RGB Noise

#include <SDL/SDL.h>
#include <cstdlib>
#include <ctime>

#define FPS 30

void
generateRGB_noise(SDL_Surface* surface)
{
  //fills all pixels in surface with random colors.
  Uint32* pixels = (Uint32*) surface->pixels;
  for(int x = 0; x < surface->w; ++x)
    {
      for(int y = 0; y < surface->h; ++y)
    {
      Uint8 r = rand() % 256;
      Uint8 g = rand() % 256;
      Uint8 b = rand() % 256;


      pixels[( y * surface->w ) + x] = SDL_MapRGB(surface->format, r, g, b);
    }
    }
  surface->pixels = pixels;
}

int
main(int argc , char** argv)
{
  //initialise window and screen
  SDL_Init(SDL_INIT_VIDEO);
  SDL_Surface* window;
  window = SDL_SetVideoMode(640, 480, 32, SDL_SWSURFACE);

  srand(time(NULL)); //set rand seed

  bool active = true;
  while(active)
    {
      SDL_Event event;
      while(SDL_PollEvent(&event))
    {
      if(event.type == SDL_KEYUP && event.key.keysym.sym == SDLK_ESCAPE)
        {
          //quit on pressing escape
          active = false;
        }
    }
      generateRGB_noise(window);
      SDL_Flip(window);

      SDL_Delay(1000 / FPS); //to not fry up cpu
    }
  SDL_Quit();
}