[sdl_omap.git] / src / video / SDL_pixels.c

/*
    SDL - Simple DirectMedia Layer
    Copyright (C) 1997-2009 Sam Lantinga

    This library is free software; you can redistribute it and/or
    modify it under the terms of the GNU Lesser General Public
    License as published by the Free Software Foundation; either
    version 2.1 of the License, or (at your option) any later version.

    This library is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
    Lesser General Public License for more details.

    You should have received a copy of the GNU Lesser General Public
    License along with this library; if not, write to the Free Software
    Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA

    Sam Lantinga
    slouken@libsdl.org
*/
#include "SDL_config.h"

/* General (mostly internal) pixel/color manipulation routines for SDL */

#include "SDL_endian.h"
#include "SDL_video.h"
#include "SDL_sysvideo.h"
#include "SDL_blit.h"
#include "SDL_pixels_c.h"
#include "SDL_RLEaccel_c.h"

/* Helper functions */
/*
 * Allocate a pixel format structure and fill it according to the given info.
 */
SDL_PixelFormat *SDL_AllocFormat(int bpp,
			Uint32 Rmask, Uint32 Gmask, Uint32 Bmask, Uint32 Amask)
{
	SDL_PixelFormat *format;
	Uint32 mask;

	/* Allocate an empty pixel format structure */
	format = SDL_malloc(sizeof(*format));
	if ( format == NULL ) {
		SDL_OutOfMemory();
		return(NULL);
	}
	SDL_memset(format, 0, sizeof(*format));
	format->alpha = SDL_ALPHA_OPAQUE;

	/* Set up the format */
	format->BitsPerPixel = bpp;
	format->BytesPerPixel = (bpp+7)/8;
	if ( Rmask || Bmask || Gmask ) { /* Packed pixels with custom mask */
		format->palette = NULL;
		format->Rshift = 0;
		format->Rloss = 8;
		if ( Rmask ) {
			for ( mask = Rmask; !(mask&0x01); mask >>= 1 )
				++format->Rshift;
			for ( ; (mask&0x01); mask >>= 1 )
				--format->Rloss;
		}
		format->Gshift = 0;
		format->Gloss = 8;
		if ( Gmask ) {
			for ( mask = Gmask; !(mask&0x01); mask >>= 1 )
				++format->Gshift;
			for ( ; (mask&0x01); mask >>= 1 )
				--format->Gloss;
		}
		format->Bshift = 0;
		format->Bloss = 8;
		if ( Bmask ) {
			for ( mask = Bmask; !(mask&0x01); mask >>= 1 )
				++format->Bshift;
			for ( ; (mask&0x01); mask >>= 1 )
				--format->Bloss;
		}
		format->Ashift = 0;
		format->Aloss = 8;
		if ( Amask ) {
			for ( mask = Amask; !(mask&0x01); mask >>= 1 )
				++format->Ashift;
			for ( ; (mask&0x01); mask >>= 1 )
				--format->Aloss;
		}
		format->Rmask = Rmask;
		format->Gmask = Gmask;
		format->Bmask = Bmask;
		format->Amask = Amask;
	} else if ( bpp > 8 ) {		/* Packed pixels with standard mask */
		/* R-G-B */
		if ( bpp > 24 )
			bpp = 24;
		format->Rloss = 8-(bpp/3);
		format->Gloss = 8-(bpp/3)-(bpp%3);
		format->Bloss = 8-(bpp/3);
		format->Rshift = ((bpp/3)+(bpp%3))+(bpp/3);
		format->Gshift = (bpp/3);
		format->Bshift = 0;
		format->Rmask = ((0xFF>>format->Rloss)<<format->Rshift);
		format->Gmask = ((0xFF>>format->Gloss)<<format->Gshift);
		format->Bmask = ((0xFF>>format->Bloss)<<format->Bshift);
	} else {
		/* Palettized formats have no mask info */
		format->Rloss = 8;
		format->Gloss = 8;
		format->Bloss = 8;
		format->Aloss = 8;
		format->Rshift = 0;
		format->Gshift = 0;
		format->Bshift = 0;
		format->Ashift = 0;
		format->Rmask = 0;
		format->Gmask = 0;
		format->Bmask = 0;
		format->Amask = 0;
	}
	if ( bpp <= 8 ) {			/* Palettized mode */
		int ncolors = 1<<bpp;
#ifdef DEBUG_PALETTE
		fprintf(stderr,"bpp=%d ncolors=%d\n",bpp,ncolors);
#endif
		format->palette = (SDL_Palette *)SDL_malloc(sizeof(SDL_Palette));
		if ( format->palette == NULL ) {
			SDL_FreeFormat(format);
			SDL_OutOfMemory();
			return(NULL);
		}
		(format->palette)->ncolors = ncolors;
		(format->palette)->colors = (SDL_Color *)SDL_malloc(
				(format->palette)->ncolors*sizeof(SDL_Color));
		if ( (format->palette)->colors == NULL ) {
			SDL_FreeFormat(format);
			SDL_OutOfMemory();
			return(NULL);
		}
		if ( Rmask || Bmask || Gmask ) {
			/* create palette according to masks */
			int i;
			int Rm=0,Gm=0,Bm=0;
			int Rw=0,Gw=0,Bw=0;
#ifdef ENABLE_PALETTE_ALPHA
			int Am=0,Aw=0;
#endif
			if(Rmask)
			{
				Rw=8-format->Rloss;
				for(i=format->Rloss;i>0;i-=Rw)
					Rm|=1<<i;
			}
#ifdef DEBUG_PALETTE
			fprintf(stderr,"Rw=%d Rm=0x%02X\n",Rw,Rm);
#endif
			if(Gmask)
			{
				Gw=8-format->Gloss;
				for(i=format->Gloss;i>0;i-=Gw)
					Gm|=1<<i;
			}
#ifdef DEBUG_PALETTE
			fprintf(stderr,"Gw=%d Gm=0x%02X\n",Gw,Gm);
#endif
			if(Bmask)
			{
				Bw=8-format->Bloss;
				for(i=format->Bloss;i>0;i-=Bw)
					Bm|=1<<i;
			}
#ifdef DEBUG_PALETTE
			fprintf(stderr,"Bw=%d Bm=0x%02X\n",Bw,Bm);
#endif
#ifdef ENABLE_PALETTE_ALPHA
			if(Amask)
			{
				Aw=8-format->Aloss;
				for(i=format->Aloss;i>0;i-=Aw)
					Am|=1<<i;
			}
# ifdef DEBUG_PALETTE
			fprintf(stderr,"Aw=%d Am=0x%02X\n",Aw,Am);
# endif
#endif
			for(i=0; i < ncolors; ++i) {
				int r,g,b;
				r=(i&Rmask)>>format->Rshift;
				r=(r<<format->Rloss)|((r*Rm)>>Rw);
				format->palette->colors[i].r=r;

