mirror of https://github.com/FWGS/xash3d-fwgs
84 lines
2.6 KiB
C
84 lines
2.6 KiB
C
/*
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s_utils.c - common sound functions
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Copyright (C) 2009 Uncle Mike
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This program is free software: you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation, either version 3 of the License, or
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(at your option) any later version.
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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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#include "common.h"
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#include "sound.h"
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//-----------------------------------------------------------------------------
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// Purpose: wrap the position wrt looping
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// Input : samplePosition - absolute position
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// Output : int - looped position
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//-----------------------------------------------------------------------------
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int S_ConvertLoopedPosition( wavdata_t *pSource, int samplePosition, qboolean use_loop )
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{
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// if the wave is looping and we're past the end of the sample
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// convert to a position within the loop
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// At the end of the loop, we return a short buffer, and subsequent call
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// will loop back and get the rest of the buffer
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if( FBitSet( pSource->flags, SOUND_LOOPED ) && samplePosition >= pSource->samples && use_loop )
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{
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// size of loop
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int loopSize = pSource->samples - pSource->loopStart;
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// subtract off starting bit of the wave
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samplePosition -= pSource->loopStart;
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if( loopSize )
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{
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// "real" position in memory (mod off extra loops)
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samplePosition = pSource->loopStart + ( samplePosition % loopSize );
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}
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// ERROR? if no loopSize
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}
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return samplePosition;
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}
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int S_GetOutputData( wavdata_t *pSource, void **pData, int samplePosition, int sampleCount, qboolean use_loop )
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{
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int totalSampleCount;
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int sampleSize;
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// handle position looping
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samplePosition = S_ConvertLoopedPosition( pSource, samplePosition, use_loop );
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// how many samples are available (linearly not counting looping)
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totalSampleCount = pSource->samples - samplePosition;
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// may be asking for a sample out of range, clip at zero
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if( totalSampleCount < 0 ) totalSampleCount = 0;
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// clip max output samples to max available
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if( sampleCount > totalSampleCount )
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sampleCount = totalSampleCount;
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sampleSize = pSource->width * pSource->channels;
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// this can never be zero -- other functions divide by this.
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// This should never happen, but avoid crashing
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if( sampleSize <= 0 ) sampleSize = 1;
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// byte offset in sample database
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samplePosition *= sampleSize;
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// if we are returning some samples, store the pointer
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if( sampleCount )
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{
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*pData = pSource->buffer + samplePosition;
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}
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return sampleCount;
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}
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