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-rw-r--r--Alc/ALu.c87
1 files changed, 40 insertions, 47 deletions
diff --git a/Alc/ALu.c b/Alc/ALu.c
index 9baf6cee..3b8be4a2 100644
--- a/Alc/ALu.c
+++ b/Alc/ALu.c
@@ -157,31 +157,18 @@ __inline ALuint aluChannelsFromFormat(ALenum format)
static __inline ALfloat lpFilter(FILTER *iir, ALfloat input)
{
- float *hist1_ptr,*hist2_ptr,*coef_ptr;
- ALfloat output,new_hist,history1,history2;
-
- coef_ptr = iir->coef; /* coefficient pointer */
-
- hist1_ptr = iir->history; /* first history */
- hist2_ptr = hist1_ptr + 1; /* next history */
-
- /* 1st number of coefficients array is overall input scale factor,
- * or filter gain */
- output = input * (*coef_ptr++);
-
- history1 = *hist1_ptr; /* history values */
- history2 = *hist2_ptr;
-
- output = output - history1 * (*coef_ptr++);
- new_hist = output - history2 * (*coef_ptr++); /* poles */
-
- output = new_hist + history1 * (*coef_ptr++);
- output = output + history2 * (*coef_ptr++); /* zeros */
-
- *hist2_ptr++ = *hist1_ptr;
- *hist1_ptr++ = new_hist;
- hist1_ptr++;
- hist2_ptr++;
+ ALfloat *history = iir->history;
+ ALfloat a = iir->coeff;
+ ALfloat output = input;
+
+ output = output + (history[0]-output)*a;
+ history[0] = output;
+ output = output + (history[1]-output)*a;
+ history[1] = output;
+ output = output + (history[2]-output)*a;
+ history[2] = output;
+ output = output + (history[3]-output)*a;
+ history[3] = output;
return output;
}
@@ -234,10 +221,6 @@ static __inline ALvoid aluMatrixVector(ALfloat *vector,ALfloat matrix[3][3])
memcpy(vector, result, sizeof(result));
}
-static __inline ALfloat aluComputeSample(ALfloat GainHF, ALfloat sample, ALfloat LowSample)
-{
- return LowSample + ((sample - LowSample) * GainHF);
-}
static ALvoid CalcSourceParams(ALCcontext *ALContext, ALsource *ALSource,
ALenum isMono, ALenum OutputFormat,
@@ -258,6 +241,7 @@ static ALvoid CalcSourceParams(ALCcontext *ALContext, ALsource *ALSource,
ALfloat RoomRolloff;
ALfloat DryGainHF = 1.0f;
ALfloat WetGainHF = 1.0f;
+ ALfloat cw, a, g;
//Get context properties
DopplerFactor = ALContext->DopplerFactor * ALSource->DopplerFactor;
@@ -604,6 +588,25 @@ static ALvoid CalcSourceParams(ALCcontext *ALContext, ALsource *ALSource,
break;
}
+ // Update filter coefficients. Calculations based on the I3DL2 spec.
+ cw = cos(2.0f*3.141592654f * LOWPASSFREQCUTOFF / ALContext->Frequency);
+ // We use four chained one-pole filters, so we need to take the fourth
+ // root of the squared gain, which is the same as the square root of
+ // the base gain.
+ // Be careful with gains < 0.0001, as that causes the coefficient to
+ // head towards 1, which will flatten the signal
+ g = aluSqrt(__max(DryGainHF, 0.0001f));
+ a = 0.0f;
+ if(g < 0.9999f) // 1-epsilon
+ a = (1 - g*cw - aluSqrt(2*g*(1-cw) - g*g*(1 - cw*cw))) / (1 - g);
+ ALSource->iirFilter.coeff = a;
+
+ g = aluSqrt(__max(WetGainHF, 0.0001f));
+ a = 0.0f;
+ if(g < 0.9999f) // 1-epsilon
+ a = (1 - g*cw - aluSqrt(2*g*(1-cw) - g*g*(1 - cw*cw))) / (1 - g);
+ ALSource->Send[0].iirFilter.coeff = a;
+
*drygainhf = DryGainHF;
*wetgainhf = WetGainHF;
}
@@ -648,8 +651,6 @@ ALvoid aluMixData(ALCcontext *ALContext,ALvoid *buffer,ALsizei size,ALenum forma
ALuint rampLength;
ALfloat dryGainStep[OUTPUTCHANNELS];
ALfloat wetGainStep[OUTPUTCHANNELS];
- ALfloat dryGainHFStep;
- ALfloat wetGainHFStep;
ALuint BlockAlign,BufferSize;
ALuint DataSize=0,DataPosInt=0,DataPosFrac=0;
ALuint Channels,Frequency,ulExtraSamples;