				g=(i&Gmask)>>format->Gshift;
				g=(g<<format->Gloss)|((g*Gm)>>Gw);
				format->palette->colors[i].g=g;

				b=(i&Bmask)>>format->Bshift;
				b=(b<<format->Bloss)|((b*Bm)>>Bw);
				format->palette->colors[i].b=b;

#ifdef ENABLE_PALETTE_ALPHA
				a=(i&Amask)>>format->Ashift;
				a=(a<<format->Aloss)|((a*Am)>>Aw);
				format->palette->colors[i].unused=a;
#else
				format->palette->colors[i].unused=0;
#endif
			}
		} else if ( ncolors == 2 ) {
			/* Create a black and white bitmap palette */
			format->palette->colors[0].r = 0xFF;
			format->palette->colors[0].g = 0xFF;
			format->palette->colors[0].b = 0xFF;
			format->palette->colors[1].r = 0x00;
			format->palette->colors[1].g = 0x00;
			format->palette->colors[1].b = 0x00;
		} else {
			/* Create an empty palette */
			SDL_memset((format->palette)->colors, 0,
				(format->palette)->ncolors*sizeof(SDL_Color));
		}
	}
	return(format);
}
SDL_PixelFormat *SDL_ReallocFormat(SDL_Surface *surface, int bpp,
			Uint32 Rmask, Uint32 Gmask, Uint32 Bmask, Uint32 Amask)
{
	if ( surface->format ) {
		SDL_FreeFormat(surface->format);
		SDL_FormatChanged(surface);
	}
	surface->format = SDL_AllocFormat(bpp, Rmask, Gmask, Bmask, Amask);
	return surface->format;
}

/*
 * Change any previous mappings from/to the new surface format
 */
void SDL_FormatChanged(SDL_Surface *surface)
{
	static int format_version = 0;
	++format_version;
	if ( format_version < 0 ) { /* It wrapped... */
		format_version = 1;
	}
	surface->format_version = format_version;
	SDL_InvalidateMap(surface->map);
}
/*
 * Free a previously allocated format structure
 */
void SDL_FreeFormat(SDL_PixelFormat *format)
{
	if ( format ) {
		if ( format->palette ) {
			if ( format->palette->colors ) {
				SDL_free(format->palette->colors);
			}
			SDL_free(format->palette);
		}
		SDL_free(format);
	}
}
/*
 * Calculate an 8-bit (3 red, 3 green, 2 blue) dithered palette of colors
 */
void SDL_DitherColors(SDL_Color *colors, int bpp)
{
	int i;
	if(bpp != 8)
		return;		/* only 8bpp supported right now */

	for(i = 0; i < 256; i++) {
		int r, g, b;
		/* map each bit field to the full [0, 255] interval,
		   so 0 is mapped to (0, 0, 0) and 255 to (255, 255, 255) */
		r = i & 0xe0;
		r |= r >> 3 | r >> 6;
		colors[i].r = r;
		g = (i << 3) & 0xe0;
		g |= g >> 3 | g >> 6;
		colors[i].g = g;
		b = i & 0x3;
		b |= b << 2;
		b |= b << 4;
		colors[i].b = b;
	}
}
/* 
 * Calculate the pad-aligned scanline width of a surface
 */
Uint16 SDL_CalculatePitch(SDL_Surface *surface)
{
	Uint16 pitch;

	/* Surface should be 4-byte aligned for speed */
	pitch = surface->w*surface->format->BytesPerPixel;
	switch (surface->format->BitsPerPixel) {
		case 1:
			pitch = (pitch+7)/8;
			break;
		case 4:
			pitch = (pitch+1)/2;
			break;
		default:
			break;
	}
	pitch = (pitch + 3) & ~3;	/* 4-byte aligning */
	return(pitch);
}
/*
 * Match an RGB value to a particular palette index
 */
Uint8 SDL_FindColor(SDL_Palette *pal, Uint8 r, Uint8 g, Uint8 b)
{
	/* Do colorspace distance matching */
	unsigned int smallest;
	unsigned int distance;
	int rd, gd, bd;
	int i;
	Uint8 pixel=0;
		
	smallest = ~0;
	for ( i=0; i<pal->ncolors; ++i ) {
		rd = pal->colors[i].r - r;
		gd = pal->colors[i].g - g;
		bd = pal->colors[i].b - b;
		distance = (rd*rd)+(gd*gd)+(bd*bd);
		if ( distance < smallest ) {
			pixel = i;
			if ( distance == 0 ) { /* Perfect match! */
				break;
			}
			smallest = distance;
		}
	}
	return(pixel);
}

