import std.stdio;
import derelict.sdl2.sdl;
import derelict.opengl3.gl3;

enum int WIDTH = 800;
enum int HEIGHT = 600;

void init()
{
    glClearColor (1.0, 0.7, 0.0, 0.0);
    glViewport(0, 0, WIDTH, HEIGHT);
}

void display(SDL_Window * window)
{
    glClear(GL_COLOR_BUFFER_BIT);
    SDL_GL_SwapWindow(window);
}

int main()
{
    DerelictSDL2.load();

    DerelictGL3.load();

    if (SDL_Init(SDL_INIT_EVERYTHING))
    {
        writeln("Failed to initialize SDL!");
        return 1;
    }

    SDL_Window * window = SDL_CreateWindow("d-dub-derelict-sdl2-gl3-demo",
                                           SDL_WINDOWPOS_UNDEFINED,
                                           SDL_WINDOWPOS_UNDEFINED,
                                           WIDTH,
                                           HEIGHT,
                                           SDL_WINDOW_OPENGL);
    SDL_GLContext context = SDL_GL_CreateContext(window);

    if (window == null)
    {
        writeln("Failed to create SDL window!");
        return 1;
    }

    DerelictGL3.reload();

    init();
    SDL_Event event;
    for (;;)
    {
        if (SDL_PollEvent(&event))
        {
            if (event.type == SDL_QUIT)
                break;
            else if (event.type == SDL_KEYDOWN)
            {
                if (event.key.keysym.scancode == SDL_SCANCODE_ESCAPE)
                    break;
            }
        }
        display(window);
    }

    SDL_GL_DeleteContext(context);

    SDL_DestroyWindow(window);

    SDL_Quit();

    return 0;
}