Cycles: motion blur is now curved and passes exactly through the midpoint.

Previously it would only interpolate between the previous and next frame,
which meant it might not hit the current frame position.

7 files changed, 54 insertions, 24 deletions

diff --git a/intern/cycles/kernel/kernel_object.h b/intern/cycles/kernel/kernel_object.h
index 602574cb736..79ff7e2020a 100644
--- a/intern/cycles/kernel/kernel_object.h
+++ b/intern/cycles/kernel/kernel_object.h
@@ -23,8 +23,9 @@ enum ObjectTransform {
 	OBJECT_INVERSE_TRANSFORM = 3,
 	OBJECT_PROPERTIES = 6,
 	OBJECT_TRANSFORM_MOTION_PRE = 8,
-	OBJECT_TRANSFORM_MOTION_POST = 12,
-	OBJECT_DUPLI = 16
+	OBJECT_TRANSFORM_MOTION_MID = 12,
+	OBJECT_TRANSFORM_MOTION_POST = 16,
+	OBJECT_DUPLI = 18
 };
 
 __device_inline Transform object_fetch_transform(KernelGlobals *kg, int object, enum ObjectTransform type)
@@ -59,11 +60,15 @@ __device_inline Transform object_fetch_transform_motion(KernelGlobals *kg, int o
 		motion.pre.z = kernel_tex_fetch(__objects, offset + 2);
 		motion.pre.w = kernel_tex_fetch(__objects, offset + 3);
 
+		motion.mid.x = kernel_tex_fetch(__objects, offset + 4);
+		motion.mid.y = kernel_tex_fetch(__objects, offset + 5);
+		motion.mid.z = kernel_tex_fetch(__objects, offset + 6);
+		motion.mid.w = kernel_tex_fetch(__objects, offset + 7);
 
-		motion.post.x = kernel_tex_fetch(__objects, offset + 4);
-		motion.post.y = kernel_tex_fetch(__objects, offset + 5);
-		motion.post.z = kernel_tex_fetch(__objects, offset + 6);
-		motion.post.w = kernel_tex_fetch(__objects, offset + 7);
+		motion.post.x = kernel_tex_fetch(__objects, offset + 8);
+		motion.post.y = kernel_tex_fetch(__objects, offset + 9);
+		motion.post.z = kernel_tex_fetch(__objects, offset + 10);
+		motion.post.w = kernel_tex_fetch(__objects, offset + 11);
 
 		transform_motion_interpolate(&tfm, &motion, time);
 
diff --git a/intern/cycles/kernel/kernel_types.h b/intern/cycles/kernel/kernel_types.h
index bcf80cb76fb..4cf414091f5 100644
--- a/intern/cycles/kernel/kernel_types.h
+++ b/intern/cycles/kernel/kernel_types.h
@@ -29,7 +29,7 @@
 CCL_NAMESPACE_BEGIN
 
 /* constants */
-#define OBJECT_SIZE 		18
+#define OBJECT_SIZE 		22
 #define LIGHT_SIZE			4
 #define FILTER_TABLE_SIZE	256
 #define RAMP_TABLE_SIZE		256
diff --git a/intern/cycles/render/camera.cpp b/intern/cycles/render/camera.cpp
index 727b9801d95..7703d0cbc8e 100644
--- a/intern/cycles/render/camera.cpp
+++ b/intern/cycles/render/camera.cpp
@@ -197,9 +197,8 @@ void Camera::device_update(Device *device, DeviceScene *dscene, Scene *scene)
 	}
 #ifdef __CAMERA_MOTION__
 	else if(need_motion == Scene::MOTION_BLUR) {
-		/* todo: exact camera position will not be hit this way */
 		if(use_motion) {
-			transform_motion_decompose(&kcam->motion, &motion);
+			transform_motion_decompose(&kcam->motion, &motion, &matrix);
 			kcam->have_motion = 1;
 		}
 	}
diff --git a/intern/cycles/render/nodes.cpp b/intern/cycles/render/nodes.cpp
index 0bd24f71930..ef139d994da 100644
--- a/intern/cycles/render/nodes.cpp
+++ b/intern/cycles/render/nodes.cpp
@@ -1254,8 +1254,6 @@ void WardBsdfNode::attributes(AttributeRequestSet *attributes)
 
 void WardBsdfNode::compile(SVMCompiler& compiler)
 {
-	ShaderInput *tangent_in = input("Tangent");
-
 	BsdfNode::compile(compiler, input("Roughness U"), input("Roughness V"));
 }
 
diff --git a/intern/cycles/render/object.cpp b/intern/cycles/render/object.cpp
index f5d78c080c8..63e904511e6 100644
--- a/intern/cycles/render/object.cpp
+++ b/intern/cycles/render/object.cpp
@@ -57,7 +57,7 @@ void Object::compute_bounds(bool motion_blur)
 
 	if(motion_blur && use_motion) {
 		MotionTransform decomp;
-		transform_motion_decompose(&decomp, &motion);
+		transform_motion_decompose(&decomp, &motion, &tfm);
 
 		bounds = BoundBox::empty;
 
@@ -219,7 +219,7 @@ void ObjectManager::device_update_transforms(Device *device, DeviceScene *dscene
 				mtfm_post = mtfm_post * itfm;
 
 			memcpy(&objects[offset+8], &mtfm_pre, sizeof(float4)*4);
-			memcpy(&objects[offset+12], &mtfm_post, sizeof(float4)*4);
+			memcpy(&objects[offset+16], &mtfm_post, sizeof(float4)*4);
 		}
 #ifdef __OBJECT_MOTION__
 		else if(need_motion == Scene::MOTION_BLUR) {
@@ -227,21 +227,21 @@ void ObjectManager::device_update_transforms(Device *device, DeviceScene *dscene
 				/* decompose transformations for interpolation */
 				MotionTransform decomp;
 
