CMakeLists.txt

cmake_minimum_required(VERSION 3.9...3.20)

if(${CMAKE_VERSION} VERSION_LESS 3.12)
    cmake_policy(VERSION ${CMAKE_MAJOR_VERSION}.${CMAKE_MINOR_VERSION})
endif()

# Prevent in source builds
if(${CMAKE_SOURCE_DIR} STREQUAL ${CMAKE_BINARY_DIR})
	if(NOT DEFINED WITH_IN_SOURCE_BUILD)
		message(FATAL_ERROR "CMake generation for Ignis is not allowed within the source directory! Define WITH_IN_SOURCE_BUILD if absolutely necessary!" )
	endif()
endif()

# Omit superfluous "Up-to-date" messages.
if(NOT DEFINED CMAKE_INSTALL_MESSAGE)
	set(CMAKE_INSTALL_MESSAGE "LAZY")
endif()

# Set default to Release
if (NOT CMAKE_BUILD_TYPE)
  set(CMAKE_BUILD_TYPE "Release")
endif()

project(Ignis
	VERSION 0.4.0
	DESCRIPTION "Experimental ray tracer")

# For whatever reason Ignis might be used as a subproject...
if(CMAKE_PROJECT_NAME STREQUAL PROJECT_NAME)
	set(IG_SUBPROJECT OFF)
else()
	set(IG_SUBPROJECT ON)
endif()

list(APPEND CMAKE_MESSAGE_CONTEXT ${PROJECT_NAME})
list(APPEND CMAKE_MODULE_PATH ${CMAKE_CURRENT_SOURCE_DIR}/cmake)

# Set corresponding output directory
set(CMAKE_RUNTIME_OUTPUT_DIRECTORY ${CMAKE_BINARY_DIR}/bin)
set(CMAKE_LIBRARY_OUTPUT_DIRECTORY ${CMAKE_BINARY_DIR}/lib)
set(CMAKE_ARCHIVE_OUTPUT_DIRECTORY ${CMAKE_BINARY_DIR}/lib)

set(CMAKE_DEBUG_POSTFIX  "_d")

string(TIMESTAMP THIS_YEAR "%Y")
set(Ignis_VENDOR "Ignis project 2020-${THIS_YEAR}")
set(Ignis_DESCRIPTION "Device agnostic raytracing framework with shared codebase for offline and realtime rendering and for CPU and GPU")
set(Ignis_URL "https://github.com/PearCoding/Ignis")
include(Git)

message(STATUS "Building Ignis Rodent ${Ignis_VERSION}")

if(NOT IG_SUBPROJECT)
    include(CTest)
endif()

# Options
option(IG_WITH_CLI           "Build commandline interface igcli" ON)
option(IG_WITH_VIEWER        "Build interactive viewer igview" ON)
option(IG_WITH_TRACER        "Build tracing frontend igtrace" ON)
option(IG_WITH_EXPLORER      "Build interactive viewer for glare analysis" ON)
option(IG_WITH_PYTHON_API    "Build python API" ON)
option(IG_WITH_TOOLS         "Build tools" ON)
option(IG_WITH_DOCUMENTATION "Build the documentation if Sphinx is available on the system" ON)
option(IG_WITH_ASSERTS       "Build with asserts even in release. It is always enabled on debug" OFF)
option(IG_WITH_DENOISER      "Integrate Intel Open Image Denoise if available" ON)
option(IG_USE_LTO 			 "Use linked time optimization if available in release" ON)

if(${CMAKE_VERSION} VERSION_GREATER_EQUAL 3.21)
	if(WIN32 OR (NOT CMAKE_INSTALL_PREFIX_INITIALIZED_TO_DEFAULT))
		set(_default ON)
	else()
		set(_default OFF)
	endif()
	option(IG_INSTALL_RUNTIME_DEPENDENCIES "Install runtime libraries together with Ignis" ${_default})
endif()

# Make the install relocatable: resolve co-located libraries relative to the binary/module
# ($ORIGIN) instead of baking in an absolute prefix. Covers bin/ -> ../lib and the python
# module api/ignis/ -> ../../lib (or a co-located runtime in a wheel).
if(APPLE)
	set(_ig_origin "@loader_path")
else()
	set(_ig_origin "$ORIGIN")
endif()
set(CMAKE_INSTALL_RPATH "${_ig_origin}" "${_ig_origin}/../lib" "${_ig_origin}/../../lib")
set(CMAKE_BUILD_RPATH_USE_ORIGIN TRUE)

if(SKBUILD)
	find_package(PythonExtensions REQUIRED)
	set(_IG_RUNTIME_SET RUNTIME_DEPENDENCY_SET ignis_runtime_set)
	message(STATUS "Using scikit-build")
elseif(IG_INSTALL_RUNTIME_DEPENDENCIES)
	set(_IG_RUNTIME_SET RUNTIME_DEPENDENCY_SET ignis_runtime_set)
endif()