/* Find the opaque pixel value corresponding to an RGB triple */
Uint32 SDL_MapRGB
(const SDL_PixelFormat * const format,
 const Uint8 r, const Uint8 g, const Uint8 b)
{
	if ( format->palette == NULL ) {
		return (r >> format->Rloss) << format->Rshift
		       | (g >> format->Gloss) << format->Gshift
		       | (b >> format->Bloss) << format->Bshift
		       | format->Amask;
	} else {
		return SDL_FindColor(format->palette, r, g, b);
	}
}

/* Find the pixel value corresponding to an RGBA quadruple */
Uint32 SDL_MapRGBA
(const SDL_PixelFormat * const format,
 const Uint8 r, const Uint8 g, const Uint8 b, const Uint8 a)
{
	if ( format->palette == NULL ) {
	        return (r >> format->Rloss) << format->Rshift
		    | (g >> format->Gloss) << format->Gshift
		    | (b >> format->Bloss) << format->Bshift
		    | ((a >> format->Aloss) << format->Ashift & format->Amask);
	} else {
		return SDL_FindColor(format->palette, r, g, b);
	}
}

void SDL_GetRGBA(Uint32 pixel, const SDL_PixelFormat * const fmt,
		 Uint8 *r, Uint8 *g, Uint8 *b, Uint8 *a)
{
	if ( fmt->palette == NULL ) {
	        /*
		 * This makes sure that the result is mapped to the
		 * interval [0..255], and the maximum value for each
		 * component is 255. This is important to make sure
		 * that white is indeed reported as (255, 255, 255),
		 * and that opaque alpha is 255.
		 * This only works for RGB bit fields at least 4 bit
		 * wide, which is almost always the case.
		 */
	        unsigned v;
		v = (pixel & fmt->Rmask) >> fmt->Rshift;
		*r = (v << fmt->Rloss) + (v >> (8 - (fmt->Rloss << 1)));
		v = (pixel & fmt->Gmask) >> fmt->Gshift;
		*g = (v << fmt->Gloss) + (v >> (8 - (fmt->Gloss << 1)));
		v = (pixel & fmt->Bmask) >> fmt->Bshift;
		*b = (v << fmt->Bloss) + (v >> (8 - (fmt->Bloss << 1)));
		if(fmt->Amask) {
		        v = (pixel & fmt->Amask) >> fmt->Ashift;
			*a = (v << fmt->Aloss) + (v >> (8 - (fmt->Aloss << 1)));
		} else {
		        *a = SDL_ALPHA_OPAQUE;
                }
	} else {
		*r = fmt->palette->colors[pixel].r;
		*g = fmt->palette->colors[pixel].g;
		*b = fmt->palette->colors[pixel].b;
		*a = SDL_ALPHA_OPAQUE;
	}
}

void SDL_GetRGB(Uint32 pixel, const SDL_PixelFormat * const fmt,
                Uint8 *r,Uint8 *g,Uint8 *b)
{
	if ( fmt->palette == NULL ) {
	        /* the note for SDL_GetRGBA above applies here too */
	        unsigned v;
		v = (pixel & fmt->Rmask) >> fmt->Rshift;
		*r = (v << fmt->Rloss) + (v >> (8 - (fmt->Rloss << 1)));
		v = (pixel & fmt->Gmask) >> fmt->Gshift;
		*g = (v << fmt->Gloss) + (v >> (8 - (fmt->Gloss << 1)));
		v = (pixel & fmt->Bmask) >> fmt->Bshift;
		*b = (v << fmt->Bloss) + (v >> (8 - (fmt->Bloss << 1)));
	} else {
		*r = fmt->palette->colors[pixel].r;
		*g = fmt->palette->colors[pixel].g;
		*b = fmt->palette->colors[pixel].b;
	}
}

/* Apply gamma to a set of colors - this is easy. :) */
void SDL_ApplyGamma(Uint16 *gamma, SDL_Color *colors, SDL_Color *output,
							int ncolors)
{
	int i;

	for ( i=0; i<ncolors; ++i ) {
		output[i].r = gamma[0*256 + colors[i].r] >> 8;
		output[i].g = gamma[1*256 + colors[i].g] >> 8;
		output[i].b = gamma[2*256 + colors[i].b] >> 8;
	}
}

/* Map from Palette to Palette */
static Uint8 *Map1to1(SDL_Palette *src, SDL_Palette *dst, int *identical)
{
	Uint8 *map;
	int i;

	if ( identical ) {
		if ( src->ncolors <= dst->ncolors ) {
			/* If an identical palette, no need to map */
			if ( SDL_memcmp(src->colors, dst->colors, src->ncolors*
						sizeof(SDL_Color)) == 0 ) {
				*identical = 1;
				return(NULL);
			}
		}
		*identical = 0;
	}
	map = (Uint8 *)SDL_malloc(src->ncolors);
	if ( map == NULL ) {
		SDL_OutOfMemory();
		return(NULL);
	}
	for ( i=0; i<src->ncolors; ++i ) {
		map[i] = SDL_FindColor(dst,
			src->colors[i].r, src->colors[i].g, src->colors[i].b);
	}
	return(map);
}
/* Map from Palette to BitField */
static Uint8 *Map1toN(SDL_PixelFormat *src, SDL_PixelFormat *dst)
{
	Uint8 *map;
	int i;
	int  bpp;
	unsigned alpha;
	SDL_Palette *pal = src->palette;

	bpp = ((dst->BytesPerPixel == 3) ? 4 : dst->BytesPerPixel);
	map = (Uint8 *)SDL_malloc(pal->ncolors*bpp);
	if ( map == NULL ) {
		SDL_OutOfMemory();
		return(NULL);
	}

	alpha = dst->Amask ? src->alpha : 0;
	/* We memory copy to the pixel map so the endianness is preserved */
	for ( i=0; i<pal->ncolors; ++i ) {
		ASSEMBLE_RGBA(&map[i*bpp], dst->BytesPerPixel, dst,
			      pal->colors[i].r, pal->colors[i].g,
			      pal->colors[i].b, alpha);
	}
	return(map);
}
/* Map from BitField to Dithered-Palette to Palette */
static Uint8 *MapNto1(SDL_PixelFormat *src, SDL_PixelFormat *dst, int *identical)
{
	/* Generate a 256 color dither palette */
	SDL_Palette dithered;
	SDL_Color colors[256];
	SDL_Palette *pal = dst->palette;
	
