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9cfc70e7fe
Previously, the cos/sin table had to be a power of 2, but there are many use cases where the number of points is not necessarily a power of 2 so this change the constructor so it now takes in the number of points rather than the number of points as the exponent of a power of 2. The restriction is that the size must be divisible by 4.
67 lines
2.0 KiB
C++
67 lines
2.0 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
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version 2
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* of the License, or (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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*/
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#ifndef COMMON_COSINETABLES_H
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#define COMMON_COSINETABLES_H
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namespace Common {
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class CosineTable {
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public:
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/**
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* Construct a cosine table given the number of points
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*
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* @param nPoints Number of distinct radian points, which must be in range [16,65536] and be divisible by 4
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*/
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CosineTable(int nPoints);
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~CosineTable();
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/**
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* Get pointer to table.
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*
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* This table contains nPoints/2 entries.
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* Prefer to use at()
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* The layout of this table is as follows:
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* - Entries 0 up to (including) nPoints/4:
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* cos(0) till (including) cos(1/2*pi)
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* - Entries (excluding) nPoints/4 up to nPoints/2:
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* (excluding) cos(3/2*pi) till (excluding) cos(2*pi)
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*/
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const float *getTable() { return _table; }
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/**
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* Returns cos(2*pi * index / nPoints )
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* Index must be in range [0, nPoints - 1]
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*/
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float at(int index) const;
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private:
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float *_table;
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double _radResolution; // Smallest radian increment
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int _refSize; // _nPoints / 4
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int _nPoints; // range of operator[]
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};
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} // End of namespace Common
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#endif // COMMON_COSINETABLES_H
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