-				transform_motion_decompose(&decomp, &ob->motion);
-				memcpy(&objects[offset+8], &decomp, sizeof(float4)*8);
+				transform_motion_decompose(&decomp, &ob->motion, &ob->tfm);
+				memcpy(&objects[offset+8], &decomp, sizeof(float4)*12);
 				flag |= SD_OBJECT_MOTION;
 				have_motion = true;
 			}
 			else {
 				float4 no_motion = make_float4(FLT_MAX);
-				memcpy(&objects[offset+8], &no_motion, sizeof(float4));
+				memcpy(&objects[offset+8], &no_motion, sizeof(float4)*12);
 			}
 		}
 #endif
 
 		/* dupli object coords */
-		objects[offset+16] = make_float4(ob->dupli_generated[0], ob->dupli_generated[1], ob->dupli_generated[2], 0.0f);
-		objects[offset+17] = make_float4(ob->dupli_uv[0], ob->dupli_uv[1], 0.0f, 0.0f);
+		objects[offset+20] = make_float4(ob->dupli_generated[0], ob->dupli_generated[1], ob->dupli_generated[2], 0.0f);
+		objects[offset+21] = make_float4(ob->dupli_uv[0], ob->dupli_uv[1], 0.0f, 0.0f);
 
 		/* object flag */
 		if(ob->use_holdout)
diff --git a/intern/cycles/util/util_transform.cpp b/intern/cycles/util/util_transform.cpp
index b3c6506dfa0..70ee13d96d7 100644
--- a/intern/cycles/util/util_transform.cpp
+++ b/intern/cycles/util/util_transform.cpp
@@ -246,9 +246,10 @@ static void transform_decompose(Transform *decomp, const Transform *tfm)
 	decomp->w = make_float4(scale.y.z, scale.z.x, scale.z.y, scale.z.z);
 }
 
-void transform_motion_decompose(MotionTransform *decomp, const MotionTransform *motion)
+void transform_motion_decompose(MotionTransform *decomp, const MotionTransform *motion, const Transform *mid)
 {
 	transform_decompose(&decomp->pre, &motion->pre);
+	transform_decompose(&decomp->mid, mid);
 	transform_decompose(&decomp->post, &motion->post);
 }
 
diff --git a/intern/cycles/util/util_transform.h b/intern/cycles/util/util_transform.h
index 3d6aefed56d..df525542207 100644
--- a/intern/cycles/util/util_transform.h
+++ b/intern/cycles/util/util_transform.h
@@ -41,6 +41,7 @@ typedef struct Transform {
 
 typedef struct MotionTransform {
 	Transform pre;
+	Transform mid;
 	Transform post;
 } MotionTransform;
 
@@ -383,11 +384,37 @@ __device void transform_motion_interpolate(Transform *tfm, const MotionTransform
 {
 	Transform decomp;
 
-	decomp.x = quat_interpolate(motion->pre.x, motion->post.x, t);
-	decomp.y = (1.0f - t)*motion->pre.y + t*motion->post.y;
-	decomp.z = (1.0f - t)*motion->pre.z + t*motion->post.z;
-	decomp.w = (1.0f - t)*motion->pre.w + t*motion->post.w;
+	/* 3 point bezier curve interpolation for position */
+	float3 Ppre = float4_to_float3(motion->pre.y);
+	float3 Pmid = float4_to_float3(motion->mid.y);
+	float3 Ppost = float4_to_float3(motion->post.y);
 
+	float3 Pcontrol = 2.0f*Pmid - 0.5f*(Ppre + Ppost);
+	float3 P = Ppre*t*t + Pcontrol*2.0f*t*(1.0f - t) + Ppost*(1.0f - t)*(1.0f - t);
+
+	decomp.y.x = P.x;
+	decomp.y.y = P.y;
+	decomp.y.z = P.z;
+
+	/* linear interpolation for rotation and scale */
+	if(t < 0.5f) {
+		t *= 2.0f;
+
+		decomp.x = quat_interpolate(motion->pre.x, motion->mid.x, t);
+		decomp.y.w = (1.0f - t)*motion->pre.y.w + t*motion->mid.y.w;
+		decomp.z = (1.0f - t)*motion->pre.z + t*motion->mid.z;
+		decomp.w = (1.0f - t)*motion->pre.w + t*motion->mid.w;
+	}
+	else {
+		t = (t - 0.5f)*2.0f;
+
+		decomp.x = quat_interpolate(motion->mid.x, motion->post.x, t);
+		decomp.y.w = (1.0f - t)*motion->mid.y.w + t*motion->post.y.w;
+		decomp.z = (1.0f - t)*motion->mid.z + t*motion->post.z;
+		decomp.w = (1.0f - t)*motion->mid.w + t*motion->post.w;
+	}
+
+	/* compose rotation, translation, scale into matrix */
 	transform_compose(tfm, &decomp);
 }
 
@@ -398,7 +425,7 @@ __device_inline bool operator==(const MotionTransform& A, const MotionTransform&
 	return (A.pre == B.pre && A.post == B.post);
 }
 
-void transform_motion_decompose(MotionTransform *decomp, const MotionTransform *motion);
+void transform_motion_decompose(MotionTransform *decomp, const MotionTransform *motion, const Transform *mid);
 
 #endif