ClassicEmu.java

package audio.gme;

// Common aspects of emulators which use BlipBuffer for sound output
// http://www.slack.net/~ant/

/* Copyright (C) 2003-2007 Shay Green. This module is free software; you
can redistribute it and/or modify it under the terms of the GNU Lesser
General Public License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version. This
module 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 Lesser General Public License for more
details. You should have received a copy of the GNU Lesser General Public
License along with this module; if not, write to the Free Software Foundation,
Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA */

class ClassicEmu extends MusicEmu
{
	protected int setSampleRate_( int rate )
	{
		buf.setSampleRate( rate, 1000 / bufLength );
		return rate;
	}
	
	public void startTrack( int track )
	{
		super.startTrack( track );
		buf.clear();
	}
	
	protected int play_( byte [] out, int count )
	{
		int pos = 0;
		while ( true )
		{
			int n = buf.readSamples( out, pos, count );
			mixSamples( out, pos, n );
			
			pos   += n;
			count -= n;
			if ( count <= 0 )
				break;
			
			if ( trackEnded_ )
			{
				java.util.Arrays.fill( out, pos, pos + count, (byte) 0 );
				break;
			}
			
			int clocks = runMsec( bufLength );
			buf.endFrame( clocks );
		}
		return pos;
	}
	
	protected final int countSamples( int time ) { return buf.countSamples( time ); }

	protected void mixSamples( byte [] out, int offset, int count )
	{
		// derived class can override and mix its own samples here
	}
	
// internal
	
	static final int bufLength = 32;
	protected StereoBuffer buf = new StereoBuffer();
	
	protected void setClockRate( int rate ) { buf.setClockRate( rate ); }
	
	// Subclass should run here for at most clockCount and return actual
	// number of clocks emulated (can be less)
	protected int runClocks( int clockCount ) { return 0; }
	
	// Subclass can also get number of msec to run, and return number of clocks emulated
	protected int runMsec( int msec )
	{
		assert bufLength == 32;
		return runClocks( buf.clockRate() >> 5 );
	}
}