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| author | Brecht Van Lommel <brechtvanlommel@gmail.com> | 2017-09-27 02:03:50 +0300 |
|---|---|---|
| committer | Brecht Van Lommel <brechtvanlommel@gmail.com> | 2017-10-04 22:11:14 +0300 |
| commit | 12f453820514e9478afdda0acf4c4fb1eac11e1c (patch) | |
| tree | e8f9293c814457361febf1908e7131b0dc9ddfbd /intern/cycles/kernel/filter | |
| parent | e3e16cecc4f080edbbd14e4bf1cfc580c5957d62 (diff) | |
Code refactor: use split variance calculation for mega kernels too.
There is no significant difference in denoised benchmark scenes and
denoising ctests, so might as well make it all consistent.
Diffstat (limited to 'intern/cycles/kernel/filter')
| -rw-r--r-- | intern/cycles/kernel/filter/filter_prefilter.h | 25 |
1 files changed, 11 insertions, 14 deletions
diff --git a/intern/cycles/kernel/filter/filter_prefilter.h b/intern/cycles/kernel/filter/filter_prefilter.h index 2aeb54a62be..eefcbfea230 100644 --- a/intern/cycles/kernel/filter/filter_prefilter.h +++ b/intern/cycles/kernel/filter/filter_prefilter.h @@ -35,8 +35,7 @@ ccl_device void kernel_filter_divide_shadow(int sample, ccl_global float *bufferVariance, int4 rect, int buffer_pass_stride, - int buffer_denoising_offset, - bool use_split_variance) + int buffer_denoising_offset) { int xtile = (x < tiles->x[1])? 0: ((x < tiles->x[2])? 1: 2); int ytile = (y < tiles->y[1])? 0: ((y < tiles->y[2])? 1: 2); @@ -57,10 +56,12 @@ ccl_device void kernel_filter_divide_shadow(int sample, float varB = center_buffer[5]; int odd_sample = (sample+1)/2; int even_sample = sample/2; - if(use_split_variance) { - varA = max(0.0f, varA - unfilteredA[idx]*unfilteredA[idx]*odd_sample); - varB = max(0.0f, varB - unfilteredB[idx]*unfilteredB[idx]*even_sample); - } + + /* Approximate variance as E[x^2] - 1/N * (E[x])^2, since online variance + * update does not work efficiently with atomics in the kernel. */ + varA = max(0.0f, varA - unfilteredA[idx]*unfilteredA[idx]*odd_sample); + varB = max(0.0f, varB - unfilteredB[idx]*unfilteredB[idx]*even_sample); + varA /= max(odd_sample - 1, 1); varB /= max(even_sample - 1, 1); @@ -84,8 +85,7 @@ ccl_device void kernel_filter_get_feature(int sample, ccl_global float *mean, ccl_global float *variance, int4 rect, int buffer_pass_stride, - int buffer_denoising_offset, - bool use_split_variance) + int buffer_denoising_offset) { int xtile = (x < tiles->x[1])? 0: ((x < tiles->x[2])? 1: 2); int ytile = (y < tiles->y[1])? 0: ((y < tiles->y[2])? 1: 2); @@ -97,12 +97,9 @@ ccl_device void kernel_filter_get_feature(int sample, mean[idx] = center_buffer[m_offset] / sample; if(sample > 1) { - if(use_split_variance) { - variance[idx] = max(0.0f, (center_buffer[v_offset] - mean[idx]*mean[idx]*sample) / (sample * (sample-1))); - } - else { - variance[idx] = center_buffer[v_offset] / (sample * (sample-1)); - } + /* Approximate variance as E[x^2] - 1/N * (E[x])^2, since online variance + * update does not work efficiently with atomics in the kernel. */ + variance[idx] = max(0.0f, (center_buffer[v_offset] - mean[idx]*mean[idx]*sample) / (sample * (sample-1))); } else { /* Can't compute variance with single sample, just set it very high. */ |