Cycles: Added Embree as BVH option for CPU renders.

Note that this is turned off by default and must be enabled at build time with the CMake WITH_CYCLES_EMBREE flag.
Embree must be built as a static library with ray masking turned on, the `make deps` scripts have been updated accordingly.
There, Embree is off by default too and must be enabled with the WITH_EMBREE flag.

Using Embree allows for much faster rendering of deformation motion blur while reducing the memory footprint.

TODO: GPU implementation, deduplication of data, leveraging more of Embrees features (e.g. tessellation cache).

Differential Revision: https://developer.blender.org/D3682

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..4b3219d575e
--- /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__ */