/*
*	SDL Graphics Extension
*	Drawing primitives
*
*	Started 990815 (split from sge_draw 010611)
*
*	License: LGPL v2+ (see the file LICENSE)
*	(c)1999-2001 Anders Lindström
*/

/*********************************************************************
 *  This library is free software; you can redistribute it and/or    *
 *  modify it under the terms of the GNU Library General Public      *
 *  License as published by the Free Software Foundation; either     *
 *  version 2 of the License, or (at your option) any later version. *
 *********************************************************************/
 
/*
*  Some of this code is taken from the "Introduction to SDL" and
*  John Garrison's PowerPak	
*/

#include "SDL.h"
#include <math.h>
#include <string.h>
#include <stdarg.h>
#include "sge_primitives.h"
#include "sge_surface.h"


/* Globals used for sge_Update/sge_Lock (defined in sge_surface) */
extern Uint8 _sge_update;
extern Uint8 _sge_lock;


/**********************************************************************************/
/**                             Line functions                                   **/
/**********************************************************************************/

//==================================================================================
// Internal draw horizontal line
//==================================================================================
void _HLine(SDL_Surface *Surface, Sint16 x1, Sint16 x2, Sint16 y, Uint32 Color)
{
	if(x1>x2){Sint16 tmp=x1; x1=x2; x2=tmp;}

	//Do the clipping
	#if SDL_VERSIONNUM(SDL_MAJOR_VERSION, SDL_MINOR_VERSION, SDL_PATCHLEVEL) < \
    SDL_VERSIONNUM(1, 1, 5)
	if(y<Surface->clip_miny || y>Surface->clip_maxy || x1>Surface->clip_maxx || x2<Surface->clip_minx)
		return;
	if(x1<Surface->clip_minx)
		x1=Surface->clip_minx;
	if(x2>Surface->clip_maxx)
		x2=Surface->clip_maxx;
	#endif
	
	SDL_Rect l;
	l.x=x1; l.y=y; l.w=x2-x1+1; l.h=1;
	
	SDL_FillRect(Surface, &l, Color);
}

//==================================================================================
// Draw horizontal line
//==================================================================================
void sge_HLine(SDL_Surface *Surface, Sint16 x1, Sint16 x2, Sint16 y, Uint32 Color)
{
	if(x1>x2){Sint16 tmp=x1; x1=x2; x2=tmp;}
	
	//Do the clipping
	#if SDL_VERSIONNUM(SDL_MAJOR_VERSION, SDL_MINOR_VERSION, SDL_PATCHLEVEL) < \
    SDL_VERSIONNUM(1, 1, 5)
	if(y<Surface->clip_miny || y>Surface->clip_maxy || x1>Surface->clip_maxx || x2<Surface->clip_minx)
		return;
	if(x1<Surface->clip_minx)
		x1=Surface->clip_minx;
	if(x2>Surface->clip_maxx)
		x2=Surface->clip_maxx;
	#endif
	
	SDL_Rect l;
	l.x=x1; l.y=y; l.w=x2-x1+1; l.h=1;
	
	SDL_FillRect(Surface, &l, Color);

	sge_UpdateRect(Surface, x1, y, x2-x1+1, 1);
}

//==================================================================================
// Draw horizontal line (RGB)
//==================================================================================
void sge_HLine(SDL_Surface *Surface, Sint16 x1, Sint16 x2, Sint16 y, Uint8 R, Uint8 G, Uint8 B)
{
	sge_HLine(Surface,x1,x2,y, SDL_MapRGB(Surface->format, R, G, B));
}


//==================================================================================
// Internal draw horizontal line (alpha)
//==================================================================================
void _HLineAlpha(SDL_Surface *Surface, Sint16 x1, Sint16 x2, Sint16 y, Uint32 Color, Uint8 alpha)
{
	Uint8 update = _sge_update;
	Uint8 lock = _sge_lock;
	_sge_update = 0;
	_sge_lock = 0;
	sge_FilledRectAlpha(Surface, x1,y,x2,y, Color, alpha);
	_sge_update = update;
	_sge_lock = lock;
}

//==================================================================================
// Draw horizontal line (alpha)
//==================================================================================
void sge_HLineAlpha(SDL_Surface *Surface, Sint16 x1, Sint16 x2, Sint16 y, Uint32 Color, Uint8 alpha)
{
	sge_FilledRectAlpha(Surface, x1,y,x2,y, Color, alpha);
}

//==================================================================================
// Draw horizontal line (alpha RGB)
//==================================================================================
void sge_HLineAlpha(SDL_Surface *Surface, Sint16 x1, Sint16 x2, Sint16 y, Uint8 R, Uint8 G, Uint8 B, Uint8 alpha)
{
	sge_HLineAlpha(Surface,x1,x2,y, SDL_MapRGB(Surface->format, R, G, B), alpha);
}


//==================================================================================
// Internal draw vertical line
//==================================================================================
void _VLine(SDL_Surface *Surface, Sint16 x, Sint16 y1, Sint16 y2, Uint32 Color)
{
	if(y1>y2){Sint16 tmp=y1; y1=y2; y2=tmp;}

	//Do the clipping
	#if SDL_VERSIONNUM(SDL_MAJOR_VERSION, SDL_MINOR_VERSION, SDL_PATCHLEVEL) < \
    SDL_VERSIONNUM(1, 1, 5)
	if(x<Surface->clip_minx || x>Surface->clip_maxx || y1>Surface->clip_maxy || y2<Surface->clip_miny)
		return;
	if(y1<Surface->clip_miny)
		y1=Surface->clip_miny;
	if(y2>Surface->clip_maxy)
		y2=Surface->clip_maxy;
	#endif
	
	SDL_Rect l;
	l.x=x; l.y=y1; l.w=1; l.h=y2-y1+1;
	
	SDL_FillRect(Surface, &l, Color);
}

//==================================================================================
// Draw vertical line
//==================================================================================
void sge_VLine(SDL_Surface *Surface, Sint16 x, Sint16 y1, Sint16 y2, Uint32 Color)
{
	if(y1>y2){Sint16 tmp=y1; y1=y2; y2=tmp;}
	
	//Do the clipping
	#if SDL_VERSIONNUM(SDL_MAJOR_VERSION, SDL_MINOR_VERSION, SDL_PATCHLEVEL) < \
    SDL_VERSIONNUM(1, 1, 5)
	if(x<Surface->clip_minx || x>Surface->clip_maxx || y1>Surface->clip_maxy || y2<Surface->clip_miny)
		return;
	if(y1<Surface->clip_miny)
		y1=Surface->clip_miny;
	if(y2>Surface->clip_maxy)
		y2=Surface->clip_maxy;
	#endif
	
	SDL_Rect l;
	l.x=x; l.y=y1; l.w=1; l.h=y2-y1+1;
	
	SDL_FillRect(Surface, &l, Color);

	sge_UpdateRect(Surface, x, y1, 1, y2-y1+1);
}

//==================================================================================
// Draw vertical line (RGB)
//==================================================================================
void sge_VLine(SDL_Surface *Surface, Sint16 x, Sint16 y1, Sint16 y2, Uint8 R, Uint8 G, Uint8 B)
{
	sge_VLine(Surface,x,y1,y2, SDL_MapRGB(Surface->format, R, G, B));
}


//==================================================================================
// Internal draw vertical line (alpha - no update)
//==================================================================================
void _VLineAlpha(SDL_Surface *Surface, Sint16 x, Sint16 y1, Sint16 y2, Uint32 Color, Uint8 alpha)
{
	Uint8 update = _sge_update;
	Uint8 lock = _sge_lock;
	_sge_update = 0;
	_sge_lock = 0;
	sge_FilledRectAlpha(Surface, x,y1,x,y2, Color, alpha);
	_sge_update = update;
	_sge_lock = lock;
}

