outsourced application handling

lib/CMakeLists.txt

@@ -0,0 +1,11 @@
+
+add_library(nm_utils STATIC
+	"Window.cpp"
+)
+
+target_include_directories(nm_utils PUBLIC ${SDL2_INCLUDE_DIRS} ${CMAKE_CURRENT_SOURCE_DIR})
+target_link_libraries(nm_utils PUBLIC ${SDL2_LIBRARIES})
+
+if(MSVC)
+	target_compile_definitions(nm_utils PUBLIC _CRT_SECURE_NO_WARNINGS)
+endif()

lib/Window.cpp

@@ -0,0 +1,150 @@
+#include "Window.hpp"
+
+#include <iostream>
+#include <SDL.h>
+
+void Window::Launch()
+{
+	SDL_ShowWindow(window);
+
+	while (!shouldClose)
+	{
+		HandleEvents();
+		Update();
+		Render();
+	}
+
+	SDL_HideWindow(window);
+}
+
+Window::Window(int width, int height, const std::string& title)
+{
+	window = nullptr;
+	renderer = nullptr;
+
+	window = SDL_CreateWindow(
+		title.c_str(),
+		SDL_WINDOWPOS_UNDEFINED, SDL_WINDOWPOS_UNDEFINED,
+		width, height,
+		SDL_WINDOW_HIDDEN
+	);
+	if (window == nullptr)
+	{
+		char errbuf[512];
+		SDL_GetErrorMsg(errbuf, 512);
+
+		std::cerr << "Failed to create SDL Window: " << std::endl
+			<< errbuf << std::endl;
+
+		return;
+	}
+
+	renderer = SDL_CreateRenderer(window, -1, SDL_RENDERER_ACCELERATED);
+	if (renderer == nullptr)
+	{
+		char errbuf[512];
+		SDL_GetErrorMsg(errbuf, 512);
+
+		std::cerr << "Failed to create SDL Renderer: " << std::endl
+			<< errbuf << std::endl;
+
+		return;
+	}
+
+	SDL_SetRenderDrawBlendMode(renderer, SDL_BLENDMODE_BLEND);
+
+	startOfLastFrame = std::chrono::steady_clock::now();
+}
+
+Window::Window(const Window& other)
+{
+	*this = other;
+}
+
+Window& Window::operator=(const Window& other)
+{
+	const char* title = SDL_GetWindowTitle(other.window);
+	int width, height;
+	SDL_GetWindowSize(other.window, &width, &height);
+
+	window = SDL_CreateWindow(
+		title,
+		SDL_WINDOWPOS_UNDEFINED, SDL_WINDOWPOS_UNDEFINED,
+		width, height,
+		SDL_WINDOW_HIDDEN
+	);
+
+	if (window == nullptr)
+	{
+		char errbuf[512];
+		SDL_GetErrorMsg(errbuf, 512);
+
+		std::cerr << "Failed to create SDL Window: " << std::endl
+			<< errbuf << std::endl;
+
+		throw std::runtime_error("");
+	}
+
+	renderer = SDL_CreateRenderer(window, -1, SDL_RENDERER_ACCELERATED);
+	if (renderer == nullptr)
+	{
+		char errbuf[512];
+		SDL_GetErrorMsg(errbuf, 512);
+
+		std::cerr << "Failed to create SDL Renderer: " << std::endl
+			<< errbuf << std::endl;
+
+		throw std::runtime_error("");
+	}
+
+	startOfLastFrame = std::chrono::steady_clock::now();
+
+	return *this;
+}
+
+Window::~Window()
+{
+	SDL_DestroyRenderer(renderer);
+	SDL_DestroyWindow(window);
+}
+
+void Window::HandleEvents()
+{
+	SDL_Event event;
+	while (SDL_PollEvent(&event))
+	{
+		switch (event.type)
+		{
+		case SDL_WINDOWEVENT:
+		{
+			switch (event.window.event)
+			{
+			case SDL_WINDOWEVENT_CLOSE:
+				shouldClose = true;
+				break;
+			}
+		} break;
+		}
+	}
+}
+
+void Window::Update()
+{
+	double dt = std::chrono::duration_cast<std::chrono::duration<double>>(std::chrono::steady_clock::now() - startOfLastFrame).count();
+	startOfLastFrame = std::chrono::steady_clock::now();
+
+	OnUpdate(dt);
+}
+
+void Window::Render()
+{
+	SDL_SetRenderDrawColor(renderer, 0, 0, 0, 255);
+	SDL_RenderClear(renderer);
+
+	OnRender(renderer);
+
+	if (renderer == nullptr)
+		throw std::runtime_error("Client window left renderer in an invalid state");
+	
+	SDL_RenderPresent(renderer);
+}

lib/Window.hpp

@@ -0,0 +1,37 @@
+#pragma once
+
+#include <string>
+#include <chrono>
+
+struct SDL_Renderer;
+struct SDL_Window;
+
+class Window
+{
+public:
+	void Launch();
+
+protected:
+	Window(int width, int height, const std::string& title);
+	Window(const Window& other);
+	Window& operator=(const Window& other);
+	~Window();
+
+
+	virtual void OnUpdate(double dt) {}
+	virtual void OnRender(SDL_Renderer* renderer) {}
+
+private:
+	void HandleEvents();
+	void Update();
+	void Render();
+
+protected:
+	SDL_Window* window;
+
+private:
+	SDL_Renderer* renderer;
+
+	bool shouldClose = false;
+	std::chrono::steady_clock::time_point startOfLastFrame;
+};