diff options
| -rw-r--r-- | Alc/effects/reverb.c | 867 |
1 files changed, 442 insertions, 425 deletions
diff --git a/Alc/effects/reverb.c b/Alc/effects/reverb.c index 7f4139c6..7911e43b 100644 --- a/Alc/effects/reverb.c +++ b/Alc/effects/reverb.c @@ -162,12 +162,29 @@ typedef struct ALreverbState { ALfloat EarlySamples[MAX_UPDATE_SAMPLES][4]; } ALreverbState; +static ALvoid ALreverbState_Destruct(ALreverbState *State) +{ + free(State->SampleBuffer); + State->SampleBuffer = NULL; +} + +static ALboolean ALreverbState_deviceUpdate(ALreverbState *State, ALCdevice *Device); +static ALvoid ALreverbState_update(ALreverbState *State, const ALCdevice *Device, const ALeffectslot *Slot); +static ALvoid ALreverbState_processStandard(ALreverbState *State, ALuint SamplesToDo, const ALfloat *restrict SamplesIn, ALfloat (*restrict SamplesOut)[BUFFERSIZE], ALuint NumChannels); +static ALvoid ALreverbState_processEax(ALreverbState *State, ALuint SamplesToDo, const ALfloat *restrict SamplesIn, ALfloat (*restrict SamplesOut)[BUFFERSIZE], ALuint NumChannels); +static ALvoid ALreverbState_process(ALreverbState *State, ALuint SamplesToDo, const ALfloat (*restrict SamplesIn)[BUFFERSIZE], ALfloat (*restrict SamplesOut)[BUFFERSIZE], ALuint NumChannels); +DECLARE_DEFAULT_ALLOCATORS(ALreverbState) + +DEFINE_ALEFFECTSTATE_VTABLE(ALreverbState); + /* This is a user config option for modifying the overall output of the reverb * effect. */ ALfloat ReverbBoost = 1.0f; -/* Specifies whether to use a standard reverb effect in place of EAX reverb */ +/* Specifies whether to use a standard reverb effect in place of EAX reverb (no + * high-pass, modulation, or echo). + */ ALboolean EmulateEAXReverb = AL_FALSE; /* This coefficient is used to define the maximum frequency range controlled @@ -221,421 +238,9 @@ static const ALfloat LATE_LINE_LENGTH[4] = static const ALfloat LATE_LINE_MULTIPLIER = 4.0f; -// Basic delay line input/output routines. -static inline ALfloat DelayLineOut(DelayLine *Delay, ALuint offset) -{ - return Delay->Line[offset&Delay->Mask]; -} - -static inline ALvoid DelayLineIn(DelayLine *Delay, ALuint offset, ALfloat in) -{ - Delay->Line[offset&Delay->Mask] = in; -} - -// Given an input sample, this function produces modulation for the late -// reverb. -static inline ALfloat EAXModulation(ALreverbState *State, ALuint offset, ALfloat in) -{ - ALfloat sinus, frac, fdelay; - ALfloat out0, out1; - ALuint delay; - - // Calculate the sinus rythm (dependent on modulation time and the - // sampling rate). The center of the sinus is moved to reduce the delay - // of the effect when the time or depth are low. - sinus = 1.0f - cosf(F_TAU * State->Mod.Index / State->Mod.Range); - - // Step the modulation index forward, keeping it bound to its range. - State->Mod.Index = (State->Mod.Index + 1) % State->Mod.Range; - - // The depth determines the range over which to read the input samples - // from, so it must be filtered to reduce the distortion caused by even - // small parameter changes. - State->Mod.Filter = lerp(State->Mod.Filter, State->Mod.Depth, - State->Mod.Coeff); - - // Calculate the read offset and fraction between it and the next sample. - frac = modff(State->Mod.Filter*sinus + 1.0f, &fdelay); - delay = fastf2u(fdelay); - - // Get the two samples crossed by the offset, and feed the delay line - // with the next input sample. - out0 = DelayLineOut(&State->Mod.Delay, offset - delay); - out1 = DelayLineOut(&State->Mod.Delay, offset - delay - 1); - DelayLineIn(&State->Mod.Delay, offset, in); - - // The output is obtained by linearly interpolating the two samples that - // were acquired above. - return lerp(out0, out1, frac); -} - -// Given some input sample, this function produces four-channel outputs for the -// early reflections. -static inline ALvoid EarlyReflection(ALreverbState *State, ALuint todo, ALfloat (*restrict out)[4]) -{ - ALfloat d[4], v, f[4]; - ALuint i; - - for(i = 0;i < todo;i++) - { - ALuint