@@ -667,7 +668,7 @@ ALvoid aluMixData(ALCcontext *ALContext,ALvoid *buffer,ALsizei size,ALenum forma
ALbufferlistitem *BufferListItem;
ALuint loop;
ALint64 DataSize64,DataPos64;
- FILTER *Filter;
+ FILTER *DryFilter, *WetFilter;
int fpuState;
SuspendContext(ALContext);
@@ -742,7 +743,8 @@ ALvoid aluMixData(ALCcontext *ALContext,ALvoid *buffer,ALsizei size,ALenum forma
//Get source info
DataPosInt = ALSource->position;
DataPosFrac = ALSource->position_fraction;
- Filter = &ALSource->iirFilter;
+ DryFilter = &ALSource->iirFilter;
+ WetFilter = &ALSource->Send[0].iirFilter;
DrySend = ALSource->DryGains;
WetSend = ALSource->WetGains;
@@ -752,10 +754,6 @@ ALvoid aluMixData(ALCcontext *ALContext,ALvoid *buffer,ALsizei size,ALenum forma
dryGainStep[i] = (newDrySend[i]-DrySend[i]) / rampLength;
wetGainStep[i] = (newWetSend[i]-WetSend[i]) / rampLength;
}
- dryGainHFStep = (DryGainHF-ALSource->DryGainHF) / rampLength;
- wetGainHFStep = (WetGainHF-ALSource->WetGainHF) / rampLength;
- DryGainHF = ALSource->DryGainHF;
- WetGainHF = ALSource->WetGainHF;
//Compute 18.14 fixed point step
increment = (ALint)(Pitch*(ALfloat)(1L<<FRACTIONBITS));
@@ -815,19 +813,16 @@ ALvoid aluMixData(ALCcontext *ALContext,ALvoid *buffer,ALsizei size,ALenum forma
DrySend[i] += dryGainStep[i];
WetSend[i] += wetGainStep[i];
}
- DryGainHF += dryGainHFStep;
- WetGainHF += wetGainHFStep;
if(Channels==1)
{
- ALfloat sample, lowsamp, outsamp;
+ ALfloat sample, outsamp;
//First order interpolator
sample = (Data[k]*((1<<FRACTIONBITS)-fraction) +
Data[k+1]*fraction) >> FRACTIONBITS;
- lowsamp = lpFilter(Filter, sample);
//Direct path final mix buffer and panning
- outsamp = aluComputeSample(DryGainHF, sample, lowsamp);
+ outsamp = lpFilter(DryFilter, sample);
DryBuffer[j][FRONT_LEFT] += outsamp*DrySend[FRONT_LEFT];
DryBuffer[j][FRONT_RIGHT] += outsamp*DrySend[FRONT_RIGHT];
DryBuffer[j][SIDE_LEFT] += outsamp*DrySend[SIDE_LEFT];
@@ -835,7 +830,7 @@ ALvoid aluMixData(ALCcontext *ALContext,ALvoid *buffer,ALsizei size,ALenum forma
DryBuffer[j][BACK_LEFT] += outsamp*DrySend[BACK_LEFT];
DryBuffer[j][BACK_RIGHT] += outsamp*DrySend[BACK_RIGHT];
//Room path final mix buffer and panning
- outsamp = aluComputeSample(WetGainHF, sample, lowsamp);
+ outsamp = lpFilter(WetFilter, sample);
WetBuffer[j][FRONT_LEFT] += outsamp*WetSend[FRONT_LEFT];
WetBuffer[j][FRONT_RIGHT] += outsamp*WetSend[FRONT_RIGHT];
WetBuffer[j][SIDE_LEFT] += outsamp*WetSend[SIDE_LEFT];
@@ -923,8 +918,6 @@ ALvoid aluMixData(ALCcontext *ALContext,ALvoid *buffer,ALsizei size,ALenum forma
//Update source info
ALSource->position = DataPosInt;
ALSource->position_fraction = DataPosFrac;
- ALSource->DryGainHF = DryGainHF;
- ALSource->WetGainHF = WetGainHF;
}
//Handle looping sources
@@ -1015,7 +1008,7 @@ ALvoid aluMixData(ALCcontext *ALContext,ALvoid *buffer,ALsizei size,ALenum forma
ALfloat LateReverbGain = ALEffectSlot->effect.Reverb.LateReverbGain;
ALfloat sample, lowsample;
- Filter = &ALEffectSlot->iirFilter;
+ WetFilter = &ALEffectSlot->iirFilter;
for(i = 0;i < SamplesToDo;i++)
{
sample = WetBuffer[i][FRONT_LEFT] +WetBuffer[i][SIDE_LEFT] +WetBuffer[i][BACK_LEFT];
@@ -1027,7 +1020,7 @@ ALvoid aluMixData(ALCcontext *ALContext,ALvoid *buffer,ALsizei size,ALenum forma
DelayBuffer[LatePos] *= LateReverbGain;
Pos = (Pos+1) % Length;
- lowsample = lpFilter(Filter, DelayBuffer[Pos]);
+ lowsample = lpFilter(WetFilter, DelayBuffer[Pos]);
lowsample += (DelayBuffer[Pos]-lowsample) * DecayHFRatio;
DelayBuffer[LatePos] += lowsample * DecayGain;
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-01 02:47:52 +0000