[Bf-blender-cvs] [cba412fba18] soc-2018-cycles-volumes: Intial commit for volume motion blur.

[Geraldine Chua]

Commit: cba412fba184959ed008a2f54d22dda8d973634b
Author: Geraldine Chua
Date:   Thu Jul 26 21:09:06 2018 +0800
Branches: soc-2018-cycles-volumes
https://developer.blender.org/rBcba412fba184959ed008a2f54d22dda8d973634b

Intial commit for volume motion blur.

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

M	intern/cycles/blender/blender_mesh.cpp
M	intern/cycles/kernel/geom/geom_volume.h
M	intern/cycles/kernel/kernel_shader.h
M	intern/cycles/kernel/kernel_types.h
M	intern/cycles/render/mesh.cpp

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

diff --git a/intern/cycles/blender/blender_mesh.cpp b/intern/cycles/blender/blender_mesh.cpp
index 8ed0e5232dc..e78aab9dc54 100644
--- a/intern/cycles/blender/blender_mesh.cpp
+++ b/intern/cycles/blender/blender_mesh.cpp
@@ -397,7 +397,7 @@ static void create_mesh_volume_attributes(Scene *scene,
 		create_mesh_volume_attribute(mesh, scene->image_manager, ATTR_STD_VOLUME_HEAT, filename, builtin_data, frame);
 	if(mesh->need_attribute(scene, ATTR_STD_VOLUME_TEMPERATURE))
 		create_mesh_volume_attribute(mesh, scene->image_manager, ATTR_STD_VOLUME_TEMPERATURE, filename, builtin_data, frame);
-	if(mesh->need_attribute(scene, ATTR_STD_VOLUME_VELOCITY))
+	if(mesh->need_attribute(scene, ATTR_STD_VOLUME_VELOCITY) || scene->need_motion() == Scene::MOTION_BLUR)
 		create_mesh_volume_attribute(mesh, scene->image_manager, ATTR_STD_VOLUME_VELOCITY, filename, builtin_data, frame);
 }
 
diff --git a/intern/cycles/kernel/geom/geom_volume.h b/intern/cycles/kernel/geom/geom_volume.h
index 346f228e961..51a7efc1457 100644
--- a/intern/cycles/kernel/geom/geom_volume.h
+++ b/intern/cycles/kernel/geom/geom_volume.h
@@ -47,11 +47,40 @@ ccl_device_inline float3 volume_normalized_position(KernelGlobals *kg,
 	return P;
 }
 
-ccl_device float volume_attribute_float(KernelGlobals *kg, const ShaderData *sd, const AttributeDescriptor desc, float *dx, float *dy)
+/* Returns normalized P.
+ * If motion blur is enabled, returns normalized and advected P. */
+
+ccl_device_inline float3 volume_get_position(KernelGlobals *kg,
+                                             const ShaderData *sd)
 {
 	float3 P = volume_normalized_position(kg, sd, sd->P);
+
+	/* Eulerian motion blur. */
+	if(kernel_data.cam.shuttertime != -1.0f) {
+		AttributeDescriptor v_desc = find_attribute(kg, sd, ATTR_STD_VOLUME_VELOCITY);
+
+		if (v_desc.offset != ATTR_STD_NOT_FOUND) {
+			InterpolationType interp = (sd->flag & SD_VOLUME_CUBIC)? INTERPOLATION_CUBIC: INTERPOLATION_NONE;
+
+			/* Find velocity. */
+			float3 velocity = float4_to_float3(kernel_tex_image_interp_3d(kg, v_desc.offset, P.x, P.y, P.z, interp));
+
+			/* Find advected velocity. */
+			P = volume_normalized_position(kg, sd, sd->P + velocity * sd->time);
+			velocity = float4_to_float3(kernel_tex_image_interp_3d(kg, v_desc.offset, P.x, P.y, P.z, interp));
+
+			/* Find advected P. */
+			P = volume_normalized_position(kg, sd, sd->P + velocity * sd->time);
+		}
+	}
+
+	return P;
+}
+
+ccl_device float volume_attribute_float(KernelGlobals *kg, const ShaderData *sd, const AttributeDescriptor desc, float *dx, float *dy)
+{
 	InterpolationType interp = (sd->flag & SD_VOLUME_CUBIC)? INTERPOLATION_CUBIC: INTERPOLATION_NONE;
-	float4 r = kernel_tex_image_interp_3d(kg, desc.offset, P.x, P.y, P.z, interp);
+	float4 r = kernel_tex_image_interp_3d(kg, desc.offset, sd->P_v.x, sd->P_v.y, sd->P_v.z, interp);
 
