/*

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

*/

#include "SDL_types.h"

#include "SDL_video.h"

#include "SDL_blit.h"

#include "SDL_sysvideo.h"

#include "SDL_endian.h"

/* Functions to blit from 8-bit surfaces to other surfaces */

static void Blit1to1(SDL_BlitInfo *info)

{

#ifndef USE_DUFFS_LOOP

int c;

#endif

int width, height;

Uint8 *src, *map, *dst;

int srcskip, dstskip;

/* Set up some basic variables */

width = info->d_width;

height = info->d_height;

src = info->s_pixels;

srcskip = info->s_skip;

dst = info->d_pixels;

dstskip = info->d_skip;

map = info->table;

while ( height-- ) {

#ifdef USE_DUFFS_LOOP

DUFFS_LOOP(

{

*dst = map[*src];

}

dst++;

src++;

, width);

#else

for ( c=width; c; --c ) {

*dst = map[*src];

dst++;

src++;

}

#endif

src += srcskip;

dst += dstskip;

}

}

/* This is now endian dependent */

#if ( SDL_BYTEORDER == SDL_LIL_ENDIAN )

#define HI 1

#define LO 0

#else /* ( SDL_BYTEORDER == SDL_BIG_ENDIAN ) */

#define HI 0

#define LO 1

#endif

static void Blit1to2(SDL_BlitInfo *info)

{

#ifndef USE_DUFFS_LOOP

int c;

#endif

int width, height;

Uint8 *src, *dst;

Uint16 *map;

int srcskip, dstskip;

/* Set up some basic variables */

width = info->d_width;

height = info->d_height;

src = info->s_pixels;

srcskip = info->s_skip;

dst = info->d_pixels;

dstskip = info->d_skip;

map = (Uint16 *)info->table;

#ifdef USE_DUFFS_LOOP

while ( height-- ) {

DUFFS_LOOP(

{

*(Uint16 *)dst = map[*src++];

dst += 2;

},

width);

src += srcskip;

dst += dstskip;

}

#else

/* Memory align at 4-byte boundary, if necessary */

if ( (long)dst & 0x03 ) {

/* Don't do anything if width is 0 */

if ( width == 0 ) {

return;

}

--width;

while ( height-- ) {

/* Perform copy alignment */

*(Uint16 *)dst = map[*src++];

dst += 2;

/* Copy in 4 pixel chunks */

for ( c=width/4; c; --c ) {

*(Uint32 *)dst =

(map[src[HI]]<<16)|(map[src[LO]]);

src += 2;

dst += 4;

*(Uint32 *)dst =

(map[src[HI]]<<16)|(map[src[LO]]);

src += 2;

dst += 4;

}

/* Get any leftovers */

switch (width & 3) {

case 3:

*(Uint16 *)dst = map[*src++];

dst += 2;

case 2:

*(Uint32 *)dst =

(map[src[HI]]<<16)|(map[src[LO]]);

src += 2;

dst += 4;

break;

case 1:

*(Uint16 *)dst = map[*src++];

dst += 2;

break;

}

src += srcskip;

dst += dstskip;

}

} else {

while ( height-- ) {

/* Copy in 4 pixel chunks */

for ( c=width/4; c; --c ) {

*(Uint32 *)dst =

(map[src[HI]]<<16)|(map[src[LO]]);

src += 2;

dst += 4;

*(Uint32 *)dst =

(map[src[HI]]<<16)|(map[src[LO]]);

src += 2;

dst += 4;

}

/* Get any leftovers */

switch (width & 3) {

case 3:

*(Uint16 *)dst = map[*src++];

dst += 2;

case 2:

*(Uint32 *)dst =

(map[src[HI]]<<16)|(map[src[LO]]);

src += 2;

dst += 4;

break;

case 1:

*(Uint16 *)dst = map[*src++];

dst += 2;

break;

}

src += srcskip;

dst += dstskip;

}

}

#endif /* USE_DUFFS_LOOP */

}

static void Blit1to3(SDL_BlitInfo *info)

{

#ifndef USE_DUFFS_LOOP

int c;

#endif

int o;

int width, height;

Uint8 *src, *map, *dst;

int srcskip, dstskip;

