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Implement basic lowpass filter path

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This commit is contained in:
Chris Robinson
2007-12-17 21:00:52 -08:00
parent 28f80fa113
commit fc43a13927
2 changed files with 47 additions and 3 deletions
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Alc/ALu.c
+44 -3
View File
@@ -150,10 +150,35 @@ static __inline ALvoid aluMatrixVector(ALfloat *vector,ALfloat matrix[3][3])
memcpy(vector, result, sizeof(result));
}
static __inline ALfloat aluComputeDrySample(ALsource *source, ALfloat DryGainHF, ALfloat sample)
{
if(DryGainHF < 1.0f)
{
sample *= DryGainHF;
sample += source->LastDrySample * (1.0f - DryGainHF);
}
source->LastDrySample = sample;
return sample;
}
static __inline ALfloat aluComputeWetSample(ALsource *source, ALfloat WetGainHF, ALfloat sample)
{
if(WetGainHF < 1.0f)
{
sample *= WetGainHF;
sample += source->LastWetSample * (1.0f - WetGainHF);
}
source->LastWetSample = sample;
return sample;
}
static ALvoid CalcSourceParams(ALCcontext *ALContext, ALsource *ALSource,
ALenum isMono, ALenum OutputFormat,
ALfloat *drysend, ALfloat *wetsend,
ALfloat *pitch)
ALfloat *pitch, ALfloat *drygainhf,
ALfloat *wetgainhf)
{
ALfloat ListenerOrientation[6],ListenerPosition[3],ListenerVelocity[3];
ALfloat InnerAngle,OuterAngle,OuterGain,Angle,Distance,DryMix,WetMix;
@@ -168,6 +193,7 @@ static ALvoid CalcSourceParams(ALCcontext *ALContext, ALsource *ALSource,
ALint HeadRelative;
ALfloat flAttenuation;
ALfloat MetersPerUnit;
ALfloat DryGainHF, WetGainHF;
//Get context properties
DopplerFactor = ALContext->DopplerFactor;
@@ -272,6 +298,8 @@ static ALvoid CalcSourceParams(ALCcontext *ALContext, ALsource *ALSource,
WetMix = __min(WetMix,MaxVolume);
WetMix = __max(WetMix,MinVolume);
//3. Apply directional soundcones
DryGainHF = 1.0f;
WetGainHF = 1.0f;
SourceToListener[0] = -Position[0];
SourceToListener[1] = -Position[1];
SourceToListener[2] = -Position[2];
@@ -334,6 +362,9 @@ static ALvoid CalcSourceParams(ALCcontext *ALContext, ALsource *ALSource,
PanningFB = 0.5f;
}
*drygainhf = DryGainHF;
*wetgainhf = WetGainHF;
//7. Convert pannings into channel volumes
switch(OutputFormat)
{
@@ -379,6 +410,9 @@ static ALvoid CalcSourceParams(ALCcontext *ALContext, ALsource *ALSource,
wetsend[3] = SourceVolume * 0.0f * ListenerGain;
pitch[0] = Pitch;
*drygainhf = 1.0;
*wetgainhf = 1.0;
}
}
@@ -388,6 +422,8 @@ ALvoid aluMixData(ALCcontext *ALContext,ALvoid *buffer,ALsizei size,ALenum forma
static float WetBuffer[BUFFERSIZE][OUTPUTCHANNELS];
ALfloat DrySend[OUTPUTCHANNELS] = { 0.0f, 0.0f, 0.0f, 0.0f };
ALfloat WetSend[OUTPUTCHANNELS] = { 0.0f, 0.0f, 0.0f, 0.0f };
ALfloat DryGainHF = 0.0f;
ALfloat WetGainHF = 0.0f;
ALuint BlockAlign,BufferSize;
ALuint DataSize=0,DataPosInt=0,DataPosFrac=0;
ALuint Channels,Bits,Frequency,ulExtraSamples;
@@ -447,7 +483,8 @@ ALvoid aluMixData(ALCcontext *ALContext,ALvoid *buffer,ALsizei size,ALenum forma
CalcSourceParams(ALContext, ALSource,
(Channels==1) ? AL_TRUE : AL_FALSE,
format, DrySend, WetSend, &Pitch);
format, DrySend, WetSend, &Pitch,
&DryGainHF, &WetGainHF);
Pitch = (Pitch*Frequency) / ALContext->Frequency;
@@ -510,13 +547,17 @@ ALvoid aluMixData(ALCcontext *ALContext,ALvoid *buffer,ALsizei size,ALenum forma
if(Channels==1)
{
//First order interpolator
value = (ALfloat)((ALshort)(((Data[k]*((1L<<FRACTIONBITS)-fraction))+(Data[k+1]*(fraction)))>>FRACTIONBITS));
ALfloat sample = (ALfloat)((ALshort)(((Data[k]*((1L<<FRACTIONBITS)-fraction))+(Data[k+1]*(fraction)))>>FRACTIONBITS));
//Direct path final mix buffer and panning
value = aluComputeDrySample(ALSource, DryGainHF, sample);
DryBuffer[j][0] += value*DrySend[0];
DryBuffer[j][1] += value*DrySend[1];
DryBuffer[j][2] += value*DrySend[2];
DryBuffer[j][3] += value*DrySend[3];
//Room path final mix buffer and panning
value = aluComputeWetSample(ALSource, WetGainHF, sample);
WetBuffer[j][0] += value*WetSend[0];
WetBuffer[j][1] += value*WetSend[1];
WetBuffer[j][2] += value*WetSend[2];
OpenAL32/Include/alSource.h
+3
View File
@@ -62,6 +62,9 @@ typedef struct ALsource_struct
ALfilter DirectFilter;
ALfloat LastDrySample;
ALfloat LastWetSample;
// Index to itself
ALuint source;