src/video/SDL_blit.c - third_party/sdl - Git at Google

 /*
     SDL - Simple DirectMedia Layer
     Copyright (C) 1997, 1998, 1999, 2000, 2001  Sam Lantinga

     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.

     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
     Library General Public License for more details.

     You should have received a copy of the GNU Library General Public
     License along with this library; if not, write to the Free
     Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

     Sam Lantinga
     slouken@libsdl.org
 */

 #ifdef SAVE_RCSID
 static char rcsid =
  "@(#) $Id$";
 #endif

 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>

 #include "SDL_error.h"
 #include "SDL_video.h"
 #include "SDL_sysvideo.h"
 #include "SDL_blit.h"
 #include "SDL_RLEaccel_c.h"
 #include "SDL_pixels_c.h"
 #include "SDL_memops.h"

 /* The general purpose software blit routine */
 static int SDL_SoftBlit(SDL_Surface *src, SDL_Rect *srcrect,
 			SDL_Surface *dst, SDL_Rect *dstrect)
 {
 	int okay;
 	int src_locked;
 	int dst_locked;

 	/* Everything is okay at the beginning...  */
 	okay = 1;

 	/* Lock the destination if it's in hardware */
 	dst_locked = 0;
 	if ( dst->flags & (SDL_HWSURFACE|SDL_ASYNCBLIT) ) {
 		SDL_VideoDevice *video = current_video;
 		SDL_VideoDevice *this  = current_video;
 		if ( video->LockHWSurface(this, dst) < 0 ) {
 			okay = 0;
 		} else {
 			dst_locked = 1;
 		}
 	}
 	/* Lock the source if it's in hardware */
 	src_locked = 0;
 	if ( src->flags & (SDL_HWSURFACE|SDL_ASYNCBLIT) ) {
 		SDL_VideoDevice *video = current_video;
 		SDL_VideoDevice *this  = current_video;
 		if ( video->LockHWSurface(this, src) < 0 ) {
 			okay = 0;
 		} else {
 			src_locked = 1;
 		}
 	}

 	/* Unencode the destination if it's RLE encoded */
 	if ( dst->flags & SDL_RLEACCEL ) {
 		SDL_UnRLESurface(dst, 1);
 		dst->flags |= SDL_RLEACCEL;	/* save accel'd state */
 	}

 	/* Set up source and destination buffer pointers, and BLIT! */
 	if ( okay  && srcrect->w && srcrect->h ) {
 		SDL_BlitInfo info;
 		SDL_loblit RunBlit;

 		/* Set up the blit information */
 		info.s_pixels = (Uint8 *)src->pixels + src->offset +
 				(Uint16)srcrect->y*src->pitch +
 				(Uint16)srcrect->x*src->format->BytesPerPixel;
 		info.s_width = srcrect->w;
 		info.s_height = srcrect->h;
 		info.s_skip=src->pitch-info.s_width*src->format->BytesPerPixel;
 		info.d_pixels = (Uint8 *)dst->pixels + dst->offset +
 				(Uint16)dstrect->y*dst->pitch +
 				(Uint16)dstrect->x*dst->format->BytesPerPixel;
 		info.d_width = dstrect->w;
 		info.d_height = dstrect->h;
 		info.d_skip=dst->pitch-info.d_width*dst->format->BytesPerPixel;
 		info.aux_data = src->map->sw_data->aux_data;
 		info.src = src->format;
 		info.table = src->map->table;
 		info.dst = dst->format;
 		RunBlit = src->map->sw_data->blit;

 		/* Run the actual software blit */
 		RunBlit(&info);
 	}

 	/* Re-encode the destination if it's RLE encoded */
 	if ( dst->flags & SDL_RLEACCEL ) {
 	        dst->flags &= ~SDL_RLEACCEL; /* stop lying */
 		SDL_RLESurface(dst);
 	}

