src/video/SDL_blit.c
author Sam Lantinga <slouken@lokigames.com>
Thu, 26 Apr 2001 16:45:43 +0000
changeset 0 74212992fb08
child 252 e8157fcb3114
permissions -rw-r--r--
Initial revision
     1 /*
     2     SDL - Simple DirectMedia Layer
     3     Copyright (C) 1997, 1998, 1999, 2000, 2001  Sam Lantinga
     4 
     5     This library is free software; you can redistribute it and/or
     6     modify it under the terms of the GNU Library General Public
     7     License as published by the Free Software Foundation; either
     8     version 2 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     Library General Public License for more details.
    14 
    15     You should have received a copy of the GNU Library General Public
    16     License along with this library; if not, write to the Free
    17     Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
    18 
    19     Sam Lantinga
    20     slouken@devolution.com
    21 */
    22 
    23 #ifdef SAVE_RCSID
    24 static char rcsid =
    25  "@(#) $Id$";
    26 #endif
    27 
    28 #include <stdio.h>
    29 #include <stdlib.h>
    30 #include <string.h>
    31 
    32 #include "SDL_error.h"
    33 #include "SDL_video.h"
    34 #include "SDL_sysvideo.h"
    35 #include "SDL_blit.h"
    36 #include "SDL_RLEaccel_c.h"
    37 #include "SDL_pixels_c.h"
    38 #include "SDL_memops.h"
    39 
    40 /* The general purpose software blit routine */
    41 static int SDL_SoftBlit(SDL_Surface *src, SDL_Rect *srcrect,
    42 			SDL_Surface *dst, SDL_Rect *dstrect)
    43 {
    44 	int okay;
    45 	int src_locked;
    46 	int dst_locked;
    47 
    48 	/* Everything is okay at the beginning...  */
    49 	okay = 1;
    50 
    51 	/* Lock the destination if it's in hardware */
    52 	dst_locked = 0;
    53 	if ( dst->flags & (SDL_HWSURFACE|SDL_ASYNCBLIT) ) {
    54 		SDL_VideoDevice *video = current_video;
    55 		SDL_VideoDevice *this  = current_video;
    56 		if ( video->LockHWSurface(this, dst) < 0 ) {
    57 			okay = 0;
    58 		} else {
    59 			dst_locked = 1;
    60 		}
    61 	}
    62 	/* Lock the source if it's in hardware */
    63 	src_locked = 0;
    64 	if ( src->flags & (SDL_HWSURFACE|SDL_ASYNCBLIT) ) {
    65 		SDL_VideoDevice *video = current_video;
    66 		SDL_VideoDevice *this  = current_video;
    67 		if ( video->LockHWSurface(this, src) < 0 ) {
    68 			okay = 0;
    69 		} else {
    70 			src_locked = 1;
    71 		}
    72 	}
    73 
    74 	/* Unencode the destination if it's RLE encoded */
    75 	if ( dst->flags & SDL_RLEACCEL ) {
    76 		SDL_UnRLESurface(dst, 1);
    77 		dst->flags |= SDL_RLEACCEL;	/* save accel'd state */
    78 	}
    79 
    80 	/* Set up source and destination buffer pointers, and BLIT! */
    81 	if ( okay  && srcrect->w && srcrect->h ) {
    82 		SDL_BlitInfo info;
    83 		SDL_loblit RunBlit;
    84 
    85 		/* Set up the blit information */
    86 		info.s_pixels = (Uint8 *)src->pixels + src->offset +
    87 				(Uint16)srcrect->y*src->pitch +
    88 				(Uint16)srcrect->x*src->format->BytesPerPixel;
    89 		info.s_width = srcrect->w;
    90 		info.s_height = srcrect->h;
    91 		info.s_skip=src->pitch-info.s_width*src->format->BytesPerPixel;
    92 		info.d_pixels = (Uint8 *)dst->pixels + dst->offset +
    93 				(Uint16)dstrect->y*dst->pitch +
    94 				(Uint16)dstrect->x*dst->format->BytesPerPixel;
