Cycles: Add Volume Direct and Volume Indirect passes for volume-scattered light

No color pass because it's hard to define what to use as color in a volume.

Reviewers: sergey, brecht

Differential Revision: https://developer.blender.org/D2903

3 files changed, 11 insertions, 3 deletions

diff --git a/intern/cycles/kernel/kernel_accumulate.h b/intern/cycles/kernel/kernel_accumulate.h
index 366f25422fd..7c1b2a015e1 100644
--- a/intern/cycles/kernel/kernel_accumulate.h
+++ b/intern/cycles/kernel/kernel_accumulate.h
@@ -187,7 +187,6 @@ ccl_device_inline void path_radiance_init(PathRadiance *L, int use_light_pass)
 		L->color_glossy = make_float3(0.0f, 0.0f, 0.0f);
 		L->color_transmission = make_float3(0.0f, 0.0f, 0.0f);
 		L->color_subsurface = make_float3(0.0f, 0.0f, 0.0f);
-		L->color_scatter = make_float3(0.0f, 0.0f, 0.0f);
 
 		L->direct_diffuse = make_float3(0.0f, 0.0f, 0.0f);
 		L->direct_glossy = make_float3(0.0f, 0.0f, 0.0f);
diff --git a/intern/cycles/kernel/kernel_passes.h b/intern/cycles/kernel/kernel_passes.h
index 4236e2c5d4f..29451b6b8b6 100644
--- a/intern/cycles/kernel/kernel_passes.h
+++ b/intern/cycles/kernel/kernel_passes.h
@@ -294,6 +294,8 @@ ccl_device_inline void kernel_write_light_passes(KernelGlobals *kg, ccl_global f
 		kernel_write_pass_float3(buffer + kernel_data.film.pass_transmission_indirect, L->indirect_transmission);
 	if(light_flag & PASSMASK(SUBSURFACE_INDIRECT))
 		kernel_write_pass_float3(buffer + kernel_data.film.pass_subsurface_indirect, L->indirect_subsurface);
+	if(light_flag & PASSMASK(VOLUME_INDIRECT))
+		kernel_write_pass_float3(buffer + kernel_data.film.pass_volume_indirect, L->indirect_scatter);
 	if(light_flag & PASSMASK(DIFFUSE_DIRECT))
 		kernel_write_pass_float3(buffer + kernel_data.film.pass_diffuse_direct, L->direct_diffuse);
 	if(light_flag & PASSMASK(GLOSSY_DIRECT))
@@ -302,6 +304,8 @@ ccl_device_inline void kernel_write_light_passes(KernelGlobals *kg, ccl_global f
 		kernel_write_pass_float3(buffer + kernel_data.film.pass_transmission_direct, L->direct_transmission);
 	if(light_flag & PASSMASK(SUBSURFACE_DIRECT))
 		kernel_write_pass_float3(buffer + kernel_data.film.pass_subsurface_direct, L->direct_subsurface);
+	if(light_flag & PASSMASK(VOLUME_DIRECT))
+		kernel_write_pass_float3(buffer + kernel_data.film.pass_volume_direct, L->direct_scatter);
 
 	if(light_flag & PASSMASK(EMISSION))
 		kernel_write_pass_float3(buffer + kernel_data.film.pass_emission, L->emission);
diff --git a/intern/cycles/kernel/kernel_types.h b/intern/cycles/kernel/kernel_types.h
index 1761ab22bd6..b6a9cf5f285 100644
--- a/intern/cycles/kernel/kernel_types.h
+++ b/intern/cycles/kernel/kernel_types.h
@@ -413,6 +413,9 @@ typedef enum PassType {
 	PASS_SUBSURFACE_DIRECT,
 	PASS_SUBSURFACE_INDIRECT,
 	PASS_SUBSURFACE_COLOR,
+	PASS_VOLUME_DIRECT,
+	PASS_VOLUME_INDIRECT,
+	/* No Scatter color since it's tricky to define what it would even mean. */
 	PASS_CATEGORY_LIGHT_END = 63,
 } PassType;
 
@@ -521,7 +524,6 @@ typedef ccl_addr_space struct PathRadiance {
 	float3 color_glossy;
 	float3 color_transmission;
 	float3 color_subsurface;
-	float3 color_scatter;
 
 	float3 direct_diffuse;
 	float3 direct_glossy;
@@ -1214,11 +1216,13 @@ typedef struct KernelFilm {
 	int pass_glossy_indirect;
 	int pass_transmission_indirect;
 	int pass_subsurface_indirect;
+	int pass_volume_indirect;
 	
 	int pass_diffuse_direct;
 	int pass_glossy_direct;
 	int pass_transmission_direct;
 	int pass_subsurface_direct;
+	int pass_volume_direct;
 	
 	int pass_emission;
 	int pass_background;
@@ -1237,7 +1241,8 @@ typedef struct KernelFilm {
 	int pass_denoising_data;
 	int pass_denoising_clean;
 	int denoising_flags;
-	int pad;
+
+	int pad1, pad2, pad3;
 
 #ifdef __KERNEL_DEBUG__
 	int pass_bvh_traversed_nodes;