 	/* We need to unlock the surfaces if they're locked */
 	if ( dst_locked ) {
 		SDL_VideoDevice *video = current_video;
 		SDL_VideoDevice *this  = current_video;
 		video->UnlockHWSurface(this, dst);
 	} else
 	if ( src_locked ) {
 		SDL_VideoDevice *video = current_video;
 		SDL_VideoDevice *this  = current_video;
 		video->UnlockHWSurface(this, src);
 	}
 	/* Blit is done! */
 	return(okay ? 0 : -1);
 }

 static void SDL_BlitCopy(SDL_BlitInfo *info)
 {
 	Uint8 *src, *dst;
 	int w, h;
 	int srcskip, dstskip;

 	w = info->d_width*info->dst->BytesPerPixel;
 	h = info->d_height;
 	src = info->s_pixels;
 	dst = info->d_pixels;
 	srcskip = w+info->s_skip;
 	dstskip = w+info->d_skip;
 	while ( h-- ) {
 		SDL_memcpy(dst, src, w);
 		src += srcskip;
 		dst += dstskip;
 	}
 }

 static void SDL_BlitCopyOverlap(SDL_BlitInfo *info)
 {
 	Uint8 *src, *dst;
 	int w, h;
 	int srcskip, dstskip;

 	w = info->d_width*info->dst->BytesPerPixel;
 	h = info->d_height;
 	src = info->s_pixels;
 	dst = info->d_pixels;
 	srcskip = w+info->s_skip;
 	dstskip = w+info->d_skip;
 	if ( dst < src ) {
 		while ( h-- ) {
 			SDL_memcpy(dst, src, w);
 			src += srcskip;
 			dst += dstskip;
 		}
 	} else {
 		src += ((h-1) * srcskip);
 		dst += ((h-1) * dstskip);
 		while ( h-- ) {
 			SDL_revcpy(dst, src, w);
 			src -= srcskip;
 			dst -= dstskip;
 		}
 	}
 }

 /* Figure out which of many blit routines to set up on a surface */
 int SDL_CalculateBlit(SDL_Surface *surface)
 {
 	int blit_index;

 	/* Clean everything out to start */
 	if ( (surface->flags & SDL_RLEACCEL) == SDL_RLEACCEL ) {
 		SDL_UnRLESurface(surface, 1);
 	}
 	surface->map->sw_blit = NULL;

 	/* Figure out if an accelerated hardware blit is possible */
 	surface->flags &= ~SDL_HWACCEL;
 	if ( surface->map->identity ) {
 		int hw_blit_ok;

 		if ( (surface->flags & SDL_HWSURFACE) == SDL_HWSURFACE ) {
 			/* We only support accelerated blitting to hardware */
 			if ( surface->map->dst->flags & SDL_HWSURFACE ) {
 				hw_blit_ok = current_video->info.blit_hw;
 			} else {
 				hw_blit_ok = 0;
 			}
 			if (hw_blit_ok && (surface->flags & SDL_SRCCOLORKEY)) {
 				hw_blit_ok = current_video->info.blit_hw_CC;
 			}
 			if ( hw_blit_ok && (surface->flags & SDL_SRCALPHA) ) {
 				hw_blit_ok = current_video->info.blit_hw_A;
 			}
 		} else {
 			/* We only support accelerated blitting to hardware */
 			if ( surface->map->dst->flags & SDL_HWSURFACE ) {
 				hw_blit_ok = current_video->info.blit_sw;
 			} else {
 				hw_blit_ok = 0;
 			}
 			if (hw_blit_ok && (surface->flags & SDL_SRCCOLORKEY)) {
 				hw_blit_ok = current_video->info.blit_sw_CC;
 			}
 			if ( hw_blit_ok && (surface->flags & SDL_SRCALPHA) ) {
 				hw_blit_ok = current_video->info.blit_sw_A;
 			}
 		}
 		if ( hw_blit_ok ) {
 			SDL_VideoDevice *video = current_video;
 			SDL_VideoDevice *this  = current_video;
 			video->CheckHWBlit(this, surface, surface->map->dst);
 		}
 	}

 	/* Get the blit function index, based on surface mode */
 	/* { 0 = nothing, 1 = colorkey, 2 = alpha, 3 = colorkey+alpha } */
 	blit_index = 0;
 	blit_index |= (!!(surface->flags & SDL_SRCCOLORKEY))      << 0;
 	if ( surface->flags & SDL_SRCALPHA
 	     && (surface->format->alpha != SDL_ALPHA_OPAQUE
 		 || surface->format->Amask) ) {
 	        blit_index |= 2;
 	}

