| 0,0 → 1,305 |
|---|
| /* |
| 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@devolution.com |
| */ |
| |
| /* 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(WIN32UNDEFINED) && !defined(_M_ALPHA) && !defined(_WIN32_WCE)) || \ |
| defined(i386) && defined(__GNUC__) && defined(USE_ASMBLIT) |
| #define USE_ASM_STRETCH |
| #endif |
| |
| #ifdef USE_ASM_STRETCH |
| |
| #if defined(WIN32UNDEFINED) || 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 WIN32UNDEFINED |
| { 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); |
| } |
| |