diff options
Diffstat (limited to 'intern/cycles/kernel/filter/filter_prefilter.h')
| -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. */ |