//==================================================================================
// Draw vertical line (alpha)
//==================================================================================
void sge_VLineAlpha(SDL_Surface *Surface, Sint16 x, Sint16 y1, Sint16 y2, Uint32 Color, Uint8 alpha)
{
	sge_FilledRectAlpha(Surface, x,y1,x,y2, Color, alpha);
}

//==================================================================================
// Draw vertical line (alpha RGB)
//==================================================================================
void sge_VLineAlpha(SDL_Surface *Surface, Sint16 x, Sint16 y1, Sint16 y2, Uint8 R, Uint8 G, Uint8 B, Uint8 alpha)
{
	sge_VLineAlpha(Surface,x,y1,y2, SDL_MapRGB(Surface->format, R, G, B), alpha);
}



//==================================================================================
// Performs Callback at each line point. (From PowerPak)
//==================================================================================
void sge_DoLine(SDL_Surface *Surface, Sint16 x1, Sint16 y1, Sint16 x2, Sint16 y2, Uint32 Color, void Callback(SDL_Surface *Surf, Sint16 X, Sint16 Y, Uint32 Color))
{
	Sint16 dx, dy, sdx, sdy, x, y, px, py;

	dx = x2 - x1;
	dy = y2 - y1;

	sdx = (dx < 0) ? -1 : 1;
	sdy = (dy < 0) ? -1 : 1;

	dx = sdx * dx + 1;
	dy = sdy * dy + 1;

	x = y = 0;

	px = x1;
	py = y1;

	if (dx >= dy){
		for (x = 0; x < dx; x++){
			Callback(Surface, px, py, Color);
	
			y += dy;
			if (y >= dx){
				y -= dx;
				py += sdy;
			}
			px += sdx;
		}
	}
	else{
		for (y = 0; y < dy; y++){
			Callback(Surface, px, py, Color);

			x += dx;
			if (x >= dy){
				x -= dy;
				px += sdx;
			}
			py += sdy;
		}
	}
}


//==================================================================================
// Performs Callback at each line point. (RGB)
//==================================================================================
void sge_DoLine(SDL_Surface *Surface, Sint16 X1, Sint16 Y1, Sint16 X2, Sint16 Y2, Uint8 R, Uint8 G, Uint8 B, void Callback(SDL_Surface *Surf, Sint16 X, Sint16 Y, Uint32 Color))
{
	sge_DoLine(Surface,X1,Y1,X2,Y2, SDL_MapRGB(Surface->format, R, G, B),Callback);
}


//==================================================================================
// Draws a line
//==================================================================================
void _Line(SDL_Surface *surface, Sint16 x1, Sint16 y1, Sint16 x2, Sint16 y2, Uint32 color)
{
	/* Clipping */
	if(x2<sge_clip_xmin(surface) || x1>sge_clip_xmax(surface) || y2<sge_clip_ymin(surface) || y1>sge_clip_ymax(surface))
		return;
	if (x1 < sge_clip_xmin(surface))
  		x1 = sge_clip_xmin(surface);
	if (x2 > sge_clip_xmax(surface))
  		x2 = sge_clip_xmax(surface);
	if (y1 < sge_clip_ymin(surface))
  		y1 = sge_clip_ymin(surface);
	if (y2 > sge_clip_ymax(surface))
  		y2 = sge_clip_ymax(surface);

	Sint16 dx, dy, sdx, sdy, x, y;

	dx = x2 - x1;
	dy = y2 - y1;

	sdx = (dx < 0) ? -1 : 1;
	sdy = (dy < 0) ? -1 : 1;

	dx = sdx * dx + 1;
	dy = sdy * dy + 1;

	x = y = 0;
	
	Sint16 pixx = surface->format->BytesPerPixel;
  	Sint16 pixy = surface->pitch;
	Uint8 *pixel = (Uint8*)surface->pixels + y1*pixy + x1*pixx;

	pixx *= sdx;
  	pixy *= sdy;

	if (dx < dy) {
		Sint32 tmp = dx; dx = dy; dy = Sint16(tmp);
		tmp = pixx; pixx = pixy; pixy = tmp;
	}	
	
	switch(surface->format->BytesPerPixel) {
		case 1: {
			for(x=0; x < dx; x++) {
				*pixel = color;
				
				y += dy; 
				if (y >= dx) {
					y -= dx; 
					pixel += pixy;
				}
				pixel += pixx;
			}
		}
		break;
	
		case 2: {
			for(x=0; x < dx; x++) {
				*(Uint16*)pixel = color;
				
				y += dy; 
				if (y >= dx) {
					y -= dx; 
					pixel += pixy;
				}
				pixel += pixx;
			}
		}
		break;
	
		case 3: {
			Uint8 rshift8 = surface->format->Rshift/8; 
			Uint8 gshift8 = surface->format->Gshift/8; 
			Uint8 bshift8 = surface->format->Bshift/8;
			Uint8 ashift8 = surface->format->Ashift/8;
			
			Uint8 R = (color>>surface->format->Rshift)&0xff;
			Uint8 G = (color>>surface->format->Gshift)&0xff;
			Uint8 B = (color>>surface->format->Bshift)&0xff;
			Uint8 A = (color>>surface->format->Ashift)&0xff;
		
			for(x=0; x < dx; x++) {
				*(pixel+rshift8) = R;
  				*(pixel+gshift8) = G;
  				*(pixel+bshift8) = B;
				*(pixel+ashift8) = A;
				
				y += dy; 
				if (y >= dx) {
					y -= dx; 
					pixel += pixy;
				}
				pixel += pixx;
			}
		}
		break;
		
		case 4: {
			for(x=0; x < dx; x++) {
				*(Uint32*)pixel = color;
				
				y += dy; 
				if (y >= dx) {
					y -= dx; 
					pixel += pixy;
				}
				pixel += pixx;
			}
		}
		break;
	}
}

void sge_Line(SDL_Surface *Surface, Sint16 x1, Sint16 y1, Sint16 x2, Sint16 y2, Uint32 Color)
{
	if (SDL_MUSTLOCK(Surface) && _sge_lock) {
		if (SDL_LockSurface(Surface) < 0)
			return;
	}

	/* Draw the line */
	_Line(Surface, x1,y1, x2,y2, Color);

	/* unlock the display */
	if (SDL_MUSTLOCK(Surface) && _sge_lock) {
		SDL_UnlockSurface(Surface);
	}

	sge_UpdateRect(Surface, (x1 < x2)? x1 : x2, (y1 < y2)? y1 : y2, ((x2-x1)<0)? (x1-x2+1) : (x2-x1+1), ((y2-y1)<0)? (y1-y2+1) : (y2-y1+1));
}


//==================================================================================
// Draws a line (RGB)
//==================================================================================
void sge_Line(SDL_Surface *Surface, Sint16 x1, Sint16 y1, Sint16 x2, Sint16 y2, Uint8 R, Uint8 G, Uint8 B)
{
	sge_Line(Surface,x1,y1,x2,y2, SDL_MapRGB(Surface->format, R, G, B));
}


//==================================================================================
// A quick hack to get alpha working with callbacks
//==================================================================================
Uint8 _sge_alpha_hack = 0;
void callback_alpha_hack(SDL_Surface *surf, Sint16 x, Sint16 y, Uint32 color)
{
	_PutPixelAlpha(surf,x,y,color,_sge_alpha_hack);
}

//==================================================================================
// Draws a line (alpha)
//==================================================================================
void sge_LineAlpha(SDL_Surface *Surface, Sint16 x1, Sint16 y1, Sint16 x2, Sint16 y2, Uint32 Color, Uint8 alpha)
{
	if (SDL_MUSTLOCK(Surface) && _sge_lock)
		if (SDL_LockSurface(Surface) < 0)
			return;

