Mercurial > sdl-ios-xcode
view src/video/SDL_stretch.c @ 520:26eb0f877ce6
Bumped version to 1.2.6 in CVS
author | Sam Lantinga <slouken@libsdl.org> |
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date | Tue, 08 Oct 2002 15:34:19 +0000 |
parents | f6ffac90895c |
children | 8b9ac38381d0 |
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/* SDL - Simple DirectMedia Layer Copyright (C) 1997, 1998, 1999, 2000, 2001, 2002 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 /* This a stretch blit implementation based on ideas given to me by Tomasz Cejner - thanks! :) April 27, 2000 - Sam Lantinga */ #include "SDL_error.h" #include "SDL_video.h" #include "SDL_blit.h" /* This isn't ready for general consumption yet - it should be folded into the general blitting mechanism. */ #if (defined(WIN32) && !defined(_M_ALPHA) && !defined(_WIN32_WCE) && \ !defined(__WATCOMC__) && !defined(__LCC__) && !defined(__FREEBCC__)) || \ (defined(i386) && defined(__GNUC__) && defined(USE_ASMBLIT)) #define USE_ASM_STRETCH #endif #ifdef USE_ASM_STRETCH #if defined(WIN32) || defined(i386) #define PREFIX16 0x66 #define STORE_BYTE 0xAA #define STORE_WORD 0xAB #define LOAD_BYTE 0xAC #define LOAD_WORD 0xAD #define RETURN 0xC3 #else #error Need assembly opcodes for this architecture #endif #if defined(__ELF__) && defined(__GNUC__) extern unsigned char _copy_row[4096] __attribute__ ((alias ("copy_row"))); #endif static unsigned char copy_row[4096]; static int generate_rowbytes(int src_w, int dst_w, int bpp) { static struct { int bpp; int src_w; int dst_w; } last; int i; int pos, inc; unsigned char *eip; unsigned char load, store; /* See if we need to regenerate the copy buffer */ if ( (src_w == last.src_w) && (dst_w == last.src_w) && (bpp == last.bpp) ) { return(0); } last.bpp = bpp; last.src_w = src_w; last.dst_w = dst_w; switch (bpp) { case 1: load = LOAD_BYTE; store = STORE_BYTE; break; case 2: case 4: load = LOAD_WORD; store = STORE_WORD; break; default: SDL_SetError("ASM stretch of %d bytes isn't supported\n", bpp); return(-1); } pos = 0x10000; inc = (src_w << 16) / dst_w; eip = copy_row; for ( i=0; i<dst_w; ++i ) { while ( pos >= 0x10000L ) { if ( bpp == 2 ) { *eip++ = PREFIX16; } *eip++ = load; pos -= 0x10000L; } if ( bpp == 2 ) { *eip++ = PREFIX16; } *eip++ = store; pos += inc; } *eip++ = RETURN; /* Verify that we didn't overflow (too late) */ if ( eip > (copy_row+sizeof(copy_row)) ) { SDL_SetError("Copy buffer overflow"); return(-1); } return(0); } #else #define DEFINE_COPY_ROW(name, type) \ void name(type *src, int src_w, type *dst, int dst_w) \ { \ int i; \ int pos, inc; \ type pixel = 0; \ \ pos = 0x10000; \ inc = (src_w << 16) / dst_w; \ for ( i=dst_w; i>0; --i ) { \ while ( pos >= 0x10000L ) { \ pixel = *src++; \ pos -= 0x10000L; \ } \ *dst++ = pixel; \ pos += inc; \ } \ } DEFINE_COPY_ROW(copy_row1, Uint8) DEFINE_COPY_ROW(copy_row2, Uint16) DEFINE_COPY_ROW(copy_row4, Uint32) #endif /* USE_ASM_STRETCH */ /* The ASM code doesn't handle 24-bpp stretch blits */ void