 	/* Check for special "identity" case -- copy blit */
 	if ( surface->map->identity && blit_index == 0 ) {
 	        surface->map->sw_data->blit = SDL_BlitCopy;

 		/* Handle overlapping blits on the same surface */
 		if ( surface == surface->map->dst ) {
 		        surface->map->sw_data->blit = SDL_BlitCopyOverlap;
 		}
 	} else {
 		if ( surface->format->BitsPerPixel < 8 ) {
 			surface->map->sw_data->blit =
 			    SDL_CalculateBlit0(surface, blit_index);
 		} else {
 			switch ( surface->format->BytesPerPixel ) {
 			    case 1:
 				surface->map->sw_data->blit =
 				    SDL_CalculateBlit1(surface, blit_index);
 				break;
 			    case 2:
 			    case 3:
 			    case 4:
 				surface->map->sw_data->blit =
 				    SDL_CalculateBlitN(surface, blit_index);
 				break;
 			    default:
 				surface->map->sw_data->blit = NULL;
 				break;
 			}
 		}
 	}
 	/* Make sure we have a blit function */
 	if ( surface->map->sw_data->blit == NULL ) {
 		SDL_InvalidateMap(surface->map);
 		SDL_SetError("Blit combination not supported");
 		return(-1);
 	}

 	/* Choose software blitting function */
 	if(surface->flags & SDL_RLEACCELOK
 	   && (surface->flags & SDL_HWACCEL) != SDL_HWACCEL) {

 	        if(surface->map->identity
 		   && (blit_index == 1
 		       || (blit_index == 3 && !surface->format->Amask))) {
 		        if ( SDL_RLESurface(surface) == 0 )
 			        surface->map->sw_blit = SDL_RLEBlit;
 		} else if(blit_index == 2 && surface->format->Amask) {
 		        if ( SDL_RLESurface(surface) == 0 )
 			        surface->map->sw_blit = SDL_RLEAlphaBlit;
 		}
 	}

 	if ( surface->map->sw_blit == NULL ) {
 		surface->map->sw_blit = SDL_SoftBlit;
 	}
 	return(0);
 }
	/*
	SDL - Simple DirectMedia Layer
	Copyright (C) 1997, 1998, 1999, 2000, 2001 Sam Lantinga

	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.

	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
	Library General Public License for more details.

	You should have received a copy of the GNU Library General Public
	License along with this library; if not, write to the Free
	Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA

	Sam Lantinga
	slouken@libsdl.org
	*/

	#ifdef SAVE_RCSID
	static char rcsid =
	"@(#) $Id$";
	#endif

	#include <stdio.h>
	#include <stdlib.h>
	#include <string.h>

	#include "SDL_error.h"
	#include "SDL_video.h"
	#include "SDL_sysvideo.h"
	#include "SDL_blit.h"
	#include "SDL_RLEaccel_c.h"
	#include "SDL_pixels_c.h"
	#include "SDL_memops.h"

	/* The general purpose software blit routine */
	static int SDL_SoftBlit(SDL_Surface src, SDL_Rect srcrect,
	SDL_Surface dst, SDL_Rect dstrect)
	{
	int okay;
	int src_locked;
	int dst_locked;

	/* Everything is okay at the beginning... */
	okay = 1;

	/* Lock the destination if it's in hardware */
	dst_locked = 0;
	if ( dst->flags & (SDL_HWSURFACE\|SDL_ASYNCBLIT) ) {
	SDL_VideoDevice *video = current_video;
	SDL_VideoDevice *this = current_video;
	if ( video->LockHWSurface(this, dst) < 0 ) {
	okay = 0;
	} else {
	dst_locked = 1;
	}
	}
	/* Lock the source if it's in hardware */
	src_locked = 0;
	if ( src->flags & (SDL_HWSURFACE\|SDL_ASYNCBLIT) ) {
	SDL_VideoDevice *video = current_video;
	SDL_VideoDevice *this = current_video;
	if ( video->LockHWSurface(this, src) < 0 ) {
	okay = 0;
	} else {
	src_locked = 1;
	}
	}