	_sge_alpha_hack = alpha;

	/* Draw the line */
	sge_DoLine(Surface, x1, y1, x2, y2, Color, callback_alpha_hack);

	/* unlock the display */
	if (SDL_MUSTLOCK(Surface) && _sge_lock) {
		SDL_UnlockSurface(Surface);
	}

	sge_UpdateRect(Surface, (x1 < x2)? x1 : x2, (y1 < y2)? y1 : y2, ((x2-x1)<0)? (x1-x2+1) : (x2-x1+1), ((y2-y1)<0)? (y1-y2+1) : (y2-y1+1));
}

//==================================================================================
// Draws a line (alpha - RGB)
//==================================================================================
void sge_LineAlpha(SDL_Surface *Surface, Sint16 x1, Sint16 y1, Sint16 x2, Sint16 y2, Uint8 R, Uint8 G, Uint8 B, Uint8 alpha)
{
	sge_LineAlpha(Surface,x1,y1,x2,y2, SDL_MapRGB(Surface->format, R, G, B), alpha);
}



//==================================================================================
// Anti-aliased line
// From SDL_gfxPrimitives written by A. Schiffler (aschiffler@home.com)
//==================================================================================
#define AAbits 8
#define AAlevels 256  /* 2^AAbits */
void sge_AALineAlpha(SDL_Surface *dst, Sint16 x1, Sint16 y1, Sint16 x2, Sint16 y2, Uint32 color, Uint8 alpha)
{
	Sint32 xx0,yy0,xx1,yy1;
	Uint32 intshift, erracc=0, erradj;
	Uint32 erracctmp, wgt, wgtcompmask;
	Sint16 dx, dy, tmp, xdir, y0p1, x0pxdir;

	/* Keep on working with 32bit numbers */
	xx0=x1;
	yy0=y1;
	xx1=x2;
	yy1=y2;
 
	/* Reorder points if required */ 
	if (yy0 > yy1) {
		tmp = yy0; yy0 = yy1; yy1 = tmp;
		tmp = xx0; xx0 = xx1; xx1 = tmp;
	}

	/* Calculate distance */
	dx = xx1 - xx0;
	dy = yy1 - yy0;

	/* Adjust for negative dx and set xdir */
	if (dx >= 0) {
		xdir=1;
	} else {
		xdir=-1;
		dx=(-dx);
	}

	/* Check for special cases */
	if (dx==0) {
		/* Vertical line */
		sge_VLineAlpha(dst, x1,y1,y2,color,alpha);
		return;
	} else if (dy==0) {
		/* Horizontal line */
		sge_HLineAlpha(dst, x1,x2,y1,color,alpha);
		return;
	} else if (dx==dy) {
		/* Diagonal line */
		if(alpha==255)
			sge_Line(dst,x1,y1,x2,y2,color);
		else
			sge_LineAlpha(dst,x1,y1,x2,y2,color,alpha);
		return;
	} 

	Uint8 a = 255-alpha;

	/* Lock surface */
	if ( SDL_MUSTLOCK(dst) && _sge_lock )
		if ( SDL_LockSurface(dst) < 0 )
			return;

	
	intshift = 32 - AAbits;  /* # of bits by which to shift erracc to get intensity level */
	wgtcompmask = AAlevels - 1;  /* Mask used to flip all bits in an intensity weighting */

	if(alpha==255)
		_PutPixel(dst,x1,y1, color);  /* Draw the initial pixel in the foreground color */
	else
		_PutPixelAlpha(dst,x1,y1, color, alpha);

	/* x-major or y-major? */
	if (dy > dx) {

		/* y-major.  Calculate 16-bit fixed point fractional part of a pixel that
		X advances every time Y advances 1 pixel, truncating the result so that
		we won't overrun the endpoint along the X axis */
		erradj = ((dx << 16) / dy)<<16;

		/* draw all pixels other than the first and last */
		x0pxdir=xx0+xdir;
		while (--dy) {
			erracctmp = erracc;
			erracc += erradj;
			if (erracc <= erracctmp) {
				/* rollover in error accumulator, x coord advances */
				xx0=x0pxdir;
				x0pxdir += xdir;
			}
			yy0++;			/* y-major so always advance Y */

			/* the AAbits most significant bits of erracc give us the intensity
			weighting for this pixel, and the complement of the weighting for
			the paired pixel. */
			wgt = (erracc >> intshift) & 255;
			
			tmp = 255-wgt-a;
			if(tmp<0)
				tmp=0;
			_PutPixelAlpha(dst,xx0,yy0,color,Uint8(tmp));
			tmp = wgt-a;
			if(tmp<0)
				tmp=0;
			_PutPixelAlpha(dst,x0pxdir,yy0,color,Uint8(tmp));          
		}
	} else {

		/* x-major line.  Calculate 16-bit fixed-point fractional part of a pixel
		that Y advances each time X advances 1 pixel, truncating the result so
		that we won't overrun the endpoint along the X axis. */
		erradj = ((dy << 16) / dx)<<16;
 
		/* draw all pixels other than the first and last */
		y0p1=yy0+1;
		while (--dx) {

			erracctmp = erracc;
			erracc += erradj;
			if (erracc <= erracctmp) {
				/* Accumulator turned over, advance y */
      			yy0=y0p1;
      			y0p1++;
    		}
			xx0 += xdir;  /* x-major so always advance X */
			
			/* the AAbits most significant bits of erracc give us the intensity
			weighting for this pixel, and the complement of the weighting for
			the paired pixel. */
			wgt = (erracc >> intshift) & 255;
			
			tmp = 255-wgt-a;
			if(tmp<0)
				tmp=0;
			_PutPixelAlpha(dst,xx0,yy0,color,tmp);
			tmp = wgt-a;
			if(tmp<0)
				tmp=0;
			_PutPixelAlpha(dst,xx0,y0p1,color,tmp);
		}
	}
 
	/* Draw final pixel, always exactly intersected by the line and doesn't
	need to be weighted. */
	if(alpha==255)
		_PutPixel(dst,x2,y2, color); 
	else
		_PutPixelAlpha(dst,x2,y2, color, alpha);

	/* unlock the display */
	if (SDL_MUSTLOCK(dst) && _sge_lock) {
		SDL_UnlockSurface(dst);
	}
	
	sge_UpdateRect(dst, (x1 < x2)? x1 : x2, (y1 < y2)? y1 : y2, ((x2-x1)<0)? (x1-x2+1) : (x2-x1+1), ((y2-y1)<0)? (y1-y2+1) : (y2-y1+1));
}

void sge_AALineAlpha(SDL_Surface *dst, Sint16 x1, Sint16 y1, Sint16 x2, Sint16 y2, Uint8 r, Uint8 g, Uint8 b, Uint8 alpha)
{
	sge_AALineAlpha(dst,x1,y1,x2,y2,SDL_MapRGB(dst->format, r, g, b),alpha);
}

void sge_AALine(SDL_Surface *dst, Sint16 x1, Sint16 y1, Sint16 x2, Sint16 y2, Uint32 color)
{
	sge_AALineAlpha(dst, x1,y1, x2,y2, color, 255);
}

void sge_AALine(SDL_Surface *dst, Sint16 x1, Sint16 y1, Sint16 x2, Sint16 y2, Uint8 r, Uint8 g, Uint8 b)
{
	sge_AALineAlpha(dst,x1,y1,x2,y2,SDL_MapRGB(dst->format, r, g, b),255);
}



/**********************************************************************************/
/**                           Figure functions                                   **/
/**********************************************************************************/