offset = State->Offset+i; - - // Obtain the decayed results of each early delay line. - d[0] = DelayLineOut(&State->Early.Delay[0], offset-State->Early.Offset[0]) * State->Early.Coeff[0]; - d[1] = DelayLineOut(&State->Early.Delay[1], offset-State->Early.Offset[1]) * State->Early.Coeff[1]; - d[2] = DelayLineOut(&State->Early.Delay[2], offset-State->Early.Offset[2]) * State->Early.Coeff[2]; - d[3] = DelayLineOut(&State->Early.Delay[3], offset-State->Early.Offset[3]) * State->Early.Coeff[3]; - - /* The following uses a lossless scattering junction from waveguide - * theory. It actually amounts to a householder mixing matrix, which - * will produce a maximally diffuse response, and means this can - * probably be considered a simple feed-back delay network (FDN). - * N - * --- - * \ - * v = 2/N / d_i - * --- - * i=1 - */ - v = (d[0] + d[1] + d[2] + d[3]) * 0.5f; - // The junction is loaded with the input here. - v += DelayLineOut(&State->Delay, offset-State->DelayTap[0]); - - // Calculate the feed values for the delay lines. - f[0] = v - d[0]; - f[1] = v - d[1]; - f[2] = v - d[2]; - f[3] = v - d[3]; - - // Re-feed the delay lines. - DelayLineIn(&State->Early.Delay[0], offset, f[0]); - DelayLineIn(&State->Early.Delay[1], offset, f[1]); - DelayLineIn(&State->Early.Delay[2], offset, f[2]); - DelayLineIn(&State->Early.Delay[3], offset, f[3]); - - // Output the results of the junction for all four channels. - out[i][0] = State->Early.Gain * f[0]; - out[i][1] = State->Early.Gain * f[1]; - out[i][2] = State->Early.Gain * f[2]; - out[i][3] = State->Early.Gain * f[3]; - } -} - -// Basic attenuated all-pass input/output routine. -static inline ALfloat AllpassInOut(DelayLine *Delay, ALuint outOffset, ALuint inOffset, ALfloat in, ALfloat feedCoeff, ALfloat coeff) -{ - ALfloat out, feed; - - out = DelayLineOut(Delay, outOffset); - feed = feedCoeff * in; - DelayLineIn(Delay, inOffset, (feedCoeff * (out - feed)) + in); - - // The time-based attenuation is only applied to the delay output to - // keep it from affecting the feed-back path (which is already controlled - // by the all-pass feed coefficient). - return (coeff * out) - feed; -} - -// All-pass input/output routine for late reverb. -static inline ALfloat LateAllPassInOut(ALreverbState *State, ALuint offset, ALuint index, ALfloat in) -{ - return AllpassInOut(&State->Late.ApDelay[index], - offset - State->Late.ApOffset[index], - offset, in, State->Late.ApFeedCoeff, - State->Late.ApCoeff[index]); -} - -// Low-pass filter input/output routine for late reverb. -static inline ALfloat LateLowPassInOut(ALreverbState *State, ALuint index, ALfloat in) -{ - in = lerp(in, State->Late.LpSample[index], State->Late.LpCoeff[index]); - State->Late.LpSample[index] = in; - return in; -} - -// Given four decorrelated input samples, this function produces four-channel -// output for the late reverb. -static inline ALvoid LateReverb(ALreverbState *State, ALuint todo, ALfloat (*restrict out)[4]) -{ - ALfloat d[4], f[4]; - ALuint i; - - for(i = 0;i < todo;i++) - { - ALuint offset = State->Offset+i; - - f[0] = DelayLineOut(&State->Decorrelator, offset); - f[1] = DelayLineOut(&State->Decorrelator, offset-State->DecoTap[0]); - f[2] = DelayLineOut(&State->Decorrelator, offset-State->DecoTap[1]); - f[3] = DelayLineOut(&State->Decorrelator, offset-State->DecoTap[2]); - - // Obtain the decayed results of the cyclical delay lines, and add the - // corresponding input channels. Then pass the results through the - // low-pass filters. - f[0] += DelayLineOut(&State->Late.Delay[0], offset-State->Late.Offset[0]) * State->Late.Coeff[0]; - f[1] += DelayLineOut(&State->Late.Delay[1], offset-State->Late.Offset[1]) * State->Late.Coeff[1]; - f[2] += DelayLineOut(&State->Late.Delay[2], offset-State->Late.Offset[2]) * State->Late.Coeff[2]; - f[3] += DelayLineOut(&State->Late.Delay[3], offset-State->Late.Offset[3]) * State->Late.Coeff[3]; - - // This is where the feed-back cycles from line 