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/*
* 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 BiLinear screen scaler
// 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"
// Bilinear scaling to 2x
// The name expands to either
// Scale_BilinearFilter (for plain C) or
// Scale_MMX_BilinearFilter (for MMX)
// Scale_SSE_BilinearFilter (for SSE)
// [others when platforms are added]
void
SCALE_(BilinearFilter) (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 pitch = src->pitch, dp = dst->pitch;
const int bpp = fmt->BytesPerPixel;
const int len = pitch / bpp, dlen = dp / bpp;
Uint32 p[4]; // influential pixels array
Uint32 *srow0 = (Uint32 *) src->pixels;
Uint32 *dst_p = (Uint32 *) dst->pixels;
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 = w;
limits.h = h;
Scale_ExpandRect (region, 1, &limits);
xend = region->x + region->w;
yend = region->y + region->h;
dsrc = len - region->w;
ddst = (dlen - region->w) * 2;
// move ptrs to the first updated pixel
srow0 += len * region->y + region->x;
dst_p += (dlen * region->y + region->x) * 2;
for (y = region->y; y < yend; ++y, dst_p += ddst, srow0 += dsrc)
{
Uint32 *srow1;
SCALE_(Prefetch) (srow0 + 16);
SCALE_(Prefetch) (srow0 + 32);
if (y < h - 1)
srow1 = srow0 + len;
else
srow1 = srow0;
SCALE_(Prefetch) (srow1 + 16);
SCALE_(Prefetch) (srow1 + 32);
for (x = region->x; x < xend; ++x, ++srow0, ++srow1, dst_p += 2)
{
if (x < w - 1)
{ // can blend directly from pixels
SCALE_BILINEAR_BLEND4 (srow0, srow1, dst_p, dlen);
}
else
{ // need to make temp pixel rows
p[0] = srow0[0];
p[1] = p[0];
p[2] = srow1[0];
p[3] = p[2];
SCALE_BILINEAR_BLEND4 (&p[0], &p[2], dst_p, dlen);
}
}
SCALE_(Prefetch) (srow0 + dsrc);
SCALE_(Prefetch) (srow0 + dsrc + 16);
SCALE_(Prefetch) (srow1 + dsrc);
SCALE_(Prefetch) (srow1 + dsrc + 16);
}
SCALE_(PlatDone) ();
}
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