 	if(dx) *dx = 0.0f;
 	if(dy) *dy = 0.0f;
@@ -61,9 +90,8 @@ ccl_device float volume_attribute_float(KernelGlobals *kg, const ShaderData *sd,
 
 ccl_device float3 volume_attribute_float3(KernelGlobals *kg, const ShaderData *sd, const AttributeDescriptor desc, float3 *dx, float3 *dy)
 {
-	float3 P = volume_normalized_position(kg, sd, sd->P);
 	InterpolationType interp = (sd->flag & SD_VOLUME_CUBIC)? INTERPOLATION_CUBIC: INTERPOLATION_NONE;
-	float4 r = kernel_tex_image_interp_3d(kg, desc.offset, P.x, P.y, P.z, interp);
+	float4 r = kernel_tex_image_interp_3d(kg, desc.offset, sd->P_v.x, sd->P_v.y, sd->P_v.z, interp);
 
 	if(dx) *dx = make_float3(0.0f, 0.0f, 0.0f);
 	if(dy) *dy = make_float3(0.0f, 0.0f, 0.0f);
diff --git a/intern/cycles/kernel/kernel_shader.h b/intern/cycles/kernel/kernel_shader.h
index 937a50cba8b..64b1e070982 100644
--- a/intern/cycles/kernel/kernel_shader.h
+++ b/intern/cycles/kernel/kernel_shader.h
@@ -1211,6 +1211,9 @@ ccl_device_inline void shader_eval_volume(KernelGlobals *kg,
 			/* todo: this is inefficient for motion blur, we should be
 			 * caching matrices instead of recomputing them each step */
 			shader_setup_object_transforms(kg, sd, sd->time);
+
+			/* Cache volume P. */
+			sd->P_v = volume_get_position(kg, sd);
 #endif
 		}
 
diff --git a/intern/cycles/kernel/kernel_types.h b/intern/cycles/kernel/kernel_types.h
index 72fbf7be557..63ff8f3ba6f 100644
--- a/intern/cycles/kernel/kernel_types.h
+++ b/intern/cycles/kernel/kernel_types.h
@@ -1058,6 +1058,11 @@ typedef ccl_addr_space struct ShaderData {
 
 	/* At the end so we can adjust size in ShaderDataTinyStorage. */
 	struct ShaderClosure closure[MAX_CLOSURE];
+
+#ifdef __VOLUME__
+	/* Normalized volume position. May be advected for motion blur. */
+	float3 P_v;
+#endif
 } ShaderData;
 
 typedef ccl_addr_space struct ShaderDataTinyStorage {
diff --git a/intern/cycles/render/mesh.cpp b/intern/cycles/render/mesh.cpp
index 7a9d604244d..1cfbb085e45 100644
--- a/intern/cycles/render/mesh.cpp
+++ b/intern/cycles/render/mesh.cpp
@@ -1543,6 +1543,11 @@ void MeshManager::device_update_attributes(Device *device, DeviceScene *dscene,
 		foreach(Shader *shader, mesh->used_shaders) {
 			mesh_attributes[i].add(shader->attributes);
 		}
+
+		/* motion blur for volumes */
+		if(scene->need_motion() == Scene::MOTION_BLUR && mesh->has_volume) {
+			mesh_attributes[i].add(ATTR_STD_VOLUME_VELOCITY);
+		}
 	}
 
 	/* mesh attribute are stored in a single array per data type. here we fill