	/* SDL_DitherColors does not initialize the 'unused' component of colors,
	   but Map1to1 compares it against pal, so we should initialize it. */  
	SDL_memset(colors, 0, sizeof(colors));

	dithered.ncolors = 256;
	SDL_DitherColors(colors, 8);
	dithered.colors = colors;
	return(Map1to1(&dithered, pal, identical));
}

SDL_BlitMap *SDL_AllocBlitMap(void)
{
	SDL_BlitMap *map;

	/* Allocate the empty map */
	map = (SDL_BlitMap *)SDL_malloc(sizeof(*map));
	if ( map == NULL ) {
		SDL_OutOfMemory();
		return(NULL);
	}
	SDL_memset(map, 0, sizeof(*map));

	/* Allocate the software blit data */
	map->sw_data = (struct private_swaccel *)SDL_malloc(sizeof(*map->sw_data));
	if ( map->sw_data == NULL ) {
		SDL_FreeBlitMap(map);
		SDL_OutOfMemory();
		return(NULL);
	}
	SDL_memset(map->sw_data, 0, sizeof(*map->sw_data));

	/* It's ready to go */
	return(map);
}
void SDL_InvalidateMap(SDL_BlitMap *map)
{
	if ( ! map ) {
		return;
	}
	map->dst = NULL;
	map->format_version = (unsigned int)-1;
	if ( map->table ) {
		SDL_free(map->table);
		map->table = NULL;
	}
}
int SDL_MapSurface (SDL_Surface *src, SDL_Surface *dst)
{
	SDL_PixelFormat *srcfmt;
	SDL_PixelFormat *dstfmt;
	SDL_BlitMap *map;

	/* Clear out any previous mapping */
	map = src->map;
	if ( (src->flags & SDL_RLEACCEL) == SDL_RLEACCEL ) {
		SDL_UnRLESurface(src, 1);
	}
	SDL_InvalidateMap(map);

	/* Figure out what kind of mapping we're doing */
	map->identity = 0;
	srcfmt = src->format;
	dstfmt = dst->format;
	switch (srcfmt->BytesPerPixel) {
	    case 1:
		switch (dstfmt->BytesPerPixel) {
		    case 1:
			/* Palette --> Palette */
			/* If both SDL_HWSURFACE, assume have same palette */
			if ( ((src->flags & SDL_HWSURFACE) == SDL_HWSURFACE) &&
			     ((dst->flags & SDL_HWSURFACE) == SDL_HWSURFACE) ) {
				map->identity = 1;
			} else {
				map->table = Map1to1(srcfmt->palette,
					dstfmt->palette, &map->identity);
			}
			if ( ! map->identity ) {
				if ( map->table == NULL ) {
					return(-1);
				}
			}
			if (srcfmt->BitsPerPixel!=dstfmt->BitsPerPixel)
				map->identity = 0;
			break;

		    default:
			/* Palette --> BitField */
			map->table = Map1toN(srcfmt, dstfmt);
			if ( map->table == NULL ) {
				return(-1);
			}
			break;
		}
		break;
	default:
		switch (dstfmt->BytesPerPixel) {
		    case 1:
			/* BitField --> Palette */
			map->table = MapNto1(srcfmt, dstfmt, &map->identity);
			if ( ! map->identity ) {
				if ( map->table == NULL ) {
					return(-1);
				}
			}
			map->identity = 0;	/* Don't optimize to copy */
			break;
		    default:
			/* BitField --> BitField */
			if ( FORMAT_EQUAL(srcfmt, dstfmt) )
				map->identity = 1;
			break;
		}
		break;
	}

	map->dst = dst;
	map->format_version = dst->format_version;

