src/video/SDL_blit.c
/* [<][>][^][v][top][bottom][index][help] */
FUNCTIONS
This source file includes following functions.
- SDL_SoftBlit
- SDL_BlitCopy
- SDL_BlitCopyOverlap
- SDL_CalculateBlit
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: SDL_blit.c,v 1.5.2.20 2001/02/10 21:21:31 hercules Exp $";
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,
/* [<][>][^][v][top][bottom][index][help] */
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)
/* [<][>][^][v][top][bottom][index][help] */
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)
/* [<][>][^][v][top][bottom][index][help] */
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)
/* [<][>][^][v][top][bottom][index][help] */
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