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Diffstat (limited to 'src/libs/graphics/sdl/triscan2x.c')
| -rw-r--r-- | src/libs/graphics/sdl/triscan2x.c | 155 |
1 files changed, 155 insertions, 0 deletions
diff --git a/src/libs/graphics/sdl/triscan2x.c b/src/libs/graphics/sdl/triscan2x.c new file mode 100644 index 0000000..830dc7c --- /dev/null +++ b/src/libs/graphics/sdl/triscan2x.c @@ -0,0 +1,155 @@ +/* + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program 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 General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. + */ + +// Core algorithm of the Triscan screen scaler (based on Scale2x) +// (for scale2x please see http://scale2x.sf.net) +// Template +// When this file is built standalone is produces a plain C version +// Also #included by 2xscalers_mmx.c for an MMX version + +#include "libs/graphics/sdl/sdl_common.h" +#include "types.h" +#include "scalers.h" +#include "scaleint.h" +#include "2xscalers.h" + + +// Triscan scaling to 2x +// derivative of scale2x -- scale2x.sf.net +// The name expands to either +// Scale_TriScanFilter (for plain C) or +// Scale_MMX_TriScanFilter (for MMX) +// [others when platforms are added] +void +SCALE_(TriScanFilter) (SDL_Surface *src, SDL_Surface *dst, SDL_Rect *r) +{ + int x, y; + const int w = src->w, h = src->h; + int xend, yend; + int dsrc, ddst; + SDL_Rect *region = r; + SDL_Rect limits; + SDL_PixelFormat *fmt = dst->format; + const int sp = src->pitch, dp = dst->pitch; + const int bpp = fmt->BytesPerPixel; + const int slen = sp / bpp, dlen = dp / bpp; + // for clarity purposes, the 'pixels' array here is transposed + Uint32 pixels[3][3]; + Uint32 *src_p = (Uint32 *)src->pixels; + Uint32 *dst_p = (Uint32 *)dst->pixels; + + int prevline, nextline; + + // these macros are for clarity; they make the current pixel (0,0) + // and allow to access pixels in all directions + #define PIX(x, y) (pixels[1 + (x)][1 + (y)]) + + #define TRISCAN_YUV_MED 100 + // medium tolerance pixel comparison + #define TRISCAN_CMPYUV(p1, p2) \ + (PIX p1 == PIX p2 || SCALE_CMPYUV (PIX p1, PIX p2, TRISCAN_YUV_MED)) + + + SCALE_(PlatInit) (); + + // expand updated region if necessary + // pixels neighbooring the updated region may + // change as a result of updates + limits.x = 0; + limits.y = 0; + limits.w = src->w; + limits.h = src->h; + Scale_ExpandRect (region, 1, &limits); + + xend = region->x + region->w; + yend = region->y + region->h; + dsrc = slen - region->w; + ddst = (dlen - region->w) * 2; + + // move ptrs to the first updated pixel + src_p += slen * region->y + region->x; + dst_p += (dlen * region->y + region->x) * 2; + + for (y = region->y; y < yend; ++y, dst_p += ddst, src_p += dsrc) + { + if (y > 0) + prevline = -slen; + else + prevline = 0; + + if (y < h - 1) + nextline = slen; + else + nextline = 0; + + // prime the (tiny) sliding-window pixel arrays + PIX( 1, 0) = src_p[0]; + + if (region->x > 0) + PIX( 0, 0) = src_p[-1]; + else + PIX( 0, 0) = PIX( 1, 0); + + for (x = region->x; x < xend; ++x, ++src_p, dst_p += 2) + { + // slide the window + PIX(-1, 0) = PIX( 0, 0); + + PIX( 0, -1) = src_p[prevline]; + PIX( 0, 0) = PIX( 1, 0); + PIX( 0, 1) = src_p[nextline]; + + if (x < w - 1) + PIX( 1, 0) = src_p[1]; + else + PIX( 1, 0) = PIX( 0, 0); + + if (!TRISCAN_CMPYUV (( 0, -1), ( 0, 1)) && + !TRISCAN_CMPYUV ((-1, 0), ( 1, 0))) + { + if (TRISCAN_CMPYUV ((-1, 0), ( 0, -1))) + dst_p[0] = Scale_Blend_11 (PIX(-1, 0), PIX(0, -1)); + else + dst_p[0] = PIX(0, 0); + + if (TRISCAN_CMPYUV (( 1, 0), ( 0, -1))) + dst_p[1] = Scale_Blend_11 (PIX(1, 0), PIX(0, -1)); + else + dst_p[1] = PIX(0, 0); + + if (TRISCAN_CMPYUV ((-1, 0), ( 0, 1))) + dst_p[dlen] = Scale_Blend_11 (PIX(-1, 0), PIX(0, 1)); + else + dst_p[dlen] = PIX(0, 0); + + if (TRISCAN_CMPYUV (( 1, 0), ( 0, 1))) + dst_p[dlen+1] = Scale_Blend_11 (PIX(1, 0), PIX(0, 1)); + else + dst_p[dlen+1] = PIX(0, 0); + } + else + { + dst_p[0] = PIX(0, 0); + dst_p[1] = PIX(0, 0); + dst_p[dlen] = PIX(0, 0); + dst_p[dlen+1] = PIX(0, 0); + } + } + } + + SCALE_(PlatDone) (); +} + |