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Merge branch 'blender-v3.0-release'

This commit is contained in:
Brecht Van Lommel 2021-11-19 18:05:17 +01:00
parent ef687bd7c2 1b686c60b5
commit 06a2e2b28c
1 changed files with 28 additions and 19 deletions
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47
intern/cycles/kernel/integrator/shade_volume.h
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@ -259,6 +259,12 @@ ccl_device void volume_shadow_heterogeneous(KernelGlobals kg,
/* Equi-angular sampling as in:
* "Importance Sampling Techniques for Path Tracing in Participating Media" */
/* Below this pdf we ignore samples, as they tend to lead to very long distances.
* This can cause performance issues with BVH traversal in OptiX, leading it to
* traverse many nodes. Since these contribute very little to the image, just ignore
* those samples. */
# define VOLUME_SAMPLE_PDF_CUTOFF 1e-8f
ccl_device float volume_equiangular_sample(ccl_private const Ray *ccl_restrict ray,
const float3 light_P,
const float xi,
@ -433,7 +439,8 @@ ccl_device_forceinline void volume_integrate_step_scattering(
/* Equiangular sampling for direct lighting. */
if (vstate.direct_sample_method == VOLUME_SAMPLE_EQUIANGULAR && !result.direct_scatter) {
if (result.direct_t >= vstate.start_t && result.direct_t <= vstate.end_t) {
if (result.direct_t >= vstate.start_t && result.direct_t <= vstate.end_t &&
vstate.equiangular_pdf > VOLUME_SAMPLE_PDF_CUTOFF) {
const float new_dt = result.direct_t - vstate.start_t;
const float3 new_transmittance = volume_color_transmittance(coeff.sigma_t, new_dt);
@ -470,26 +477,28 @@ ccl_device_forceinline void volume_integrate_step_scattering(
const float3 new_transmittance = volume_color_transmittance(coeff.sigma_t, new_dt);
const float distance_pdf = dot(channel_pdf, coeff.sigma_t * new_transmittance);
/* throughput */
result.indirect_scatter = true;
result.indirect_t = new_t;
result.indirect_throughput *= coeff.sigma_s * new_transmittance / distance_pdf;
shader_copy_volume_phases(&result.indirect_phases, sd);
if (vstate.distance_pdf * distance_pdf > VOLUME_SAMPLE_PDF_CUTOFF) {
/* throughput */
result.indirect_scatter = true;
result.indirect_t = new_t;
result.indirect_throughput *= coeff.sigma_s * new_transmittance / distance_pdf;
shader_copy_volume_phases(&result.indirect_phases, sd);
if (vstate.direct_sample_method != VOLUME_SAMPLE_EQUIANGULAR) {
/* If using distance sampling for direct light, just copy parameters
* of indirect light since we scatter at the same point then. */
result.direct_scatter = true;
result.direct_t = result.indirect_t;
result.direct_throughput = result.indirect_throughput;
shader_copy_volume_phases(&result.direct_phases, sd);
if (vstate.direct_sample_method != VOLUME_SAMPLE_EQUIANGULAR) {
/* If using distance sampling for direct light, just copy parameters
* of indirect light since we scatter at the same point then. */
result.direct_scatter = true;
result.direct_t = result.indirect_t;
result.direct_throughput = result.indirect_throughput;
shader_copy_volume_phases(&result.direct_phases, sd);
/* Multiple importance sampling. */
if (vstate.use_mis) {
const float equiangular_pdf = volume_equiangular_pdf(ray, equiangular_light_P, new_t);
const float mis_weight = power_heuristic(vstate.distance_pdf * distance_pdf,
equiangular_pdf);
result.direct_throughput *= 2.0f * mis_weight;
/* Multiple importance sampling. */
if (vstate.use_mis) {
const float equiangular_pdf = volume_equiangular_pdf(ray, equiangular_light_P, new_t);
const float mis_weight = power_heuristic(vstate.distance_pdf * distance_pdf,
equiangular_pdf);
result.direct_throughput *= 2.0f * mis_weight;
}
}
}
}