79bc2dc1ef
This is the code from the 'gimp-2.9' branch of the plug-in, integrated into GIMP's build system.
68 lines
1.8 KiB
C
68 lines
1.8 KiB
C
/*
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DDS GIMP plugin
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Copyright (C) 2004-2012 Shawn Kirst <skirst@gmail.com>,
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with parts (C) 2003 Arne Reuter <homepage@arnereuter.de> where specified.
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This program is free software; you can redistribute it and/or
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modify it under the terms of the GNU General Public
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License as published by the Free Software Foundation; either
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version 2 of the License, or (at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; see the file COPYING. If not, write to
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the Free Software Foundation, 51 Franklin Street, Fifth Floor
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Boston, MA 02110-1301, USA.
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*/
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#ifndef IMATH_H
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#define IMATH_H
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#ifndef MIN
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# ifdef __GNUC__
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# define MIN(a, b) ({typeof(a) _a=(a); typeof(b) _b=(b); _a < _b ? _a : _b;})
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# else
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# define MIN(a, b) ((a) < (b) ? (a) : (b))
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# endif
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#endif
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#ifndef MAX
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# ifdef __GNUC__
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# define MAX(a, b) ({typeof(a) _a=(a); typeof(b) _b=(b); _a > _b ? _a : _b;})
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# else
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# define MAX(a, b) ((a) > (b) ? (a) : (b))
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# endif
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#endif
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#define IS_POW2(x) (!((x) & ((x) - 1)))
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#define IS_MUL4(x) (((x) & 3) == 0)
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/* round integer x up to next multiple of 4 */
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#define RND_MUL4(x) ((x) + (4 - ((x) & 3)))
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static inline int mul8bit(int a, int b)
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{
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int t = a * b + 128;
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return((t + (t >> 8)) >> 8);
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}
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static inline int blerp(int a, int b, int x)
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{
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return(a + mul8bit(b - a, x));
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}
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static inline int icerp(int a, int b, int c, int d, int x)
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{
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int p = (d - c) - (a - b);
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int q = (a - b) - p;
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int r = c - a;
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return((x * (x * (x * p + (q << 7)) + (r << 14)) + (b << 21)) >> 21);
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}
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#endif
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