[Bf-blender-cvs] [fb10bd4fa46] cycles-x: Cycles X: don't use ray position when sampling light for volume segment
Brecht Van Lommel
noreply at git.blender.org
Fri Jul 23 19:29:02 CEST 2021
Commit: fb10bd4fa46ee8b8c6c9f95b9ea8bb3eb9c2bd29
Author: Brecht Van Lommel
Date: Mon Jul 19 18:04:58 2021 +0200
Branches: cycles-x
https://developer.blender.org/rBfb10bd4fa46ee8b8c6c9f95b9ea8bb3eb9c2bd29
Cycles X: don't use ray position when sampling light for volume segment
Area light solid importance sampling can introduce a lot of noise otherwise
if the ray start position happens to be close to the light, but the volume
segment also passes closely to other parts of the area light.
Ref D11845
===================================================================
M intern/cycles/kernel/integrator/integrator_shade_surface.h
M intern/cycles/kernel/integrator/integrator_shade_volume.h
M intern/cycles/kernel/kernel_light.h
===================================================================
diff --git a/intern/cycles/kernel/integrator/integrator_shade_surface.h b/intern/cycles/kernel/integrator/integrator_shade_surface.h
index cf271eccdff..391aeb58d55 100644
--- a/intern/cycles/kernel/integrator/integrator_shade_surface.h
+++ b/intern/cycles/kernel/integrator/integrator_shade_surface.h
@@ -119,7 +119,8 @@ ccl_device_forceinline void integrate_surface_direct_light(INTEGRATOR_STATE_ARGS
float light_u, light_v;
path_state_rng_2D(kg, rng_state, PRNG_LIGHT_U, &light_u, &light_v);
- if (!light_sample(kg, light_u, light_v, sd->time, sd->P, bounce, path_flag, &ls)) {
+ if (!light_distribution_sample_from_position(
+ kg, light_u, light_v, sd->time, sd->P, bounce, path_flag, &ls)) {
return;
}
}
diff --git a/intern/cycles/kernel/integrator/integrator_shade_volume.h b/intern/cycles/kernel/integrator/integrator_shade_volume.h
index ac5907c8074..5a58ad30e8f 100644
--- a/intern/cycles/kernel/integrator/integrator_shade_volume.h
+++ b/intern/cycles/kernel/integrator/integrator_shade_volume.h
@@ -646,7 +646,8 @@ ccl_device_forceinline bool integrate_volume_sample_light(INTEGRATOR_STATE_ARGS,
float light_u, light_v;
path_state_rng_2D(kg, rng_state, PRNG_LIGHT_U, &light_u, &light_v);
- light_sample(kg, light_u, light_v, sd->time, sd->P, bounce, path_flag, ls);
+ light_distribution_sample_from_volume_segment(
+ kg, light_u, light_v, sd->time, sd->P, bounce, path_flag, ls);
if (ls->shader & SHADER_EXCLUDE_SCATTER) {
return false;
@@ -677,7 +678,8 @@ ccl_device_forceinline void integrate_volume_direct_light(INTEGRATOR_STATE_ARGS,
float light_u, light_v;
path_state_rng_2D(kg, rng_state, PRNG_LIGHT_U, &light_u, &light_v);
- if (!light_sample(kg, light_u, light_v, sd->time, P, bounce, path_flag, ls)) {
+ if (!light_distribution_sample_from_position(
+ kg, light_u, light_v, sd->time, P, bounce, path_flag, ls)) {
return;
}
}
diff --git a/intern/cycles/kernel/kernel_light.h b/intern/cycles/kernel/kernel_light.h
index ad83f79ca48..a653ff5b218 100644
--- a/intern/cycles/kernel/kernel_light.h
+++ b/intern/cycles/kernel/kernel_light.h
@@ -44,8 +44,13 @@ typedef struct LightSample {
/* Regular Light */
-ccl_device_inline bool light_sample_from_position(
- const KernelGlobals *kg, int lamp, float randu, float randv, float3 P, LightSample *ls)
+template<bool in_volume_segment>
+ccl_device_inline bool light_sample(const KernelGlobals *kg,
+ const int lamp,
+ const float randu,
+ const float randv,
+ const float3 P,
+ LightSample *ls)
{
const ccl_global KernelLight *klight = &kernel_tex_fetch(__lights, lamp);
LightType type = (LightType)klight->type;
@@ -57,6 +62,18 @@ ccl_device_inline bool light_sample_from_position(
ls->u = randu;
ls->v = randv;
+ if (in_volume_segment && (type == LIGHT_DISTANT || type == LIGHT_BACKGROUND)) {
+ /* Distant lights in a volume get a dummy sample, position will not actually
+ * be used in that case. Only when sampling from a specific scatter position
+ * do we actually need to evaluate these. */
+ ls->P = zero_float3();
+ ls->Ng = zero_float3();
+ ls->D = zero_float3();
+ ls->pdf = true;
+ ls->t = FLT_MAX;
+ return true;
+ }
+
if (type == LIGHT_DISTANT) {
