}
template<class DestFloat>
-unsigned combine_samples(const Tap<float> *src, Tap<DestFloat> *dst, unsigned src_size, unsigned num_src_samples, unsigned max_samples_saved)
+unsigned combine_samples(const Tap<float> *src, Tap<DestFloat> *dst, float num_subtexels, float inv_num_subtexels, unsigned num_src_samples, unsigned max_samples_saved)
{
// Cut off near-zero values at both sides.
unsigned num_samples_saved = 0;
fp16_int_t pos, total_weight;
float sum_sq_error;
- combine_two_samples(w1, w2, pos1, pos2, src_size, &pos, &total_weight, &sum_sq_error);
+ combine_two_samples(w1, w2, pos1, pos2, num_subtexels, inv_num_subtexels, &pos, &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,
template<class DestFloat>
unsigned combine_many_samples(const Tap<float> *weights, unsigned src_size, unsigned src_samples, unsigned dst_samples, Tap<DestFloat> **bilinear_weights)
{
- int src_bilinear_samples = 0;
- for (unsigned y = 0; y < dst_samples; ++y) {
- unsigned num_samples_saved = combine_samples<DestFloat>(weights + y * src_samples, NULL, src_size, src_samples, UINT_MAX);
- src_bilinear_samples = max<int>(src_bilinear_samples, src_samples - num_samples_saved);
+ float num_subtexels = src_size / movit_texel_subpixel_precision;
+ float inv_num_subtexels = movit_texel_subpixel_precision / src_size;
+
+ unsigned max_samples_saved = UINT_MAX;
+ for (unsigned y = 0; y < dst_samples && max_samples_saved > 0; ++y) {
+ unsigned num_samples_saved = combine_samples<DestFloat>(weights + y * src_samples, NULL, num_subtexels, inv_num_subtexels, src_samples, max_samples_saved);
+ max_samples_saved = min(max_samples_saved, num_samples_saved);
}
// Now that we know the right width, actually combine the samples.
+ unsigned src_bilinear_samples = src_samples - max_samples_saved;
*bilinear_weights = new Tap<DestFloat>[dst_samples * src_bilinear_samples];
for (unsigned y = 0; y < dst_samples; ++y) {
Tap<DestFloat> *bilinear_weights_ptr = *bilinear_weights + y * src_bilinear_samples;
unsigned num_samples_saved = combine_samples(
weights + y * src_samples,
bilinear_weights_ptr,
- src_size,
+ num_subtexels,
+ inv_num_subtexels,
src_samples,
- src_samples - src_bilinear_samples);
- assert(int(src_samples) - int(num_samples_saved) == src_bilinear_samples);
+ max_samples_saved);
+ assert(num_samples_saved == max_samples_saved);
normalize_sum(bilinear_weights_ptr, src_bilinear_samples);
}
return src_bilinear_samples;