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Better sort the main delay line taps

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This commit is contained in:
Chris Robinson 2016-10-06 20:05:16 -07:00
parent f826f86842
commit 698eddbb0c
1 changed files with 39 additions and 60 deletions
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99
Alc/effects/reverb.c
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@ -90,15 +90,11 @@ typedef struct ALreverbState {
/* Core delay line (early reflections and late reverb tap from this). */
DelayLine Delay;
/* The tap points for the initial delay. First tap goes to early
/* The tap points for the initial delay. First set go to early
* reflections, second to late reverb.
*/
ALuint DelayTap[2];
/* There are actually 4 decorrelator taps, but the first occurs at the late
* reverb tap.
*/
ALuint EarlyDecoTap[3];
ALuint LateDecoTap[3];
ALuint EarlyDelayTap[4];
ALuint LateDelayTap[4];
struct {
// Early reflections are done with 4 delay lines.
@ -221,14 +217,10 @@ static void ALreverbState_Construct(ALreverbState *state)
state->Delay.Mask = 0;
state->Delay.Line = NULL;
state->DelayTap[0] = 0;
state->DelayTap[1] = 0;
state->EarlyDecoTap[0] = 0;
state->EarlyDecoTap[1] = 0;
state->EarlyDecoTap[2] = 0;
state->LateDecoTap[0] = 0;
state->LateDecoTap[1] = 0;
state->LateDecoTap[2] = 0;
for(index = 0;index < 4;index++)
state->EarlyDelayTap[index] = 0;
for(index = 0;index < 4;index++)
state->LateDelayTap[index] = 0;
for(index = 0;index < 4;index++)
{
@ -330,7 +322,7 @@ static const ALfloat ECHO_ALLPASS_LENGTH = 0.0133f;
/* Input into the early reflections and late reverb are decorrelated between
* four channels. Their timings are dependent on a fraction and multiplier. See
* the UpdateDecorrelator() routine for the calculations involved.
* the UpdateDelayLine() routine for the calculations involved.
*/
static const ALfloat DECO_FRACTION = 0.15f;
static const ALfloat DECO_MULTIPLIER = 2.0f;
@ -669,12 +661,27 @@ static ALvoid UpdateModulator(ALfloat modTime, ALfloat modDepth, ALuint frequenc
2.0f * frequency;
}
// Update the offsets for the initial effect delay line.
static ALvoid UpdateDelayLine(ALfloat earlyDelay, ALfloat lateDelay, ALuint frequency, ALreverbState *State)
// Update the offsets for the main effect delay line.
static ALvoid UpdateDelayLine(ALfloat earlyDelay, ALfloat lateDelay, ALfloat density, ALuint frequency, ALreverbState *State)
{
// Calculate the initial delay taps.
State->DelayTap[0] = fastf2u(earlyDelay * frequency);
State->DelayTap[1] = fastf2u((earlyDelay + lateDelay) * frequency);
ALfloat length;
ALuint i;
State->EarlyDelayTap[0] = fastf2u(earlyDelay * frequency);
for(i = 1;i < 4;i++)
{
length = (DECO_FRACTION * powf(DECO_MULTIPLIER, (ALfloat)i-1.0f)) *
EARLY_LINE_LENGTH[0];
State->EarlyDelayTap[i] = fastf2u(length * frequency) + State->EarlyDelayTap[0];
}
State->LateDelayTap[0] = fastf2u((earlyDelay + lateDelay) * frequency);
for(i = 1;i < 4;i++)
{
length = (DECO_FRACTION * powf(DECO_MULTIPLIER, (ALfloat)i-1.0f)) *
LATE_LINE_LENGTH[0] * (1.0f + (density * LATE_LINE_MULTIPLIER));
State->LateDelayTap[i] = fastf2u(length * frequency) + State->LateDelayTap[0];
}
}
// Update the early reflections mix and line coefficients.
@ -690,31 +697,6 @@ static ALvoid UpdateEarlyLines(ALfloat lateDelay, ALreverbState *State)
lateDelay);
}
// Update the offsets for the decorrelator line.
static ALvoid UpdateDecorrelator(ALfloat density, ALuint frequency, ALreverbState *State)
{
ALuint index;
ALfloat length;
/* The early reflections and late reverb inputs are decorrelated to provide
* time-varying reflections, smooth out the reverb tail, and reduce harsh
* echos. The first tap occurs immediately, while the remaining taps are
* delayed by multiples of a fraction of the smallest cyclical delay time.
