CMakeLists.txt

# CMake entry point
cmake_minimum_required(VERSION 3.16 FATAL_ERROR)

project(engine)

if( CMAKE_BINARY_DIR STREQUAL CMAKE_SOURCE_DIR )
    message( FATAL_ERROR "Please select another Build Directory" )
endif()
if( CMAKE_SOURCE_DIR MATCHES " " )
	message( "Your Source Directory contains spaces. If you experience problems when compiling, this can be the cause." )
endif()
if( CMAKE_BINARY_DIR MATCHES " " )
	message( "Your Build Directory contains spaces. If you experience problems when compiling, this can be the cause." )
endif()

# configure compiler
set(CMAKE_CXX_STANDARD 17)
set(CMAKE_CXX_STANDARD_REQUIRED ON)
set(CMAKE_CXX_EXTENSIONS OFF)
if(MSVC)
	set(_GLFW_WIN32, true)
endif(MSVC)

if ("${CMAKE_CXX_COMPILER_ID}" STREQUAL "MSVC")
	set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} /std:c++17")
else()
  set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++17")
endif()

#
# configuration flags
#
set(GENERATE_DEBUG_SYMBOLS ON)
set(CMAKE_CONFIGURATION_TYPES "Debug;Release;Distribution")
set(DOUBLE_PRECISION OFF)

# opengl
set(OpenGL_GL_PREFERENCE GLVND)
find_package(OpenGL REQUIRED)

# glm
add_compile_definitions(GLM_FORCE_SSE2)

# Jolt physics
#set(CMAKE_INTERPROCEDURAL_OPTIMIZATION ON)
#set(INTERPROCEDURAL_OPTIMIZATION ON)
set(CROSS_PLATFORM_DETERMINISTIC OFF) # deterministic across platforms
set(FLOATING_POINT_EXCEPTIONS_ENABLED OFF) # only on msvc
set(OBJECT_LAYER_BITS 16)
set(USE_SSE4_1 ON)
set(USE_SSE4_2 ON)
set(USE_AVX ON)
set(USE_AVX2 ON)
set(USE_AVX512 OFF)
set(USE_LZCNT ON)
set(USE_TZCNT ON)
set(USE_F16C ON)
set(USE_FMADD ON)

if (MSVC)
	# 64 bit architecture
	set(CMAKE_VS_PLATFORM_TOOLSET_HOST_ARCHITECTURE "x64")

	# Set runtime library
	if (USE_STATIC_MSVC_RUNTIME_LIBRARY)
		set(CMAKE_MSVC_RUNTIME_LIBRARY "MultiThreaded$<$<CONFIG:Debug>:Debug>")
	else()
		set(CMAKE_MSVC_RUNTIME_LIBRARY "MultiThreaded$<$<CONFIG:Debug>:Debug>DLL")
	endif()

	# Set general compiler flags
	set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} /Zc:__cplusplus /Gm- /W4 /MP /nologo /diagnostics:classic /FC /fp:except-")
	
	# Optionally generate debug symbols
	if (GENERATE_DEBUG_SYMBOLS)
		set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} /Zi")
	endif()

	# Remove any existing compiler flag that enables RTTI
	string(REPLACE "/GR" "" CMAKE_CXX_FLAGS ${CMAKE_CXX_FLAGS})

	# Set compiler flag for disabling RTTI
	set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} /GR-")

	if ("${CMAKE_VS_PLATFORM_NAME}" STREQUAL "ARM")
		# On ARM the exception handling flag is missing which causes warnings
		set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} /EHsc")
	endif()

	# Set compiler flags for various configurations
	set(CMAKE_CXX_FLAGS_DEBUG "${CMAKE_CXX_FLAGS_DEBUG} /GS /Od /Ob0 /RTC1")
	set(CMAKE_CXX_FLAGS_RELEASE "${CMAKE_CXX_FLAGS_RELEASE} /GS- /Gy /O2 /Oi /Ot")
	set(CMAKE_CXX_FLAGS_DISTRIBUTION "${CMAKE_CXX_FLAGS_DISTRIBUTION} /GS- /Gy /O2 /Oi /Ot")

	# Set linker flags
	if ("${CMAKE_CXX_COMPILER_ID}" STREQUAL "MSVC")
		if (CROSS_PLATFORM_DETERMINISTIC)
			set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} /fp:precise")
		else()
			set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} /fp:fast") # Clang doesn't use fast math because it cannot be turned off inside a single compilation unit
		endif()
	elseif ("${CMAKE_CXX_COMPILER_ID}" STREQUAL "Clang")
		set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} /showFilenames")
		set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Qunused-arguments") # Clang emits warnings about unused arguments such as /MP and /GL
	endif()
else()
	# Set general compiler flags
	set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wall")

