Cycles: add Optix device backend

This uses hardware-accelerated raytracing on NVIDIA RTX graphics cards.

It is still currently experimental. Most features are supported, but a few
are still missing like baking, branched path tracing and using CPU memory.
https://wiki.blender.org/wiki/Reference/Release_Notes/2.81/Cycles#NVIDIA_RTX

For building with Optix support, the Optix SDK must be installed. See here for
build instructions:
https://wiki.blender.org/wiki/Building_Blender/CUDA

Differential Revision: https://developer.blender.org/D5363

2 files changed, 29 insertions, 1 deletions

diff --git a/intern/cycles/util/util_debug.cpp b/intern/cycles/util/util_debug.cpp
index e52fda26845..3ce65802cff 100644
--- a/intern/cycles/util/util_debug.cpp
+++ b/intern/cycles/util/util_debug.cpp
@@ -86,6 +86,16 @@ void DebugFlags::CUDA::reset()
   split_kernel = false;
 }
 
+DebugFlags::OptiX::OptiX()
+{
+  reset();
+}
+
+void DebugFlags::OptiX::reset()
+{
+  cuda_streams = 1;
+}
+
 DebugFlags::OpenCL::OpenCL() : device_type(DebugFlags::OpenCL::DEVICE_ALL), debug(false)
 {
   reset();
@@ -130,6 +140,7 @@ void DebugFlags::reset()
   viewport_static_bvh = false;
   cpu.reset();
   cuda.reset();
+  optix.reset();
   opencl.reset();
 }
 
@@ -145,7 +156,10 @@ std::ostream &operator<<(std::ostream &os, DebugFlagsConstRef debug_flags)
      << "  Split      : " << string_from_bool(debug_flags.cpu.split_kernel) << "\n";
 
   os << "CUDA flags:\n"
-     << " Adaptive Compile: " << string_from_bool(debug_flags.cuda.adaptive_compile) << "\n";
+     << "  Adaptive Compile : " << string_from_bool(debug_flags.cuda.adaptive_compile) << "\n";
+
+  os << "OptiX flags:\n"
+     << "  CUDA streams : " << debug_flags.optix.cuda_streams << "\n";
 
   const char *opencl_device_type;
   switch (debug_flags.opencl.device_type) {
diff --git a/intern/cycles/util/util_debug.h b/intern/cycles/util/util_debug.h
index 5b0004ea768..cf6b442b878 100644
--- a/intern/cycles/util/util_debug.h
+++ b/intern/cycles/util/util_debug.h
@@ -99,6 +99,17 @@ class DebugFlags {
     bool split_kernel;
   };
 
+  /* Descriptor of OptiX feature-set to be used. */
+  struct OptiX {
+    OptiX();
+
+    /* Reset flags to their defaults. */
+    void reset();
+
+    /* Number of CUDA streams to launch kernels concurrently from. */
+    int cuda_streams;
+  };
+
   /* Descriptor of OpenCL feature-set to be used. */
   struct OpenCL {
     OpenCL();
@@ -165,6 +176,9 @@ class DebugFlags {
   /* Requested CUDA flags. */
   CUDA cuda;
 
+  /* Requested OptiX flags. */
+  OptiX optix;
+
   /* Requested OpenCL flags. */
   OpenCL opencl;