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Send multi-channel sources to auxiliary effect slots

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They are downmixed to mono using a volume-preserving scalar, and passed
through a 1-pole low-pass filter (not chained)
This commit is contained in:
Chris Robinson 2009-11-26 00:39:32 -08:00
parent 1a0676f0eb
commit 69f9ab88b9
2 changed files with 50 additions and 11 deletions
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59
Alc/ALu.c
View File

@ -478,8 +478,29 @@ static ALvoid CalcSourceParams(const ALCcontext *ALContext, ALsource *ALSource,
ALSource->Params.DryGains[FRONT_CENTER] = DryMix * ListenerGain;
ALSource->Params.DryGains[BACK_CENTER] = DryMix * ListenerGain;
ALSource->Params.DryGains[LFE] = DryMix * ListenerGain;
for(i = 0;i < MAX_SENDS;i++)
for(i = 0;i < NumSends;i++)
{
WetGain[i] = SourceVolume;
WetGain[i] = __min(WetGain[i],MaxVolume);
WetGain[i] = __max(WetGain[i],MinVolume);
WetGainHF[i] = 1.0f;
switch(ALSource->Send[i].WetFilter.type)
{
case AL_FILTER_LOWPASS:
WetGain[i] *= ALSource->Send[i].WetFilter.Gain;
WetGainHF[i] *= ALSource->Send[i].WetFilter.GainHF;
break;
}
ALSource->Params.WetGains[i] = WetGain[i] * ListenerGain;
}
for(i = NumSends;i < MAX_SENDS;i++)
{
ALSource->Params.WetGains[i] = 0.0f;
WetGainHF[i] = 1.0f;
}
/* Update filter coefficients. Calculations based on the I3DL2
* spec. */
@ -495,8 +516,18 @@ static ALvoid CalcSourceParams(const ALCcontext *ALContext, ALsource *ALSource,
a = (1 - g*cw - aluSqrt(2*g*(1-cw) - g*g*(1 - cw*cw))) /
(1 - g);
ALSource->Params.iirFilter.coeff = a;
for(i = 0;i < MAX_SENDS;i++)
ALSource->Params.Send[i].iirFilter.coeff = 0.0f;
for(i = 0;i < NumSends;i++)
{
/* We use a one-pole filter, so we need to take the squared gain */
g = __max(WetGainHF[i], 0.1f);
g *= g;
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->Params.Send[i].iirFilter.coeff = a;
}
return;
}
@ -832,7 +863,7 @@ static void MixSomeSources(ALCcontext *ALContext, float (*DryBuffer)[OUTPUTCHANN
ALfloat wetGainStep[MAX_SENDS];
ALuint i, j, k, out;
ALsource *ALSource;
ALfloat value;
ALfloat value, outsamp;
ALbufferlistitem *BufferListItem;
ALint64 DataSize64,DataPos64;
FILTER *DryFilter, *WetFilter[MAX_SENDS];
@ -1009,8 +1040,6 @@ another_source:
if(Channels == 1) /* Mono */
{
ALfloat outsamp;
while(BufferSize--)
{
for(i = 0;i < OUTPUTCHANNELS;i++)
@ -1050,21 +1079,27 @@ another_source:
const int chans[] = {
FRONT_LEFT, FRONT_RIGHT
};
const ALfloat scaler = aluSqrt(1.0f/Channels);
#define DO_MIX() do { \
for(i = 0;i < MAX_SENDS;i++) \
WetSend[i] += wetGainStep[i]*BufferSize; \
while(BufferSize--) \
{ \
for(i = 0;i < OUTPUTCHANNELS;i++) \
DrySend[i] += dryGainStep[i]; \
for(i = 0;i < MAX_SENDS;i++) \
WetSend[i] += wetGainStep[i]; \
\
for(i = 0;i < Channels;i++) \
{ \
value = lerp(Data[k*Channels + i], Data[(k+1)*Channels + i], DataPosFrac); \
value = lpFilter2P(DryFilter, chans[i]*2, value)*DrySend[chans[i]]; \
outsamp = lpFilter2P(DryFilter, chans[i]*2, value)*DrySend[chans[i]]; \
for(out = 0;out < OUTPUTCHANNELS;out++) \
DryBuffer[j][out] += value*Matrix[chans[i]][out]; \
DryBuffer[j][out] += outsamp*Matrix[chans[i]][out]; \
for(out = 0;out < MAX_SENDS;out++) \
{ \
outsamp = lpFilter1P(WetFilter[out], chans[out], value); \
WetBuffer[out][j] += outsamp*WetSend[out]*scaler; \
} \
} \
\
DataPosFrac += increment; \
@ -1082,6 +1117,7 @@ another_source:
FRONT_LEFT, FRONT_RIGHT,
BACK_LEFT, BACK_RIGHT
};
const ALfloat scaler = aluSqrt(1.0f/Channels);
DO_MIX();
}
@ -1092,6 +1128,7 @@ another_source:
FRONT_CENTER, LFE,
BACK_LEFT, BACK_RIGHT
};
const ALfloat scaler = aluSqrt(1.0f/Channels);
DO_MIX();
}
@ -1103,6 +1140,7 @@ another_source:
BACK_CENTER,
SIDE_LEFT, SIDE_RIGHT
};
const ALfloat scaler = aluSqrt(1.0f/Channels);
DO_MIX();
}
@ -1114,6 +1152,7 @@ another_source:
BACK_LEFT, BACK_RIGHT,
SIDE_LEFT, SIDE_RIGHT
};
const ALfloat scaler = aluSqrt(1.0f/Channels);
DO_MIX();
#undef DO_MIX

2
OpenAL32/Include/alSource.h
View File

@ -93,7 +93,7 @@ typedef struct ALsource
struct {
FILTER iirFilter;
ALfloat history[2];
ALfloat history[OUTPUTCHANNELS];
} Send[MAX_SENDS];
FILTER iirFilter;