Commit: 9e61dcc6b89f21420bf64c25741c3a259c4158ba
Author: Brecht Van Lommel
Date: Thu May 29 13:20:42 2014 +0200
https://developer.blender.org/rB9e61dcc6b89f21420bf64c25741c3a259c4158ba
Fix T40408: world MIS + equiangular sampling giving unnecessary noise.
It's actually not possible to do equiangular sampling for distant lights, now
it reverts to distance sampling in this case.
===================================================================
M intern/cycles/kernel/kernel_volume.h
===================================================================
diff --git a/intern/cycles/kernel/kernel_volume.h
b/intern/cycles/kernel/kernel_volume.h
index faaa68e..75c8194 100644
--- a/intern/cycles/kernel/kernel_volume.h
+++ b/intern/cycles/kernel/kernel_volume.h
@@ -226,7 +226,7 @@ ccl_device float kernel_volume_equiangular_pdf(Ray *ray,
float3 light_P, float s
return pdf;
}
-ccl_device bool kernel_volume_equiangular_light_position(KernelGlobals *kg,
PathState *state, Ray *ray, RNG *rng, float3 *light_P)
+ccl_device bool kernel_volume_equiangular_light_position(KernelGlobals *kg,
PathState *state, Ray *ray, RNG *rng, float3 *light_P, bool *distant)
{
/* light RNGs */
float light_t = path_state_rng_1D(kg, rng, state, PRNG_LIGHT);
@@ -240,17 +240,9 @@ ccl_device bool
kernel_volume_equiangular_light_position(KernelGlobals *kg, Path
return false;
*light_P = ls.P;
- return true;
-}
-
-ccl_device float kernel_volume_decoupled_equiangular_pdf(KernelGlobals *kg,
PathState *state, Ray *ray, RNG *rng, float sample_t)
-{
- float3 light_P;
+ *distant = ls.t == FLT_MAX;
- if(!kernel_volume_equiangular_light_position(kg, state, ray, rng,
&light_P))
- return 0.0f;
-
- return kernel_volume_equiangular_pdf(ray, light_P, sample_t);
+ return true;
}
/* Distance sampling */
@@ -357,12 +349,20 @@ ccl_device VolumeIntegrateResult
kernel_volume_integrate_homogeneous(KernelGloba
/* equiangular sampling */
float3 light_P;
float equi_pdf;
-
if(!kernel_volume_equiangular_light_position(kg, state, ray, rng, &light_P))
+ bool light_distant;
+
+
if(!kernel_volume_equiangular_light_position(kg, state, ray, rng, &light_P,
&light_distant))
return VOLUME_PATH_MISSED;
- sample_t =
kernel_volume_equiangular_sample(ray, light_P, xi, &equi_pdf);
- transmittance =
volume_color_transmittance(sigma_t, sample_t);
- pdf = make_float3(equi_pdf, equi_pdf, equi_pdf);
+ if(light_distant) {
+ /* distant light, revert to distance
sampling because position is infinitely far away */
+ sample_t =
kernel_volume_distance_sample(ray->t, sigma_t, channel, xi, &transmittance,
&pdf);
+ }
+ else {
+ sample_t =
kernel_volume_equiangular_sample(ray, light_P, xi, &equi_pdf);
+ transmittance =
volume_color_transmittance(sigma_t, sample_t);
+ pdf = make_float3(equi_pdf, equi_pdf,
equi_pdf);
+ }
}
/* modifiy pdf for hit/miss decision */
@@ -720,8 +720,23 @@ ccl_device VolumeIntegrateResult
kernel_volume_decoupled_scatter(
float3 transmittance;
float pdf, sample_t;
+ /* pick position on light for equiangular */
+ bool equiangular = (kernel_data.integrator.volume_homogeneous_sampling
!= 0 && kernel_data.integrator.num_all_lights);
+ float3 light_P;
+
+ if(equiangular) {
+ bool light_distant;
+
+ if(!kernel_volume_equiangular_light_position(kg, state, ray,
rng, &light_P, &light_distant))
+ return VOLUME_PATH_MISSED;
+
+ /* distant light, revert to distance sampling because position
is infinitely far away */
+ if(light_distant)
+ equiangular = false;
+ }
+
/* distance sampling */
- if(kernel_data.integrator.volume_homogeneous_sampling == 0 ||
!kernel_data.integrator.num_all_lights) {
+ if(!equiangular) {
/* find step in cdf */
step = segment->steps;
@@ -762,11 +777,6 @@ ccl_device VolumeIntegrateResult
kernel_volume_decoupled_scatter(
}
/* equi-angular sampling */
else {
- /* pick position on light */
- float3 light_P;
- if(!kernel_volume_equiangular_light_position(kg, state, ray,
rng, &light_P))
- return VOLUME_PATH_MISSED;
-
/* sample distance */
sample_t = kernel_volume_equiangular_sample(ray, light_P, xi,
&pdf);
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