Episode 3

/*
Compile command:
g++ -o test main.cpp -lSDLmain -lSDL -lGL -lSDL_image

Windows users:
Linker parameters:
-lmingw32 -lSDLmain -lSDL -lopengl32 -lglu32
 */

// specific headers
#include "SDL/SDL.h"
#include "SDL/SDL_opengl.h"
#include "SDL/SDL_image.h"
#include <iostream>
#include <string>

int main( int agrc, char* args[] )
{
  SDL_Init(SDL_INIT_EVERYTHING);

  //Set OpenGL memory usage
  SDL_GL_SetAttribute( SDL_GL_RED_SIZE, 8 );
  SDL_GL_SetAttribute( SDL_GL_GREEN_SIZE, 8);
  SDL_GL_SetAttribute( SDL_GL_BLUE_SIZE, 8 );
  SDL_GL_SetAttribute( SDL_GL_ALPHA_SIZE, 8);
  SDL_GL_SetAttribute( SDL_GL_BUFFER_SIZE, 32);
  SDL_GL_SetAttribute( SDL_GL_DEPTH_SIZE, 16 );
  SDL_GL_SetAttribute( SDL_GL_DOUBLEBUFFER, 1 );

  //Caption of the window
  SDL_WM_SetCaption( "Our first game", NULL );

  //Size of the window
  SDL_SetVideoMode(600,400,32, SDL_OPENGL );

  //Specific the clear color
  glClearColor(1,1,1,1); //RED,GREEN,BLUE,ALPHA

  //What portion of the screen we will display
  glViewport(0,0,600,400);

  //2D rendering
  glMatrixMode(GL_PROJECTION);

  //"Save" it
  glLoadIdentity();

  //Disable depth checking
  glDisable(GL_DEPTH_TEST);

  std::cout << "OpenGL is running" << std::endl;

  //Handle the main loop
  bool isRunning = true;

  //For handling events
  SDL_Event event;

  //Main game loop
  while ( isRunning )
    {
      //EVENTS
      while ( SDL_PollEvent(&event) )
    {
      if ( event.type == SDL_QUIT ) //If X on windows has been pressed
        {
          isRunning = false;
        }

      //If a key has been released, and the key is ESCAPE
      if ( event.type = SDL_KEYUP && event.key.keysym.sym == SDLK_ESCAPE )
        {
          isRunning = false;
        }

      //If a key has been released and the key is 'r'
      if ( event.type = SDL_KEYUP & event.key.keysym.sym == SDLK_r )
        {
          glClearColor(1,0,0,1); //Red clear color
        }
    }

      //LOGIC

      //RENDERING
      glClear(GL_COLOR_BUFFER_BIT);


      SDL_GL_SwapBuffers();
    }

  //Quit SDL
  SDL_Quit();

  return 0;
}