Problème d'écran bleu lors de l'éxécution de mon programme

#include <iostream>
#include <SDL/SDL.h>
#include <GL/gl.h>
#include <GL/glu.h>

using namespace std;

int main(int argc, char *argv[])
{
	if( SDL_Init(SDL_INIT_VIDEO) < 0)
	{
		cerr << "Echec SDL_Init : " << SDL_GetError() << endl;
		return (EXIT_FAILURE);
	}
	atexit(SDL_Quit);
	SDL_GL_SetAttribute(SDL_GL_DOUBLEBUFFER, 1);
	SDL_Surface *ecran = SDL_SetVideoMode(800, 600, 32, SDL_OPENGL);
	if(ecran==NULL)
	{
		cerr << "Echec lors de la création de fenêtre:" << SDL_GetError() << endl;
		return (EXIT_FAILURE);
	}
	int valeurBuffer;
	if(SDL_GL_GetAttribute(SDL_GL_DOUBLEBUFFER, &valeurBuffer)<0)
	{
		cerr << "Echec de recuperation du parametre SDL_GL_DOUBLEBUFFER : " << SDL_GetError() << endl;
		return (EXIT_FAILURE);
	}
	if(valeurBuffer!=1)
	{
		cerr << "Erreur : SDL_GL_DOUBLEBUFFER inactif" << endl;
		return (EXIT_FAILURE);
	}
	bool continuer = true;
	SDL_Event event;
	while(continuer)
	{
		SDL_WaitEvent(&event);
		switch(event.type)
		{
			case SDL_QUIT:
				continuer = false;
				exit(EXIT_SUCCESS);
			break;
			case SDL_KEYDOWN:
				switch(event.key.keysym.sym)
				{
					case SDLK_ESCAPE:
						continuer = false;
						exit(EXIT_SUCCESS);
					break;
					default:
					break;
				}
			break;
		}
		glClear(GL_COLOR_BUFFER_BIT);
		
		glBegin(GL_TRIANGLES);
			glColor3ub(255, 0, 0); glVertex2d(-0.75, -0.75);
			glColor3ub(0, 255, 0); glVertex2d(0, 0.75);
			glColor3ub(0, 0, 255); glVertex2d(0.75, -0.75);
		glEnd();

		glFlush();
		SDL_GL_SwapBuffers();
	}
	return EXIT_SUCCESS;
}