0 to 1 to 3 to 2 and - // back to 0. - d[0] = LateLowPassInOut(State, 2, f[2]); - d[1] = LateLowPassInOut(State, 0, f[0]); - d[2] = LateLowPassInOut(State, 3, f[3]); - d[3] = LateLowPassInOut(State, 1, f[1]); - - // To help increase diffusion, run each line through an all-pass filter. - // When there is no diffusion, the shortest all-pass filter will feed - // the shortest delay line. - d[0] = LateAllPassInOut(State, offset, 0, d[0]); - d[1] = LateAllPassInOut(State, offset, 1, d[1]); - d[2] = LateAllPassInOut(State, offset, 2, d[2]); - d[3] = LateAllPassInOut(State, offset, 3, d[3]); - - /* Late reverb is done with a modified feed-back delay network (FDN) - * topology. Four input lines are each fed through their own all-pass - * filter and then into the mixing matrix. The four outputs of the - * mixing matrix are then cycled back to the inputs. Each output feeds - * a different input to form a circlular feed cycle. - * - * The mixing matrix used is a 4D skew-symmetric rotation matrix - * derived using a single unitary rotational parameter: - * - * [ d, a, b, c ] 1 = a^2 + b^2 + c^2 + d^2 - * [ -a, d, c, -b ] - * [ -b, -c, d, a ] - * [ -c, b, -a, d ] - * - * The rotation is constructed from the effect's diffusion parameter, - * yielding: 1 = x^2 + 3 y^2; where a, b, and c are the coefficient y - * with differing signs, and d is the coefficient x. The matrix is - * thus: - * - * [ x, y, -y, y ] n = sqrt(matrix_order - 1) - * [ -y, x, y, y ] t = diffusion_parameter * atan(n) - * [ y, -y, x, y ] x = cos(t) - * [ -y, -y, -y, x ] y = sin(t) / n - * - * To reduce the number of multiplies, the x coefficient is applied - * with the cyclical delay line coefficients. Thus only the y - * coefficient is applied when mixing, and is modified to be: y / x. - */ - f[0] = d[0] + (State->Late.MixCoeff * ( d[1] + -d[2] + d[3])); - f[1] = d[1] + (State->Late.MixCoeff * (-d[0] + d[2] + d[3])); - f[2] = d[2] + (State->Late.MixCoeff * ( d[0] + -d[1] + d[3])); - f[3] = d[3] + (State->Late.MixCoeff * (-d[0] + -d[1] + -d[2] )); - - // Output the results of the matrix for all four channels, attenuated by - // the late reverb gain (which is attenuated by the 'x' mix coefficient). - // Mix early reflections and late reverb. - out[i][0] = State->Late.Gain * f[0]; - out[i][1] = State->Late.Gain * f[1]; - out[i][2] = State->Late.Gain * f[2]; - out[i][3] = State->Late.Gain * f[3]; - - // Re-feed the cyclical delay lines. - DelayLineIn(&State->Late.Delay[0], offset, f[0]); - DelayLineIn(&State->Late.Delay[1], offset, f[1]); - DelayLineIn(&State->Late.Delay[2], offset, f[2]); - DelayLineIn(&State->Late.Delay[3], offset, f[3]); - } -} - -// Given an input sample, this function mixes echo into the four-channel late -// reverb. -static inline ALvoid EAXEcho(ALreverbState *State, ALuint todo, ALfloat (*restrict late)[4]) -{ - ALfloat out, feed; - ALuint i; - - for(i = 0;i < todo;i++) - { - ALuint offset = State->Offset+i; - - // Get the latest attenuated echo sample for output. - feed = DelayLineOut(&State->Echo.Delay, offset-State->Echo.Offset) * - State->Echo.Coeff; - - // Mix the output into the late reverb channels. - out = State->Echo.MixCoeff * feed; - late[i][0] += out; - late[i][1] += out; - late[i][2] += out; - late[i][3] += out; - - // 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]) * - State->Echo.DensityGain; - feed = lerp(feed, State->Echo.LpSample, State->Echo.LpCoeff); - State->Echo.LpSample = feed; - - // Then the echo all-pass filter. - feed = AllpassInOut(&State->Echo.ApDelay, offset-State->Echo.ApOffset, - offset, feed, State->Echo.ApFeedCoeff, - State->Echo.ApCoeff); - - // Feed the delay with the mixed and filtered sample. - DelayLineIn(&State->Echo.Delay, offset, feed); - } -} - -// Perform the non-EAX reverb pass on a given input sample, resulting in -// four-channel output. -static inline ALvoid VerbPass(ALreverbState *State, ALuint todo, const ALfloat *in, ALfloat (*restrict early)[4], ALfloat (*restrict late)[4]) -{ - ALuint i; - - // Low-pass filter the incoming samples. - for(i = 0;i < todo;i++) - DelayLineIn(&State->Delay, State->Offset+i, - ALfilterState_processSingle(&State->LpFilter, in[i]) - ); - - // Calculate the early reflection from the first delay tap. - EarlyReflection(State, todo, early); - - // Feed the decorrelator from the energy-attenuated output of the second - // delay tap. - for(i = 0;i < todo;i++) - { - ALuint offset = State->Offset+i; - ALfloat sample = DelayLineOut(&State->Delay, offset - State->DelayTap[1]) * - State->Late.DensityGain; - DelayLineIn(&State->Decorrelator, offset, sample); - } - - // Calculate the late reverb from the decorrelator taps. - LateReverb(State, todo, late); - - // Step all delays forward one sample. - State->Offset += todo; -} - -// Perform the EAX reverb pass on a given input sample, resulting in four- -// channel output. -static inline ALvoid EAXVerbPass(ALreverbState *State, ALuint todo, const ALfloat *input, ALfloat (*restrict early)[4], ALfloat (*restrict late)[4]) -{ - ALuint i; - - // Band-pass and modulate the incoming samples. - for(i = 0;i < todo;i++) - { - ALfloat sample = input[i]; - sample = ALfilterState_processSingle(&State->LpFilter, sample); - sample = ALfilterState_processSingle(&State->HpFilter, sample); - - // Perform any modulation on the input. - sample = EAXModulation(State, State->Offset+i, sample); - - // Feed the initial delay line. - DelayLineIn(&State->Delay, State->Offset+i, sample); - } - - // Calculate the early reflection from the first delay tap. - EarlyReflection(State, todo, early); - - // Feed the decorrelator from the energy-attenuated output of the second - // delay tap. - for(i = 0;i < todo;i++) - { - ALuint offset = State->Offset+i; - ALfloat sample = DelayLineOut(&State->Delay, offset - State->DelayTap[1]) * - State->Late.DensityGain; - DelayLineIn(&State->Decorrelator, offset, sample); - } - - // Calculate the late reverb from the decorrelator taps. - LateReverb(State, todo, late); - - // Calculate and mix in any echo. - EAXEcho(State, todo, late); - - // Step all delays forward. - State->Offset += todo; -} - -static ALvoid ALreverbState_processStandard(ALreverbState *State, ALuint SamplesToDo, const ALfloat *restrict SamplesIn, ALfloat (*restrict SamplesOut)[BUFFERSIZE], ALuint NumChannels) -{ - ALfloat (*restrict early)[4] = State->EarlySamples; - ALfloat (*restrict late)[4] = State->ReverbSamples; - ALuint index, c, i, l; - ALfloat gain; - - /* Process reverb for these samples. */ - for(index = 0;index < SamplesToDo;) - { - ALuint todo = minu(SamplesToDo-index, MAX_UPDATE_SAMPLES); - - VerbPass(State, todo, &SamplesIn[index], early, late); - - for(l = 0;l < 4;l++) - { - for(c = 0;c < NumChannels;c++) - { - gain = State->Early.PanGain[l][c]; - if(fabsf(gain) > GAIN_SILENCE_THRESHOLD) - { - for(i = 0;i < todo;i++) - SamplesOut[c][index+i] += gain*early[i][l]; - } - gain = State->Late.PanGain[l][c]; - if(fabsf(gain) > GAIN_SILENCE_THRESHOLD) - { - for(i = 0;i < todo;i++) - SamplesOut[c][index+i] += gain*late[i][l]; - } - } - } - - index += todo; - } -} - -static ALvoid ALreverbState_processEax(ALreverbState *State, ALuint SamplesToDo, const ALfloat *restrict SamplesIn, ALfloat (*restrict SamplesOut)[BUFFERSIZE], ALuint NumChannels) -{ - ALfloat (*restrict early)[4] = State->EarlySamples; - ALfloat (*restrict late)[4] = State->ReverbSamples; - ALuint index, c, i, l; - ALfloat gain; - - /* Process reverb for these samples. */ - for(index = 0;index < SamplesToDo;) - { - ALuint todo = minu(SamplesToDo-index, MAX_UPDATE_SAMPLES); - - EAXVerbPass(State, todo, &SamplesIn[index], early, late); - - for(l = 0;l < 4;l++) - { - for(c = 0;c < NumChannels;c++) - { - gain = State->Early.PanGain[l][c]; - if(fabsf(gain) > GAIN_SILENCE_THRESHOLD) - { - for(i = 0;i < todo;i++) - SamplesOut[c][index+i] += gain*early[i][l]; - } - gain = State->Late.PanGain[l][c]; - if(fabsf(gain) > GAIN_SILENCE_THRESHOLD) - { - for(i = 0;i < todo;i++) - SamplesOut[c][index+i] += gain*late[i][l]; - } - } - } - - index += todo; - } -} - -static ALvoid ALreverbState_process(ALreverbState *State, ALuint SamplesToDo, const ALfloat (*restrict SamplesIn)[BUFFERSIZE], ALfloat (*restrict SamplesOut)[BUFFERSIZE], ALuint NumChannels) -{ - if(State->IsEax) - ALreverbState_processEax(State, SamplesToDo, SamplesIn[0], SamplesOut, NumChannels); - else - ALreverbState_processStandard(State, SamplesToDo, SamplesIn[0], SamplesOut, NumChannels); -} +/************************************** + * Device Update * + **************************************/ // Given the allocated sample buffer, this function updates each delay line // offset. @@ -772,10 +377,8 @@ static ALboolean ALreverbState_deviceUpdate(ALreverbState *State, ALCdevice *Dev // so their offsets only need to be calculated once. for(index = 0;index < 4;index++) { - State->Early.Offset[index] = fastf2u(EARLY_LINE_LENGTH[index] * - frequency); - State->Late.ApOffset[index] = fastf2u(ALLPASS_LINE_LENGTH[index] * - frequency); + State->Early.Offset[index] = fastf2u(EARLY_LINE_LENGTH[index] * frequency); + State->Late.ApOffset[index] = fastf2u(ALLPASS_LINE_LENGTH[index] * frequency); } // The echo all-pass filter line length is static, so its offset only @@ -785,6 +388,10 @@ static ALboolean ALreverbState_deviceUpdate(ALreverbState *State, ALCdevice *Dev return AL_TRUE; } +/************************************** + * Effect Update * + **************************************/ + // Calculate a decay coefficient given the length of each cycle and the time // until the decay reaches -60 dB. static inline ALfloat CalcDecayCoeff(ALfloat length, ALfloat decayTime) @@ -1285,15 +892,425 @@ static ALvoid ALreverbState_update(ALreverbState *State, const ALCdevice *Device } -static ALvoid ALreverbState_Destruct(ALreverbState *State) +/************************************** + * Effect Processing * + **************************************/ + +// Basic delay line input/output routines. +static inline ALfloat DelayLineOut(DelayLine *Delay, ALuint offset) { - free(State->SampleBuffer); - State->SampleBuffer = NULL; + return Delay->Line[offset&Delay->Mask]; } -DECLARE_DEFAULT_ALLOCATORS(ALreverbState) +static inline ALvoid DelayLineIn(DelayLine *Delay, ALuint offset, ALfloat in) +{ + Delay->Line[offset&Delay->Mask] = in; +} -DEFINE_ALEFFECTSTATE_VTABLE(ALreverbState); +// Given an input sample, this function produces modulation for the late +// reverb. +static inline ALfloat EAXModulation(ALreverbState *State, ALuint offset, ALfloat in) +{ + ALfloat sinus, frac, fdelay; + ALfloat out0, out1; + ALuint delay; + + // Calculate the sinus rythm (dependent on modulation time and the + // sampling rate). The center of the sinus is moved to reduce the delay + // of the effect when the time or depth are low. + sinus = 1.0f - cosf(F_TAU * State->Mod.Index / State->Mod.Range); + + // Step the modulation index forward, keeping it bound to its range. + State->Mod.Index = (State->Mod.Index + 1) % State->Mod.Range; + + // The depth determines the range over which to read the input samples + // from, so it must be filtered to reduce the distortion caused by even + // small parameter changes. + State->Mod.Filter = lerp(State->Mod.Filter, State->Mod.Depth, + State->Mod.Coeff); + + // Calculate the read offset and fraction between it and the next sample. + frac = modff(State->Mod.Filter*sinus + 1.0f, &fdelay); + delay = fastf2u(fdelay); + + // Get the two samples crossed by the offset, and feed the delay line + // with the next input sample. + out0 = DelayLineOut(&State->Mod.Delay, offset - delay); + out1 = DelayLineOut(&State->Mod.Delay, offset - delay - 1); + DelayLineIn(&State->Mod.Delay, offset, in); + + // The output is obtained by linearly interpolating the two samples that + // were acquired above. + return lerp(out0, out1, frac); +} + +// Given some input sample, this function produces