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

4 files changed, 62 insertions, 0 deletions

diff --git a/build_files/buildbot/slave_compile.py b/build_files/buildbot/slave_compile.py
index 84667e663f6..0da0ead819f 100644
--- a/build_files/buildbot/slave_compile.py
+++ b/build_files/buildbot/slave_compile.py
@@ -34,6 +34,9 @@ def get_cmake_options(builder):
     elif builder.platform == 'linux':
         config_file = "build_files/buildbot/config/blender_linux.cmake"
 
+    optix_sdk_dir = os.path.join(builder.blender_dir, '..', '..', 'NVIDIA-Optix-SDK')
+    options.append('-DOPTIX_ROOT_DIR:PATH=' + optix_sdk_dir)
+
     options.append("-C" + os.path.join(builder.blender_dir, config_file))
     options.append("-DCMAKE_INSTALL_PREFIX=%s" % (builder.install_dir))
 
diff --git a/build_files/cmake/Modules/FindOptiX.cmake b/build_files/cmake/Modules/FindOptiX.cmake
new file mode 100644
index 00000000000..56fd2fd1396
--- /dev/null
+++ b/build_files/cmake/Modules/FindOptiX.cmake
@@ -0,0 +1,57 @@
+# - Find OptiX library
+# Find the native OptiX includes and library
+# This module defines
+#  OPTIX_INCLUDE_DIRS, where to find optix.h, Set when
+#                         OPTIX_INCLUDE_DIR is found.
+#  OPTIX_ROOT_DIR, The base directory to search for OptiX.
+#                     This can also be an environment variable.
+#  OPTIX_FOUND, If false, do not try to use OptiX.
+
+#=============================================================================
+# Copyright 2019 Blender Foundation.
+#
+# Distributed under the OSI-approved BSD License (the "License");
+# see accompanying file Copyright.txt for details.
+#
+# This software is distributed WITHOUT ANY WARRANTY; without even the
+# implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+# See the License for more information.
+#=============================================================================
+
+# If OPTIX_ROOT_DIR was defined in the environment, use it.
+IF(NOT OPTIX_ROOT_DIR AND NOT $ENV{OPTIX_ROOT_DIR} STREQUAL "")
+  SET(OPTIX_ROOT_DIR $ENV{OPTIX_ROOT_DIR})
+ENDIF()
+
+SET(_optix_SEARCH_DIRS
+  ${OPTIX_ROOT_DIR}
+  "$ENV{PROGRAMDATA}/NVIDIA Corporation/OptiX SDK 7.0.0"
+  /usr/local
+  /sw # Fink
+  /opt/local # DarwinPorts
+)
+
+FIND_PATH(OPTIX_INCLUDE_DIR
+  NAMES
+    optix.h
+  HINTS
+    ${_optix_SEARCH_DIRS}
+  PATH_SUFFIXES
+    include
+)
+
+# handle the QUIETLY and REQUIRED arguments and set OPTIX_FOUND to TRUE if
+# all listed variables are TRUE
+INCLUDE(FindPackageHandleStandardArgs)
+FIND_PACKAGE_HANDLE_STANDARD_ARGS(OptiX DEFAULT_MSG
+    OPTIX_INCLUDE_DIR)
+
+IF(OPTIX_FOUND)
+  SET(OPTIX_INCLUDE_DIRS ${OPTIX_INCLUDE_DIR})
+ENDIF(OPTIX_FOUND)
+
+MARK_AS_ADVANCED(
+  OPTIX_INCLUDE_DIR
+)
+
+UNSET(_optix_SEARCH_DIRS)
diff --git a/build_files/cmake/config/blender_lite.cmake b/build_files/cmake/config/blender_lite.cmake
index e98f4f098bb..37cbfa27972 100644
--- a/build_files/cmake/config/blender_lite.cmake
+++ b/build_files/cmake/config/blender_lite.cmake
@@ -17,6 +17,7 @@ set(WITH_CODEC_FFMPEG        OFF CACHE BOOL "" FORCE)
 set(WITH_CODEC_SNDFILE       OFF CACHE BOOL "" FORCE)
 set(WITH_CYCLES              OFF CACHE BOOL "" FORCE)
 set(WITH_CYCLES_OSL          OFF CACHE BOOL "" FORCE)
+set(WITH_CYCLES_DEVICE_OPTIX OFF CACHE BOOL "" FORCE)
 set(WITH_DRACO               OFF CACHE BOOL "" FORCE)
 set(WITH_FFTW3               OFF CACHE BOOL "" FORCE)
 set(WITH_LIBMV               OFF CACHE BOOL "" FORCE)
diff --git a/build_files/cmake/config/blender_release.cmake b/build_files/cmake/config/blender_release.cmake
index 2d7b167764b..cb338f40a7b 100644
--- a/build_files/cmake/config/blender_release.cmake
+++ b/build_files/cmake/config/blender_release.cmake
@@ -57,6 +57,7 @@ set(WITH_MEM_JEMALLOC          ON  CACHE BOOL "" FORCE)
 set(WITH_CYCLES_CUDA_BINARIES  ON  CACHE BOOL "" FORCE)
 set(WITH_CYCLES_CUBIN_COMPILER OFF CACHE BOOL "" FORCE)
 set(CYCLES_CUDA_BINARIES_ARCH sm_30;sm_35;sm_37;sm_50;sm_52;sm_60;sm_61;sm_70;sm_75 CACHE STRING "" FORCE)
+set(WITH_CYCLES_DEVICE_OPTIX   ON CACHE BOOL "" FORCE)
 
 # platform dependent options
 if(UNIX AND NOT APPLE)