Provide non-X11 support, using fullscreen EGL video and SDL2 controls

CMakeLists.txt

@@ -4,10 +4,13 @@ project(eglut LANGUAGES CXX)
 
 include(BuildSettings.cmake)
 
+set(CMAKE_MODULE_PATH ${CMAKE_MODULE_PATH} "${CMAKE_CURRENT_SOURCE_DIR}/cmake/")
+
 set(GAMEWINDOW_SOURCES include/game_window.h include/game_window_manager.h src/game_window_manager.cpp src/game_window_error_handler.cpp src/joystick_manager.cpp)
 set(GAMEWINDOW_SOURCES_LINUX_GAMEPAD src/joystick_manager_linux_gamepad.cpp src/joystick_manager_linux_gamepad.h src/window_with_linux_gamepad.cpp src/window_with_linux_gamepad.h)
 set(GAMEWINDOW_SOURCES_EGLUT src/window_eglut.h src/window_eglut.cpp src/window_manager_eglut.cpp src/window_manager_eglut.h)
 set(GAMEWINDOW_SOURCES_GLFW src/window_glfw.h src/window_glfw.cpp src/window_manager_glfw.cpp src/window_manager_glfw.h src/joystick_manager_glfw.cpp src/joystick_manager_glfw.h)
+set(GAMEWINDOW_SOURCES_SDL2 src/window_sdl2.h src/window_sdl2.cpp src/window_manager_sdl2.cpp src/window_manager_sdl2.h)
 
 add_library(gamewindow ${GAMEWINDOW_SOURCES})
 target_include_directories(gamewindow PUBLIC include/)
@@ -18,4 +21,11 @@ if (GAMEWINDOW_SYSTEM STREQUAL "EGLUT")
 elseif (GAMEWINDOW_SYSTEM STREQUAL "GLFW")
     target_sources(gamewindow PRIVATE ${GAMEWINDOW_SOURCES_GLFW})
     target_link_libraries(gamewindow PUBLIC glfw3)
-endif()
+elseif (GAMEWINDOW_SYSTEM STREQUAL "SDL2")
+    find_package(EGL REQUIRED)
+    message(STATUS "Found EGL")
+    find_package(SDL2 REQUIRED)
+    message(STATUS "Found SDL2: -I" ${SDL2_INCLUDE_DIRS} " " ${SDL2_LIBRARIES})
+    target_sources(gamewindow PRIVATE ${GAMEWINDOW_SOURCES_SDL2})
+    target_link_libraries(gamewindow ${EGL_LIBRARIES} ${SDL2_LIBRARIES})
+endif()

cmake/FindEGL.cmake

@@ -0,0 +1,25 @@
+# Finds the `egl` library.
+# This file is released under the Public Domain.
+# Once done this will define
+#  EGL_FOUND - Set to true if egl has been found
+#  EGL_INCLUDE_DIRS - The egl include directories
+#  EGL_LIBRARIES - The libraries needed to use egl
+
+find_package(PkgConfig)
+pkg_check_modules(PC_EGL QUIET egl)
+
+find_path(EGL_INCLUDE_DIR
+        NAMES EGL/egl.h
+        HINTS ${PC_EGL_INCLUDEDIR} ${PC_EGL_INCLUDE_DIRS})
+find_library(EGL_LIBRARY
+        NAMES EGL libEGL
+        HINTS ${PC_EGL_LIBDIR} ${PC_EGL_LIBRARY_DIRS})
+
+include(FindPackageHandleStandardArgs)
+find_package_handle_standard_args(EGL DEFAULT_MSG
+        EGL_LIBRARY EGL_INCLUDE_DIR)
+
+mark_as_advanced(EGL_INCLUDE_DIR EGL_LIBRARY)
+
+set(EGL_LIBRARIES ${EGL_LIBRARY})
+set(EGL_INCLUDE_DIRS ${EGL_INCLUDE_DIR})

src/window_manager_sdl2.cpp

@@ -0,0 +1,59 @@
+#include "window_manager_sdl2.h"
+#include "window_sdl2.h"
+#include <EGL/egl.h>
+#include <dlfcn.h>
+
+GameWindowManager::ProcAddrFunc dlsymGetProcAddress(const char* sym) {
+    if (!sym)
+        return NULL;
+    void *eglFunc;
+
+    // try official EGL method first
+    eglFunc = (void*)eglGetProcAddress(sym);
+    if (eglFunc)
+        return (GameWindowManager::ProcAddrFunc)eglFunc;
+
+    // manual fallback "If the EGL version is not 1.5 or greater, only queries of EGL and client API extension functions will succeed."
+    void *libEGL;
+    libEGL = dlopen("libEGL.so", RTLD_LAZY | RTLD_GLOBAL);
+    if (!libEGL) {
+        printf("Error: Unable to open libEGL.so for symbol processing");
+        return NULL;
+    }
+
+    eglFunc = dlsym(libEGL, sym);
+    dlclose(libEGL);
+
+    return (GameWindowManager::ProcAddrFunc)eglFunc;
+}
+
+SDL2WindowManager::SDL2WindowManager() {
+    /*
+    nothing instantiated yet
+    just a handle to:
+      1. access the GL libraries via dlsymGetProcAddress()
+      2. the future window
+    */
+}
+
+GameWindowManager::ProcAddrFunc SDL2WindowManager::getProcAddrFunc() {
+    return (GameWindowManager::ProcAddrFunc) dlsymGetProcAddress;
+}
+
+std::shared_ptr<GameWindow> SDL2WindowManager::createWindow(const std::string& title, int width, int height,
+                                                             GraphicsApi api) {
+    return std::shared_ptr<GameWindow>(new SDL2GameWindow(title, width, height, api));
+}
+
+void SDL2WindowManager::addGamepadMappingFile(const std::string &path) {
+    printf("Loaded %d more controller mappings from %s\n", SDL_GameControllerAddMappingsFromFile(path.c_str()), path.c_str());
+}
+
+void SDL2WindowManager::addGamePadMapping(const std::string &content) {
+    // NOOP
+}
+
+// Define this window manager as the used one
+std::shared_ptr<GameWindowManager> GameWindowManager::createManager() {
+    return std::shared_ptr<GameWindowManager>(new SDL2WindowManager());
+}

src/window_manager_sdl2.h

@@ -0,0 +1,21 @@
+#pragma once
+
+#include "game_window_manager.h"
+
+
+GameWindowManager::ProcAddrFunc dlsymGetProcAddress(const char*);
+
+
+class SDL2WindowManager : public GameWindowManager {
+
+public:
+    SDL2WindowManager();
+
+    ProcAddrFunc getProcAddrFunc() override;
+
+    std::shared_ptr<GameWindow> createWindow(const std::string& title, int width, int height, GraphicsApi api) override;
+
+    void addGamepadMappingFile(const std::string& path) override;
+
+    void addGamePadMapping(const std::string &content) override;
+};