94 lines
2.0 KiB
C
94 lines
2.0 KiB
C
/*
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* Copyright (C) 2004 Christopher John Purnell
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* cjp@lost.org.uk
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*
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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 2 of the License, or
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* (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., 675 Mass Ave, Cambridge, MA 02139, USA.
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*/
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#include "al_source.h"
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#include "al_error.h"
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#include "alc_context.h"
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static ALfloat _alDistanceNone(AL_source *src, ALfloat dist ATTRIBUTE_UNUSED)
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{
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return src->gain;
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}
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ALfloat _alDistanceInverse(AL_source *src, ALfloat dist)
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{
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ALfloat ref = src->reference_distance;
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if (dist < ref)
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{
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dist = ref;
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}
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return src->gain * ref / (ref + src->rolloff_factor * (dist - ref));
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}
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static ALfloat _alDistanceInverseClamped(AL_source *src, ALfloat dist)
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{
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ALfloat ref = src->reference_distance;
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if (dist < ref)
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{
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dist = ref;
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}
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if (dist > src->max_distance)
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{
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dist = src->max_distance;
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}
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return src->gain * ref / (ref + src->rolloff_factor * (dist - ref));
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}
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ALvoid alDistanceModel(ALenum model)
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{
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AL_context *ctx;
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ALfloat (*df)(AL_source *, ALfloat);
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if (!(ctx = _alcCurrentContext))
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{
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_alSetError(AL_INVALID_OPERATION);
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return;
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}
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_alcLockContext(ctx);
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switch (model)
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{
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case AL_NONE:
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df = _alDistanceNone;
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break;
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case AL_INVERSE_DISTANCE:
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df = _alDistanceInverse;
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break;
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case AL_INVERSE_DISTANCE_CLAMPED:
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df = _alDistanceInverseClamped;
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break;
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default:
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_alSetError(AL_ILLEGAL_ENUM);
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goto unlock;
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}
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ctx->distance_model = model;
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ctx->distance_func = df;
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unlock:
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_alcUnlockContext(ctx);
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}
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