Cycles: Add CPU+GPU rendering support with OptiX

Adds support for building multiple BVH types in order to support using both CPU and OptiX
devices for rendering simultaneously. Primitive packing for Embree and OptiX is now
standalone, so it only needs to be run once and can be shared between the two. Additionally,
BVH building was made a device call, so that each device backend can decide how to
perform the building. The multi-device for instance creates a special multi-BVH that holds
references to several sub-BVHs, one for each sub-device.

Reviewed By: brecht, kevindietrich

Differential Revision: https://developer.blender.org/D9718

1 files changed, 28 insertions, 11 deletions

diff --git a/intern/cycles/bvh/bvh2.h b/intern/cycles/bvh/bvh2.h
index fa3e45b72d2..1030a0f76c7 100644
--- a/intern/cycles/bvh/bvh2.h
+++ b/intern/cycles/bvh/bvh2.h
@@ -26,23 +26,30 @@
 
 CCL_NAMESPACE_BEGIN
 
-class BVHNode;
-struct BVHStackEntry;
-class BVHParams;
-class BoundBox;
-class LeafNode;
-class Object;
-class Progress;
-
 #define BVH_NODE_SIZE 4
 #define BVH_NODE_LEAF_SIZE 1
 #define BVH_UNALIGNED_NODE_SIZE 7
 
+/* Pack Utility */
+struct BVHStackEntry {
+  const BVHNode *node;
+  int idx;
+
+  BVHStackEntry(const BVHNode *n = 0, int i = 0);
+  int encodeIdx() const;
+};
+
 /* BVH2
  *
  * Typical BVH with each node having two children.
  */
 class BVH2 : public BVH {
+ public:
+  void build(Progress &progress, Stats *stats);
+  void refit(Progress &progress);
+
+  PackedBVH pack;
+
  protected:
   /* constructor */
   friend class BVH;
@@ -51,10 +58,10 @@ class BVH2 : public BVH {
        const vector<Object *> &objects);
 
   /* Building process. */
-  virtual BVHNode *widen_children_nodes(const BVHNode *root) override;
+  virtual BVHNode *widen_children_nodes(const BVHNode *root);
 
   /* pack */
-  void pack_nodes(const BVHNode *root) override;
+  void pack_nodes(const BVHNode *root);
 
   void pack_leaf(const BVHStackEntry &e, const LeafNode *leaf);
   void pack_inner(const BVHStackEntry &e, const BVHStackEntry &e0, const BVHStackEntry &e1);
@@ -84,8 +91,18 @@ class BVH2 : public BVH {
                            uint visibility1);
 
   /* refit */
-  void refit_nodes() override;
+  void refit_nodes();
   void refit_node(int idx, bool leaf, BoundBox &bbox, uint &visibility);
+
+  /* Refit range of primitives. */
+  void refit_primitives(int start, int end, BoundBox &bbox, uint &visibility);
+
+  /* triangles and strands */
+  void pack_primitives();
+  void pack_triangle(int idx, float4 storage[3]);
+
+  /* merge instance BVH's */
+  void pack_instances(size_t nodes_size, size_t leaf_nodes_size);
 };
 
 CCL_NAMESPACE_END