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51c11efbbc
A new internal table has been added so that no if checks need to be performed for the at() lookup. The old table can still be accessed using getTable or atLegacy(). at() and atLegacy() return the same values, but at() is faster.
75 lines
2.2 KiB
C++
75 lines
2.2 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 _tableEOS; }
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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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* Faster than atLegacy
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*/
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float at(int index) const;
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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 atLegacy(int index) const;
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private:
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float *_tableEOS;
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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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