	/* Choose your blitters wisely */
	return(SDL_CalculateBlit(src));
}
void SDL_FreeBlitMap(SDL_BlitMap *map)
{
	if ( map ) {
		SDL_InvalidateMap(map);
		if ( map->sw_data != NULL ) {
			SDL_free(map->sw_data);
		}
		SDL_free(map);
	}
}
Commit	Line	Data
e14743d1	1	/*
	2	SDL - Simple DirectMedia Layer
	3	Copyright (C) 1997-2009 Sam Lantinga
	4
	5	This library is free software; you can redistribute it and/or
	6	modify it under the terms of the GNU Lesser General Public
	7	License as published by the Free Software Foundation; either
	8	version 2.1 of the License, or (at your option) any later version.
	9
	10	This library is distributed in the hope that it will be useful,
	11	but WITHOUT ANY WARRANTY; without even the implied warranty of
	12	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
	13	Lesser General Public License for more details.
	14
	15	You should have received a copy of the GNU Lesser General Public
	16	License along with this library; if not, write to the Free Software
	17	Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
	18
	19	Sam Lantinga
	20	slouken@libsdl.org
	21	*/
	22	#include "SDL_config.h"
	23
	24	/* General (mostly internal) pixel/color manipulation routines for SDL */
	25
	26	#include "SDL_endian.h"
	27	#include "SDL_video.h"
	28	#include "SDL_sysvideo.h"
	29	#include "SDL_blit.h"
	30	#include "SDL_pixels_c.h"
	31	#include "SDL_RLEaccel_c.h"
	32
	33	/* Helper functions */
	34	/*
	35	* Allocate a pixel format structure and fill it according to the given info.
	36	*/
	37	SDL_PixelFormat *SDL_AllocFormat(int bpp,
	38	Uint32 Rmask, Uint32 Gmask, Uint32 Bmask, Uint32 Amask)
	39	{
	40	SDL_PixelFormat *format;
	41	Uint32 mask;
	42
	43	/* Allocate an empty pixel format structure */
	44	format = SDL_malloc(sizeof(*format));
	45	if ( format == NULL ) {
	46	SDL_OutOfMemory();
	47	return(NULL);
	48	}
	49	SDL_memset(format, 0, sizeof(*format));
	50	format->alpha = SDL_ALPHA_OPAQUE;
	51
	52	/* Set up the format */
	53	format->BitsPerPixel = bpp;
	54	format->BytesPerPixel = (bpp+7)/8;
	55	if ( Rmask \|\| Bmask \|\| Gmask ) { /* Packed pixels with custom mask */
	56	format->palette = NULL;
	57	format->Rshift = 0;
	58	format->Rloss = 8;
	59	if ( Rmask ) {
	60	for ( mask = Rmask; !(mask&0x01); mask >>= 1 )
	61	++format->Rshift;
	62	for ( ; (mask&0x01); mask >>= 1 )
	63	--format->Rloss;
	64	}
65	format->Gshift = 0;
66	format->Gloss = 8;
67	if ( Gmask ) {
68	for ( mask = Gmask; !(mask&0x01); mask >>= 1 )
69	++format->Gshift;
70	for ( ; (mask&0x01); mask >>= 1 )
71	--format->Gloss;
72	}
73	format->Bshift = 0;
74	format->Bloss = 8;
75	if ( Bmask ) {
76	for ( mask = Bmask; !(mask&0x01); mask >>= 1 )
77	++format->Bshift;
78	for ( ; (mask&0x01); mask >>= 1 )
79	--format->Bloss;
80	}
81	format->Ashift = 0;
82	format->Aloss = 8;
83	if ( Amask ) {
84	for ( mask = Amask; !(mask&0x01); mask >>= 1 )
85	++format->Ashift;
86	for ( ; (mask&0x01); mask >>= 1 )
87	--format->Aloss;
88	}
89	format->Rmask = Rmask;
90	format->Gmask = Gmask;
91	format->Bmask = Bmask;
92	format->Amask = Amask;
93	} else if ( bpp > 8 ) { /* Packed pixels with standard mask */
94	/* R-G-B */
95	if ( bpp > 24 )
96	bpp = 24;
97	format->Rloss = 8-(bpp/3);
98	format->Gloss = 8-(bpp/3)-(bpp%3);
99	format->Bloss = 8-(bpp/3);
100	format->Rshift = ((bpp/3)+(bpp%3))+(bpp/3);
101	format->Gshift = (bpp/3);
102	format->Bshift = 0;
103	format->Rmask = ((0xFF>>format->Rloss)<<format->Rshift);
104	format->Gmask = ((0xFF>>format->Gloss)<<format->Gshift);
105	format->Bmask = ((0xFF>>format->Bloss)<<format->Bshift);
106	} else {
107	/* Palettized formats have no mask info */
108	format->Rloss = 8;
109	format->Gloss = 8;
110	format->Bloss = 8;
111	format->Aloss = 8;
112	format->Rshift = 0;
113	format->Gshift = 0;
114	format->Bshift = 0;
115	format->Ashift = 0;
116	format->Rmask = 0;
117	format->Gmask = 0;
118	format->Bmask = 0;
119	format->Amask = 0;
120	}
121	if ( bpp <= 8 ) { /* Palettized mode */
122	int ncolors = 1<<bpp;
123	#ifdef DEBUG_PALETTE
124	fprintf(stderr,"bpp=%d ncolors=%d\n",bpp,ncolors);
125	#endif
126	format->palette = (SDL_Palette *)SDL_malloc(sizeof(SDL_Palette));
127	if ( format->palette == NULL ) {
128	SDL_FreeFormat(format);
129	SDL_OutOfMemory();
130	return(NULL);
131	}
132	(format->palette)->ncolors = ncolors;
133	(format->palette)->colors = (SDL_Color *)SDL_malloc(
134	(format->palette)->ncolors*sizeof(SDL_Color));
135	if ( (format->palette)->colors == NULL ) {