copy_row3(Uint8 *src, int src_w, Uint8 *dst, int dst_w) { int i; int pos, inc; Uint8 pixel[3]; pos = 0x10000; inc = (src_w << 16) / dst_w; for ( i=dst_w; i>0; --i ) { while ( pos >= 0x10000L ) { pixel[0] = *src++; pixel[1] = *src++; pixel[2] = *src++; pos -= 0x10000L; } *dst++ = pixel[0]; *dst++ = pixel[1]; *dst++ = pixel[2]; pos += inc; } } /* Perform a stretch blit between two surfaces of the same format. NOTE: This function is not safe to call from multiple threads! */ int SDL_SoftStretch(SDL_Surface *src, SDL_Rect *srcrect, SDL_Surface *dst, SDL_Rect *dstrect) { int pos, inc; int dst_width; int dst_maxrow; int src_row, dst_row; Uint8 *srcp = NULL; Uint8 *dstp; SDL_Rect full_src; SDL_Rect full_dst; #if defined(USE_ASM_STRETCH) && defined(__GNUC__) int u1, u2; #endif const int bpp = dst->format->BytesPerPixel; if ( src->format->BitsPerPixel != dst->format->BitsPerPixel ) { SDL_SetError("Only works with same format surfaces"); return(-1); } /* Verify the blit rectangles */ if ( srcrect ) { if ( (srcrect->x < 0) || (srcrect->y < 0) || ((srcrect->x+srcrect->w) > src->w) || ((srcrect->y+srcrect->h) > src->h) ) { SDL_SetError("Invalid source blit rectangle"); return(-1); } } else { full_src.x = 0; full_src.y = 0; full_src.w = src->w; full_src.h = src->h; srcrect = &full_src; } if ( dstrect ) { if ( (dstrect->x < 0) || (dstrect->y < 0) || ((dstrect->x+dstrect->w) > dst->w) || ((dstrect->y+dstrect->h) > dst->h) ) { SDL_SetError("Invalid destination blit rectangle"); return(-1); } } else { full_dst.x = 0; full_dst.y = 0; full_dst.w = dst->w; full_dst.h = dst->h; dstrect = &full_dst; } /* Set up the data... */ pos = 0x10000; inc = (srcrect->h << 16) / dstrect->h; src_row = srcrect->y; dst_row = dstrect->y; dst_width = dstrect->w*bpp; #ifdef USE_ASM_STRETCH /* Write the opcodes for this stretch */ if ( (bpp != 3) && (generate_rowbytes(srcrect->w, dstrect->w, bpp) < 0) ) { return(-1); } #endif /* Perform the stretch blit */ for ( dst_maxrow = dst_row+dstrect->h; dst_row<dst_maxrow; ++dst_row ) { dstp = (Uint8 *)dst->pixels + (dst_row*dst->pitch) + (dstrect->x*bpp); while ( pos >= 0x10000L ) { srcp = (Uint8 *)src->pixels + (src_row*src->pitch) + (srcrect->x*bpp); ++src_row; pos -= 0x10000L; } #ifdef USE_ASM_STRETCH switch (bpp) { case 3: copy_row3(srcp, srcrect->w, dstp, dstrect->w); break; default: #ifdef __GNUC__ __asm__ __volatile__ (" call _copy_row " : "=&D" (u1), "=&S" (u2) : "0" (dstp), "1" (srcp) : "memory" ); #else #ifdef WIN32 { void *code = ©_row; __asm { push edi push esi mov edi, dstp mov esi, srcp call dword ptr code pop esi pop edi } } #else #error Need inline assembly for this compiler #endif #endif /* __GNUC__ */ break; } #else switch (bpp) { case 1: copy_row1(srcp, srcrect->w, dstp, dstrect->w); break; case 2: copy_row2((Uint16 *)srcp, srcrect->w, (Uint16 *)dstp, dstrect->w); break; case 3: copy_row3(srcp, srcrect->w, dstp, dstrect->w); break; case 4: copy_row4((Uint32 *)srcp, srcrect->w, (Uint32 *)dstp, dstrect->w); break; } #endif pos += inc; } return(0); }