/* distant light */
float3 lightD = make_float3(klight->co[0], klight->co[1], klight->co[2]);
@@ -130,13 +147,15 @@ ccl_device_inline bool light_sample_from_position(
float invarea = fabsf(klight->area.invarea);
bool is_round = (klight->area.invarea < 0.0f);
- if (dot(ls->P - P, Ng) > 0.0f) {
- return false;
+ if (!in_volume_segment) {
+ if (dot(ls->P - P, Ng) > 0.0f) {
+ return false;
+ }
}
float3 inplane;
- if (is_round) {
+ if (is_round || in_volume_segment) {
inplane = ellipse_sample(axisu * 0.5f, axisv * 0.5f, randu, randv);
ls->P += inplane;
ls->pdf = invarea;
@@ -536,6 +555,7 @@ ccl_device_forceinline float triangle_light_pdf(const KernelGlobals *kg,
}
}
+template<bool in_volume_segment>
ccl_device_forceinline void triangle_light_sample(const KernelGlobals *kg,
int prim,
int object,
@@ -576,7 +596,7 @@ ccl_device_forceinline void triangle_light_sample(const KernelGlobals *kg,
float distance_to_plane = fabsf(dot(N0, V[0] - P) / dot(N0, N0));
- if (longest_edge_squared > distance_to_plane * distance_to_plane) {
+ if (!in_volume_segment && (longest_edge_squared > distance_to_plane * distance_to_plane)) {
/* see James Arvo, "Stratified Sampling of Spherical Triangles"
* http://www.graphics.cornell.edu/pubs/1995/Arv95c.pdf */
@@ -750,14 +770,15 @@ ccl_device_inline bool light_select_reached_max_bounces(const KernelGlobals *kg,
return (bounce > kernel_tex_fetch(__lights, index).max_bounces);
}
-ccl_device_noinline bool light_sample(const KernelGlobals *kg,
- float randu,
- const float randv,
- const float time,
- const float3 P,
- const int bounce,
- const int path_flag,
- LightSample *ls)
+template<bool in_volume_segment>
+ccl_device_noinline bool light_distribution_sample(const KernelGlobals *kg,
+ float randu,
+ const float randv,
+ const float time,
+ const float3 P,
+ const int bounce,
+ const int path_flag,
+ LightSample *ls)
{
/* Sample light index from distribution. */
const int index = light_distribution_sample(kg, &randu);
@@ -776,7 +797,7 @@ ccl_device_noinline bool light_sample(const KernelGlobals *kg,
}
const int shader_flag = kdistribution->mesh_light.shader_flag;
- triangle_light_sample(kg, prim, object, randu, randv, time, ls, P);
+ triangle_light_sample<in_volume_segment>(kg, prim, object, randu, randv, time, ls, P);
ls->shader |= shader_flag;
return (ls->pdf > 0.0f);
}
@@ -787,23 +808,47 @@ ccl_device_noinline bool light_sample(const KernelGlobals *kg,
return false;
}
- return light_sample_from_position(kg, lamp, randu, randv, P, ls);
+ return light_sample<in_volume_segment>(kg, lamp, randu, randv, P, ls);
+}
+
+ccl_device_inline bool light_distribution_sample_from_volume_segment(const KernelGlobals *kg,
+ float randu,
+ const float randv,
+ const float time,
+ const float3 P,
+ const int bounce,
+ const int path_flag,
+ LightSample *ls)
+{
+ return light_distribution_sample<true>(kg, randu, randv, time, P, bounce, path_flag, ls);
+}
+
+ccl_device_inline bool light_distribution_sample_from_position(const KernelGlobals *kg,
+ float randu,
+ const float randv,
+ const float time,
+ const float3 P,
+ const int bounce,
+ const int path_flag,
+ LightSample *ls)
+{
+ return light_distribution_sample<false>(kg, randu, randv, time, P, bounce, path_flag, ls);
}
-ccl_device_inline bool light_sample_new_position(const KernelGlobals *kg,
- const float randu,
- const float randv,
- const float time,
- const float3 P,
- LightSample *ls)
+ccl_device_inline bool light_distribution_sample_new_position(const KernelGlobals *kg,
+ const float randu,
+ const float randv,
+ const float time,
+ const float3 P,
+ LightSample *ls)
{
/* Sample a new position on the same light, for volume sampling. */
if (ls->type == LIGHT_TRIANGLE) {
- triangle_light_sample(kg, ls->prim, ls->object, randu, randv, time, ls, P);
+ triangle_light_sample<false>(kg, ls->prim, ls->object, randu, randv, time, ls, P);
return (ls->pdf > 0.0f);
}
else {
- return light_sample_from_position(kg, ls->lamp, randu, randv, P, ls);
+ return light_sample<false>(kg, ls->lamp, randu, randv, P, ls);
}
}
More information about the Bf-blender-cvs
mailing list