136	SDL_FreeFormat(format);
137	SDL_OutOfMemory();
138	return(NULL);
139	}
140	if ( Rmask \|\| Bmask \|\| Gmask ) {
141	/* create palette according to masks */
142	int i;
143	int Rm=0,Gm=0,Bm=0;
144	int Rw=0,Gw=0,Bw=0;
145	#ifdef ENABLE_PALETTE_ALPHA
146	int Am=0,Aw=0;
147	#endif
148	if(Rmask)
149	{
150	Rw=8-format->Rloss;
151	for(i=format->Rloss;i>0;i-=Rw)
152	Rm\|=1<<i;
153	}
154	#ifdef DEBUG_PALETTE
155	fprintf(stderr,"Rw=%d Rm=0x%02X\n",Rw,Rm);
156	#endif
157	if(Gmask)
158	{
159	Gw=8-format->Gloss;
160	for(i=format->Gloss;i>0;i-=Gw)
161	Gm\|=1<<i;
162	}
163	#ifdef DEBUG_PALETTE
164	fprintf(stderr,"Gw=%d Gm=0x%02X\n",Gw,Gm);
165	#endif
166	if(Bmask)
167	{
168	Bw=8-format->Bloss;
169	for(i=format->Bloss;i>0;i-=Bw)
170	Bm\|=1<<i;
171	}
172	#ifdef DEBUG_PALETTE
173	fprintf(stderr,"Bw=%d Bm=0x%02X\n",Bw,Bm);
174	#endif
175	#ifdef ENABLE_PALETTE_ALPHA
176	if(Amask)
177	{
178	Aw=8-format->Aloss;
179	for(i=format->Aloss;i>0;i-=Aw)
180	Am\|=1<<i;
181	}
182	# ifdef DEBUG_PALETTE
183	fprintf(stderr,"Aw=%d Am=0x%02X\n",Aw,Am);
184	# endif
185	#endif
186	for(i=0; i < ncolors; ++i) {
187	int r,g,b;
188	r=(i&Rmask)>>format->Rshift;
189	r=(r<<format->Rloss)\|((r*Rm)>>Rw);
190	format->palette->colors[i].r=r;
191
192	g=(i&Gmask)>>format->Gshift;
193	g=(g<<format->Gloss)\|((g*Gm)>>Gw);
194	format->palette->colors[i].g=g;
195
196	b=(i&Bmask)>>format->Bshift;
197	b=(b<<format->Bloss)\|((b*Bm)>>Bw);
198	format->palette->colors[i].b=b;
199
200	#ifdef ENABLE_PALETTE_ALPHA
201	a=(i&Amask)>>format->Ashift;
202	a=(a<<format->Aloss)\|((a*Am)>>Aw);
203	format->palette->colors[i].unused=a;
204	#else
205	format->palette->colors[i].unused=0;
206	#endif
207	}
208	} else if ( ncolors == 2 ) {
209	/* Create a black and white bitmap palette */
210	format->palette->colors[0].r = 0xFF;
211	format->palette->colors[0].g = 0xFF;
212	format->palette->colors[0].b = 0xFF;
213	format->palette->colors[1].r = 0x00;
214	format->palette->colors[1].g = 0x00;
215	format->palette->colors[1].b = 0x00;
216	} else {
217	/* Create an empty palette */
218	SDL_memset((format->palette)->colors, 0,
219	(format->palette)->ncolors*sizeof(SDL_Color));
220	}
221	}
222	return(format);
223	}
224	SDL_PixelFormat SDL_ReallocFormat(SDL_Surface surface, int bpp,
225	Uint32 Rmask, Uint32 Gmask, Uint32 Bmask, Uint32 Amask)
226	{
227	if ( surface->format ) {
228	SDL_FreeFormat(surface->format);
229	SDL_FormatChanged(surface);
230	}
231	surface->format = SDL_AllocFormat(bpp, Rmask, Gmask, Bmask, Amask);
232	return surface->format;
233	}
234
235	/*
236	* Change any previous mappings from/to the new surface format
237	*/
238	void SDL_FormatChanged(SDL_Surface *surface)
239	{
240	static int format_version = 0;
241	++format_version;
242	if ( format_version < 0 ) { /* It wrapped... */
243	format_version = 1;
244	}
245	surface->format_version = format_version;
246	SDL_InvalidateMap(surface->map);
247	}
248	/*
249	* Free a previously allocated format structure
250	*/
251	void SDL_FreeFormat(SDL_PixelFormat *format)
252	{
253	if ( format ) {
254	if ( format->palette ) {
255	if ( format->palette->colors ) {
256	SDL_free(format->palette->colors);
257	}
258	SDL_free(format->palette);
259	}
260	SDL_free(format);
261	}
262	}
263	/*
264	* Calculate an 8-bit (3 red, 3 green, 2 blue) dithered palette of colors
265	*/
266	void SDL_DitherColors(SDL_Color *colors, int bpp)
267	{
268	int i;
269	if(bpp != 8)
270	return; /* only 8bpp supported right now */
271
272	for(i = 0; i < 256; i++) {
273	int r, g, b;
274	/* map each bit field to the full [0, 255] interval,
275	so 0 is mapped to (0, 0, 0) and 255 to (255, 255, 255) */
276	r = i & 0xe0;
277	r \|= r >> 3 \| r >> 6;
278	colors[i].r = r;
279	g = (i << 3) & 0xe0;
280	g \|= g >> 3 \| g >> 6;
281	colors[i].g = g;
282	b = i & 0x3;
283	b \|= b << 2;
284	b \|= b << 4;
285	colors[i].b = b;
286	}
287	}
288	/*
289	* Calculate the pad-aligned scanline width of a surface
290	*/
291	Uint16 SDL_CalculatePitch(SDL_Surface *surface)
292	{
293	Uint16 pitch;
294
295	/* Surface should be 4-byte aligned for speed */
296	pitch = surface->w*surface->format->BytesPerPixel;
297	switch (surface->format->BitsPerPixel) {
298	case 1:
299	pitch = (pitch+7)/8;
300	break;
301	case 4:
302	pitch = (pitch+1)/2;
303	break;
304	default:
305	break;
306	}
307	pitch = (pitch + 3) & ~3; /* 4-byte aligning */
308	return(pitch);
309	}
310	/*
311	* Match an RGB value to a particular palette index
