Cycles: Improved robustness of hair motion blur.motion_curve_fix

In some instances, the number of control vertices of a hair could change mid-frame.
Cycles would then be unable to calculate proper motion blur for those hairs. This adds
interpolated CVs to fill in for the missing data. While this will not necessarily result in
a fully accurate reconstruction of the guide hair, it preserves motion blur instead of disabling it.

Reviewers: #cycles, sergey

Reviewed By: #cycles, sergey

Subscribers: sergey, brecht, #cycles

Tags: #cycles

Differential Revision: https://developer.blender.org/D3695

1 files changed, 79 insertions, 0 deletions

diff --git a/intern/cycles/bvh/bvh_embree.h b/intern/cycles/bvh/bvh_embree.h
new file mode 100644
index 00000000000..9990826ba98
--- /dev/null
+++ b/intern/cycles/bvh/bvh_embree.h
@@ -0,0 +1,79 @@
+/*
+ * Copyright 2018, Blender Foundation.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef __BVH_EMBREE_H__
+#define __BVH_EMBREE_H__
+
+#ifdef WITH_EMBREE
+
+#include <embree3/rtcore.h>
+#include <embree3/rtcore_scene.h>
+
+#include "bvh/bvh.h"
+#include "bvh/bvh_params.h"
+
+#include "util/util_thread.h"
+#include "util/util_types.h"
+#include "util/util_vector.h"
+
+CCL_NAMESPACE_BEGIN
+
+class Mesh;
+
+class BVHEmbree : public BVH
+{
+public:
+	virtual void build(Progress& progress, Stats *stats) override;
+	virtual ~BVHEmbree();
+	RTCScene scene;
+	static void destroy(RTCScene);
+protected:
+	friend class BVH;
+	BVHEmbree(const BVHParams& params, const vector<Object*>& objects);
+
+	virtual void pack_nodes(const BVHNode*) override;
+	virtual void refit_nodes() override;
+
+	void add_object(Object *ob, int i);
+	void add_instance(Object *ob, int i);
+	void add_curves(Object *ob, int i);
+	void add_triangles(Object *ob, int i);
+
+	ssize_t mem_used;
+
+	void add_delayed_delete_scene(RTCScene scene) { delayed_delete_scenes.push_back(scene); }
+	BVHEmbree *top_level;
+private:
+	void delete_rtcScene();
+	void update_tri_vertex_buffer(RTCGeometry geom_id, const Mesh* mesh);
+	void update_curve_vertex_buffer(RTCGeometry geom_id, const Mesh* mesh);
+
+	static RTCDevice rtc_shared_device;
+	static int rtc_shared_users;
+	static thread_mutex rtc_shared_mutex;
+
+	Stats *stats;
+	vector<RTCScene> delayed_delete_scenes;
+	int curve_subdivisions;
+	enum RTCBuildQuality build_quality;
+	bool use_curves, use_ribbons, dynamic_scene;
+};
+
+CCL_NAMESPACE_END
+
+#endif  /* WITH_EMBREE */
+
+#endif  /* __BVH_EMBREE_H__ */