*
* offset[index] = (FRACTION (MULTIPLIER^index)) smallest_delay
*/
for(index = 0;index < 3;index++)
{
length = (DECO_FRACTION * powf(DECO_MULTIPLIER, (ALfloat)index)) *
EARLY_LINE_LENGTH[0];
State->EarlyDecoTap[index] = fastf2u(length * frequency) + State->DelayTap[0];
length = (DECO_FRACTION * powf(DECO_MULTIPLIER, (ALfloat)index)) *
LATE_LINE_LENGTH[0] * (1.0f + (density * LATE_LINE_MULTIPLIER));
State->LateDecoTap[index] = fastf2u(length * frequency) + State->DelayTap[1];
}
}
// Update the late reverb mix, line lengths, and line coefficients.
static ALvoid UpdateLateLines(ALfloat xMix, ALfloat density, ALfloat decayTime, ALfloat diffusion, ALfloat echoDepth, ALfloat hfRatio, ALfloat cw, ALuint frequency, ALreverbState *State)
{
@ -975,12 +957,9 @@ static ALvoid ALreverbState_update(ALreverbState *State, const ALCdevice *Device
UpdateModulator(props->Reverb.ModulationTime, props->Reverb.ModulationDepth,
frequency, State);
// Update the initial effect delay.
// Update the main effect delay.
UpdateDelayLine(props->Reverb.ReflectionsDelay, props->Reverb.LateReverbDelay,
frequency, State);
// Update the decorrelator.
UpdateDecorrelator(props->Reverb.Density, frequency, State);
props->Reverb.Density, frequency, State);
// Update the early lines.
UpdateEarlyLines(props->Reverb.LateReverbDelay, State);
@ -1112,10 +1091,10 @@ static ALvoid EarlyReflection(ALreverbState *State, ALuint todo, ALfloat (*restr
ALuint offset = State->Offset+i;
/* Obtain the first reflection samples from the main delay line. */
f[0] = DelayLineOut(&State->Delay, (offset-State->DelayTap[0])*4 + 0);
f[1] = DelayLineOut(&State->Delay, (offset-State->EarlyDecoTap[0])*4 + 1);
f[2] = DelayLineOut(&State->Delay, (offset-State->EarlyDecoTap[1])*4 + 2);
f[3] = DelayLineOut(&State->Delay, (offset-State->EarlyDecoTap[2])*4 + 3);
f[0] = DelayLineOut(&State->Delay, (offset-State->EarlyDelayTap[0])*4 + 0);
f[1] = DelayLineOut(&State->Delay, (offset-State->EarlyDelayTap[1])*4 + 1);
f[2] = DelayLineOut(&State->Delay, (offset-State->EarlyDelayTap[2])*4 + 2);
f[3] = DelayLineOut(&State->Delay, (offset-State->EarlyDelayTap[3])*4 + 3);
/* The following uses a lossless scattering junction from waveguide
* theory. It actually amounts to a householder mixing matrix, which
@ -1201,10 +1180,10 @@ static ALvoid LateReverb(ALreverbState *State, ALuint todo, ALfloat (*restrict o
for(i = 0;i < tmp_todo;i++)
{
/* Obtain four decorrelated input samples. */
f[0] = DelayLineOut(&State->Delay, (offset-State->DelayTap[1])*4 + 0) * State->Late.DensityGain;
f[1] = DelayLineOut(&State->Delay, (offset-State->LateDecoTap[0])*4 + 1) * State->Late.DensityGain;
f[2] = DelayLineOut(&State->Delay, (offset-State->LateDecoTap[1])*4 + 2) * State->Late.DensityGain;
f[3] = DelayLineOut(&State->Delay, (offset-State->LateDecoTap[2])*4 + 3) * State->Late.DensityGain;
f[0] = DelayLineOut(&State->Delay, (offset-State->LateDelayTap[0])*4 + 0) * State->Late.DensityGain;
f[1] = DelayLineOut(&State->Delay, (offset-State->LateDelayTap[1])*4 + 1) * State->Late.DensityGain;
f[2] = DelayLineOut(&State->Delay, (offset-State->LateDelayTap[2])*4 + 2) * State->Late.DensityGain;
f[3] = DelayLineOut(&State->Delay, (offset-State->LateDelayTap[3])*4 + 3) * State->Late.DensityGain;
/* Add the decayed results of the cyclical delay lines, then pass
* the results through the low-pass filters.
@ -1313,7 +1292,7 @@ static ALvoid EAXEcho(ALreverbState *State, ALuint todo, ALfloat (*restrict late
// Mix the energy-attenuated input with the output and pass it through
// the echo low-pass filter.
feed += DelayLineOut(&State->Delay, (offset-State->DelayTap[1])*4 + c) *
feed += DelayLineOut(&State->Delay, (offset-State->LateDelayTap[0])*4 + c) *
State->Echo.DensityGain;
feed = lerp(feed, State->Echo.LpSample[c], State->Echo.LpCoeff);
State->Echo.LpSample[c] = feed;