	/* Unencode the destination if it's RLE encoded */
	if ( dst->flags & SDL_RLEACCEL ) {
	SDL_UnRLESurface(dst, 1);
	dst->flags \|= SDL_RLEACCEL; /* save accel'd state */
	}

	/* Set up source and destination buffer pointers, and BLIT! */
	if ( okay && srcrect->w && srcrect->h ) {
	SDL_BlitInfo info;
	SDL_loblit RunBlit;

	/* Set up the blit information */
	info.s_pixels = (Uint8 *)src->pixels + src->offset +
	(Uint16)srcrect->y*src->pitch +
	(Uint16)srcrect->x*src->format->BytesPerPixel;
	info.s_width = srcrect->w;
	info.s_height = srcrect->h;
	info.s_skip=src->pitch-info.s_width*src->format->BytesPerPixel;
	info.d_pixels = (Uint8 *)dst->pixels + dst->offset +
	(Uint16)dstrect->y*dst->pitch +
	(Uint16)dstrect->x*dst->format->BytesPerPixel;
	info.d_width = dstrect->w;
	info.d_height = dstrect->h;
	info.d_skip=dst->pitch-info.d_width*dst->format->BytesPerPixel;
	info.aux_data = src->map->sw_data->aux_data;
	info.src = src->format;
	info.table = src->map->table;
	info.dst = dst->format;
	RunBlit = src->map->sw_data->blit;

	/* Run the actual software blit */
	RunBlit(&info);
	}

	/* Re-encode the destination if it's RLE encoded */
	if ( dst->flags & SDL_RLEACCEL ) {
	dst->flags &= ~SDL_RLEACCEL; /* stop lying */
	SDL_RLESurface(dst);
	}

	/* We need to unlock the surfaces if they're locked */
	if ( dst_locked ) {
	SDL_VideoDevice *video = current_video;
	SDL_VideoDevice *this = current_video;
	video->UnlockHWSurface(this, dst);
	} else
	if ( src_locked ) {
	SDL_VideoDevice *video = current_video;
	SDL_VideoDevice *this = current_video;
	video->UnlockHWSurface(this, src);
	}
	/* Blit is done! */
	return(okay ? 0 : -1);
	}

	static void SDL_BlitCopy(SDL_BlitInfo *info)
	{
	Uint8 src, dst;
	int w, h;
	int srcskip, dstskip;

	w = info->d_width*info->dst->BytesPerPixel;
	h = info->d_height;
	src = info->s_pixels;
	dst = info->d_pixels;
	srcskip = w+info->s_skip;
	dstskip = w+info->d_skip;
	while ( h-- ) {
	SDL_memcpy(dst, src, w);
	src += srcskip;
	dst += dstskip;
	}
	}

	static void SDL_BlitCopyOverlap(SDL_BlitInfo *info)
	{
	Uint8 src, dst;
	int w, h;
	int srcskip, dstskip;

	w = info->d_width*info->dst->BytesPerPixel;
	h = info->d_height;
	src = info->s_pixels;
	dst = info->d_pixels;
	srcskip = w+info->s_skip;
	dstskip = w+info->d_skip;
	if ( dst < src ) {
	while ( h-- ) {
	SDL_memcpy(dst, src, w);
	src += srcskip;
	dst += dstskip;
	}
	} else {
	src += ((h-1) * srcskip);
	dst += ((h-1) * dstskip);
	while ( h-- ) {
	SDL_revcpy(dst, src, w);
	src -= srcskip;
	dst -= dstskip;
	}
	}
	}

	/* Figure out which of many blit routines to set up on a surface */
	int SDL_CalculateBlit(SDL_Surface *surface)
	{
	int blit_index;

	/* Clean everything out to start */
	if ( (surface->flags & SDL_RLEACCEL) == SDL_RLEACCEL ) {
	SDL_UnRLESurface(surface, 1);
	}
	surface->map->sw_blit = NULL;

