Cycles: Move primitive splitting into own functions

This way it's easy to add more reference types allowed for splitting to the
BVH reference split function without making this function too much big. This
way it's possible to experiment with such features as splitting object instance
references.

So far should not be any functional changes.

1 files changed, 93 insertions, 55 deletions

diff --git a/intern/cycles/bvh/bvh_split.cpp b/intern/cycles/bvh/bvh_split.cpp
index 2290c4143ad..2e14eee36f0 100644
--- a/intern/cycles/bvh/bvh_split.cpp
+++ b/intern/cycles/bvh/bvh_split.cpp
@@ -243,75 +243,113 @@ void BVHSpatialSplit::split(BVHBuild *builder, BVHRange& left, BVHRange& right,
 	right = BVHRange(right_bounds, right_start, right_end - right_start);
 }
 
-void BVHSpatialSplit::split_reference(BVHBuild *builder, BVHReference& left, BVHReference& right, const BVHReference& ref, int dim, float pos)
+void BVHSpatialSplit::split_triangle_reference(const BVHReference& ref,
+                                               const Mesh *mesh,
+                                               int dim,
+                                               float pos,
+                                               BoundBox& left_bounds,
+                                               BoundBox& right_bounds)
 {
-	/* initialize boundboxes */
-	BoundBox left_bounds = BoundBox::empty;
-	BoundBox right_bounds = BoundBox::empty;
-
-	/* loop over vertices/edges. */
-	Object *ob = builder->objects[ref.prim_object()];
-	const Mesh *mesh = ob->mesh;
-
-	if(ref.prim_type() & PRIMITIVE_ALL_TRIANGLE) {
-		const int *inds = mesh->triangles[ref.prim_index()].v;
-		const float3 *verts = &mesh->verts[0];
-		const float3* v1 = &verts[inds[2]];
-
-		for(int i = 0; i < 3; i++) {
-			const float3* v0 = v1;
-			int vindex = inds[i];
-			v1 = &verts[vindex];
-			float v0p = (*v0)[dim];
-			float v1p = (*v1)[dim];
-
-			/* insert vertex to the boxes it belongs to. */
-			if(v0p <= pos)
-				left_bounds.grow(*v0);
-
-			if(v0p >= pos)
-				right_bounds.grow(*v0);
-
-			/* edge intersects the plane => insert intersection to both boxes. */
-			if((v0p < pos && v1p > pos) || (v0p > pos && v1p < pos)) {
-				float3 t = lerp(*v0, *v1, clamp((pos - v0p) / (v1p - v0p), 0.0f, 1.0f));
-				left_bounds.grow(t);
-				right_bounds.grow(t);
-			}
-		}
-	}
-	else {
-		/* curve split: NOTE - Currently ignores curve width and needs to be fixed.*/
-		const int k0 = mesh->curves[ref.prim_index()].first_key + PRIMITIVE_UNPACK_SEGMENT(ref.prim_type());
-		const int k1 = k0 + 1;
-		const float4 key0 = mesh->curve_keys[k0];
-		const float4 key1 = mesh->curve_keys[k1];
-		const float3 v0 = float4_to_float3(key0);
-		const float3 v1 = float4_to_float3(key1);
+	const int *inds = mesh->triangles[ref.prim_index()].v;
+	const float3 *verts = &mesh->verts[0];
+	const float3 *v1 = &verts[inds[2]];
 
-		float v0p = v0[dim];
-		float v1p = v1[dim];
+	for(int i = 0; i < 3; i++) {
+		const float3 *v0 = v1;
+		int vindex = inds[i];
+		v1 = &verts[vindex];
+		float v0p = (*v0)[dim];
+		float v1p = (*v1)[dim];
 
 		/* insert vertex to the boxes it belongs to. */
 		if(v0p <= pos)
-			left_bounds.grow(v0);
+			left_bounds.grow(*v0);
 
 		if(v0p >= pos)
-			right_bounds.grow(v0);
-
-		if(v1p <= pos)
-			left_bounds.grow(v1);
-
-		if(v1p >= pos)
-			right_bounds.grow(v1);
+			right_bounds.grow(*v0);
 
 		/* edge intersects the plane => insert intersection to both boxes. */
 		if((v0p < pos && v1p > pos) || (v0p > pos && v1p < pos)) {
-			float3 t = lerp(v0, v1, clamp((pos - v0p) / (v1p - v0p), 0.0f, 1.0f));
+			float3 t = lerp(*v0, *v1, clamp((pos - v0p) / (v1p - v0p), 0.0f, 1.0f));
 			left_bounds.grow(t);
 			right_bounds.grow(t);
 		}
 	}
+}
+
+void BVHSpatialSplit::split_curve_reference(const BVHReference& ref,
+                                            const Mesh *mesh,
+                                            int dim,
+                                            float pos,
+                                            BoundBox& left_bounds,
+                                            BoundBox& right_bounds)
+{
+	/* curve split: NOTE - Currently ignores curve width and needs to be fixed.*/
+	const int k0 = mesh->curves[ref.prim_index()].first_key + PRIMITIVE_UNPACK_SEGMENT(ref.prim_type());
+	const int k1 = k0 + 1;
+	const float4 key0 = mesh->curve_keys[k0];
+	const float4 key1 = mesh->curve_keys[k1];
+	const float3 v0 = float4_to_float3(key0);
+	const float3 v1 = float4_to_float3(key1);
+
+	float v0p = v0[dim];
+	float v1p = v1[dim];
+
+	/* insert vertex to the boxes it belongs to. */
+	if(v0p <= pos)
+		left_bounds.grow(v0);
+
+	if(v0p >= pos)
+		right_bounds.grow(v0);
+
+	if(v1p <= pos)
+		left_bounds.grow(v1);
+
+	if(v1p >= pos)
+		right_bounds.grow(v1);
+
+	/* edge intersects the plane => insert intersection to both boxes. */
+	if((v0p < pos && v1p > pos) || (v0p > pos && v1p < pos)) {
+		float3 t = lerp(v0, v1, clamp((pos - v0p) / (v1p - v0p), 0.0f, 1.0f));
+		left_bounds.grow(t);
+		right_bounds.grow(t);
+	}
+}
+
+void BVHSpatialSplit::split_reference(BVHBuild *builder,
+                                      BVHReference& left,
+                                      BVHReference& right,
+                                      const BVHReference& ref,
+                                      int dim,
+                                      float pos)
+{
+	/* initialize boundboxes */
+	BoundBox left_bounds = BoundBox::empty;
+	BoundBox right_bounds = BoundBox::empty;
+
+	/* loop over vertices/edges. */
+	Object *ob = builder->objects[ref.prim_object()];
+	const Mesh *mesh = ob->mesh;
+
+	if(ref.prim_type() & PRIMITIVE_ALL_TRIANGLE) {
+		split_triangle_reference(ref,
+		                         mesh,
+		                         dim,
+		                         pos,
+		                         left_bounds,
+		                         right_bounds);
+	}
+	else if(ref.prim_type() & PRIMITIVE_ALL_CURVE) {
+		split_curve_reference(ref,
+		                      mesh,
+		                      dim,
+		                      pos,
+		                      left_bounds,
+		                      right_bounds);
+	}
+	else {
+		assert(!"Unknown primitive type in BVH reference split.");
+	}
 
 	/* intersect with original bounds. */
 	left_bounds.max[dim] = pos;