/* Set up some basic variables */

width = info->d_width;

height = info->d_height;

src = info->s_pixels;

srcskip = info->s_skip;

dst = info->d_pixels;

dstskip = info->d_skip;

map = info->table;

while ( height-- ) {

#ifdef USE_DUFFS_LOOP

DUFFS_LOOP(

{

o = *src * 4;

dst[0] = map[o++];

dst[1] = map[o++];

dst[2] = map[o++];

}

src++;

dst += 3;

, width);

#else

for ( c=width; c; --c ) {

o = *src * 4;

dst[0] = map[o++];

dst[1] = map[o++];

dst[2] = map[o++];

src++;

dst += 3;

}

#endif /* USE_DUFFS_LOOP */

src += srcskip;

dst += dstskip;

}

}

static void Blit1to4(SDL_BlitInfo *info)

{

#ifndef USE_DUFFS_LOOP

int c;

#endif

int width, height;

Uint8 *src;

Uint32 *map, *dst;

int srcskip, dstskip;

/* Set up some basic variables */

width = info->d_width;

height = info->d_height;

src = info->s_pixels;

srcskip = info->s_skip;

dst = (Uint32 *)info->d_pixels;

dstskip = info->d_skip/4;

map = (Uint32 *)info->table;

while ( height-- ) {

#ifdef USE_DUFFS_LOOP

DUFFS_LOOP(

*dst++ = map[*src++];

, width);

#else

for ( c=width/4; c; --c ) {

*dst++ = map[*src++];

*dst++ = map[*src++];

*dst++ = map[*src++];

*dst++ = map[*src++];

}

switch ( width & 3 ) {

case 3:

*dst++ = map[*src++];

case 2:

*dst++ = map[*src++];

case 1:

*dst++ = map[*src++];

}

#endif /* USE_DUFFS_LOOP */

src += srcskip;

dst += dstskip;

}

}

static void Blit1to1Key(SDL_BlitInfo *info)

{

int width = info->d_width;

int height = info->d_height;

Uint8 *src = info->s_pixels;

int srcskip = info->s_skip;

Uint8 *dst = info->d_pixels;

int dstskip = info->d_skip;

Uint8 *palmap = info->table;

Uint32 ckey = info->src->colorkey;

if ( palmap ) {

while ( height-- ) {

DUFFS_LOOP(

{

if ( *src != ckey ) {

*dst = palmap[*src];

}

dst++;

src++;

},

width);

src += srcskip;

dst += dstskip;

}

} else {

while ( height-- ) {

DUFFS_LOOP(

{

if ( *src != ckey ) {

*dst = *src;

}

dst++;

src++;

},

width);

src += srcskip;

dst += dstskip;

}

}

}

static void Blit1to2Key(SDL_BlitInfo *info)

{

int width = info->d_width;

int height = info->d_height;

Uint8 *src = info->s_pixels;

int srcskip = info->s_skip;

Uint16 *dstp = (Uint16 *)info->d_pixels;

int dstskip = info->d_skip;

Uint16 *palmap = (Uint16 *)info->table;

Uint32 ckey = info->src->colorkey;

/* Set up some basic variables */

dstskip /= 2;

while ( height-- ) {

DUFFS_LOOP(

{

if ( *src != ckey ) {

*dstp=palmap[*src];

}

src++;

dstp++;

},

width);

src += srcskip;

dstp += dstskip;

}

}

static void Blit1to3Key(SDL_BlitInfo *info)

{

int width = info->d_width;

int height = info->d_height;

Uint8 *src = info->s_pixels;

int srcskip = info->s_skip;

Uint8 *dst = info->d_pixels;

int dstskip = info->d_skip;

Uint8 *palmap = info->table;

Uint32 ckey = info->src->colorkey;

int o;

while ( height-- ) {

DUFFS_LOOP(

{

if ( *src != ckey ) {

o = *src * 4;

dst[0] = palmap[o++];

dst[1] = palmap[o++];

dst[2] = palmap[o++];

}

src++;

dst += 3;

},

width);

src += srcskip;

dst += dstskip;

}

}

static void Blit1to4Key(SDL_BlitInfo *info)

{

int width = info->d_width;

int height = info->d_height;

