[Bf-blender-cvs] [031620a] master: Cycles: Avoid redundant call to volume_stack_is_heterogeneous() for Distance Sampling.

[Thomas Dinges]

Commit: 031620aba22d153ed71c86f8378b3637444ece3e
Author: Thomas Dinges
Date:   Sun Aug 24 16:15:57 2014 +0200
Branches: master
https://developer.blender.org/rB031620aba22d153ed71c86f8378b3637444ece3e

Cycles: Avoid redundant call to volume_stack_is_heterogeneous() for Distance Sampling.

===================================================================

M	intern/cycles/kernel/kernel_path.h
M	intern/cycles/kernel/kernel_volume.h

===================================================================

diff --git a/intern/cycles/kernel/kernel_path.h b/intern/cycles/kernel/kernel_path.h
index dfca312..0c8b462 100644
--- a/intern/cycles/kernel/kernel_path.h
+++ b/intern/cycles/kernel/kernel_path.h
@@ -149,7 +149,7 @@ ccl_device void kernel_path_indirect(KernelGlobals *kg, RNG *rng, Ray ray,
 				/* integrate along volume segment with distance sampling */
 				ShaderData volume_sd;
 				VolumeIntegrateResult result = kernel_volume_integrate(
-					kg, &state, &volume_sd, &volume_ray, L, &throughput, rng);
+					kg, &state, &volume_sd, &volume_ray, L, &throughput, rng, heterogeneous);
 
 #ifdef __VOLUME_SCATTER__
 				if(result == VOLUME_PATH_SCATTERED) {
@@ -536,7 +536,7 @@ ccl_device float4 kernel_path_integrate(KernelGlobals *kg, RNG *rng, int sample,
 				/* integrate along volume segment with distance sampling */
 				ShaderData volume_sd;
 				VolumeIntegrateResult result = kernel_volume_integrate(
-					kg, &state, &volume_sd, &volume_ray, &L, &throughput, rng);
+					kg, &state, &volume_sd, &volume_ray, &L, &throughput, rng, heterogeneous);
 
 #ifdef __VOLUME_SCATTER__
 				if(result == VOLUME_PATH_SCATTERED) {
@@ -815,10 +815,11 @@ ccl_device float4 kernel_branched_path_integrate(KernelGlobals *kg, RNG *rng, in
 		if(state.volume_stack[0].shader != SHADER_NONE) {
 			Ray volume_ray = ray;
 			volume_ray.t = (hit)? isect.t: FLT_MAX;
+			
+			bool heterogeneous = volume_stack_is_heterogeneous(kg, state.volume_stack);
 
 #ifdef __VOLUME_DECOUPLED__
 			/* decoupled ray marching only supported on CPU */
-			bool heterogeneous = volume_stack_is_heterogeneous(kg, state.volume_stack);
 
 			/* cache steps along volume for repeated sampling */
 			VolumeSegment volume_segment;
@@ -901,7 +902,7 @@ ccl_device float4 kernel_branched_path_integrate(KernelGlobals *kg, RNG *rng, in
 				path_state_branch(&ps, j, num_samples);
 
 				VolumeIntegrateResult result = kernel_volume_integrate(
-					kg, &ps, &volume_sd, &volume_ray, &L, &tp, rng);
+					kg, &ps, &volume_sd, &volume_ray, &L, &tp, rng, heterogeneous);
 				
 #ifdef __VOLUME_SCATTER__
 				if(result == VOLUME_PATH_SCATTERED) {
diff --git a/intern/cycles/kernel/kernel_volume.h b/intern/cycles/kernel/kernel_volume.h
index 402867f..ea02ede 100644
--- a/intern/cycles/kernel/kernel_volume.h
+++ b/intern/cycles/kernel/kernel_volume.h
@@ -560,13 +560,12 @@ ccl_device VolumeIntegrateResult kernel_volume_integrate_heterogeneous_distance(
  * between the endpoints. distance sampling is used to decide if we will
  * scatter or not. */
 ccl_device_noinline VolumeIntegrateResult kernel_volume_integrate(KernelGlobals *kg,
-	PathState *state, ShaderData *sd, Ray *ray, PathRadiance *L, float3 *throughput, RNG *rng)
+	PathState *state, ShaderData *sd, Ray *ray, PathRadiance *L, float3 *throughput, RNG *rng, bool heterogeneous)
 {
 	/* workaround to fix correlation bug in T38710, can find better solution
 	 * in random number generator later, for now this is done here to not impact
 	 * performance of rendering without volumes */
 	RNG tmp_rng = cmj_hash(*rng, state->rng_offset);
-	bool heterogeneous = volume_stack_is_heterogeneous(kg, state->volume_stack);
 
 	shader_setup_from_volume(kg, sd, ray, state->bounce, state->transparent_bounce);