67 lines
2.4 KiB
C++
67 lines
2.4 KiB
C++
// soundgenerator.hxx -- simple sound generation
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//
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// Written by Curtis Olson, started March 2001.
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//
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// Copyright (C) 2001 Curtis L. Olson - http://www.flightgear.org/~curt
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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 as
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// published by the Free Software Foundation; either version 2 of the
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// 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, but
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// WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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// 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 _FGSOUNDGENERATOR_HXX
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#define _FGSOUNDGENERATOR_HXX
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#ifdef HAVE_CONFIG_H
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# include <config.h>
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#endif
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class FGSoundGenerator {
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public:
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static const int BYTES_PER_SECOND = 22050;
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// static const int BEAT_LENGTH = 240; // milleseconds (5 wpm)
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static const int BEAT_LENGTH = 92; // milleseconds (13 wpm)
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static const int TRANSITION_BYTES = (int)(0.005 * BYTES_PER_SECOND);
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static const int COUNT_SIZE = BYTES_PER_SECOND * BEAT_LENGTH / 1000;
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static const int DIT_SIZE = 2 * COUNT_SIZE; // 2 counts
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static const int DAH_SIZE = 4 * COUNT_SIZE; // 4 counts
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static const int SPACE_SIZE = 3 * COUNT_SIZE; // 3 counts
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static const int LO_FREQUENCY = 1020; // AIM 1-1-7 (f) specified in Hz
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static const int HI_FREQUENCY = 1350; // AIM 1-1-7 (f) specified in Hz
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protected:
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/**
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* \relates FGMorse
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* Make a tone of specified freq and total_len with trans_len ramp in
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* and out and only the first len bytes with sound, the rest with
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* silence.
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* @param buf unsigned char pointer to sound buffer
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* @param freq desired frequency of tone
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* @param len length of tone within sound
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* @param total_len total length of sound (anything more than len is padded
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* with silence.
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* @param trans_len length of ramp up and ramp down to avoid audio "pop"
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*/
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static void make_tone( unsigned char *buf, int freq,
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int len, int total_len, int trans_len );
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public:
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virtual ~FGSoundGenerator();
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};
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#endif // _FGSOUNDGENERATOR_HXX
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