//==================================================================================
// Draws a rectangle
//==================================================================================
void sge_Rect(SDL_Surface *Surface, Sint16 x1, Sint16 y1, Sint16 x2, Sint16 y2, Uint32 color)
{
	_HLine(Surface,x1,x2,y1,color);
	_HLine(Surface,x1,x2,y2,color);
	_VLine(Surface,x1,y1,y2,color);
	_VLine(Surface,x2,y1,y2,color);

	sge_UpdateRect(Surface, x1, y1, x2-x1, 1);
	sge_UpdateRect(Surface, x1, y2, x2-x1+1, 1); /* Hmm? */
	sge_UpdateRect(Surface, x1, y1, 1, y2-y1);
	sge_UpdateRect(Surface, x2, y1, 1, y2-y1);
}

//==================================================================================
// Draws a rectangle (RGB)
//==================================================================================
void sge_Rect(SDL_Surface *Surface, Sint16 x1, Sint16 y1, Sint16 x2, Sint16 y2, Uint8 R, Uint8 G, Uint8 B)
{
	sge_Rect(Surface,x1,y1,x2,y2, SDL_MapRGB(Surface->format, R, G, B));
}


//==================================================================================
// Draws a rectangle (alpha)
//==================================================================================
void sge_RectAlpha(SDL_Surface *Surface, Sint16 x1, Sint16 y1, Sint16 x2, Sint16 y2, Uint32 color, Uint8 alpha)
{
	if (SDL_MUSTLOCK(Surface) && _sge_lock)
		if (SDL_LockSurface(Surface) < 0)
			return;

	_HLineAlpha(Surface,x1,x2,y1,color,alpha);
	_HLineAlpha(Surface,x1,x2,y2,color,alpha);
	_VLineAlpha(Surface,x1,y1,y2,color,alpha);
	_VLineAlpha(Surface,x2,y1,y2,color,alpha);

	if (SDL_MUSTLOCK(Surface) && _sge_lock) {
		SDL_UnlockSurface(Surface);
	}

	sge_UpdateRect(Surface, x1, y1, x2-x1, 1);
	sge_UpdateRect(Surface, x1, y2, x2-x1+1, 1); /* Hmm? */
	sge_UpdateRect(Surface, x1, y1, 1, y2-y1);
	sge_UpdateRect(Surface, x2, y1, 1, y2-y1);
}

//==================================================================================
// Draws a rectangle (RGB)
//==================================================================================
void sge_RectAlpha(SDL_Surface *Surface, Sint16 x1, Sint16 y1, Sint16 x2, Sint16 y2, Uint8 R, Uint8 G, Uint8 B, Uint8 alpha)
{
	sge_RectAlpha(Surface,x1,y1,x2,y2, SDL_MapRGB(Surface->format, R, G, B), alpha);
}


//==================================================================================
// Draws a filled rectangle
//==================================================================================
void sge_FilledRect(SDL_Surface *Surface, Sint16 x1, Sint16 y1, Sint16 x2, Sint16 y2, Uint32 color)
{
	Sint16 tmp;
	if(x1>x2){
		tmp=x1; x1=x2; x2=tmp;
	}
	if(y1>y2){
		tmp=y1; y1=y2; y2=tmp;
	}

	#if SDL_VERSIONNUM(SDL_MAJOR_VERSION, SDL_MINOR_VERSION, SDL_PATCHLEVEL) < \
    SDL_VERSIONNUM(1, 1, 5)
	if(x2<Surface->clip_minx || x1>Surface->clip_maxx || y2<Surface->clip_miny || y1>Surface->clip_maxy)
		return;
	if (x1 < Surface->clip_minx)
  		x1=Surface->clip_minx;
	if (x2 > Surface->clip_maxx)
  		x2=Surface->clip_maxx;
	if (y1 < Surface->clip_miny)
  		y1=Surface->clip_miny;
	if (y2 > Surface->clip_maxy)
  		y2=Surface->clip_maxy;
	#endif

	SDL_Rect area;
	area.x=x1; area.y=y1;
	area.w=x2-x1+1; area.h=y2-y1+1;

	SDL_FillRect(Surface,&area,color);

	sge_UpdateRect(Surface, x1, y1, x2-x1+1, y2-y1+1);
}

//==================================================================================
// Draws a filled rectangle (RGB)
//==================================================================================
void sge_FilledRect(SDL_Surface *Surface, Sint16 x1, Sint16 y1, Sint16 x2, Sint16 y2, Uint8 R, Uint8 G, Uint8 B)
{
	sge_FilledRect(Surface,x1,y1,x2,y2, SDL_MapRGB(Surface->format, R, G, B));	
}


//==================================================================================
// Draws a filled rectangle (alpha)
//==================================================================================
void sge_FilledRectAlpha(SDL_Surface *surface, Sint16 x1, Sint16 y1, Sint16 x2, Sint16 y2, Uint32 color, Uint8 alpha)
{
	/*if( alpha == 255 ){
		sge_FilledRect(surface,x1,y1,x2,y2,color);
		return;
	}*/
	
	/* Fix coords */
	Sint16 tmp;
	if(x1>x2){
		tmp=x1; x1=x2; x2=tmp;
	}
	if(y1>y2){
		tmp=y1; y1=y2; y2=tmp;
	}
	
	/* Clipping */
	if(x2<sge_clip_xmin(surface) || x1>sge_clip_xmax(surface) || y2<sge_clip_ymin(surface) || y1>sge_clip_ymax(surface))
		return;
	if (x1 < sge_clip_xmin(surface))
  		x1 = sge_clip_xmin(surface);
	if (x2 > sge_clip_xmax(surface))
  		x2 = sge_clip_xmax(surface);
	if (y1 < sge_clip_ymin(surface))
  		y1 = sge_clip_ymin(surface);
	if (y2 > sge_clip_ymax(surface))
  		y2 = sge_clip_ymax(surface);

	Uint32 Rmask = surface->format->Rmask, Gmask = surface->format->Gmask, Bmask = surface->format->Bmask, Amask = surface->format->Amask;
	Uint32 R,G,B,A=0;
	Sint16 x,y;
	
	if (SDL_MUSTLOCK(surface) && _sge_lock)
		if (SDL_LockSurface(surface) < 0)
			return;
	
	switch (surface->format->BytesPerPixel) {
		case 1: { /* Assuming 8-bpp */
			Uint8 *row, *pixel;
			Uint8 dR, dG, dB;
			
			Uint8 sR = surface->format->palette->colors[color].r;
			Uint8 sG = surface->format->palette->colors[color].g;
			Uint8 sB = surface->format->palette->colors[color].b;
			
			for(y = y1; y<=y2; y++){
				row = (Uint8 *)surface->pixels + y*surface->pitch;
				for(x = x1; x <= x2; x++){
					pixel = row + x;
					
					dR = surface->format->palette->colors[*pixel].r;
					dG = surface->format->palette->colors[*pixel].g;
					dB = surface->format->palette->colors[*pixel].b;
					
					dR = dR + ((sR-dR)*alpha >> 8);
					dG = dG + ((sG-dG)*alpha >> 8);
					dB = dB + ((sB-dB)*alpha >> 8);
				
					*pixel = SDL_MapRGB(surface->format, dR, dG, dB);
				}
			}
		}
		break;

		case 2: { /* Probably 15-bpp or 16-bpp */
			Uint16 *row, *pixel;
			Uint32 dR=(color & Rmask),dG=(color & Gmask),dB=(color & Bmask),dA=(color & Amask);
			
			for(y = y1; y<=y2; y++){
				row = (Uint16 *)surface->pixels + y*surface->pitch/2;
				for(x = x1; x <= x2; x++){
					pixel = row + x;

