Add SDL2 initialization library & use it in app

libs/app/CMakeLists.txt

@@ -1,5 +1,3 @@
-find_package(SDL2 REQUIRED)
-
 file(GLOB_RECURSE PSEMEK_APP_HEADERS RELATIVE "${CMAKE_CURRENT_SOURCE_DIR}" "include/*.hpp")
 file(GLOB_RECURSE PSEMEK_APP_SOURCES RELATIVE "${CMAKE_CURRENT_SOURCE_DIR}" "source/*.cpp")
 

libs/app/source/app.cpp

@@ -1,43 +1,20 @@
 #include <psemek/app/app.hpp>
 #include <psemek/gfx/gl.hpp>
 #include <psemek/log/log.hpp>
+#include <psemek/sdl2/init.hpp>
 
 #include <SDL2/SDL.h>
 
 namespace psemek::app
 {
 
-	namespace
-	{
-
-		[[noreturn]] void sdl_fail(std::string const & message)
-		{
-			throw std::runtime_error(message + SDL_GetError());
-		}
-
-		struct sdl_initializer
-		{
-			sdl_initializer()
-			{
-				if (SDL_Init(SDL_INIT_VIDEO) != 0)
-					sdl_fail("Failed to initialize SDL2: ");
-			}
-
-			~sdl_initializer()
-			{
-				SDL_Quit();
-			}
-		};
-
-	}
-
 	using clock = std::chrono::high_resolution_clock;
 
 	struct app::impl
 	{
 		app * parent;
 
-		sdl_initializer init;
+		std::shared_ptr<void> sdl_init;
 		SDL_Window * window = nullptr;
 		SDL_GLContext gl_context = nullptr;
 
@@ -51,6 +28,7 @@ namespace psemek::app
 
 		impl(app * parent)
 			: parent(parent)
+			, sdl_init(sdl2::init(SDL_INIT_VIDEO))
 		{}
 
 		~impl()
@@ -97,11 +75,11 @@ namespace psemek::app
 
 		impl().window = SDL_CreateWindow(name.data(), SDL_WINDOWPOS_UNDEFINED, SDL_WINDOWPOS_UNDEFINED, 800, 600, SDL_WINDOW_RESIZABLE | SDL_WINDOW_OPENGL | SDL_WINDOW_MAXIMIZED);
 		if (!impl().window)
-			sdl_fail("Failed to create window: ");
+			sdl2::fail("Failed to create window: ");
 
 		impl().gl_context = SDL_GL_CreateContext(impl().window);
 		if (!impl().gl_context)
-			sdl_fail("Failed to create OpenGL context: ");
+			sdl2::fail("Failed to create OpenGL context: ");
 
 		SDL_GL_MakeCurrent(impl().window, impl().gl_context);
 

libs/sdl2/CMakeLists.txt

@@ -0,0 +1,8 @@
+find_package(SDL2 REQUIRED)
+
+file(GLOB_RECURSE PSEMEK_SDL2_HEADERS RELATIVE "${CMAKE_CURRENT_SOURCE_DIR}" "include/*.hpp")
+file(GLOB_RECURSE PSEMEK_SDL2_SOURCES RELATIVE "${CMAKE_CURRENT_SOURCE_DIR}" "source/*.cpp")
+
+add_library(psemek-sdl2 ${PSEMEK_SDL2_HEADERS} ${PSEMEK_SDL2_SOURCES})
+target_include_directories(psemek-sdl2 PUBLIC "${CMAKE_CURRENT_SOURCE_DIR}/include" "${SDL2_INCLUDE_DIRS}")
+target_link_libraries(psemek-sdl2 PUBLIC ${SDL2_LIBRARIES})

libs/sdl2/include/psemek/sdl2/init.hpp

@@ -0,0 +1,13 @@
+#pragma once
+
+#include <memory>
+#include <cstdint>
+
+namespace psemek::sdl2
+{
+
+	[[noreturn]] void fail(std::string const & message);
+
+	std::shared_ptr<void> init(std::uint32_t subsystems);
+
+}

libs/sdl2/source/init.cpp

@@ -0,0 +1,68 @@
+#include <psemek/sdl2/init.hpp>
+
+#include <SDL2/SDL.h>
+
+namespace psemek::sdl2
+{
+
+	namespace
+	{
+
+		struct sdl_initializer
+		{
+			sdl_initializer()
+			{
+				if (SDL_Init(0) != 0)
+					fail("Failed to initialize SDL2: ");
+			}
+
+			~sdl_initializer()
+			{
+				SDL_Quit();
+			}
+
+			static std::shared_ptr<sdl_initializer> instance()
+			{
+				static std::weak_ptr<sdl_initializer> ptr;
+
+				if (auto p = ptr.lock(); p)
+					return p;
+
+				auto p = std::make_shared<sdl_initializer>();
+				ptr = p;
+				return p;
+			}
+		};
+
+		struct subsystem_initializer
+		{
+			std::shared_ptr<sdl_initializer> sdl_init;
+			std::uint32_t subsystems;
+
+			subsystem_initializer(std::uint32_t subsystems)
+				: sdl_init(sdl_initializer::instance())
+				, subsystems(subsystems)
+			{
+				if (SDL_InitSubSystem(subsystems) != 0)
+					fail("Failed to initialize SDL2 subsystems: ");
+			}
+
+			~subsystem_initializer()
+			{
+				SDL_QuitSubSystem(subsystems);
+			}
+		};
+
+	}
+
+	[[noreturn]] void fail(std::string const & message)
+	{
+		throw std::runtime_error(message + SDL_GetError());
+	}
+
+	std::shared_ptr<void> init(std::uint32_t subsystems)
+	{
+		return std::make_shared<subsystem_initializer>(subsystems);
+	}
+
+}