	/* Figure out if an accelerated hardware blit is possible */
	surface->flags &= ~SDL_HWACCEL;
	if ( surface->map->identity ) {
	int hw_blit_ok;

	if ( (surface->flags & SDL_HWSURFACE) == SDL_HWSURFACE ) {
	/* We only support accelerated blitting to hardware */
	if ( surface->map->dst->flags & SDL_HWSURFACE ) {
	hw_blit_ok = current_video->info.blit_hw;
	} else {
	hw_blit_ok = 0;
	}
	if (hw_blit_ok && (surface->flags & SDL_SRCCOLORKEY)) {
	hw_blit_ok = current_video->info.blit_hw_CC;
	}
	if ( hw_blit_ok && (surface->flags & SDL_SRCALPHA) ) {
	hw_blit_ok = current_video->info.blit_hw_A;
	}
	} else {
	/* We only support accelerated blitting to hardware */
	if ( surface->map->dst->flags & SDL_HWSURFACE ) {
	hw_blit_ok = current_video->info.blit_sw;
	} else {
	hw_blit_ok = 0;
	}
	if (hw_blit_ok && (surface->flags & SDL_SRCCOLORKEY)) {
	hw_blit_ok = current_video->info.blit_sw_CC;
	}
	if ( hw_blit_ok && (surface->flags & SDL_SRCALPHA) ) {
	hw_blit_ok = current_video->info.blit_sw_A;
	}
	}
	if ( hw_blit_ok ) {
	SDL_VideoDevice *video = current_video;
	SDL_VideoDevice *this = current_video;
	video->CheckHWBlit(this, surface, surface->map->dst);
	}
	}

	/* Get the blit function index, based on surface mode */
	/* { 0 = nothing, 1 = colorkey, 2 = alpha, 3 = colorkey+alpha } */
	blit_index = 0;
	blit_index \|= (!!(surface->flags & SDL_SRCCOLORKEY)) << 0;
	if ( surface->flags & SDL_SRCALPHA
	&& (surface->format->alpha != SDL_ALPHA_OPAQUE
	\|\| surface->format->Amask) ) {
	blit_index \|= 2;
	}

	/* Check for special "identity" case -- copy blit */
	if ( surface->map->identity && blit_index == 0 ) {
	surface->map->sw_data->blit = SDL_BlitCopy;

	/* Handle overlapping blits on the same surface */
	if ( surface == surface->map->dst ) {
	surface->map->sw_data->blit = SDL_BlitCopyOverlap;
	}
	} else {
	if ( surface->format->BitsPerPixel < 8 ) {
	surface->map->sw_data->blit =
	SDL_CalculateBlit0(surface, blit_index);
	} else {
	switch ( surface->format->BytesPerPixel ) {
	case 1:
	surface->map->sw_data->blit =
	SDL_CalculateBlit1(surface, blit_index);
	break;
	case 2:
	case 3:
	case 4:
	surface->map->sw_data->blit =
	SDL_CalculateBlitN(surface, blit_index);
	break;
	default:
	surface->map->sw_data->blit = NULL;
	break;
	}
	}
	}
	/* Make sure we have a blit function */
	if ( surface->map->sw_data->blit == NULL ) {
	SDL_InvalidateMap(surface->map);
	SDL_SetError("Blit combination not supported");
	return(-1);
	}

	/* Choose software blitting function */
	if(surface->flags & SDL_RLEACCELOK
	&& (surface->flags & SDL_HWACCEL) != SDL_HWACCEL) {

	if(surface->map->identity
	&& (blit_index == 1
	\|\| (blit_index == 3 && !surface->format->Amask))) {
	if ( SDL_RLESurface(surface) == 0 )
	surface->map->sw_blit = SDL_RLEBlit;
	} else if(blit_index == 2 && surface->format->Amask) {
	if ( SDL_RLESurface(surface) == 0 )
	surface->map->sw_blit = SDL_RLEAlphaBlit;
	}
	}

	if ( surface->map->sw_blit == NULL ) {
	surface->map->sw_blit = SDL_SoftBlit;
	}
	return(0);
	}