/* $Id: graphics.hpp,v 1.4 2005/10/20 19:46:52 chfreund Exp $ */

#ifndef _GRAPHICS_HPP_
#define _GRAPHICS_HPP_

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

class Graphics {
	public:
		static void setPixel( SDL_Surface* surface, const int x, const int y, const Uint32 color );
		static Uint32 getPixel( SDL_Surface *surface, const int x, const int y );
		
		static void setPixelClip( SDL_Surface* surface, const int x, const int y, const Uint32 color ) {
			if( x >= 0 && y >= 0 && x < surface->w && y < surface->h )
				setPixel( surface, x, y, color );
		}

		static void drawLine( SDL_Surface* surface, int x1, int y1, int x2, int y2, const Uint32 color ) {
			int i;
			int sx, sy;  // step positive or negative (1 or -1)
			int dx, dy;  // delta (difference in X and Y between points)
			int e;

			dx = abs( x2 - x1 );
			sx = (x2 - x1 > 0) ? 1 : -1;
			dy = abs( y2 - y1 );
			sy = (y2 - y1 > 0) ? 1 : -1;

			if( dy <= dx ) {
				e = (dy << 1) - dx;
				for( i = 0; i <= dx; i++ ) {
					setPixelClip( surface, x1, y1, color );

					if( e >= 0 ) {
						y1 += sy; e -= (dx << 1);
					}
					x1 += sx; e += (dy << 1);
				}
			}
			else {
		#define SWAP(a,b) {int tmpswap = a; a = b; b = tmpswap;}
				SWAP(x1, y1); SWAP(dx, dy); SWAP(sx, sy);
		#undef SWAP
				e = (dy << 1) - dx;
				for( i = 0; i <= dx; i++ ) {
					setPixelClip( surface, y1, x1, color );

					if( e >= 0 ) {
						y1 += sy; e -= (dx << 1);
					}
					x1 += sx; e += (dy << 1);
				}
			}
		}
	
	static void drawCircle( SDL_Surface* surface, int xc, int yc, int r, const Uint32 color ) {
		Sint32 x = 0;
		Sint32 y = r;
		double d = 1.25 - static_cast<double>( r );
		
		setPixelClip( surface, xc, yc + r, color );
		setPixelClip( surface, xc, yc - r, color );
		setPixelClip( surface, xc + r, yc, color );
		setPixelClip( surface, xc - r, yc, color );
		
		while ( y > x ) {
			x++;
			if ( d > 0 ) {
				y--;
				d += 2.0 * (x - y);
			}
			else {
				d += 2.0 * x + 1.0;
			}
			
			setPixelClip( surface, xc - x, yc + y, color );
			setPixelClip( surface, xc + x, yc + y, color );
			setPixelClip( surface, xc - x, yc - y, color );
			setPixelClip( surface, xc + x, yc - y, color );
			setPixelClip( surface, xc - y, yc + x, color );
			setPixelClip( surface, xc + y, yc + x, color );
			setPixelClip( surface, xc - y, yc - x, color );
			setPixelClip( surface, xc + y, yc - x, color );
		}
	}
};

#endif // _GRAPHICS_HPP_