	# Optionally generate debug symbols
	if (GENERATE_DEBUG_SYMBOLS)
		set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -g")
	endif()

	if ("${CMAKE_CXX_COMPILER_ID}" STREQUAL "GNU")
		# Also disable -Wstringop-overflow or it will generate false positives that can't be disabled from code when link-time optimizations are enabled
		# Also turn off automatic fused multiply add contractions, there doesn't seem to be a way to do this selectively through the macro JPH_PRECISE_MATH_OFF
		set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wno-stringop-overflow -ffp-contract=off")
	else()
		# Do not use -ffast-math since it cannot be turned off in a single compilation unit under clang, see Core.h
    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -ffp-model=precise")

		# On clang 14 and later we can turn off float contraction through a pragma, older versions and deterministic versions need it off always, see Core.h
		if (CMAKE_CXX_COMPILER_VERSION LESS 14 OR CROSS_PLATFORM_DETERMINISTIC)
			set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -ffp-contract=off")
		endif()
	endif()

	# Set compiler flags for various configurations
	set(CMAKE_CXX_FLAGS_DEBUG "${CMAKE_CXX_FLAGS_DEBUG}")
	set(CMAKE_CXX_FLAGS_RELEASE "${CMAKE_CXX_FLAGS_RELEASE} -O3")
	set(CMAKE_CXX_FLAGS_DISTRIBUTION "${CMAKE_CXX_FLAGS_DISTRIBUTION} -O3")

	# Set linker flags
	if (NOT ("${CMAKE_SYSTEM_NAME}" STREQUAL "Windows"))
		set(CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS} -pthread")
	endif()
endif()

set(CMAKE_EXE_LINKER_FLAGS_DISTRIBUTION "${CMAKE_EXE_LINKER_FLAGS_RELEASE}") # Set linker flags
set(CMAKE_EXPORT_COMPILE_COMMANDS ON) # generate compile_commands.json


include_directories(
	external/glfw-3.3.7/include/
	external/glm-0.9.7.1/
	external/soloud20200207/include/
	external/glew-2.1.0/include/
	external/assimp-5.3.1/include/
	external/imgui/include/
	external/stb/
	external/lightmapper/
	external/indicators/
	external/xatlas/
	external/JoltPhysics-4.0.1/Jolt
	include/
)

# Compile external dependencies 
add_subdirectory(external)

set(ALL_LIBS
	${OPENGL_LIBRARY}
	glfw
	GLEW_210
	assimp
	SOLOUD
	ImGui
	XAtlas
	Jolt
)

add_definitions(
	-DTW_STATIC
	-DTW_NO_LIB_PRAGMA
	-DTW_NO_DIRECT3D
	-DGLEW_STATIC
	-D_CRT_SECURE_NO_WARNINGS
	-DUSE_ASSIMP
	-DNOMINMAX
)

set(SOURCES 
	src/controls/core.cpp
	src/controls/behaviour.cpp
	src/controls/globals.cpp

	src/camera/core.cpp
	src/camera/globals.cpp

	src/shader/core.cpp
	src/shader/globals.cpp

	src/utilities/math.cpp
	src/utilities/strings.cpp

	src/level.cpp
	src/renderer.cpp
	src/serialize.cpp
	src/threadpool.cpp
	src/texture.cpp
	src/editor.cpp
	src/assets.cpp
	src/primitives.cpp
	src/entities.cpp
	src/game_behaviour.cpp
	src/lightmapper.cpp
	src/graphics.cpp
	src/physics.cpp

	src/main.cpp
)

add_executable (engine ${SOURCES})
target_link_libraries(engine ${ALL_LIBS})

set_property(DIRECTORY PROPERTY VS_STARTUP_PROJECT "engine")
set_target_properties(engine PROPERTIES VS_DEBUGGER_WORKING_DIRECTORY "${CMAKE_SOURCE_DIR}")

# Copy compile_commands.json
if( EXISTS "${CMAKE_CURRENT_BINARY_DIR}/compile_commands.json" )
  EXECUTE_PROCESS( COMMAND ${CMAKE_COMMAND} -E copy_if_different
    ${CMAKE_CURRENT_BINARY_DIR}/compile_commands.json
    ${CMAKE_CURRENT_SOURCE_DIR}/compile_commands.json
  )
endif()