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

2 files changed, 2 insertions, 3 deletions

diff --git a/intern/cycles/blender/addon/properties.py b/intern/cycles/blender/addon/properties.py
index 1cb29fc6cb0..2f204b2c658 100644
--- a/intern/cycles/blender/addon/properties.py
+++ b/intern/cycles/blender/addon/properties.py
@@ -1570,7 +1570,7 @@ class CyclesPreferences(bpy.types.AddonPreferences):
             elif entry.type == 'CPU':
                 cpu_devices.append(entry)
         # Extend all GPU devices with CPU.
-        if compute_device_type in {'CUDA', 'OPENCL'}:
+        if compute_device_type in {'CUDA', 'OPTIX', 'OPENCL'}:
             devices.extend(cpu_devices)
         return devices
 
diff --git a/intern/cycles/blender/blender_device.cpp b/intern/cycles/blender/blender_device.cpp
index ffcaef0b2a9..977f8297de1 100644
--- a/intern/cycles/blender/blender_device.cpp
+++ b/intern/cycles/blender/blender_device.cpp
@@ -90,8 +90,7 @@ DeviceInfo blender_device_info(BL::Preferences &b_preferences, BL::Scene &b_scen
         mask |= DEVICE_MASK_CUDA;
       }
       else if (compute_device == COMPUTE_DEVICE_OPTIX) {
-        /* Cannot use CPU and OptiX device at the same time right now, so replace mask. */
-        mask = DEVICE_MASK_OPTIX;
+        mask |= DEVICE_MASK_OPTIX;
       }
       else if (compute_device == COMPUTE_DEVICE_OPENCL) {
         mask |= DEVICE_MASK_OPENCL;