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110 lines
3.2 KiB
C
110 lines
3.2 KiB
C
#ifndef _AL_FILTER_H_
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#define _AL_FILTER_H_
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#include "AL/al.h"
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#include "alu.h"
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#ifdef __cplusplus
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extern "C" {
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#endif
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typedef struct {
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ALfloat coeff;
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#ifndef _MSC_VER
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ALfloat history[0];
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#else
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ALfloat history[1];
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#endif
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} FILTER;
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static __inline ALfloat lpFilter2P(FILTER *iir, ALuint offset, ALfloat input)
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{
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ALfloat *history = &iir->history[offset*2];
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ALfloat a = iir->coeff;
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ALfloat output = input;
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output = output + (history[0]-output)*a;
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history[0] = output;
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output = output + (history[1]-output)*a;
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history[1] = output;
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return output;
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}
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static __inline ALfloat lpFilter1P(FILTER *iir, ALuint offset, ALfloat input)
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{
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ALfloat *history = &iir->history[offset];
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ALfloat a = iir->coeff;
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ALfloat output = input;
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output = output + (history[0]-output)*a;
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history[0] = output;
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return output;
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}
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static __inline ALfloat lpFilter2PC(const FILTER *iir, ALuint offset, ALfloat input)
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{
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const ALfloat *history = &iir->history[offset*2];
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ALfloat a = iir->coeff;
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ALfloat output = input;
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output = output + (history[0]-output)*a;
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output = output + (history[1]-output)*a;
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return output;
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}
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static __inline ALfloat lpFilter1PC(FILTER *iir, ALuint offset, ALfloat input)
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{
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const ALfloat *history = &iir->history[offset];
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ALfloat a = iir->coeff;
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ALfloat output = input;
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output = output + (history[0]-output)*a;
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return output;
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}
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/* Calculates the low-pass filter coefficient given the pre-scaled gain and
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* cos(w) value. Note that g should be pre-scaled (sqr(gain) for one-pole,
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* sqrt(gain) for four-pole, etc) */
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ALfloat lpCoeffCalc(ALfloat g, ALfloat cw);
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typedef struct ALfilter {
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// Filter type (AL_FILTER_NULL, ...)
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ALenum type;
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ALfloat Gain;
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ALfloat GainHF;
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void (*SetParami)(struct ALfilter *filter, ALCcontext *context, ALenum param, ALint val);
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void (*SetParamiv)(struct ALfilter *filter, ALCcontext *context, ALenum param, const ALint *vals);
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void (*SetParamf)(struct ALfilter *filter, ALCcontext *context, ALenum param, ALfloat val);
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void (*SetParamfv)(struct ALfilter *filter, ALCcontext *context, ALenum param, const ALfloat *vals);
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void (*GetParami)(struct ALfilter *filter, ALCcontext *context, ALenum param, ALint *val);
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void (*GetParamiv)(struct ALfilter *filter, ALCcontext *context, ALenum param, ALint *vals);
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void (*GetParamf)(struct ALfilter *filter, ALCcontext *context, ALenum param, ALfloat *val);
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void (*GetParamfv)(struct ALfilter *filter, ALCcontext *context, ALenum param, ALfloat *vals);
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// Index to itself
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ALuint filter;
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} ALfilter;
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#define ALfilter_SetParami(x, c, p, v) ((x)->SetParami((x),(c),(p),(v)))
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#define ALfilter_SetParamiv(x, c, p, v) ((x)->SetParamiv((x),(c),(p),(v)))
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#define ALfilter_SetParamf(x, c, p, v) ((x)->SetParamf((x),(c),(p),(v)))
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#define ALfilter_SetParamfv(x, c, p, v) ((x)->SetParamfv((x),(c),(p),(v)))
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#define ALfilter_GetParami(x, c, p, v) ((x)->GetParami((x),(c),(p),(v)))
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#define ALfilter_GetParamiv(x, c, p, v) ((x)->GetParamiv((x),(c),(p),(v)))
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#define ALfilter_GetParamf(x, c, p, v) ((x)->GetParamf((x),(c),(p),(v)))
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#define ALfilter_GetParamfv(x, c, p, v) ((x)->GetParamfv((x),(c),(p),(v)))
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ALvoid ReleaseALFilters(ALCdevice *device);
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#ifdef __cplusplus
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}
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#endif
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#endif
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