312	*/
313	Uint8 SDL_FindColor(SDL_Palette *pal, Uint8 r, Uint8 g, Uint8 b)
314	{
315	/* Do colorspace distance matching */
316	unsigned int smallest;
317	unsigned int distance;
318	int rd, gd, bd;
319	int i;
320	Uint8 pixel=0;
321
322	smallest = ~0;
323	for ( i=0; i<pal->ncolors; ++i ) {
324	rd = pal->colors[i].r - r;
325	gd = pal->colors[i].g - g;
326	bd = pal->colors[i].b - b;
327	distance = (rdrd)+(gdgd)+(bd*bd);
328	if ( distance < smallest ) {
329	pixel = i;
330	if ( distance == 0 ) { /* Perfect match! */
331	break;
332	}
333	smallest = distance;
334	}
335	}
336	return(pixel);
337	}
338
339	/* Find the opaque pixel value corresponding to an RGB triple */
340	Uint32 SDL_MapRGB
341	(const SDL_PixelFormat * const format,
342	const Uint8 r, const Uint8 g, const Uint8 b)
343	{
344	if ( format->palette == NULL ) {
345	return (r >> format->Rloss) << format->Rshift
346	\| (g >> format->Gloss) << format->Gshift
347	\| (b >> format->Bloss) << format->Bshift
348	\| format->Amask;
349	} else {
350	return SDL_FindColor(format->palette, r, g, b);
351	}
352	}
353
354	/* Find the pixel value corresponding to an RGBA quadruple */
355	Uint32 SDL_MapRGBA
356	(const SDL_PixelFormat * const format,
357	const Uint8 r, const Uint8 g, const Uint8 b, const Uint8 a)
358	{
359	if ( format->palette == NULL ) {
360	return (r >> format->Rloss) << format->Rshift
361	\| (g >> format->Gloss) << format->Gshift
362	\| (b >> format->Bloss) << format->Bshift
363	\| ((a >> format->Aloss) << format->Ashift & format->Amask);
364	} else {
365	return SDL_FindColor(format->palette, r, g, b);
366	}
367	}
368
369	void SDL_GetRGBA(Uint32 pixel, const SDL_PixelFormat * const fmt,
370	Uint8 r, Uint8 g, Uint8 b, Uint8 a)
371	{
372	if ( fmt->palette == NULL ) {
373	/*
374	* This makes sure that the result is mapped to the
375	* interval [0..255], and the maximum value for each
376	* component is 255. This is important to make sure
377	* that white is indeed reported as (255, 255, 255),
378	* and that opaque alpha is 255.
379	* This only works for RGB bit fields at least 4 bit
380	* wide, which is almost always the case.
381	*/
382	unsigned v;
383	v = (pixel & fmt->Rmask) >> fmt->Rshift;
384	*r = (v << fmt->Rloss) + (v >> (8 - (fmt->Rloss << 1)));
385	v = (pixel & fmt->Gmask) >> fmt->Gshift;
386	*g = (v << fmt->Gloss) + (v >> (8 - (fmt->Gloss << 1)));
387	v = (pixel & fmt->Bmask) >> fmt->Bshift;
388	*b = (v << fmt->Bloss) + (v >> (8 - (fmt->Bloss << 1)));
389	if(fmt->Amask) {
390	v = (pixel & fmt->Amask) >> fmt->Ashift;
391	*a = (v << fmt->Aloss) + (v >> (8 - (fmt->Aloss << 1)));
392	} else {
393	*a = SDL_ALPHA_OPAQUE;
394	}
395	} else {
396	*r = fmt->palette->colors[pixel].r;
397	*g = fmt->palette->colors[pixel].g;
398	*b = fmt->palette->colors[pixel].b;
399	*a = SDL_ALPHA_OPAQUE;
400	}
401	}
402
403	void SDL_GetRGB(Uint32 pixel, const SDL_PixelFormat * const fmt,
404	Uint8 r,Uint8 g,Uint8 *b)
405	{
406	if ( fmt->palette == NULL ) {
407	/* the note for SDL_GetRGBA above applies here too */
408	unsigned v;
409	v = (pixel & fmt->Rmask) >> fmt->Rshift;
410	*r = (v << fmt->Rloss) + (v >> (8 - (fmt->Rloss << 1)));
411	v = (pixel & fmt->Gmask) >> fmt->Gshift;
412	*g = (v << fmt->Gloss) + (v >> (8 - (fmt->Gloss << 1)));
413	v = (pixel & fmt->Bmask) >> fmt->Bshift;
414	*b = (v << fmt->Bloss) + (v >> (8 - (fmt->Bloss << 1)));
415	} else {
416	*r = fmt->palette->colors[pixel].r;
417	*g = fmt->palette->colors[pixel].g;
418	*b = fmt->palette->colors[pixel].b;
419	}
420	}
421
422	/* Apply gamma to a set of colors - this is easy. :) */
423	void SDL_ApplyGamma(Uint16 gamma, SDL_Color colors, SDL_Color *output,
424	int ncolors)
425	{
426	int i;
427
428	for ( i=0; i<ncolors; ++i ) {
429	output[i].r = gamma[0*256 + colors[i].r] >> 8;
430	output[i].g = gamma[1*256 + colors[i].g] >> 8;
431	output[i].b = gamma[2*256 + colors[i].b] >> 8;
432	}
433	}
434
435	/* Map from Palette to Palette */
436	static Uint8 Map1to1(SDL_Palette src, SDL_Palette dst, int identical)
437	{
438	Uint8 *map;
439	int i;
440
441	if ( identical ) {
442	if ( src->ncolors <= dst->ncolors ) {
443	/* If an identical palette, no need to map */
444	if ( SDL_memcmp(src->colors, dst->colors, src->ncolors*
445	sizeof(SDL_Color)) == 0 ) {
446	*identical = 1;
447	return(NULL);
448	}
449	}
450	*identical = 0;
451	}
452	map = (Uint8 *)SDL_malloc(src->ncolors);
453	if ( map == NULL ) {
454	SDL_OutOfMemory();
