區別如下：
| SDL_SWSURFACE | 從系統記憶體配置使用(system memory) |
|---|---|
| SDL_HWSURFACE | 從顯示卡記憶體配置使用(video memory if possible), 讀寫Pixels時，需要先呼叫SDL_LockSurface()鎖住記憶體 |
(SDL 1.2.15)src/video/SDL_video.c
583 SDL_Surface * SDL_SetVideoMode (int width, int height, int bpp, Uint32 flags) ... 683 mode = video->SetVideoMode(this, prev_mode,video_w,video_h,video_bpp,flags);
(SDL 1.2.15)src/video/fbcon/SDL_fbvideo.c
998 static SDL_Surface *FB_SetVideoMode(_THIS, SDL_Surface *current,
999 int width, int height, int bpp, Uint32 flags)
...
1132 /* Set up the new mode framebuffer */
1133 current->flags &= SDL_FULLSCREEN;
1134 if (shadow_fb) {
1135 current->flags |= SDL_SWSURFACE;
1136 } else {
1137 current->flags |= SDL_HWSURFACE;
1138 }
1139 current->w = vinfo.xres;
1140 current->h = vinfo.yres;
1141 if (shadow_fb) {
1142 current->pitch = current->w * ((vinfo.bits_per_pixel + 7) / 8);
1143 current->pixels = shadow_mem;
1144 physlinebytes = finfo.line_length;
1145 } else {
1146 current->pitch = finfo.line_length;
1147 current->pixels = mapped_mem+mapped_offset;
1148 }
1149
1150 /* Set up the information for hardware surfaces */
1151 surfaces_mem = (char *)current->pixels +
1152 vinfo.yres_virtual*current->pitch;
1153 surfaces_len = (shadow_fb) ?
1154 0 : (mapped_memlen-(surfaces_mem-mapped_mem));
1155
1156 FB_FreeHWSurfaces(this);
1157 FB_InitHWSurfaces(this, current, surfaces_mem, surfaces_len);
1218 static int FB_InitHWSurfaces(_THIS, SDL_Surface *screen, char *base, int size)
1219 {
1220 vidmem_bucket *bucket;
1221
1222 surfaces_memtotal = size;
1223 surfaces_memleft = size;
1224
1225 if ( surfaces_memleft > 0 ) {
1226 bucket = (vidmem_bucket *)SDL_malloc(sizeof(*bucket));
(SDL 1.2.15)src/stdlib/SDL_malloc.c
614 #define malloc SDL_malloc