    95 		info.d_width = dstrect->w;
    96 		info.d_height = dstrect->h;
    97 		info.d_skip=dst->pitch-info.d_width*dst->format->BytesPerPixel;
    98 		info.aux_data = src->map->sw_data->aux_data;
    99 		info.src = src->format;
   100 		info.table = src->map->table;
   101 		info.dst = dst->format;
   102 		RunBlit = src->map->sw_data->blit;
   103 
   104 		/* Run the actual software blit */
   105 		RunBlit(&info);
   106 	}
   107 
   108 	/* Re-encode the destination if it's RLE encoded */
   109 	if ( dst->flags & SDL_RLEACCEL ) {
   110 	        dst->flags &= ~SDL_RLEACCEL; /* stop lying */
   111 		SDL_RLESurface(dst);
   112 	}
   113 
   114 	/* We need to unlock the surfaces if they're locked */
   115 	if ( dst_locked ) {
   116 		SDL_VideoDevice *video = current_video;
   117 		SDL_VideoDevice *this  = current_video;
   118 		video->UnlockHWSurface(this, dst);
   119 	} else
   120 	if ( src_locked ) {
   121 		SDL_VideoDevice *video = current_video;
   122 		SDL_VideoDevice *this  = current_video;
   123 		video->UnlockHWSurface(this, src);
   124 	}
   125 	/* Blit is done! */
   126 	return(okay ? 0 : -1);
   127 }
   128 
   129 static void SDL_BlitCopy(SDL_BlitInfo *info)
   130 {
   131 	Uint8 *src, *dst;
   132 	int w, h;
   133 	int srcskip, dstskip;
   134 
   135 	w = info->d_width*info->dst->BytesPerPixel;
   136 	h = info->d_height;
   137 	src = info->s_pixels;
   138 	dst = info->d_pixels;
   139 	srcskip = w+info->s_skip;
   140 	dstskip = w+info->d_skip;
   141 	while ( h-- ) {
   142 		SDL_memcpy(dst, src, w);
   143 		src += srcskip;
   144 		dst += dstskip;
   145 	}
   146 }
   147 
   148 static void SDL_BlitCopyOverlap(SDL_BlitInfo *info)
   149 {
   150 	Uint8 *src, *dst;
   151 	int w, h;
   152 	int srcskip, dstskip;
   153 
   154 	w = info->d_width*info->dst->BytesPerPixel;
   155 	h = info->d_height;
   156 	src = info->s_pixels;
   157 	dst = info->d_pixels;
   158 	srcskip = w+info->s_skip;
   159 	dstskip = w+info->d_skip;
   160 	if ( dst < src ) {
   161 		while ( h-- ) {
   162 			SDL_memcpy(dst, src, w);
   163 			src += srcskip;
   164 			dst += dstskip;
   165 		}
   166 	} else {
   167 		src += ((h-1) * srcskip);
   168 		dst += ((h-1) * dstskip);
   169 		while ( h-- ) {
   170 			SDL_revcpy(dst, src, w);
   171 			src -= srcskip;
   172 			dst -= dstskip;
   173 		}
   174 	}
   175 }
   176 
   177 /* Figure out which of many blit routines to set up on a surface */
   178 int SDL_CalculateBlit(SDL_Surface *surface)
   179 {
   180 	int blit_index;
   181 
   182 	/* Clean everything out to start */
   183 	if ( (surface->flags & SDL_RLEACCEL) == SDL_RLEACCEL ) {
   184 		SDL_UnRLESurface(surface, 1);
   185 	}
   186 	surface->map->sw_blit = NULL;
   187 
   188 	/* Figure out if an accelerated hardware blit is possible */
   189 	surface->flags &= ~SDL_HWACCEL;
   190 	if ( surface->map->identity ) {
   191 		int hw_blit_ok;
   192 
   193 		if ( (surface->flags & SDL_HWSURFACE) == SDL_HWSURFACE ) {
   194 			/* We only support accelerated blitting to hardware */
   195 			if ( surface->map->dst->flags & SDL_HWSURFACE ) {
   196 				hw_blit_ok = current_video->info.blit_hw;
   197 			} else {
   198 				hw_blit_ok = 0;
   199 			}
   200 			if (hw_blit_ok && (surface->flags & SDL_SRCCOLORKEY)) {
   201 				hw_blit_ok = current_video->info.blit_hw_CC;
