[SDL2 와 OpenGL]윈도우 생성과 2D그래픽

#include <iostream>
#include <SDL2/SDL.h>

using namespace std;

#define UNUSED(x) (void)(x)

int sdl_window_example()
{
    SDL_Window *window;                    // Declare a pointer

    SDL_Init(SDL_INIT_VIDEO);              // Initialize SDL2

    // Create an application window with the following settings:
    window = SDL_CreateWindow(
        "An SDL2 window",                  // window title
        SDL_WINDOWPOS_UNDEFINED,           // initial x position
        SDL_WINDOWPOS_UNDEFINED,           // initial y position
        640,                               // width, in pixels
        480,                               // height, in pixels
        SDL_WINDOW_OPENGL                  // flags - see below
    );

    // Check that the window was successfully created
    if (window == nullptr) {
        // In the case that the window could not be made...
        printf("Could not create window: %s\n", SDL_GetError());
        return 1;
    }

    auto renderer = SDL_CreateRenderer(window, -1, SDL_RENDERER_ACCELERATED | SDL_RENDERER_PRESENTVSYNC);

    if(renderer == nullptr)
        goto destroy_window;

    SDL_SetRenderDrawColor(renderer, 0, 255, 0, 255);
    SDL_RenderClear(renderer);
    SDL_RenderPresent(renderer);

    // The window is open: could enter program loop here (see SDL_PollEvent())

    SDL_Delay(3000);  // Pause execution for 3000 milliseconds, for example

    // Close and destroy the renderer
    SDL_DestroyRenderer(renderer);

destroy_window:
    // Close and destroy the window
    SDL_DestroyWindow(window);

    // Clean up
    SDL_Quit();

    return 0;
}

int main(int argc, char *argv[])
{
    UNUSED(argc);
    UNUSED(argv);

    cout << "Hello World!" << endl;

    return sdl_window_example();
}