					R = ((*pixel & Rmask) + (( dR - (*pixel & Rmask) ) * alpha >> 8)) & Rmask;
					G = ((*pixel & Gmask) + (( dG - (*pixel & Gmask) ) * alpha >> 8)) & Gmask;
					B = ((*pixel & Bmask) + (( dB - (*pixel & Bmask) ) * alpha >> 8)) & Bmask;
					if( Amask )
						A = ((*pixel & Amask) + (( dA - (*pixel & Amask) ) * alpha >> 8)) & Amask;

					*pixel= R | G | B | A;
				}
			}
		}
		break;

		case 3: { /* Slow 24-bpp mode, usually not used */
			Uint8 *row,*pix;
			Uint8 dR, dG, dB, dA;
  			Uint8 rshift8=surface->format->Rshift/8; 
			Uint8 gshift8=surface->format->Gshift/8; 
			Uint8 bshift8=surface->format->Bshift/8;
			Uint8 ashift8=surface->format->Ashift/8;
			
			Uint8 sR = (color>>surface->format->Rshift)&0xff;
			Uint8 sG = (color>>surface->format->Gshift)&0xff;
			Uint8 sB = (color>>surface->format->Bshift)&0xff;
			Uint8 sA = (color>>surface->format->Ashift)&0xff;
				
			for(y = y1; y<=y2; y++){
				row = (Uint8 *)surface->pixels + y * surface->pitch;
				for(x = x1; x <= x2; x++){
					pix = row + x*3;

					dR = *((pix)+rshift8); 
            		dG = *((pix)+gshift8);
            		dB = *((pix)+bshift8);
					dA = *((pix)+ashift8);
					
					dR = dR + ((sR-dR)*alpha >> 8);
					dG = dG + ((sG-dG)*alpha >> 8);
					dB = dB + ((sB-dB)*alpha >> 8);
					dA = dA + ((sA-dA)*alpha >> 8);

					*((pix)+rshift8) = dR; 
            		*((pix)+gshift8) = dG;
            		*((pix)+bshift8) = dB;
					*((pix)+ashift8) = dA;
				}
			}
					
		}
		break;

		case 4: { /* Probably 32-bpp */
			Uint32 *row, *pixel;
			Uint32 dR=(color & Rmask),dG=(color & Gmask),dB=(color & Bmask),dA=(color & Amask);
		
			for(y = y1; y<=y2; y++){
				row = (Uint32 *)surface->pixels + y*surface->pitch/4;
				for(x = x1; x <= x2; x++){
					pixel = row + x;

					R = ((*pixel & Rmask) + (( dR - (*pixel & Rmask) ) * alpha >> 8)) & Rmask;
					G = ((*pixel & Gmask) + (( dG - (*pixel & Gmask) ) * alpha >> 8)) & Gmask;
					B = ((*pixel & Bmask) + (( dB - (*pixel & Bmask) ) * alpha >> 8)) & Bmask;
					if( Amask )
						A = ((*pixel & Amask) + (( dA - (*pixel & Amask) ) * alpha >> 8)) & Amask;

					*pixel= R | G | B | A;
				}
			}
		}
		break;
	}
	
	if (SDL_MUSTLOCK(surface) && _sge_lock) {
		SDL_UnlockSurface(surface);
	}
	
	sge_UpdateRect(surface, x1, y1, x2-x1+1, y2-y1+1);
}

void sge_FilledRectAlpha(SDL_Surface *Surface, Sint16 x1, Sint16 y1, Sint16 x2, Sint16 y2, Uint8 R, Uint8 G, Uint8 B, Uint8 alpha)
{
	sge_FilledRectAlpha(Surface,x1,y1,x2,y2, SDL_MapRGB(Surface->format, R, G, B), alpha);	
}


//==================================================================================
// Performs Callback at each ellipse point.
// (from Allegro)
//==================================================================================
void sge_DoEllipse(SDL_Surface *Surface, Sint16 x, Sint16 y, Sint16 rx, Sint16 ry, Uint32 color, void Callback(SDL_Surface *Surf, Sint16 X, Sint16 Y, Uint32 Color) )
{
	int ix, iy;
	int h, i, j, k;
	int oh, oi, oj, ok;

	if (rx < 1)
		rx = 1;

	if (ry < 1)
		ry = 1;

	h = i = j = k = 0xFFFF;

	if (rx > ry) {
		ix = 0;
		iy = rx * 64;

 		do {
			oh = h;
	 		oi = i;
	 		oj = j;
			ok = k;

	 		h = (ix + 32) >> 6;
	 		i = (iy + 32) >> 6;
	 		j = (h * ry) / rx;
	 		k = (i * ry) / rx;

	 		if (((h != oh) || (k != ok)) && (h < oi)) {
				Callback(Surface, x+h, y+k, color);
	   			if (h)
	    			Callback(Surface, x-h, y+k, color);
	   			if (k) {
	    			Callback(Surface, x+h, y-k, color);
	     			if (h)
		  				Callback(Surface, x-h, y-k, color);
	  			}
			}

	 		if (((i != oi) || (j != oj)) && (h < i)) {
				Callback(Surface, x+i, y+j, color);
	  			if (i)
	    			Callback(Surface, x-i, y+j, color);
	  			if (j) {
	   				Callback(Surface, x+i, y-j, color);
	   				if (i)
		  				Callback(Surface, x-i, y-j, color);
	 			}
	 		}

			ix = ix + iy / rx;
	 		iy = iy - ix / rx;

		} while (i > h);
	}
	else {
		ix = 0;
		iy = ry * 64;

  		do {
	 		oh = h;
	 		oi = i;
	 		oj = j;
	 		ok = k;

	 		h = (ix + 32) >> 6;
	 		i = (iy + 32) >> 6;
	 		j = (h * rx) / ry;
	 		k = (i * rx) / ry;

	 		if (((j != oj) || (i != oi)) && (h < i)) {
	    		Callback(Surface, x+j, y+i, color);
	    		if (j)
	      			Callback(Surface, x-j, y+i, color);
	    		if (i) {
	       			Callback(Surface, x+j, y-i, color);
	       			if (j)
		  				Callback(Surface, x-j, y-i, color);
	    		}
	 		}

	 		if (((k != ok) || (h != oh)) && (h < oi)) {
	    		Callback(Surface, x+k, y+h, color);
	   			if (k)
	     			Callback(Surface, x-k, y+h, color);
	    		if (h) {
	      			Callback(Surface, x+k, y-h, color);
	    			if (k)
		  				Callback(Surface, x-k, y-h, color);
	    		}
	 		}

	 		ix = ix + iy / ry;
	 		iy = iy - ix / ry;

  		} while(i > h);
	}	
}


//==================================================================================
// Performs Callback at each ellipse point. (RGB)
//==================================================================================
void sge_DoEllipse(SDL_Surface *Surface, Sint16 x, Sint16 y, Sint16 rx, Sint16 ry, Uint8 R, Uint8 G, Uint8 B, void Callback(SDL_Surface *Surf, Sint16 X, Sint16 Y, Uint32 Color) )
{
	sge_DoEllipse(Surface,x,y,rx,ry,SDL_MapRGB(Surface->format, R, G, B),Callback);
}


//==================================================================================
// Draws an ellipse
//==================================================================================
void sge_Ellipse(SDL_Surface *Surface, Sint16 x, Sint16 y, Sint16 rx, Sint16 ry, Uint32 color)
{
	if (SDL_MUSTLOCK(Surface) && _sge_lock) {
      if (SDL_LockSurface(Surface) < 0)
         return;
   }

   sge_DoEllipse(Surface, x, y, rx, ry, color, _PutPixel);

   if (SDL_MUSTLOCK(Surface) && _sge_lock) {
      SDL_UnlockSurface(Surface);
   }

	sge_UpdateRect(Surface, x-rx, y-ry, 2*rx+1, 2*ry+1);
	