   202 			}
   203 			if ( hw_blit_ok && (surface->flags & SDL_SRCALPHA) ) {
   204 				hw_blit_ok = current_video->info.blit_hw_A;
   205 			}
   206 		} else {
   207 			/* We only support accelerated blitting to hardware */
   208 			if ( surface->map->dst->flags & SDL_HWSURFACE ) {
   209 				hw_blit_ok = current_video->info.blit_sw;
   210 			} else {
   211 				hw_blit_ok = 0;
   212 			}
   213 			if (hw_blit_ok && (surface->flags & SDL_SRCCOLORKEY)) {
   214 				hw_blit_ok = current_video->info.blit_sw_CC;
   215 			}
   216 			if ( hw_blit_ok && (surface->flags & SDL_SRCALPHA) ) {
   217 				hw_blit_ok = current_video->info.blit_sw_A;
   218 			}
   219 		}
   220 		if ( hw_blit_ok ) {
   221 			SDL_VideoDevice *video = current_video;
   222 			SDL_VideoDevice *this  = current_video;
   223 			video->CheckHWBlit(this, surface, surface->map->dst);
   224 		}
   225 	}
   226 
   227 	/* Get the blit function index, based on surface mode */
   228 	/* { 0 = nothing, 1 = colorkey, 2 = alpha, 3 = colorkey+alpha } */
   229 	blit_index = 0;
   230 	blit_index |= (!!(surface->flags & SDL_SRCCOLORKEY))      << 0;
   231 	if ( surface->flags & SDL_SRCALPHA
   232 	     && (surface->format->alpha != SDL_ALPHA_OPAQUE
   233 		 || surface->format->Amask) ) {
   234 	        blit_index |= 2;
   235 	}
   236 
   237 	/* Check for special "identity" case -- copy blit */
   238 	if ( surface->map->identity && blit_index == 0 ) {
   239 	        surface->map->sw_data->blit = SDL_BlitCopy;
   240 
   241 		/* Handle overlapping blits on the same surface */
   242 		if ( surface == surface->map->dst ) {
   243 		        surface->map->sw_data->blit = SDL_BlitCopyOverlap;
   244 		}
   245 	} else {
   246 		if ( surface->format->BitsPerPixel < 8 ) {
   247 			surface->map->sw_data->blit =
   248 			    SDL_CalculateBlit0(surface, blit_index);
   249 		} else {
   250 			switch ( surface->format->BytesPerPixel ) {
   251 			    case 1:
   252 				surface->map->sw_data->blit =
   253 				    SDL_CalculateBlit1(surface, blit_index);
   254 				break;
   255 			    case 2:
   256 			    case 3:
   257 			    case 4:
   258 				surface->map->sw_data->blit =
   259 				    SDL_CalculateBlitN(surface, blit_index);
   260 				break;
   261 			    default:
   262 				surface->map->sw_data->blit = NULL;
   263 				break;
   264 			}
   265 		}
   266 	}
   267 	/* Make sure we have a blit function */
   268 	if ( surface->map->sw_data->blit == NULL ) {
   269 		SDL_InvalidateMap(surface->map);
   270 		SDL_SetError("Blit combination not supported");
   271 		return(-1);
   272 	}
   273 
   274 	/* Choose software blitting function */
   275 	if(surface->flags & SDL_RLEACCELOK
   276 	   && (surface->flags & SDL_HWACCEL) != SDL_HWACCEL) {
   277 
   278 	        if(surface->map->identity
   279 		   && (blit_index == 1
   280 		       || (blit_index == 3 && !surface->format->Amask))) {
   281 		        if ( SDL_RLESurface(surface) == 0 )
   282 			        surface->map->sw_blit = SDL_RLEBlit;
   283 		} else if(blit_index == 2 && surface->format->Amask) {
   284 		        if ( SDL_RLESurface(surface) == 0 )
   285 			        surface->map->sw_blit = SDL_RLEAlphaBlit;
   286 		}
   287 	}
   288 	
   289 	if ( surface->map->sw_blit == NULL ) {
   290 		surface->map->sw_blit = SDL_SoftBlit;
   291 	}
   292 	return(0);
   293 }
   294