CMakeLists.txt

cmake_minimum_required(VERSION 3.24 FATAL_ERROR)
# CUDA_ARCHITECTURES native is available in CMake since 3.24

set(PROJ_NAME "cuda-pt")
project(${PROJ_NAME} LANGUAGES CUDA CXX)

option(USE_SOA "Use struct of arrays" OFF)
if (USE_SOA)
	add_definitions(-DUSE_SOA)
	message(STATUS "Using SoA3 (struct of arrays) for GPU containers.")
else()
	message(STATUS "Using AoS3 (array of structs) for GPU containers.")
endif()

find_package(Threads REQUIRED)
find_package(OpenMP REQUIRED)
IF("${CMAKE_BUILD_TYPE}" STREQUAL "Debug" OR "${CMAKE_BUILD_TYPE}" STREQUAL "debug" OR "${CMAKE_BUILD_TYPE}" STREQUAL "DEBUG")
	set(CMAKE_BUILD_TYPE Debug)
	if (MSVC)
		message(STATUS "MSVC: Building project in DEBUG mode.")
		set(CMAKE_CUDA_FLAGS "${CMAKE_CUDA_FLAGS} -maxrregcount=56 -lineinfo -arch=native -g -G")
		set(CMAKE_CUDA_FLAGS_DEBUG "${CMAKE_CUDA_FLAGS_DEBUG} -G -g -lineinfo")
		set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} /W3 /g /Od /Zi /MDd")
	else()
		message(STATUS "GCC & G++: Building project in DEBUG mode.")
		set(CMAKE_CUDA_FLAGS "${CMAKE_CUDA_FLAGS} -Wall -G -O0 -lineinfo -maxrregcount=56 -arch=native")
		set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wall -g -O0")
	endif ()
ELSE()
	# to check register usage, please set "-Xptxas -v"
	# to cap the register usage to boost occupancy, set ""
	set(CMAKE_BUILD_TYPE Release)
	if (MSVC)
		if (OPENMP_FOUND)
			set (CMAKE_C_FLAGS "${CMAKE_C_FLAGS} /openmp")
			set (CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} /openmp")
			set (CMAKE_CUDA_FLAGS "${CMAKE_CUDA_FLAGS} -Xcompiler /openmp")
		else()
			message(FATAL_ERROR "OpenMP can not be found but it is required by wavefront path tracer. Manual overriding is required to skip this exception.")
		endif()
		message(STATUS "MSVC: Building project in RELEASE mode.")
		set(CMAKE_CUDA_FLAGS "${CMAKE_CUDA_FLAGS} -maxrregcount=56 -lineinfo -arch=native")
		set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} /O2")
	else()
		message(STATUS "GCC & G++: Building project in RELEASE mode.")
		set(CMAKE_CUDA_FLAGS "${CMAKE_CUDA_FLAGS} -O3 --maxrregcount=56 -lineinfo -arch=native")
		set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -O3")
		if (OPENMP_FOUND)
			set (CMAKE_C_FLAGS "${CMAKE_C_FLAGS} ${OpenMP_C_FLAGS}")
			set (CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} ${OpenMP_CXX_FLAGS}")
			set (CMAKE_CUDA_FLAGS "${CMAKE_CUDA_FLAGS} ${OpenMP_CXX_FLAGS}")
		else()
			message(FATAL_ERROR "OpenMP can not be found but it is required by wavefront path tracer. Manual overriding is required to skip this exception.")
		endif()
	endif ()
ENDIF()

set(CMAKE_CXX_STANDARD 17)
set(CMAKE_CXX_STANDARD_REQUIRED ON)

set(CMAKE_CUDA_SEPARABLE_COMPILATION ON)

include_directories(
	${CMAKE_CURRENT_LIST_DIR}/src 
	${CMAKE_CURRENT_LIST_DIR}/src/ext/imgui
	${CMAKE_CURRENT_LIST_DIR}/src/ext/glfw/include
)

add_subdirectory(src/ext/tinyxml2)
add_subdirectory(src/ext/tinyobjloader)
add_subdirectory(src/ext/imgui)
add_subdirectory(src/ext/glfw)

find_package(OpenGL REQUIRED)
if (MSVC)
	list(APPEND CMAKE_PREFIX_PATH "E:\\glew-2.2.0\\glew")
	set(GLEW_USE_STATIC_LIBS false)
	find_package(GLEW REQUIRED)
else()
	find_package(GLEW REQUIRED)
endif()

aux_source_directory(src/impl CPT_IMPL_SRC)
aux_source_directory(src/pt_impl CPT_PT_IMPL_SRC)
aux_source_directory(src/viewer_impl CPT_VIEWER_IMPL_SRC)

set(EXEC1_NAME "depth")
	add_executable(${EXEC1_NAME}
	app/depth_renderer.cu
	src/ext/lodepng/lodepng.cpp
	${CPT_IMPL_SRC}
)

target_link_libraries(
	${EXEC1_NAME} PRIVATE
	tinyxml2 tinyobjloader
)

set_target_properties(
	${EXEC1_NAME} PROPERTIES
	CUDA_SEPARABLE_COMPILATION ON
	CUDA_ARCHITECTURES native
)

target_compile_options(
	${EXEC1_NAME} PRIVATE
	$<$<COMPILE_LANGUAGE:CUDA>:
	--expt-relaxed-constexpr
	>
)

set(EXEC2_NAME "pt")
add_executable(${EXEC2_NAME}
	app/pt_renderer.cu
	src/ext/lodepng/lodepng.cpp
	${CPT_IMPL_SRC}
	${CPT_PT_IMPL_SRC}
)

target_link_libraries(
	${EXEC2_NAME} PRIVATE
	tinyxml2 tinyobjloader
)

set_target_properties(
	${EXEC2_NAME} PROPERTIES
	CUDA_SEPARABLE_COMPILATION ON
	CUDA_ARCHITECTURES native
)

target_compile_options(
	${EXEC2_NAME} PRIVATE
	$<$<COMPILE_LANGUAGE:CUDA>:
	--expt-relaxed-constexpr
	>
)

set(EXEC3_NAME "cpt")
add_executable(${EXEC3_NAME}
	app/viewer.cu
	src/ext/lodepng/lodepng.cpp
	${CPT_VIEWER_IMPL_SRC}
	${CPT_IMPL_SRC}
	${CPT_PT_IMPL_SRC}
)

target_link_libraries(
	${EXEC3_NAME} PRIVATE
	tinyxml2 tinyobjloader
	GLEW::glew
	glfw
	imgui
	${OPENGL_gl_LIBRARY}
)

set_target_properties(
	${EXEC3_NAME} PROPERTIES
	CUDA_SEPARABLE_COMPILATION ON
	CUDA_ARCHITECTURES native
)

target_compile_options(
	${EXEC3_NAME} PRIVATE
	$<$<COMPILE_LANGUAGE:CUDA>:
	--expt-relaxed-constexpr
	>
)

# ========================================= unit-test ===============================================

add_executable(sensor_test test/parsers/sensor_parse.cc)

target_link_libraries(sensor_test PRIVATE tinyxml2)

add_executable(obj_test test/parsers/obj_parser.cu)

target_link_libraries(obj_test PRIVATE tinyxml2 tinyobjloader)


# CUDA_SEPARABLE_COMPILATION ON: member function declaration and implementation can be separate
# https://developer.nvidia.com/blog/separate-compilation-linking-cuda-device-code/

# CUDA_ARCHITECTURES native: CUDA_ARCHITECTURES is detected automatically
# https://stackoverflow.com/questions/68223398/how-can-i-get-cmake-to-automatically-detect-the-value-for-cuda-architectures