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/*
pygame - Python Game Library
Copyright (C) 2000-2001 Pete Shinners
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
Pete Shinners
pete@shinners.org
*/
/*
This implements the AdvanceMAME Scale2x feature found on this page,
http://advancemame.sourceforge.net/scale2x.html
It is an incredibly simple and powerful image doubling routine that does
an astonishing job of doubling game graphic data while interpolating out
the jaggies. Congrats to the AdvanceMAME team, I'm very impressed and
surprised with this code!
*/
#include <SDL.h>
#define MAX(a, b) (((a) > (b)) ? (a) : (b))
#define MIN(a, b) (((a) < (b)) ? (a) : (b))
#define READINT24(x) ((x)[0] << 16 | (x)[1] << 8 | (x)[2])
#define WRITEINT24(x, i) \
{ \
(x)[0] = i >> 16; \
(x)[1] = (i >> 8) & 0xff; \
x[2] = i & 0xff; \
}
/*
this requires a destination surface already setup to be twice as
large as the source. oh, and formats must match too. this will just
blindly assume you didn't flounder.
*/
void
scale2x(SDL_Surface *src, SDL_Surface *dst)
{
int looph, loopw;
Uint8 *srcpix = (Uint8 *)src->pixels;
Uint8 *dstpix = (Uint8 *)dst->pixels;
const int srcpitch = src->pitch;
const int dstpitch = dst->pitch;
const int width = src->w;
const int height = src->h;
switch (src->format->BytesPerPixel) {
case 1: {
Uint8 E0, E1, E2, E3, B, D, E, F, H;
for (looph = 0; looph < height; ++looph) {
for (loopw = 0; loopw < width; ++loopw) {
B = *(Uint8 *)(srcpix + (MAX(0, looph - 1) * srcpitch) +
(1 * loopw));
D = *(Uint8 *)(srcpix + (looph * srcpitch) +
(1 * MAX(0, loopw - 1)));
E = *(Uint8 *)(srcpix + (looph * srcpitch) + (1 * loopw));
F = *(Uint8 *)(srcpix + (looph * srcpitch) +
(1 * MIN(width - 1, loopw + 1)));
H = *(Uint8 *)(srcpix +
(MIN(height - 1, looph + 1) * srcpitch) +
(1 * loopw));
E0 = D == B && B != F && D != H ? D : E;
E1 = B == F && B != D && F != H ? F : E;
E2 = D == H && D != B && H != F ? D : E;
E3 = H == F && D != H && B != F ? F : E;
*(Uint8 *)(dstpix + looph * 2 * dstpitch + loopw * 2 * 1) =
E0;
*(Uint8 *)(dstpix + looph * 2 * dstpitch +
(loopw * 2 + 1) * 1) = E1;
*(Uint8 *)(dstpix + (looph * 2 + 1) * dstpitch +
loopw * 2 * 1) = E2;
*(Uint8 *)(dstpix + (looph * 2 + 1) * dstpitch +
(loopw * 2 + 1) * 1) = E3;
}
}
break;
}
case 2: {
Uint16 E0, E1, E2, E3, B, D, E, F, H;
for (looph = 0; looph < height; ++looph) {
for (loopw = 0; loopw < width; ++loopw) {
B = *(Uint16 *)(srcpix + (MAX(0, looph - 1) * srcpitch) +
(2 * loopw));
D = *(Uint16 *)(srcpix + (looph * srcpitch) +
(2 * MAX(0, loopw - 1)));
E = *(Uint16 *)(srcpix + (looph * srcpitch) + (2 * loopw));
F = *(Uint16 *)(srcpix + (looph * srcpitch) +
(2 * MIN(width - 1, loopw + 1)));
H = *(Uint16 *)(srcpix +
(MIN(height - 1, looph + 1) * srcpitch) +
(2 * loopw));
E0 = D == B && B != F && D != H ? D : E;
E1 = B == F && B != D && F != H ? F : E;
E2 = D == H && D != B && H != F ? D : E;
E3 = H == F && D != H && B != F ? F : E;
*(Uint16 *)(dstpix + looph * 2 * dstpitch +
loopw * 2 * 2) = E0;
*(Uint16 *)(dstpix + looph * 2 * dstpitch +
(loopw * 2 + 1) * 2) = E1;
*(Uint16 *)(dstpix + (looph * 2 + 1) * dstpitch +
loopw * 2 * 2) = E2;
*(Uint16 *)(dstpix + (looph * 2 + 1) * dstpitch +
(loopw * 2 + 1) * 2) = E3;
}
}
break;
}
case 3: {
int E0, E1, E2, E3, B, D, E, F, H;
for (looph = 0; looph < height; ++looph) {
for (loopw = 0; loopw < width; ++loopw) {
B = READINT24(srcpix + (MAX(0, looph - 1) * srcpitch) +
(3 * loopw));
D = READINT24(srcpix + (looph * srcpitch) +
(3 * MAX(0, loopw - 1)));
E = READINT24(srcpix + (looph * srcpitch) + (3 * loopw));
F = READINT24(srcpix + (looph * srcpitch) +
(3 * MIN(width - 1, loopw + 1)));
H = READINT24(srcpix +
(MIN(height - 1, looph + 1) * srcpitch) +
(3 * loopw));
E0 = D == B && B != F && D != H ? D : E;
E1 = B == F && B != D && F != H ? F : E;
E2 = D == H && D != B && H != F ? D : E;
E3 = H == F && D != H && B != F ? F : E;
WRITEINT24((dstpix + looph * 2 * dstpitch + loopw * 2 * 3),
E0);
WRITEINT24(
(dstpix + looph * 2 * dstpitch + (loopw * 2 + 1) * 3),
E1);
WRITEINT24(
(dstpix + (looph * 2 + 1) * dstpitch + loopw * 2 * 3),
E2);
WRITEINT24((dstpix + (looph * 2 + 1) * dstpitch +
(loopw * 2 + 1) * 3),
E3);
}
}
break;
}
default: { /*case 4:*/
Uint32 E0, E1, E2, E3, B, D, E, F, H;
for (looph = 0; looph < height; ++looph) {
for (loopw = 0; loopw < width; ++loopw) {
B = *(Uint32 *)(srcpix + (MAX(0, looph - 1) * srcpitch) +
(4 * loopw));
D = *(Uint32 *)(srcpix + (looph * srcpitch) +
(4 * MAX(0, loopw - 1)));
E = *(Uint32 *)(srcpix + (looph * srcpitch) + (4 * loopw));
F = *(Uint32 *)(srcpix + (looph * srcpitch) +
(4 * MIN(width - 1, loopw + 1)));
H = *(Uint32 *)(srcpix +
(MIN(height - 1, looph + 1) * srcpitch) +
(4 * loopw));
E0 = D == B && B != F && D != H ? D : E;
E1 = B == F && B != D && F != H ? F : E;
E2 = D == H && D != B && H != F ? D : E;
E3 = H == F && D != H && B != F ? F : E;
*(Uint32 *)(dstpix + looph * 2 * dstpitch +
loopw * 2 * 4) = E0;
*(Uint32 *)(dstpix + looph * 2 * dstpitch +
(loopw * 2 + 1) * 4) = E1;
*(Uint32 *)(dstpix + (looph * 2 + 1) * dstpitch +
loopw * 2 * 4) = E2;
*(Uint32 *)(dstpix + (looph * 2 + 1) * dstpitch +
(loopw * 2 + 1) * 4) = E3;
}
}
break;
}
}
}
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