}


//==================================================================================
// Draws an ellipse (RGB)
//==================================================================================
void sge_Ellipse(SDL_Surface *Surface, Sint16 x, Sint16 y, Sint16 rx, Sint16 ry, Uint8 R, Uint8 G, Uint8 B)
{
	sge_Ellipse(Surface,x,y,rx,ry,SDL_MapRGB(Surface->format, R, G, B));
}


//==================================================================================
// Draws an ellipse (alpha)
//==================================================================================
void sge_EllipseAlpha(SDL_Surface *Surface, Sint16 x, Sint16 y, Sint16 rx, Sint16 ry, Uint32 color, Uint8 alpha)
{
	if (SDL_MUSTLOCK(Surface) && _sge_lock)
		if (SDL_LockSurface(Surface) < 0)
			return;

	_sge_alpha_hack = alpha;
	sge_DoEllipse(Surface, x, y, rx, ry, color, callback_alpha_hack);

	if (SDL_MUSTLOCK(Surface) && _sge_lock) {
		SDL_UnlockSurface(Surface);
	}

	sge_UpdateRect(Surface, x-rx, y-ry, 2*rx+1, 2*ry+1);
}


//==================================================================================
// Draws an ellipse (alpha - RGB)
//==================================================================================
void sge_EllipseAlpha(SDL_Surface *Surface, Sint16 x, Sint16 y, Sint16 rx, Sint16 ry, Uint8 R, Uint8 G, Uint8 B, Uint8 alpha)
{
	sge_EllipseAlpha(Surface,x,y,rx,ry,SDL_MapRGB(Surface->format, R, G, B),alpha);
}


//==================================================================================
// Draws a filled ellipse
//==================================================================================
void sge_FilledEllipse(SDL_Surface *Surface, Sint16 x, Sint16 y, Sint16 rx, Sint16 ry, Uint32 color)
{
	int ix, iy;
	int h, i, j, k;
	int oh, oi, oj, ok;

	if (rx < 1)
		rx = 1;

	if (ry < 1)
		ry = 1;

	oh = oi = oj = ok = 0xFFFF;

	if (rx > ry) {
  		ix = 0;
   		iy = rx * 64;

 		do {
	 		h = (ix + 32) >> 6;
	 		i = (iy + 32) >> 6;
	 		j = (h * ry) / rx;
	 		k = (i * ry) / rx;

	 		if ((k!=ok) && (k!=oj)) {
	   			if (k){
	   		  		_HLine(Surface,x-h,x+h,y-k,color);
					_HLine(Surface,x-h,x+h,y+k,color);
				}else
					_HLine(Surface,x-h,x+h,y,color);
				ok=k;
			}

	 		if ((j!=oj) && (j!=ok) && (k!=j))  {
	  			if (j){
	  		 		_HLine(Surface,x-i,x+i,y-j,color);
					_HLine(Surface,x-i,x+i,y+j,color);
				}else
					_HLine(Surface,x-i,x+i,y,color);
				oj=j;
	 		}

			ix = ix + iy / rx;
	 		iy = iy - ix / rx;

		} while (i > h);
	}
	else {
		ix = 0;
		iy = ry * 64;

		do {
	 		h = (ix + 32) >> 6;
	 		i = (iy + 32) >> 6;
	 		j = (h * rx) / ry;
	 		k = (i * rx) / ry;

	 		if ((i!=oi) && (i!=oh)) {
	    		if (i){
	    			_HLine(Surface,x-j,x+j,y-i,color);
					_HLine(Surface,x-j,x+j,y+i,color);
				}else
					_HLine(Surface,x-j,x+j,y,color);
				oi=i;
	 		}

	 		if ((h!=oh) && (h!=oi) && (i!=h)) {
	    		if (h){
	    			_HLine(Surface,x-k,x+k,y-h,color);
					_HLine(Surface,x-k,x+k,y+h,color);
				}else
					_HLine(Surface,x-k,x+k,y,color);
				oh=h;
	 		}

	 		ix = ix + iy / ry;
	 		iy = iy - ix / ry;

  		} while(i > h);
	}
}


//==================================================================================
// Draws a filled ellipse (RGB)
//==================================================================================
void sge_FilledEllipse(SDL_Surface *Surface, Sint16 x, Sint16 y, Sint16 rx, Sint16 ry, Uint8 R, Uint8 G, Uint8 B)
{
	sge_FilledEllipse(Surface,x,y,rx,ry,SDL_MapRGB(Surface->format, R, G, B));
}



//==================================================================================
// Draws a filled ellipse (alpha)
//==================================================================================
void sge_FilledEllipseAlpha(SDL_Surface *Surface, Sint16 x, Sint16 y, Sint16 rx, Sint16 ry, Uint32 color, Uint8 alpha)
{
	int ix, iy;
	int h, i, j, k;
	int oh, oi, oj, ok;

	if (SDL_MUSTLOCK(Surface) && _sge_lock)
		if (SDL_LockSurface(Surface) < 0)
			return;

	if (rx < 1)
		rx = 1;

	if (ry < 1)
		ry = 1;

	oh = oi = oj = ok = 0xFFFF;

	if (rx > ry) {
  		ix = 0;
   		iy = rx * 64;

 		do {
	 		h = (ix + 32) >> 6;
	 		i = (iy + 32) >> 6;
	 		j = (h * ry) / rx;
	 		k = (i * ry) / rx;

	 		if ((k!=ok) && (k!=oj)) {
	   			if (k){
	   		  		_HLineAlpha(Surface,x-h,x+h,y-k,color,alpha);
					_HLineAlpha(Surface,x-h,x+h,y+k,color,alpha);
				}else
					_HLineAlpha(Surface,x-h,x+h,y,color,alpha);
				ok=k;
			}

	 		if ((j!=oj) && (j!=ok) && (k!=j))  {
	  			if (j){
	  		 		_HLineAlpha(Surface,x-i,x+i,y-j,color,alpha);
					_HLineAlpha(Surface,x-i,x+i,y+j,color,alpha);
				}else
					_HLineAlpha(Surface,x-i,x+i,y,color,alpha);
				oj=j;
	 		}

			ix = ix + iy / rx;
	 		iy = iy - ix / rx;

		} while (i > h);
	}
	else {
		ix = 0;
		iy = ry * 64;

		do {
	 		h = (ix + 32) >> 6;
	 		i = (iy + 32) >> 6;
	 		j = (h * rx) / ry;
	 		k = (i * rx) / ry;

	 		if ((i!=oi) && (i!=oh)) {
	    		if (i){
	    			_HLineAlpha(Surface,x-j,x+j,y-i,color,alpha);
					_HLineAlpha(Surface,x-j,x+j,y+i,color,alpha);
				}else
					_HLineAlpha(Surface,x-j,x+j,y,color,alpha);
				oi=i;
	 		}

	 		if ((h!=oh) && (h!=oi) && (i!=h)) {
	    		if (h){
	    			_HLineAlpha(Surface,x-k,x+k,y-h,color,alpha);
					_HLineAlpha(Surface,x-k,x+k,y+h,color,alpha);
				}else
					_HLineAlpha(Surface,x-k,x+k,y,color,alpha);
				oh=h;
	 		}

	 		ix = ix + iy / ry;
	 		iy = iy - ix / ry;

  		} while(i > h);
	}

	if (SDL_MUSTLOCK(Surface) && _sge_lock) {
		SDL_UnlockSurface(Surface);
	}

}


//==================================================================================
// Draws a filled ellipse (alpha - RGB)
//==================================================================================
void sge_FilledEllipseAlpha(SDL_Surface *Surface, Sint16 x, Sint16 y, Sint16 rx, Sint16 ry, Uint8 R, Uint8 G, Uint8 B, Uint8 alpha)
{
	sge_FilledEllipseAlpha(Surface,x,y,rx,ry,SDL_MapRGB(Surface->format, R, G, B),alpha);
}