four-channel outputs for the +// early reflections. +static inline ALvoid EarlyReflection(ALreverbState *State, ALuint todo, ALfloat (*restrict out)[4]) +{ + ALfloat d[4], v, f[4]; + ALuint i; + + for(i = 0;i < todo;i++) + { + ALuint offset = State->Offset+i; + + // Obtain the decayed results of each early delay line. + d[0] = DelayLineOut(&State->Early.Delay[0], offset-State->Early.Offset[0]) * State->Early.Coeff[0]; + d[1] = DelayLineOut(&State->Early.Delay[1], offset-State->Early.Offset[1]) * State->Early.Coeff[1]; + d[2] = DelayLineOut(&State->Early.Delay[2], offset-State->Early.Offset[2]) * State->Early.Coeff[2]; + d[3] = DelayLineOut(&State->Early.Delay[3], offset-State->Early.Offset[3]) * State->Early.Coeff[3]; + + /* The following uses a lossless scattering junction from waveguide + * theory. It actually amounts to a householder mixing matrix, which + * will produce a maximally diffuse response, and means this can + * probably be considered a simple feed-back delay network (FDN). + * N + * --- + * \ + * v = 2/N / d_i + * --- + * i=1 + */ + v = (d[0] + d[1] + d[2] + d[3]) * 0.5f; + // The junction is loaded with the input here. + v += DelayLineOut(&State->Delay, offset-State->DelayTap[0]); + + // Calculate the feed values for the delay lines. + f[0] = v - d[0]; + f[1] = v - d[1]; + f[2] = v - d[2]; + f[3] = v - d[3]; + + // Re-feed the delay lines. + DelayLineIn(&State->Early.Delay[0], offset, f[0]); + DelayLineIn(&State->Early.Delay[1], offset, f[1]); + DelayLineIn(&State->Early.Delay[2], offset, f[2]); + DelayLineIn(&State->Early.Delay[3], offset, f[3]); + + // Output the results of the junction for all four channels. + out[i][0] = State->Early.Gain * f[0]; + out[i][1] = State->Early.Gain * f[1]; + out[i][2] = State->Early.Gain * f[2]; + out[i][3] = State->Early.Gain * f[3]; + } +} + +// Basic attenuated all-pass input/output routine. +static inline ALfloat AllpassInOut(DelayLine *Delay, ALuint outOffset, ALuint inOffset, ALfloat in, ALfloat feedCoeff, ALfloat coeff) +{ + ALfloat out, feed; + + out = DelayLineOut(Delay, outOffset); + feed = feedCoeff * in; + DelayLineIn(Delay, inOffset, (feedCoeff * (out - feed)) + in); + + // The time-based attenuation is only applied to the delay output to + // keep it from affecting the feed-back path (which is already controlled + // by the all-pass feed coefficient). + return (coeff * out) - feed; +} + +// All-pass input/output routine for late reverb. +static inline ALfloat LateAllPassInOut(ALreverbState *State, ALuint offset, ALuint index, ALfloat in) +{ + return AllpassInOut(&State->Late.ApDelay[index], + offset - State->Late.ApOffset[index], + offset, in, State->Late.ApFeedCoeff, + State->Late.ApCoeff[index]); +} + +// Low-pass filter input/output routine for late reverb. +static inline ALfloat LateLowPassInOut(ALreverbState *State, ALuint index, ALfloat in) +{ + in = lerp(in, State->Late.LpSample[index], State->Late.LpCoeff[index]); + State->Late.LpSample[index] = in; + return in; +} + +// Given four decorrelated input samples, this function produces four-channel +// output for the late reverb. +static inline ALvoid LateReverb(ALreverbState *State, ALuint todo, ALfloat (*restrict out)[4]) +{ + ALfloat d[4], f[4]; + ALuint i; + + for(i = 0;i < todo;i++) + { + ALuint offset = State->Offset+i; + + f[0] = DelayLineOut(&State->Decorrelator, offset); + f[1] = DelayLineOut(&State->Decorrelator, offset-State->DecoTap[0]); + f[2] = DelayLineOut(&State->Decorrelator, offset-State->DecoTap[1]); + f[3] = DelayLineOut(&State->Decorrelator, offset-State->DecoTap[2]); + + // Obtain the decayed results of the cyclical delay lines, and add the + // corresponding input channels. Then pass the results through the + // low-pass filters. + f[0] += DelayLineOut(&State->Late.Delay[0], offset-State->Late.Offset[0]) * State->Late.Coeff[0]; + f[1] += DelayLineOut(&State->Late.Delay[1], offset-State->Late.Offset[1]) * State->Late.Coeff[1]; + f[2] += DelayLineOut(&State->Late.Delay[2], offset-State->Late.Offset[2]) * State->Late.Coeff[2]; + f[3] += DelayLineOut(&State->Late.Delay[3], offset-State->Late.Offset[3]) * State->Late.Coeff[3]; + + // This