#include <SDL.h>
#include <SDL_opengl.h>
#include <GL/glu.h>
#include "kiss.h"

char *title = "SDL 50 - SDL and OpenGL 2";
SDL_Window *window;
SDL_GLContext gl_context;
bool draw_quad = 1;

int
init_sdlgl(void)
{
   int status = -1;

   SDL_INIT(SDL_INIT_VIDEO);
   SDL_GL_SETATTRIBUTE(SDL_GL_CONTEXT_MAJOR_VERSION, 2);
   SDL_GL_SETATTRIBUTE(SDL_GL_CONTEXT_MINOR_VERSION, 1);

   window = SDL_CREATEWINDOW(title, 50, 50, 800, 600, SDL_WINDOW_OPENGL);
   gl_context = SDL_GL_CREATECONTEXT(window);
   SDL_GL_SetSwapInterval(1);

   glMatrixMode(GL_PROJECTION);
   glLoadIdentity();

   GL_CHECK("GL init 1");

   glMatrixMode(GL_MODELVIEW);
   glLoadIdentity();

   GL_CHECK("GL init 2");

   glClearColor(0, 0, 1, 1);

   GL_CHECK("GL init 3");

   // TODO On OS X make sure you bind 0 to the draw framebuffer before swapping the window, otherwise nothing will happen.  ???

   status = 0;
error:
   return status;
}

#define INIT_SDLGL(...) SDL_ZERO(init_sdlgl, __VA_ARGS__)

void
close_sdl(void)
{
   SDL_DestroyWindow(window);
   SDL_Quit();
}

void
draw(void)
{
   glClear(GL_COLOR_BUFFER_BIT);

   if (!draw_quad)
     return;

   glColor4f(0, 1, 0.5, 1);
   glBegin(GL_QUADS);
   glVertex2f(-.5, -.6);
   glVertex2f(.6, -.5);
   glVertex2f(.5, .6);
   glVertex2f(-.6, .5);
   glEnd();
}

void
key_down(SDL_Keycode k)
{
   switch (k)
     {
      case SDLK_SPACE:
        draw_quad = !draw_quad;
        break;
     }
}

int
main(void)
{
   int exit_status = EXIT_FAILURE;
   bool quit = 0;
   SDL_Event e;

   INIT_SDLGL();

   while (!quit)
     {
        while (SDL_PollEvent(&e))
          {
             if (e.type == SDL_QUIT)
               quit = 1;
             if (e.type == SDL_KEYDOWN)
               key_down(e.key.keysym.sym);
          }

        draw();
        SDL_GL_SwapWindow(window);
        GL_CHECK("GL Frame");
     }

   exit_status = EXIT_SUCCESS;
error:
   close_sdl();
   exit(exit_status);
}