cmake: add SDL2 support to cmake build script

CMakeLists.txt

@@ -1,7 +1,8 @@
 cmake_minimum_required(VERSION 3.8)
-
 project(librw C CXX)
 
+list(APPEND CMAKE_MODULE_PATH "${CMAKE_CURRENT_LIST_DIR}/cmake")
+
 if(PS2DEV AND EE)
     include("${CMAKE_CURRENT_LIST_DIR}/cmake/ee.cmake")
 endif()
@@ -19,6 +20,16 @@ if(NOT LIBRW_PLATFORM IN_LIST LIBRW_PLATFORMS)
     message(FATAL_ERROR "Illegal LIBRW_PLATFORM=${LIBRW_PLATFORM}")
 endif()
 
+set(LIBRW_GL3_GFXLIBS "GLFW" "SDL2")
+set(LIBRW_GL3_GFXLIB "GLFW" CACHE STRING "gfxlib for gl3")
+set_property(CACHE LIBRW_GL3_GFXLIB PROPERTY STRINGS ${LIBRW_GL3_GFXLIBS})
+if(LIBRW_PLATFORM_GL3)
+    message(STATUS "LIBRW_GL3_GFXLIB = ${LIBRW_GL3_GFXLIB} (choices=${LIBRW_GL3_GFXLIBS})")
+endif()
+if(NOT LIBRW_GL3_GFXLIB IN_LIST LIBRW_GL3_GFXLIBS)
+    message(FATAL_ERROR "Illegal LIBRW_GL3_GFXLIB=${LIBRW_GL3_GFXLIB}")
+endif()
+
 if(LIBRW_PLATFORM_PS2)
     enable_language(DSM)
 endif()
@@ -41,7 +52,7 @@ endif()
 
 if(LIBRW_INSTALL)
     include(CMakePackageConfigHelpers)
-    configure_package_config_file(librw-config.cmake.in librw-config.cmake
+    configure_package_config_file(cmake/librw-config.cmake.in librw-config.cmake
         INSTALL_DESTINATION "${CMAKE_INSTALL_PREFIX}"
         )
     install(

cmake/FindSDL2.cmake

@@ -0,0 +1,27 @@
+find_package(PkgConfig QUIET)
+if(PKG_CONFIG_FOUND)
+    pkg_check_modules(SDL2 IMPORTED_TARGET "sdl2")
+    if(TARGET PkgConfig::SDL2 AND NOT TARGET sdl2::sdl2)
+        add_library(_sdl2 INTERFACE)
+        target_link_libraries(_sdl2 INTERFACE PkgConfig::SDL2)
+        add_library(SDL2::SDL2 ALIAS _sdl2)
+    endif()
+endif()
+
+if(NOT SDL2_FOUND)
+    find_path(SDL2_INCLUDE_DIR sdl2.h)
+    find_library(SDL2_LIBRARY sdl2)
+
+    include(FindPackageHandleStandardArgs)
+    find_package_handle_standard_args(libuv
+        REQUIRED_VARS SDL2_INCLUDE_DIR SDL2_LIBRARY
+    )
+
+    if(NOT TARGET SDL2::SDL2)
+        add_library(SDL2::SDL2 UNKNOWN IMPORTED)
+        set_target_properties(SDL2::SDL2 PROPERTIES
+            IMPORTED_LOCATION "${SDL2_LIBRARY}"
+            INTERFACE_INCLUDE_DIRECTORIES "${SDL2_INCLUDE_DIR}"
+        )
+    endif()
+endif()

cmake/librw-config.cmake.in

@@ -0,0 +1,19 @@
+include("${CMAKE_CURRENT_LIST_DIR}/librw-targets.cmake")
+
+set(LIBRW_PLATFORM "@LIBRW_PLATFORM@")
+set(LIBRW_PLATFORMS "@LIBRW_PLATFORMS@")
+set(LIBRW_PLATFORM_@LIBRW_PLATFORM@ ON)
+
+if(LIBRW_PLATFORM_GL3)
+    set(LIBRW_GL3_GFXLIB "@LIBRW_GL3_GFXLIB@")
+    set(LIBRW_GL3_GFXLIBS "@LIBRW_GL3_GFXLIBS@")
+
+    set(OpenGL_GL_PREFERENCE GLVND)
+    find_package(OpenGL REQUIRED)
+    if(LIBRW_GL3_GFXLIB STREQUAL "GLFW")
+        find_package(GLEW REQUIRED)
+        find_package(glfw3 REQUIRED)
+    elseif(LIBRW_GL3_GFXLIB STREQUAL "GLFW")
+        find_package(SDL2 REQUIRED)
+    endif()
+endif()

librw-config.cmake.in

@@ -1,12 +0,0 @@
-include("${CMAKE_CURRENT_LIST_DIR}/librw-targets.cmake")
-
-set(LIBRW_PLATFORM "@LIBRW_PLATFORM@")
-set(LIBRW_PLATFORMS "@LIBRW_PLATFORMS@")
-set(LIBRW_PLATFORM_@LIBRW_PLATFORM@ ON)
-
-if(LIBRW_PLATFORM_GL3)
-    set(OpenGL_GL_PREFERENCE GLVND)
-    find_package(OpenGL REQUIRED)
-    find_package(GLEW REQUIRED)
-    find_package(glfw3 REQUIRED)
-endif()

skeleton/CMakeLists.txt

@@ -1,5 +1,6 @@
 add_library(librw_skeleton
         glfw.cpp
+        sdl2.cpp
         skeleton.cpp
         skeleton.h
         win.cpp

src/CMakeLists.txt

@@ -1,10 +1,3 @@
-if(LIBRW_PLATFORM_GL3)
-    set(OpenGL_GL_PREFERENCE GLVND)
-    find_package(OpenGL REQUIRED)
-    find_package(GLEW REQUIRED)
-    find_package(glfw3 REQUIRED)
-endif()
-
 add_library(librw
     "${PROJECT_SOURCE_DIR}/args.h"
     "${PROJECT_SOURCE_DIR}/rw.h"
@@ -145,12 +138,33 @@ set_target_properties(librw
     )
 
 if(LIBRW_PLATFORM_GL3)
+
+
+if(LIBRW_PLATFORM_GL3)
+    set(OpenGL_GL_PREFERENCE GLVND)
+    find_package(OpenGL REQUIRED)
+    find_package(GLEW REQUIRED)
+
     target_link_libraries(librw
         PUBLIC
-            glfw
-            GLEW::GLEW
             OpenGL::GL
+            GLEW::GLEW
         )
+    if (LIBRW_GL3_GFXLIB STREQUAL "GLFW")
+        find_package(glfw3 REQUIRED)
+        target_link_libraries(librw
+            PUBLIC
+                glfw
+            )
+    elseif (LIBRW_GL3_GFXLIB STREQUAL "SDL2")
+        find_package(SDL2 REQUIRED)
+        target_compile_definitions(librw PUBLIC LIBRW_SDL2)
+        target_link_libraries(librw
+            PUBLIC
+                SDL2::SDL2
+            )
+    endif()
+endif()
 elseif(LIBRW_PLATFORM_D3D9)
     target_link_libraries(librw
         PUBLIC