is where the feed-back cycles from line 0 to 1 to 3 to 2 and + // back to 0. + d[0] = LateLowPassInOut(State, 2, f[2]); + d[1] = LateLowPassInOut(State, 0, f[0]); + d[2] = LateLowPassInOut(State, 3, f[3]); + d[3] = LateLowPassInOut(State, 1, f[1]); + + // To help increase diffusion, run each line through an all-pass filter. + // When there is no diffusion, the shortest all-pass filter will feed + // the shortest delay line. + d[0] = LateAllPassInOut(State, offset, 0, d[0]); + d[1] = LateAllPassInOut(State, offset, 1, d[1]); + d[2] = LateAllPassInOut(State, offset, 2, d[2]); + d[3] = LateAllPassInOut(State, offset, 3, d[3]); + + /* Late reverb is done with a modified feed-back delay network (FDN) + * topology. Four input lines are each fed through their own all-pass + * filter and then into the mixing matrix. The four outputs of the + * mixing matrix are then cycled back to the inputs. Each output feeds + * a different input to form a circlular feed cycle. + * + * The mixing matrix used is a 4D skew-symmetric rotation matrix + * derived using a single unitary rotational parameter: + * + * [ d, a, b, c ] 1 = a^2 + b^2 + c^2 + d^2 + * [ -a, d, c, -b ] + * [ -b, -c, d, a ] + * [ -c, b, -a, d ] + * + * The rotation is constructed from the effect's diffusion parameter, + * yielding: 1 = x^2 + 3 y^2; where a, b, and c are the coefficient y + * with differing signs, and d is the coefficient x. The matrix is + * thus: + * + * [ x, y, -y, y ] n = sqrt(matrix_order - 1) + * [ -y, x, y, y ] t = diffusion_parameter * atan(n) + * [ y, -y, x, y ] x = cos(t) + * [ -y, -y, -y, x ] y = sin(t) / n + * + * To reduce the number of multiplies, the x coefficient is applied + * with the cyclical delay line coefficients. Thus only the y + * coefficient is applied when mixing, and is modified to be: y / x. + */ + f[0] = d[0] + (State->Late.MixCoeff * ( d[1] + -d[2] + d[3])); + f[1] = d[1] + (State->Late.MixCoeff * (-d[0] + d[2] + d[3])); + f[2] = d[2] + (State->Late.MixCoeff * ( d[0] + -d[1] + d[3])); + f[3] = d[3] + (State->Late.MixCoeff * (-d[0] + -d[1] + -d[2] )); + + // Output the results of the matrix for all four channels, attenuated by + // the late reverb gain (which is attenuated by the 'x' mix coefficient). + // Mix early reflections and late reverb. + out[i][0] = State->Late.Gain * f[0]; + out[i][1] = State->Late.Gain * f[1]; + out[i][2] = State->Late.Gain * f[2]; + out[i][3] = State->Late.Gain * f[3]; + + // Re-feed the cyclical delay lines. + DelayLineIn(&State->Late.Delay[0], offset, f[0]); + DelayLineIn(&State->Late.Delay[1], offset, f[1]); + DelayLineIn(&State->Late.Delay[2], offset, f[2]); + DelayLineIn(&State->Late.Delay[3], offset, f[3]); + } +} + +// Given an input sample, this function mixes echo into the four-channel late +// reverb. +static inline ALvoid EAXEcho(ALreverbState *State, ALuint todo, ALfloat (*restrict late)[4]) +{ + ALfloat out, feed; + ALuint i; + + for(i = 0;i < todo;i++) + { + ALuint offset = State->Offset+i; + + // Get the latest attenuated echo sample for output. + feed = DelayLineOut(&State->Echo.Delay, offset-State->Echo.Offset) * + State->Echo.Coeff; + + // Mix the output into the late reverb channels. + out = State->Echo.MixCoeff * feed; + late[i][0] += out; + late[i][1] += out; + late[i][2] += out; + late[i][3] += out; + + // 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]) * + State->Echo.DensityGain; + feed = lerp(feed, State->Echo.LpSample, State->Echo.LpCoeff); + State->Echo.LpSample = feed; + + // Then the echo all-pass filter. + feed = AllpassInOut(&State->Echo.ApDelay, offset-State->Echo.ApOffset, + offset, feed, State->Echo.ApFeedCoeff, + State->Echo.ApCoeff); + + // Feed the delay with the mixed and filtered sample. + DelayLineIn(&State->Echo.Delay, offset, feed); + } +} + +// Perform