Integrated Box2D with build system

We introduced 2 custom CMake options:
- `VOLT_USE_SIMD` :: Enable SIMD math
- `VOLT_USE_AVX2` :: Enable AVX2 instruction set

CMakeLists.txt

@@ -1,6 +1,9 @@
 cmake_minimum_required(VERSION 3.20)
+
+include(CMakeDependentOption)
 include(cmake/build_type.cmake)
 include(cmake/c_compiler.cmake)
+include(cmake/volt_options.cmake)
 include(cmake/cxx_compiler.cmake)
 include(cmake/c_compiler_options.cmake)
 include(cmake/cxx_compiler_options.cmake)
@@ -19,6 +22,7 @@ set(CMAKE_PROJECT_VERSION 0.2-alpha)
 
 volt_set_c_compiler_options()
 volt_set_cxx_compiler_options()
+volt_set_options()
 
 message(STATUS "The requested build target is ${CMAKE_SYSTEM}")
 

cmake/volt_options.cmake

@@ -0,0 +1,21 @@
+function (volt_set_options)
+  option(VOLT_USE_SIMD "Enable SIMD math" ON)
+  if (CMAKE_SYSTEM_PROCESSOR MATCHES "x86_64|AMD64")
+    cmake_dependent_option(VOLT_USE_AVX2 "Enable AVX2 instruction set" ON "VOLT_USE_SIMD" OFF)
+  endif()
+
+  # Check VOLT_USE_SIMD value is valid
+  if (NOT VOLT_USE_SIMD STREQUAL "ON" AND NOT VOLT_USE_SIMD STREQUAL "OFF")
+    message(WARNING "VOLT_USE_SIMD is set to an invalid value (${VOLT_USE_SIMD}), defaulting to ON")
+    set(VOLT_USE_SIMD ON CACHE STRING "Enable SIMD math" FORCE)
+  endif()
+
+  # Check VOLT_USE_AVX2 value is valid
+  if (NOT VOLT_USE_AVX2 STREQUAL "ON" AND NOT VOLT_USE_AVX2 STREQUAL "OFF")
+    message(WARNING "VOLT_USE_AVX2 is set to an invalid value (${VOLT_USE_AVX2}), defaulting to ON")
+    set(VOLT_USE_AVX2 ON CACHE STRING "Enable AVX2 instruction set" FORCE)
+  endif()
+
+  message(STATUS "Use SIMD: ${VOLT_USE_SIMD}")
+  message(STATUS "Use AVX2: ${VOLT_USE_AVX2}")
+endfunction()

vendor/CMakeLists.txt

@@ -1,23 +1,40 @@
 file(GLOB IMGUI_SRCS CONFIGURE_DEPENDS "imgui/*.cpp")
+file(GLOB BOX2D_SRCS CONFIGURE_DEPENDS "box2d/src/*.c")
 file(GLOB RAYLIB_SRCS CONFIGURE_DEPENDS "raylib/src/*.c")
 file(GLOB IMGUIZMO_SRCS CONFIGURE_DEPENDS "imguizmo/*.cpp")
 file(GLOB_RECURSE YAML_CPP_SRCS CONFIGURE_DEPENDS "yaml-cpp/src/*.cpp")
 file(GLOB IMGUI_IMPL_RAYLIB_SRCS CONFIGURE_DEPENDS "imgui_impl_raylib/*.cpp")
 
 add_library(imgui OBJECT ${IMGUI_SRCS})
+add_library(box2d OBJECT ${BOX2D_SRCS})
 add_library(raylib OBJECT ${RAYLIB_SRCS})
 add_library(imguizmo OBJECT ${IMGUIZMO_SRCS})
 add_library(yaml_cpp OBJECT ${YAML_CPP_SRCS})
 add_library(imgui_impl_raylib OBJECT ${IMGUI_IMPL_RAYLIB_SRCS})
 
 target_compile_definitions(raylib PRIVATE PLATFORM_DESKTOP)
 target_compile_definitions(yaml_cpp PRIVATE YAML_CPP_STATIC_DEFINE)
+if (VOLT_USE_SIMD)
+  target_compile_definitions(box2d PRIVATE BOX2D_ENABLE_SIMD)
+endif()
 
 target_include_directories(imguizmo SYSTEM PUBLIC imgui)
+target_include_directories(box2d SYSTEM PUBLIC box2d/include)
 target_include_directories(imgui_impl_raylib SYSTEM PUBLIC imgui)
+target_include_directories(box2d SYSTEM PUBLIC box2d/extern/simde)
 target_include_directories(yaml_cpp SYSTEM PUBLIC yaml-cpp/include)
 target_include_directories(imgui_impl_raylib SYSTEM PUBLIC raylib/src)
 target_include_directories(raylib SYSTEM PUBLIC raylib/src/external/glfw/include)
 
 target_compile_options(raylib PRIVATE "-w")
+target_compile_options(box2d PRIVATE "-ffp-contract=off")
 target_compile_options(raylib PRIVATE "-Wno-implicit-function-declaration")
+
+if (VOLT_USE_AVX2)
+  target_compile_definitions(box2d PRIVATE BOX2D_AVX2)
+  if (MSVC)
+    target_compile_options(box2d PRIVATE "/arch:AVX2")
+  else()
+    target_compile_options(box2d PRIVATE "-mavx2")
+  endif()
+endif()