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112 lines
2.8 KiB
112 lines
2.8 KiB
15 years ago
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/*
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* Copyright (c) 2005 Adrian Page <adrian@pagenet.plus.com>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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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
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
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*/
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#ifndef KIS_INTEGER_MATHS_H
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#define KIS_INTEGER_MATHS_H
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#define UINT8_MAX 255u
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#define UINT8_MIN 0u
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#define UINT16_MAX 65535u
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#define UINT16_MIN 0u
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#define UINT32_MAX (4294967295u)
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#define UINT32_MIN 0u
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#define INT16_MAX 32767
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#define INT16_MIN -32768
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/// take a and scale it up by 256*b/255
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inline uint UINT8_SCALEBY(uint a, uint b)
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{
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uint c = a * b + 0x80u;
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return (c >> 8) + c;
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}
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inline uint UINT8_MULT(uint a, uint b)
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{
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uint c = a * b + 0x80u;
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return ((c >> 8) + c) >> 8;
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}
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inline uint UINT8_DIVIDE(uint a, uint b)
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{
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uint c = (a * UINT8_MAX + (b / 2u)) / b;
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return c;
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}
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inline uint UINT8_BLEND(uint a, uint b, uint alpha)
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{
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// Basically we do a*alpha + b*(1-alpha)
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// However refactored to (a-b)*alpha + b since that saves a multiplication
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// Signed arithmetic is needed since a-b might be negative
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int c = ((int(a) - int(b)) * int(alpha)) >> 8;
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return uint(c + b);
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}
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inline uint UINT16_MULT(uint a, uint b)
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{
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uint c = a * b + 0x8000u;
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return ((c >> 16) + c) >> 16;
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}
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inline int INT16_MULT(int a, int b)
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{
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return (a*b) / INT16_MAX;
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}
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inline uint UINT16_DIVIDE(uint a, uint b)
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{
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uint c = (a * UINT16_MAX + (b / 2u)) / b;
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return c;
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}
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inline uint UINT16_BLEND(uint a, uint b, uint alpha)
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{
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// Basically we do a*alpha + b*(1-alpha)
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// However refactored to (a-b)*alpha + b since that saves a multiplication
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// Signed arithmetic is needed since a-b might be negative
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int c = ((int(a) - int(b)) * int(alpha)) >> 16;
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return uint(c + b);
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}
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inline uint UINT8_TO_UINT16(uint c)
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{
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return c | (c<<8);
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}
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inline uint UINT16_TO_UINT8(uint c)
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{
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//return round(c / 257.0);
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//For all UINT16 this calculation is the same and a lot faster (off by c/65656 which for every c is 0)
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c = c - (c >> 8) + 128;
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return c >>8;
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}
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inline int INT16_BLEND(int a, int b, uint alpha)
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{
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// Basically we do a*alpha + b*(1-alpha)
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// However refactored to (a-b)*alpha + b since that saves a multiplication
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int c = ((int(a) - int(b)) * int(alpha)) >> 16;
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return c + b;
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}
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#endif
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