.5f && subpixel_offset <= 0.5f);
unique_ptr<Tap<float>[]> weights(new Tap<float>[dst_samples * src_samples]);
float subpixel_offset = offset - lrintf(offset); // The part not covered by whole_pixel_offset.
assert(subpixel_offset >= -0.5f && subpixel_offset <= 0.5f);
+ float inv_scaling_factor = 1.0f / scaling_factor;
for (unsigned y = 0; y < dst_samples; ++y) {
// Find the point around which we want to sample the source image,
// compensating for differing pixel centers as the scale changes.
for (unsigned y = 0; y < dst_samples; ++y) {
// Find the point around which we want to sample the source image,
// compensating for differing pixel centers as the scale changes.
- float center_src_y = (y + 0.5f) / scaling_factor - 0.5f;
+ float center_src_y = (y + 0.5f) * inv_scaling_factor - 0.5f;
int base_src_y = lrintf(center_src_y);
// Now sample <int_radius> pixels on each side around that point.
int base_src_y = lrintf(center_src_y);
// Now sample <int_radius> pixels on each side around that point.