/*

SDL - Simple DirectMedia Layer

Copyright (C) 1997-2006 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

*/

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

#include "SDL_error.h"

#include "SDL_endian.h"

#include "SDL_video.h"

#include "SDL_stdlib.h"

#include "SDL_string.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(SDL_PixelFormat *format, Uint8 r, Uint8 g, 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(SDL_PixelFormat *format, Uint8 r, Uint8 g, Uint8 b, 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, SDL_PixelFormat *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, SDL_PixelFormat *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_Palette *src, SDL_PixelFormat *dst)

{

Uint8 *map;

int i;

int bpp;

unsigned alpha;

bpp = ((dst->BytesPerPixel == 3) ? 4 : dst->BytesPerPixel);

map = (Uint8 *)SDL_malloc(src->ncolors*bpp);

if ( map == NULL ) {

SDL_OutOfMemory();

return(NULL);

}

alpha = dst->Amask ? SDL_ALPHA_OPAQUE : 0;

/* We memory copy to the pixel map so the endianness is preserved */

for ( i=0; i<src->ncolors; ++i ) {

ASSEMBLE_RGBA(&map[i*bpp], dst->BytesPerPixel, dst,

src->colors[i].r, src->colors[i].g,

src->colors[i].b, alpha);

}

return(map);

}

/* Map from BitField to Dithered-Palette to Palette */

static Uint8 *MapNto1(SDL_PixelFormat *src, SDL_Palette *dst, int *identical)

{

/* Generate a 256 color dither palette */

SDL_Palette dithered;

SDL_Color colors[256];

/* SDL_DitherColors does not initialize the 'unused' component of colors,

but Map1to1 compares it against dst, so we should initialize it. */

SDL_memset(colors, 0, sizeof(colors));

dithered.ncolors = 256;

SDL_DitherColors(colors, 8);

dithered.colors = colors;

return(Map1to1(&dithered, dst, 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->palette, dstfmt);

if ( map->table == NULL ) {

return(-1);

}

break;

}

break;

default:

switch (dstfmt->BytesPerPixel) {

case 1:

/* BitField --> Palette */

map->table = MapNto1(srcfmt,

dstfmt->palette, &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);

}

}