#include <SDL/SDL.h>
#include <complex.h>
#include <math.h>

#define rgb(r,g,b) ( (r)*256*256 + (g)*256 + (b) )
#define min(x,y)  ( (x>y) ? y : x )
#define max(x,y)  ( (y>x) ? y : x )
#define sqr(x)    ((x)*(x))

void draw_point(SDL_Surface *surf, int x, int y, Uint32 col);
int get_point_mandelbrot(double x, double y);
int hsv(double h,double s,double v);

int main(int argc, char *argv[])
{
    Uint8 *keystates = SDL_GetKeyState(NULL);
    SDL_Surface *screen = NULL;
    SDL_Rect position, clip;
    SDL_Event event;
    int a_t = 0, p_t = 0;
    int x,y;
   
   SDL_Init(SDL_INIT_VIDEO);
    screen = SDL_SetVideoMode(640, 480, 32, SDL_HWSURFACE | SDL_DOUBLEBUF);
   
   for(x=0 ; x<640 ; x++)
      for(y=0 ; y<480 ; y++)
        *((Uint32*)(screen->pixels) + x + y * screen->w)
        = get_point_mandelbrot( ((double)x-430)/200 , ((double)y-240)/200 );

    for(;;)
    {
        SDL_PollEvent(&event);
        if (event.type==SDL_QUIT) break;
        SDL_PumpEvents();
        if(keystates[SDLK_ESCAPE]) break;
       
        a_t = SDL_GetTicks();
        if (a_t - p_t < 20)  SDL_Delay(20 - a_t + p_t);
        p_t = SDL_GetTicks();
       
        SDL_Flip(screen);
    }
   SDL_FreeSurface(screen);
    SDL_Quit();
    return EXIT_SUCCESS;
}

int get_point_mandelbrot(double x, double y)
{
    int m,iter = 30;
    complex z = 0, c = x + y*I;
   
    for(m=0 ; m<=iter && sqrt(sqr(creal(z))+sqr(cimag(z)))<=2  ; m+=1)
    z = z*z + c;
   
    if (m <= iter)
    return hsv(255-m*8,255,255);
    return 0;
}

int hsv(double h,double s,double v)
{
    double r,g,b;

    r = min(255,max(510-min(h,255-h)/42.5*255,0))/255*v;
    g = min(255,max(510-max(85-h,h-85)/42.5*255,0))/255*v;
    b = min(255,max(510-max(170-h,h-170)/42.5*255,0))/255*v;

    r += (v-r)*(1-s/255);
    g += (v-g)*(1-s/255);
    b += (v-b)*(1-s/255);
   
    return rgb(max(0,(int)r),max(0,(int)g),max(0,(int)b));
}