diff options
Diffstat (limited to 'Alc/effects')
| -rw-r--r-- | Alc/effects/reverb.c | 29 |
1 files changed, 19 insertions, 10 deletions
diff --git a/Alc/effects/reverb.c b/Alc/effects/reverb.c index 46883104..7dfa37d1 100644 --- a/Alc/effects/reverb.c +++ b/Alc/effects/reverb.c @@ -97,6 +97,7 @@ typedef struct ALreverbState { /* There are actually 4 decorrelator taps, but the first occurs at the late * reverb tap. */ + ALuint EarlyDecoTap[3]; ALuint LateDecoTap[3]; struct { @@ -222,6 +223,9 @@ static void ALreverbState_Construct(ALreverbState *state) 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; @@ -324,9 +328,10 @@ static const ALfloat MODULATION_FILTER_CONST = 100000.0f; // the echo effect. It uses the following line length (in seconds). static const ALfloat ECHO_ALLPASS_LENGTH = 0.0133f; -// Input into the late reverb is decorrelated between four channels. Their -// timings are dependent on a fraction and multiplier. See the -// UpdateDecorrelator() routine for the calculations involved. +/* 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. + */ static const ALfloat DECO_FRACTION = 0.15f; static const ALfloat DECO_MULTIPLIER = 2.0f; @@ -691,16 +696,20 @@ static ALvoid UpdateDecorrelator(ALfloat density, ALuint frequency, ALreverbStat ALuint index; ALfloat length; - /* The late reverb inputs are decorrelated to smooth 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. + /* 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]; } @@ -1104,9 +1113,9 @@ static ALvoid EarlyReflection(ALreverbState *State, ALuint todo, ALfloat (*restr /* 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->DelayTap[0])*4 + 1); - f[2] = DelayLineOut(&State->Delay, (offset-State->DelayTap[0])*4 + 2); - f[3] = DelayLineOut(&State->Delay, (offset-State->DelayTap[0])*4 + 3); + 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); /* The following uses a lossless scattering junction from waveguide * theory. It actually amounts to a householder mixing matrix, which |