minimal sdl2/opengl example

b.cc

// g++ -I/usr/local/include/SDL2 -I/usr/include/GL b.cc -lSDL2 -lGL -lGLU -o b

#include <SDL2/SDL.h>
#include <SDL2/SDL_opengl.h>
#include <gl.h>

static SDL_Window *window;
static SDL_Renderer *renderer;

#define width 640
#define height 480

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

  window = SDL_CreateWindow("sdl opengl test", SDL_WINDOWPOS_CENTERED,
                            SDL_WINDOWPOS_CENTERED, width, height,
                            SDL_WINDOW_OPENGL | SDL_WINDOW_SHOWN);

  SDL_GLContext context = SDL_GL_CreateContext(window);

  for (;;) {
    SDL_Event event;
    while (SDL_PollEvent(&event)) {
      switch (event.type) {
      case SDL_QUIT:
      case SDL_KEYDOWN:
        goto done;
      }
    }

    glDisable(GL_DEPTH_TEST);

    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

    glViewport(0, 0, width, height);

    glMatrixMode(GL_PROJECTION);
    glLoadIdentity();

    glMatrixMode(GL_MODELVIEW);
    glLoadIdentity();

    glColor3f(1, 0.5, 0.5);
    glRectf(-0.9, -0.9, 0.9, 0.9);

    SDL_GL_SwapWindow(window);
    SDL_Delay(1);
  }

done:
  SDL_GL_DeleteContext(context);
  SDL_DestroyWindow(window);
  SDL_Quit();

  return 0;
}