//==================================================================================
// Performs Callback at each circle point.
//==================================================================================
void sge_DoCircle(SDL_Surface *Surface, Sint16 x, Sint16 y, Sint16 r, Uint32 color, void Callback(SDL_Surface *Surf, Sint16 X, Sint16 Y, Uint32 Color))
{
	Sint16 cx = 0;
 	Sint16 cy = r;
 	Sint16 df = 1 - r;
 	Sint16 d_e = 3;
 	Sint16 d_se = -2 * r + 5;

	do {
		Callback(Surface, x+cx, y+cy, color);
		Callback(Surface, x-cx, y+cy, color);
		Callback(Surface, x+cx, y-cy, color);
		Callback(Surface, x-cx, y-cy, color);
		Callback(Surface, x+cy, y+cx, color);
		Callback(Surface, x+cy, y-cx, color);
		Callback(Surface, x-cy, y+cx, color);
		Callback(Surface, x-cy, y-cx, color);

		if (df < 0)  {
			df += d_e;
			d_e += 2;
			d_se += 2;
		}
		else {
			df += d_se;
			d_e += 2;
			d_se += 4;
			cy--;
		}

		cx++;

	}while(cx <= cy);
	
}


//==================================================================================
// Performs Callback at each circle point. (RGB)
//==================================================================================
void sge_DoCircle(SDL_Surface *Surface, Sint16 x, Sint16 y, Sint16 r, Uint8 R, Uint8 G, Uint8 B, void Callback(SDL_Surface *Surf, Sint16 X, Sint16 Y, Uint32 Color))
{
	sge_DoCircle(Surface,x,y,r,SDL_MapRGB(Surface->format, R, G, B),Callback);
}


//==================================================================================
// Draws a circle
//==================================================================================
void sge_Circle(SDL_Surface *Surface, Sint16 x, Sint16 y, Sint16 r, Uint32 color)
{
	if (SDL_MUSTLOCK(Surface) && _sge_lock) {
      if (SDL_LockSurface(Surface) < 0)
         return;
   }

   sge_DoCircle(Surface, x, y, r, color, _PutPixel);

   if (SDL_MUSTLOCK(Surface) && _sge_lock) {
      SDL_UnlockSurface(Surface);
   }

	sge_UpdateRect(Surface, x-r, y-r, 2*r+1, 2*r+1);	
}

//==================================================================================
// Draws a circle (RGB)
//==================================================================================
void sge_Circle(SDL_Surface *Surface, Sint16 x, Sint16 y, Sint16 r, Uint8 R, Uint8 G, Uint8 B)
{
	sge_Circle(Surface,x,y,r,SDL_MapRGB(Surface->format, R, G, B));
}


//==================================================================================
// Draws a circle (alpha)
//==================================================================================
void sge_CircleAlpha(SDL_Surface *Surface, Sint16 x, Sint16 y, Sint16 r, Uint32 color, Uint8 alpha)
{
	if (SDL_MUSTLOCK(Surface) && _sge_lock)
		if (SDL_LockSurface(Surface) < 0)
			return;

	_sge_alpha_hack = alpha;
	sge_DoCircle(Surface, x, y, r, color, callback_alpha_hack);

	if (SDL_MUSTLOCK(Surface) && _sge_lock) {
		SDL_UnlockSurface(Surface);
	}

	sge_UpdateRect(Surface, x-r, y-r, 2*r+1, 2*r+1);	
}

//==================================================================================
// Draws a circle (alpha - RGB)
//==================================================================================
void sge_CircleAlpha(SDL_Surface *Surface, Sint16 x, Sint16 y, Sint16 r, Uint8 R, Uint8 G, Uint8 B, Uint8 alpha)
{
	sge_CircleAlpha(Surface,x,y,r,SDL_MapRGB(Surface->format, R, G, B),alpha);
}


//==================================================================================
// Draws a filled circle
//==================================================================================
void sge_FilledCircle(SDL_Surface *Surface, Sint16 x, Sint16 y, Sint16 r, Uint32 color)
{
	Sint16 cx = 0;
 	Sint16 cy = r;
	bool draw=true;
 	Sint16 df = 1 - r;
 	Sint16 d_e = 3;
 	Sint16 d_se = -2 * r + 5;

 	do {
		if(draw){
 			_HLine(Surface,x-cx,x+cx,y+cy,color);
			_HLine(Surface,x-cx,x+cx,y-cy,color);
			draw=false;
		}
		if(cx!=cy){
			if(cx){
				_HLine(Surface,x-cy,x+cy,y-cx,color);
	 			_HLine(Surface,x-cy,x+cy,y+cx,color);
			}else
				_HLine(Surface,x-cy,x+cy,y,color);
		}
		
		if (df < 0)  {
	 		df += d_e;
	 		d_e += 2;
	 		d_se += 2;
 		}
   		else {
	 		df += d_se;
	 		d_e += 2;
	 		d_se += 4;
	 		cy--;
			draw=true;
   		}
  		cx++;
	}while(cx <= cy);

	sge_UpdateRect(Surface, x-r, y-r, 2*r+1, 2*r+1);				
}

//==================================================================================
// Draws a filled circle (RGB)
//==================================================================================
void sge_FilledCircle(SDL_Surface *Surface, Sint16 x, Sint16 y, Sint16 r, Uint8 R, Uint8 G, Uint8 B)
{
	sge_FilledCircle(Surface,x,y,r,SDL_MapRGB(Surface->format, R, G, B));
}


//==================================================================================
// Draws a filled circle (alpha)
//==================================================================================
void sge_FilledCircleAlpha(SDL_Surface *Surface, Sint16 x, Sint16 y, Sint16 r, Uint32 color, Uint8 alpha)
{
	Sint16 cx = 0;
 	Sint16 cy = r;
	bool draw=true;
 	Sint16 df = 1 - r;
 	Sint16 d_e = 3;
 	Sint16 d_se = -2 * r + 5;

	if (SDL_MUSTLOCK(Surface) && _sge_lock)
		if (SDL_LockSurface(Surface) < 0)
			return;

 	do {
		if(draw){
 			_HLineAlpha(Surface,x-cx,x+cx,y+cy,color,alpha);
			_HLineAlpha(Surface,x-cx,x+cx,y-cy,color,alpha);
			draw=false;
		}
		if(cx!=cy){
			if(cx){
				_HLineAlpha(Surface,x-cy,x+cy,y-cx,color,alpha);
	 			_HLineAlpha(Surface,x-cy,x+cy,y+cx,color,alpha);
			}else
				_HLineAlpha(Surface,x-cy,x+cy,y,color,alpha);
		}

		if (df < 0)  {
	 		df += d_e;
	 		d_e += 2;
	 		d_se += 2;
 		}
   		else {
	 		df += d_se;
	 		d_e += 2;
	 		d_se += 4;
	 		cy--;
			draw=true;
   		}
  		cx++;
	}while(cx <= cy);
	
	if (SDL_MUSTLOCK(Surface) && _sge_lock) {
		SDL_UnlockSurface(Surface);
	}

	sge_UpdateRect(Surface, x-r, y-r, 2*r+1, 2*r+1);				
}

//==================================================================================
// Draws a filled circle (alpha - RGB)
//==================================================================================
void sge_FilledCircleAlpha(SDL_Surface *Surface, Sint16 x, Sint16 y, Sint16 r, Uint8 R, Uint8 G, Uint8 B, Uint8 alpha)
{
	sge_FilledCircleAlpha(Surface,x,y,r,SDL_MapRGB(Surface->format, R, G, B),alpha);
}



