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, 29 insertions, 4 deletions

diff --git a/intern/cycles/device/device_cpu.cpp b/intern/cycles/device/device_cpu.cpp
index 6912ac1e638..fea4fc53d1f 100644
--- a/intern/cycles/device/device_cpu.cpp
+++ b/intern/cycles/device/device_cpu.cpp
@@ -47,6 +47,8 @@
 #include "kernel/osl/osl_globals.h"
 // clang-format on
 
+#include "bvh/bvh_embree.h"
+
 #include "render/buffers.h"
 #include "render/coverage.h"
 
@@ -188,6 +190,7 @@ class CPUDevice : public Device {
 #endif
   thread_spin_lock oidn_task_lock;
 #ifdef WITH_EMBREE
+  RTCScene embree_scene = NULL;
   RTCDevice embree_device;
 #endif
 
@@ -472,6 +475,15 @@ class CPUDevice : public Device {
 
   virtual void const_copy_to(const char *name, void *host, size_t size) override
   {
+#if WITH_EMBREE
+    if (strcmp(name, "__data") == 0) {
+      assert(size <= sizeof(KernelData));
+
+      // Update scene handle (since it is different for each device on multi devices)
+      KernelData *const data = (KernelData *)host;
+      data->bvh.scene = embree_scene;
+    }
+#endif
     kernel_const_copy(&kernel_globals, name, host, size);
   }
 
@@ -537,13 +549,26 @@ class CPUDevice : public Device {
 #endif
   }
 
-  void *bvh_device() const override
+  void build_bvh(BVH *bvh, Progress &progress, bool refit) override
   {
 #ifdef WITH_EMBREE
-    return embree_device;
-#else
-    return NULL;
+    if (bvh->params.bvh_layout == BVH_LAYOUT_EMBREE ||
+        bvh->params.bvh_layout == BVH_LAYOUT_MULTI_OPTIX_EMBREE) {
+      BVHEmbree *const bvh_embree = static_cast<BVHEmbree *>(bvh);
+      if (refit) {
+        bvh_embree->refit(progress);
+      }
+      else {
+        bvh_embree->build(progress, &stats, embree_device);
+      }
+
+      if (bvh->params.top_level) {
+        embree_scene = bvh_embree->scene;
+      }
+    }
+    else
 #endif
+      Device::build_bvh(bvh, progress, refit);
   }
 
   void thread_run(DeviceTask &task)