455	return(NULL);
456	}
457	for ( i=0; i<src->ncolors; ++i ) {
458	map[i] = SDL_FindColor(dst,
459	src->colors[i].r, src->colors[i].g, src->colors[i].b);
460	}
461	return(map);
462	}
463	/* Map from Palette to BitField */
464	static Uint8 Map1toN(SDL_PixelFormat src, SDL_PixelFormat *dst)
465	{
466	Uint8 *map;
467	int i;
468	int bpp;
469	unsigned alpha;
470	SDL_Palette *pal = src->palette;
471
472	bpp = ((dst->BytesPerPixel == 3) ? 4 : dst->BytesPerPixel);
473	map = (Uint8 )SDL_malloc(pal->ncolorsbpp);
474	if ( map == NULL ) {
475	SDL_OutOfMemory();
476	return(NULL);
477	}
478
479	alpha = dst->Amask ? src->alpha : 0;
480	/* We memory copy to the pixel map so the endianness is preserved */
481	for ( i=0; i<pal->ncolors; ++i ) {
482	ASSEMBLE_RGBA(&map[i*bpp], dst->BytesPerPixel, dst,
483	pal->colors[i].r, pal->colors[i].g,
484	pal->colors[i].b, alpha);
485	}
486	return(map);
487	}
488	/* Map from BitField to Dithered-Palette to Palette */
489	static Uint8 MapNto1(SDL_PixelFormat src, SDL_PixelFormat dst, int identical)
490	{
491	/* Generate a 256 color dither palette */
492	SDL_Palette dithered;
493	SDL_Color colors[256];
494	SDL_Palette *pal = dst->palette;
495
496	/* SDL_DitherColors does not initialize the 'unused' component of colors,
497	but Map1to1 compares it against pal, so we should initialize it. */
498	SDL_memset(colors, 0, sizeof(colors));
499
500	dithered.ncolors = 256;
501	SDL_DitherColors(colors, 8);
502	dithered.colors = colors;
503	return(Map1to1(&dithered, pal, identical));
504	}
505
506	SDL_BlitMap *SDL_AllocBlitMap(void)
507	{
508	SDL_BlitMap *map;
509
510	/* Allocate the empty map */
511	map = (SDL_BlitMap )SDL_malloc(sizeof(map));
512	if ( map == NULL ) {
513	SDL_OutOfMemory();
514	return(NULL);
515	}
516	SDL_memset(map, 0, sizeof(*map));
517
518	/* Allocate the software blit data */
519	map->sw_data = (struct private_swaccel )SDL_malloc(sizeof(map->sw_data));
520	if ( map->sw_data == NULL ) {
521	SDL_FreeBlitMap(map);
522	SDL_OutOfMemory();
523	return(NULL);
524	}
525	SDL_memset(map->sw_data, 0, sizeof(*map->sw_data));
526
527	/* It's ready to go */
528	return(map);
529	}
530	void SDL_InvalidateMap(SDL_BlitMap *map)
531	{
532	if ( ! map ) {
533	return;
534	}
535	map->dst = NULL;
536	map->format_version = (unsigned int)-1;
537	if ( map->table ) {
538	SDL_free(map->table);
539	map->table = NULL;
540	}
541	}
542	int SDL_MapSurface (SDL_Surface src, SDL_Surface dst)
543	{
544	SDL_PixelFormat *srcfmt;
545	SDL_PixelFormat *dstfmt;
546	SDL_BlitMap *map;
547
548	/* Clear out any previous mapping */
549	map = src->map;
550	if ( (src->flags & SDL_RLEACCEL) == SDL_RLEACCEL ) {
551	SDL_UnRLESurface(src, 1);
552	}
553	SDL_InvalidateMap(map);
554
555	/* Figure out what kind of mapping we're doing */
556	map->identity = 0;
557	srcfmt = src->format;
558	dstfmt = dst->format;
559	switch (srcfmt->BytesPerPixel) {
560	case 1:
561	switch (dstfmt->BytesPerPixel) {
562	case 1:
563	/* Palette --> Palette */
564	/* If both SDL_HWSURFACE, assume have same palette */
565	if ( ((src->flags & SDL_HWSURFACE) == SDL_HWSURFACE) &&
566	((dst->flags & SDL_HWSURFACE) == SDL_HWSURFACE) ) {
567	map->identity = 1;
568	} else {
569	map->table = Map1to1(srcfmt->palette,
570	dstfmt->palette, &map->identity);
571	}
572	if ( ! map->identity ) {
573	if ( map->table == NULL ) {
574	return(-1);
575	}
576	}
577	if (srcfmt->BitsPerPixel!=dstfmt->BitsPerPixel)
578	map->identity = 0;
579	break;
580
581	default:
582	/* Palette --> BitField */
583	map->table = Map1toN(srcfmt, dstfmt);
584	if ( map->table == NULL ) {
585	return(-1);
586	}
587	break;
588	}
589	break;
590	default:
591	switch (dstfmt->BytesPerPixel) {
592	case 1:
593	/* BitField --> Palette */
594	map->table = MapNto1(srcfmt, dstfmt, &map->identity);
595	if ( ! map->identity ) {
596	if ( map->table == NULL ) {
597	return(-1);
598	}
599	}
600	map->identity = 0; /* Don't optimize to copy */
601	break;
602	default:
603	/* BitField --> BitField */
604	if ( FORMAT_EQUAL(srcfmt, dstfmt) )
605	map->identity = 1;
606	break;
607	}
608	break;
609	}
610
611	map->dst = dst;
612	map->format_version = dst->format_version;
613
614	/* Choose your blitters wisely */
615	return(SDL_CalculateBlit(src));
616	}
617	void SDL_FreeBlitMap(SDL_BlitMap *map)
618	{
619	if ( map ) {
620	SDL_InvalidateMap(map);
621	if ( map->sw_data != NULL ) {
622	SDL_free(map->sw_data);
623	}
624	SDL_free(map);
625	}
626	}