//==================================================================================
// Draws a bezier line 
//==================================================================================
/* Macro to do the line... 'function' is the line drawing routine */
#define DO_BEZIER(function)\
	/*
	*  Note: I don't think there is any great performance win in translating this to fixed-point integer math,
	*  most of the time is spent in the line drawing routine.
	*/\
	float x = float(x1), y = float(y1);\
	float xp = x, yp = y;\
	float delta;\
	float dx, d2x, d3x;\
	float dy, d2y, d3y;\
	float a, b, c;\
	int i;\
	int n = 1;\
	Sint16 xmax=x1, ymax=y1, xmin=x1, ymin=y1;\
	\
	/* compute number of iterations */\
	if(level < 1)\
		level=1;\
	if(level >= 15)\
		level=15; \
	while (level-- > 0)\
		n*= 2;\
	delta = 1.0 / float(n);\
	\
	/* compute finite differences */\
	/* a, b, c are the coefficient of the polynom in t defining the parametric curve */\
	/* The computation is done independently for x and y */\
	a = float(-x1 + 3*x2 - 3*x3 + x4);\
	b = float(3*x1 - 6*x2 + 3*x3);\
	c = float(-3*x1 + 3*x2);\
	\
	d3x = 6 * a * delta*delta*delta;\
	d2x = d3x + 2 * b * delta*delta;\
	dx = a * delta*delta*delta + b * delta*delta + c * delta;\
	\
	a = float(-y1 + 3*y2 - 3*y3 + y4);\
	b = float(3*y1 - 6*y2 + 3*y3);\
	c = float(-3*y1 + 3*y2);\
	\
	d3y = 6 * a * delta*delta*delta;\
	d2y = d3y + 2 * b * delta*delta;\
	dy = a * delta*delta*delta + b * delta*delta + c * delta;\
	\
	if (SDL_MUSTLOCK(surface) && _sge_lock) {\
		if (SDL_LockSurface(surface) < 0)\
			return;\
	}\
	\
	/* iterate */\
	for (i = 0; i < n; i++) {\
		x += dx; dx += d2x; d2x += d3x;\
		y += dy; dy += d2y; d2y += d3y;\
		if(Sint16(xp) != Sint16(x) || Sint16(yp) != Sint16(y)){\
			function;\
			if(_sge_update==1){\
				xmax= (xmax>Sint16(xp))? xmax : Sint16(xp);  ymax= (ymax>Sint16(yp))? ymax : Sint16(yp);\
				xmin= (xmin<Sint16(xp))? xmin : Sint16(xp);  ymin= (ymin<Sint16(yp))? ymin : Sint16(yp);\
				xmax= (xmax>Sint16(x))? xmax : Sint16(x);    ymax= (ymax>Sint16(y))? ymax : Sint16(y);\
				xmin= (xmin<Sint16(x))? xmin : Sint16(x);    ymin= (ymin<Sint16(y))? ymin : Sint16(y);\
			}\
		}\
		xp = x; yp = y;\
	}\
	\
	/* unlock the display */\
	if (SDL_MUSTLOCK(surface) && _sge_lock) {\
		SDL_UnlockSurface(surface);\
	}\
	\
	/* Update the area */\
	sge_UpdateRect(surface, xmin, ymin, xmax-xmin+1, ymax-ymin+1);
	
//==================================================================================
// Draws a bezier line 
//==================================================================================	
void sge_Bezier(SDL_Surface *surface, Sint16 x1, Sint16 y1, Sint16 x2, Sint16 y2,Sint16 x3, Sint16 y3, Sint16 x4, Sint16 y4, int level, Uint32 color)
{
	DO_BEZIER(_Line(surface, Sint16(xp),Sint16(yp), Sint16(x),Sint16(y), color));
}

//==================================================================================
// Draws a bezier line (RGB)
//==================================================================================
void sge_Bezier(SDL_Surface *surface, Sint16 x1, Sint16 y1, Sint16 x2, Sint16 y2,Sint16 x3, Sint16 y3, Sint16 x4, Sint16 y4, int level, Uint8 R, Uint8 G, Uint8 B)
{
	sge_Bezier(surface,x1,y1,x2,y2,x3,y3,x4,y4,level, SDL_MapRGB(surface->format,R,G,B));
}


//==================================================================================
// Draws a bezier line (alpha)
//==================================================================================
void sge_BezierAlpha(SDL_Surface *surface, Sint16 x1, Sint16 y1, Sint16 x2, Sint16 y2,Sint16 x3, Sint16 y3, Sint16 x4, Sint16 y4, int level, Uint32 color, Uint8 alpha)
{
	_sge_alpha_hack = alpha;
	
	DO_BEZIER(sge_DoLine(surface, Sint16(xp),Sint16(yp), Sint16(x),Sint16(y), color, callback_alpha_hack));			
}

//==================================================================================
// Draws a bezier line (alpha - RGB)
//==================================================================================
void sge_BezierAlpha(SDL_Surface *surface, Sint16 x1, Sint16 y1, Sint16 x2, Sint16 y2,Sint16 x3, Sint16 y3, Sint16 x4, Sint16 y4, int level, Uint8 R, Uint8 G, Uint8 B, Uint8 alpha)
{
	sge_BezierAlpha(surface,x1,y1,x2,y2,x3,y3,x4,y4,level, SDL_MapRGB(surface->format,R,G,B),alpha);
}


//==================================================================================
// Draws an AA bezier line (alpha)
//==================================================================================
void sge_AABezierAlpha(SDL_Surface *surface, Sint16 x1, Sint16 y1, Sint16 x2, Sint16 y2,Sint16 x3, Sint16 y3, Sint16 x4, Sint16 y4, int level, Uint32 color, Uint8 alpha)
{
	Uint8 update = _sge_update;
	Uint8 lock = _sge_lock;
	_sge_update = 0;
	_sge_lock = 0;
	
	if (SDL_MUSTLOCK(surface) && lock)
		if (SDL_LockSurface(surface) < 0)
			return;
	
	DO_BEZIER(sge_AALineAlpha(surface, Sint16(xp),Sint16(yp), Sint16(x),Sint16(y), color, alpha));
	
	if (SDL_MUSTLOCK(surface) && lock) {
		SDL_UnlockSurface(surface);
	}
	
	_sge_update = update;
	_sge_lock = lock;
	
	sge_UpdateRect(surface, xmin, ymin, xmax-xmin+1, ymax-ymin+1);
}

//==================================================================================
// Draws an AA bezier line (alpha - RGB)
//==================================================================================
void sge_AABezierAlpha(SDL_Surface *surface, Sint16 x1, Sint16 y1, Sint16 x2, Sint16 y2,Sint16 x3, Sint16 y3, Sint16 x4, Sint16 y4, int level, Uint8 R, Uint8 G, Uint8 B, Uint8 alpha)
{
	sge_AABezierAlpha(surface,x1,y1,x2,y2,x3,y3,x4,y4,level, SDL_MapRGB(surface->format,R,G,B),alpha);
}


//==================================================================================
// Draws an AA bezier line
//==================================================================================
void sge_AABezier(SDL_Surface *surface, Sint16 x1, Sint16 y1, Sint16 x2, Sint16 y2,Sint16 x3, Sint16 y3, Sint16 x4, Sint16 y4, int level, Uint32 color)
{
	sge_AABezierAlpha(surface, x1,y1, x2,y2, x3,y3, x4,y4, level, color, 255);
}

//==================================================================================
// Draws an AA bezier line (RGB)
//==================================================================================
void sge_AABezier(SDL_Surface *surface, Sint16 x1, Sint16 y1, Sint16 x2, Sint16 y2,Sint16 x3, Sint16 y3, Sint16 x4, Sint16 y4, int level, Uint8 R, Uint8 G, Uint8 B)
{
	sge_AABezierAlpha(surface,x1,y1,x2,y2,x3,y3,x4,y4,level, SDL_MapRGB(surface->format,R,G,B),255);
}