Uint8 *src = info->s_pixels;

int srcskip = info->s_skip;

Uint32 *dstp = (Uint32 *)info->d_pixels;

int dstskip = info->d_skip;

Uint32 *palmap = (Uint32 *)info->table;

Uint32 ckey = info->src->colorkey;

/* Set up some basic variables */

dstskip /= 4;

while ( height-- ) {

DUFFS_LOOP(

{

if ( *src != ckey ) {

*dstp = palmap[*src];

}

src++;

dstp++;

},

width);

src += srcskip;

dstp += dstskip;

}

}

static void Blit1toNAlpha(SDL_BlitInfo *info)

{

int width = info->d_width;

int height = info->d_height;

Uint8 *src = info->s_pixels;

int srcskip = info->s_skip;

Uint8 *dst = info->d_pixels;

int dstskip = info->d_skip;

SDL_PixelFormat *dstfmt = info->dst;

const SDL_Color *srcpal = info->src->palette->colors;

int dstbpp;

const int A = info->src->alpha;

/* Set up some basic variables */

dstbpp = dstfmt->BytesPerPixel;

while ( height-- ) {

int sR, sG, sB;

int dR, dG, dB;

DUFFS_LOOP4(

{

Uint32 pixel;

sR = srcpal[*src].r;

sG = srcpal[*src].g;

sB = srcpal[*src].b;

DISEMBLE_RGB(dst, dstbpp, dstfmt,

pixel, dR, dG, dB);

ALPHA_BLEND(sR, sG, sB, A, dR, dG, dB);

ASSEMBLE_RGB(dst, dstbpp, dstfmt, dR, dG, dB);

src++;

dst += dstbpp;

},

width);

src += srcskip;

dst += dstskip;

}

}

static void Blit1toNAlphaKey(SDL_BlitInfo *info)

{

int width = info->d_width;

int height = info->d_height;

Uint8 *src = info->s_pixels;

int srcskip = info->s_skip;

Uint8 *dst = info->d_pixels;

int dstskip = info->d_skip;

SDL_PixelFormat *srcfmt = info->src;

SDL_PixelFormat *dstfmt = info->dst;

const SDL_Color *srcpal = info->src->palette->colors;

Uint32 ckey = srcfmt->colorkey;

int dstbpp;

const int A = srcfmt->alpha;

/* Set up some basic variables */

dstbpp = dstfmt->BytesPerPixel;

while ( height-- ) {

int sR, sG, sB;

int dR, dG, dB;

DUFFS_LOOP(

{

if ( *src != ckey ) {

Uint32 pixel;

sR = srcpal[*src].r;

sG = srcpal[*src].g;

sB = srcpal[*src].b;

DISEMBLE_RGB(dst, dstbpp, dstfmt,

pixel, dR, dG, dB);

ALPHA_BLEND(sR, sG, sB, A, dR, dG, dB);

ASSEMBLE_RGB(dst, dstbpp, dstfmt, dR, dG, dB);

}

src++;

dst += dstbpp;

},

width);

src += srcskip;

dst += dstskip;

}

}

static SDL_loblit one_blit[] = {

NULL, Blit1to1, Blit1to2, Blit1to3, Blit1to4

};

static SDL_loblit one_blitkey[] = {

NULL, Blit1to1Key, Blit1to2Key, Blit1to3Key, Blit1to4Key

};

SDL_loblit SDL_CalculateBlit1(SDL_Surface *surface, int blit_index)

{

int which;

SDL_PixelFormat *dstfmt;

dstfmt = surface->map->dst->format;

if ( dstfmt->BitsPerPixel < 8 ) {

which = 0;

} else {

which = dstfmt->BytesPerPixel;

}

switch(blit_index) {

case 0: /* copy */

return one_blit[which];

case 1: /* colorkey */

return one_blitkey[which];

case 2: /* alpha */

/* Supporting 8bpp->8bpp alpha is doable but requires lots of

tables which consume space and takes time to precompute,

so is better left to the user */

return which >= 2 ? Blit1toNAlpha : NULL;

case 3: /* alpha + colorkey */

return which >= 2 ? Blit1toNAlphaKey : NULL;

}

return NULL;

}