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63 lines
1.8 KiB
C
63 lines
1.8 KiB
C
/* ScummVM - Graphic Adventure Engine
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*
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* ScummVM is the legal property of its developers, whose names
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* are too numerous to list here. Please refer to the COPYRIGHT
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* file distributed with this source distribution.
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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 3 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, see <http://www.gnu.org/licenses/>.
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*
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*/
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#ifndef COMMON_FRAC_H
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#define COMMON_FRAC_H
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#include "common/scummsys.h"
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/**
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* @defgroup common_frac Fixed-point fractions
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* @ingroup common
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*
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* @brief API for fixed-point fractions.
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*
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* @{
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*/
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/**
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* The precision of the fractional (fixed-point) type that is defined below.
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* Normally, you should never need to modify this value.
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*/
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enum {
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FRAC_BITS = 16,
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FRAC_LO_MASK = ((1L << FRAC_BITS) - 1),
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FRAC_HI_MASK = ((1L << FRAC_BITS) - 1) << FRAC_BITS,
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FRAC_ONE = (1L << FRAC_BITS), // 1.0
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FRAC_HALF = (1L << (FRAC_BITS-1)) // 0.5
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};
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/**
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* Fixed-point fractions, used by the sound rate converter and other code.
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*/
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typedef int32 frac_t;
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inline frac_t doubleToFrac(double value) { return (frac_t)(value * FRAC_ONE); }
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inline double fracToDouble(frac_t value) { return ((double)value) / FRAC_ONE; }
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inline frac_t intToFrac(int16 value) { return value * (1 << FRAC_BITS); }
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inline int16 fracToInt(frac_t value) { return value / (1 << FRAC_BITS); }
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/** @} */
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#endif
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