From be292e5f0b71745ce4a5ce668fae2529a3fdd084 Mon Sep 17 00:00:00 2001 From: Chris Robinson Date: Thu, 2 Oct 2008 23:53:46 -0700 Subject: [PATCH] Don't hold the whole-number position in the fractional value This will help prevent overflows when the max pitch is increased --- Alc/ALu.c | 43 +++++++++++++++++++------------------------ 1 file changed, 19 insertions(+), 24 deletions(-) diff --git a/Alc/ALu.c b/Alc/ALu.c index 3b8be4a2..c85ddb9e 100644 --- a/Alc/ALu.c +++ b/Alc/ALu.c @@ -638,6 +638,11 @@ static ALvoid CalcSourceParams(ALCcontext *ALContext, ALsource *ALSource, } } +static __inline ALshort lerp(ALshort val1, ALshort val2, ALint frac) +{ + return (val1*((1<> FRACTIONBITS; +} + ALvoid aluMixData(ALCcontext *ALContext,ALvoid *buffer,ALsizei size,ALenum format) { static float DryBuffer[BUFFERSIZE][OUTPUTCHANNELS]; @@ -656,7 +661,7 @@ ALvoid aluMixData(ALCcontext *ALContext,ALvoid *buffer,ALsizei size,ALenum forma ALuint Channels,Frequency,ulExtraSamples; ALfloat Pitch; ALint Looping,State; - ALint fraction,increment; + ALint increment; ALuint Buffer; ALuint SamplesToDo; ALsource *ALSource; @@ -802,12 +807,10 @@ ALvoid aluMixData(ALCcontext *ALContext,ALvoid *buffer,ALsizei size,ALenum forma BufferSize = min(BufferSize, (SamplesToDo-j)); //Actual sample mixing loop + k = 0; Data += DataPosInt*Channels; while(BufferSize--) { - k = DataPosFrac>>FRACTIONBITS; - fraction = DataPosFrac&FRACTIONMASK; - for(i = 0;i < OUTPUTCHANNELS;i++) { DrySend[i] += dryGainStep[i]; @@ -818,8 +821,7 @@ ALvoid aluMixData(ALCcontext *ALContext,ALvoid *buffer,ALsizei size,ALenum forma { ALfloat sample, outsamp; //First order interpolator - sample = (Data[k]*((1<> FRACTIONBITS; + sample = lerp(Data[k], Data[k+1], DataPosFrac); //Direct path final mix buffer and panning outsamp = lpFilter(DryFilter, sample); @@ -842,13 +844,11 @@ ALvoid aluMixData(ALCcontext *ALContext,ALvoid *buffer,ALsizei size,ALenum forma { ALfloat samp1, samp2; //First order interpolator (front left) - samp1 = (Data[k*Channels]*((1<> FRACTIONBITS; + samp1 = lerp(Data[k*Channels], Data[(k+1)*Channels], DataPosFrac); DryBuffer[j][FRONT_LEFT] += samp1*DrySend[FRONT_LEFT]; WetBuffer[j][FRONT_LEFT] += samp1*WetSend[FRONT_LEFT]; //First order interpolator (front right) - samp2 = (Data[k*Channels+1]*((1<> FRACTIONBITS; + samp2 = lerp(Data[k*Channels+1], Data[(k+1)*Channels+1], DataPosFrac); DryBuffer[j][FRONT_RIGHT] += samp2*DrySend[FRONT_RIGHT]; WetBuffer[j][FRONT_RIGHT] += samp2*WetSend[FRONT_RIGHT]; if(Channels >= 4) @@ -859,42 +859,36 @@ ALvoid aluMixData(ALCcontext *ALContext,ALvoid *buffer,ALsizei size,ALenum forma if(Channels != 7) { //First order interpolator (center) - value = (Data[k*Channels+i]*((1<> FRACTIONBITS; + value = lerp(Data[k*Channels+i], Data[(k+1)*Channels+i], DataPosFrac); DryBuffer[j][CENTER] += value*DrySend[CENTER]; WetBuffer[j][CENTER] += value*WetSend[CENTER]; i++; } //First order interpolator (lfe) - value = (Data[k*Channels+i]*((1<> FRACTIONBITS; + value = lerp(Data[k*Channels+i], Data[(k+1)*Channels+i], DataPosFrac); DryBuffer[j][LFE] += value*DrySend[LFE]; WetBuffer[j][LFE] += value*WetSend[LFE]; i++; } //First order interpolator (back left) - value = (Data[k*Channels+i]*((1<> FRACTIONBITS; + value = lerp(Data[k*Channels+i], Data[(k+1)*Channels+i], DataPosFrac); DryBuffer[j][BACK_LEFT] += value*DrySend[BACK_LEFT]; WetBuffer[j][BACK_LEFT] += value*WetSend[BACK_LEFT]; i++; //First order interpolator (back right) - value = (Data[k*Channels+i]*((1<> FRACTIONBITS; + value = lerp(Data[k*Channels+i], Data[(k+1)*Channels+i], DataPosFrac); DryBuffer[j][BACK_RIGHT] += value*DrySend[BACK_RIGHT]; WetBuffer[j][BACK_RIGHT] += value*WetSend[BACK_RIGHT]; i++; if(Channels >= 7) { //First order interpolator (side left) - value = (Data[k*Channels+i]*((1<> FRACTIONBITS; + value = lerp(Data[k*Channels+i], Data[(k+1)*Channels+i], DataPosFrac); DryBuffer[j][SIDE_LEFT] += value*DrySend[SIDE_LEFT]; WetBuffer[j][SIDE_LEFT] += value*WetSend[SIDE_LEFT]; i++; //First order interpolator (side right) - value = (Data[k*Channels+i]*((1<> FRACTIONBITS; + value = lerp(Data[k*Channels+i], Data[(k+1)*Channels+i], DataPosFrac); DryBuffer[j][SIDE_RIGHT] += value*DrySend[SIDE_RIGHT]; WetBuffer[j][SIDE_RIGHT] += value*WetSend[SIDE_RIGHT]; i++; @@ -910,10 +904,11 @@ ALvoid aluMixData(ALCcontext *ALContext,ALvoid *buffer,ALsizei size,ALenum forma } } DataPosFrac += increment; + k += DataPosFrac>>FRACTIONBITS; + DataPosFrac &= FRACTIONMASK; j++; } - DataPosInt += (DataPosFrac>>FRACTIONBITS); - DataPosFrac = (DataPosFrac&FRACTIONMASK); + DataPosInt += k; //Update source info ALSource->position = DataPosInt; -- 2.11.4.GIT