scummvm/common/dct.h

/* ScummVM - Graphic Adventure Engine
 *
 * ScummVM is the legal property of its developers, whose names
 * are too numerous to list here. Please refer to the COPYRIGHT
 * file distributed with this source distribution.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.

 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.

 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 *
 */

// Based on eos' (I)RDFT code which is in turn
// Based upon the (I)DCT code in FFmpeg
// Copyright (c) 2009 Peter Ross <pross@xvid.org>
// Copyright (c) 2010 Alex Converse <alex.converse@gmail.com>
// Copyright (c) 2010 Vitor Sessak

#ifndef COMMON_DCT_H
#define COMMON_DCT_H

#include "common/scummsys.h"
#include "common/math.h"
#include "common/rdft.h"

#include "common/cosinetables.h"

namespace Common {

/**
 * (Inverse) Discrete Cosine Transforms.
 *
 * Used in engines:
 *  - scumm
 */
class DCT {
public:
	enum TransformType {
		DCT_II,
		DCT_III,
		DCT_I,
		DST_I
	};

	DCT(int bits, TransformType trans);
	~DCT();

	void calc(float *data);

private:
	int _bits;
	TransformType _trans;

	CosineTable _cos;
	const float *_tCos;

	float *_csc2;

	RDFT *_rdft;

	void calcDCTI  (float *data);
	void calcDCTII (float *data);
	void calcDCTIII(float *data);
	void calcDSTI  (float *data);
};

} // End of namespace Common

#endif // COMMON_DCT_H