# Setup artic clang flags
if(APPLE)
	set(IG_ARTIC_CLANG_FLAGS_DEFAULT -ffast-math)
else()
	set(IG_ARTIC_CLANG_FLAGS_DEFAULT -march=native -ffast-math)
endif()
set(IG_ARTIC_CLANG_FLAGS ${IG_ARTIC_CLANG_FLAGS_DEFAULT} CACHE STRING "Additional artic clang compilation options")
set(IG_ARTIC_FLAGS CACHE STRING "Additional artic compilation options")
mark_as_advanced(IG_ARTIC_CLANG_FLAGS IG_ARTIC_FLAGS)

# Setup CPM
include(cmake/SetupCPM.cmake)

# Make sure the filesystem library is available
find_package(Filesystem REQUIRED)

# Locate tbb
find_package(TBB REQUIRED) 

# ZLib is used in the generator
find_package(ZLIB REQUIRED)

# Locate AnyDSL runtime (general purpose)
find_package(AnyDSL_runtime REQUIRED)

if(IG_WITH_DENOISER)
	find_package(OpenImageDenoise)
endif()

include(cmake/Dependencies.cmake)
include(cmake/GetDependencies.cmake)
include(cmake/Bash.cmake)
include(cmake/ExtraUtils.cmake)

# Enable folders for Visual Studio
set_property(GLOBAL PROPERTY USE_FOLDERS ON)

# Make sure we use march native
option(IG_OPTIMIZE_FOR_NATIVE "Build with -march=native if possible. Not recommended for deployment" OFF)
include(CheckCXXCompilerFlag)
if(IG_OPTIMIZE_FOR_NATIVE)
	set(NATIVE_FLAG "-march=native")
	check_cxx_compiler_flag("${NATIVE_FLAG}" COMPILER_SUPPORTS_MARCH_NATIVE)
	if(COMPILER_SUPPORTS_MARCH_NATIVE)
		message(STATUS "Added compiler flag '${NATIVE_FLAG}' to targets")
		add_compile_options(${NATIVE_FLAG})
	endif()
endif()

# Optional GUI
# set(IG_HAS_UI OFF)
if(IG_WITH_VIEWER OR IG_WITH_EXPLORER)
    find_package(OpenGL)

    if(OpenGL_FOUND)
        set(IG_HAS_UI ON)
	else()
    	message(WARNING "Interactive viewer was requested but no OpenGL libraries were found. Disabling viewer")
    endif()
endif()

if(IG_HAS_UI AND IG_WITH_VIEWER)
    message(STATUS "Building with interactive viewer")
endif()

if(IG_HAS_UI AND IG_WITH_EXPLORER)
    message(STATUS "Building with interactive glare explorer")
endif()

if(IG_WITH_PYTHON_API)
	set(Python_FIND_VIRTUALENV FIRST) # Take virtual environments into account
	if (WIN32 AND CMAKE_VERSION VERSION_GREATER_EQUAL 3.26 AND Python_INTERPRETER_ID STREQUAL "Python")
		# Windows stable ABI builds for CPython require Development.SABIModule provided by CMake>=3.26
		find_package(Python 3.8 COMPONENTS Interpreter Development.Module Development.SABIModule)
	elseif (CMAKE_VERSION VERSION_GREATER_EQUAL 3.26)
		# Request Development.SABIModule (optional) so nanobind produces a stable-ABI (abi3)
		# module. A single abi3 build then imports into any CPython >= the build version,
		# instead of a version-locked cpython-3XX module.
		find_package(Python 3.8 COMPONENTS Interpreter Development OPTIONAL_COMPONENTS Development.SABIModule)
	else()
		# The following suffices in all other cases
		find_package(Python 3.8 COMPONENTS Interpreter Development)
	endif()
	if(Python_FOUND)
		set(IG_HAS_PYTHON_API ON)
		message(STATUS "Building with Python API (${Python_VERSION})")
	else()
		message(WARNING "Python API was requested but no Python libraries were found. Disabling Python API")
	endif()
endif()

# Add warnings per default
set(WARNING_FLAGS -Wall -Wextra -pedantic)
check_cxx_compiler_flag("${WARNING_FLAGS}" COMPILER_SUPPORTS_WARNINGS_GNU)
if(COMPILER_SUPPORTS_WARNINGS_GNU)
	add_compile_options(${WARNING_FLAGS})
else()
	set(WARNING_FLAGS /W4)
	check_cxx_compiler_flag("${WARNING_FLAGS}" COMPILER_SUPPORTS_WARNINGS_MSVC)
	if(COMPILER_SUPPORTS_WARNINGS_MSVC)
		add_compile_options(${WARNING_FLAGS})
	endif()
endif()

# Traverse to underlying directories
add_subdirectory(src)

if(IG_WITH_DOCUMENTATION)
	add_subdirectory(docs)
endif()

add_subdirectory(scenes)
add_subdirectory(scripts)

# Handle install
include(cmake/Install.cmake)