the non-EAX reverb pass on a given input sample, resulting in +// four-channel output. +static inline ALvoid VerbPass(ALreverbState *State, ALuint todo, const ALfloat *in, ALfloat (*restrict early)[4], ALfloat (*restrict late)[4]) +{ + ALuint i; + + // Low-pass filter the incoming samples. + for(i = 0;i < todo;i++) + DelayLineIn(&State->Delay, State->Offset+i, + ALfilterState_processSingle(&State->LpFilter, in[i]) + ); + + // Calculate the early reflection from the first delay tap. + EarlyReflection(State, todo, early); + + // Feed the decorrelator from the energy-attenuated output of the second + // delay tap. + for(i = 0;i < todo;i++) + { + ALuint offset = State->Offset+i; + ALfloat sample = DelayLineOut(&State->Delay, offset - State->DelayTap[1]) * + State->Late.DensityGain; + DelayLineIn(&State->Decorrelator, offset, sample); + } + + // Calculate the late reverb from the decorrelator taps. + LateReverb(State, todo, late); + + // Step all delays forward one sample. + State->Offset += todo; +} + +// Perform the EAX reverb pass on a given input sample, resulting in four- +// channel output. +static inline ALvoid EAXVerbPass(ALreverbState *State, ALuint todo, const ALfloat *input, ALfloat (*restrict early)[4], ALfloat (*restrict late)[4]) +{ + ALuint i; + + // Band-pass and modulate the incoming samples. + for(i = 0;i < todo;i++) + { + ALfloat sample = input[i]; + sample = ALfilterState_processSingle(&State->LpFilter, sample); + sample = ALfilterState_processSingle(&State->HpFilter, sample); + + // Perform any modulation on the input. + sample = EAXModulation(State, State->Offset+i, sample); + + // Feed the initial delay line. + DelayLineIn(&State->Delay, State->Offset+i, sample); + } + + // Calculate the early reflection from the first delay tap. + EarlyReflection(State, todo, early); + + // Feed the decorrelator from the energy-attenuated output of the second + // delay tap. + for(i = 0;i < todo;i++) + { + ALuint offset = State->Offset+i; + ALfloat sample = DelayLineOut(&State->Delay, offset - State->DelayTap[1]) * + State->Late.DensityGain; + DelayLineIn(&State->Decorrelator, offset, sample); + } + + // Calculate the late reverb from the decorrelator taps. + LateReverb(State, todo, late); + + // Calculate and mix in any echo. + EAXEcho(State, todo, late); + + // Step all delays forward. + State->Offset += todo; +} + +static ALvoid ALreverbState_processStandard(ALreverbState *State, ALuint SamplesToDo, const ALfloat *restrict SamplesIn, ALfloat (*restrict SamplesOut)[BUFFERSIZE], ALuint NumChannels) +{ + ALfloat (*restrict early)[4] = State->EarlySamples; + ALfloat (*restrict late)[4] = State->ReverbSamples; + ALuint index, c, i, l; + ALfloat gain; + + /* Process reverb for these samples. */ + for(index = 0;index < SamplesToDo;) + { + ALuint todo = minu(SamplesToDo-index, MAX_UPDATE_SAMPLES); + + VerbPass(State, todo, &SamplesIn[index], early, late); + + for(l = 0;l < 4;l++) + { + for(c = 0;c < NumChannels;c++) + { + gain = State->Early.PanGain[l][c]; + if(fabsf(gain) > GAIN_SILENCE_THRESHOLD) + { + for(i = 0;i < todo;i++) + SamplesOut[c][index+i] += gain*early[i][l]; + } + gain = State->Late.PanGain[l][c]; + if(fabsf(gain) > GAIN_SILENCE_THRESHOLD) + { + for(i = 0;i < todo;i++) + SamplesOut[c][index+i] += gain*late[i][l]; + } + } + } + + index += todo; + } +} + +static ALvoid ALreverbState_processEax(ALreverbState *State, ALuint SamplesToDo, const ALfloat *restrict SamplesIn, ALfloat (*restrict SamplesOut)[BUFFERSIZE], ALuint NumChannels) +{ + ALfloat (*restrict early)[4] = State->EarlySamples; + ALfloat (*restrict late)[4] = State->ReverbSamples; + ALuint index, c, i, l; + ALfloat gain; + + /* Process reverb for these samples. */ + for(index = 0;index < SamplesToDo;) + { + ALuint todo = minu(SamplesToDo-index, MAX_UPDATE_SAMPLES); + + EAXVerbPass(State, todo, &SamplesIn[index], early, late); + + for(l = 0;l < 4;l++) + { + for(c = 0;c < NumChannels;c++) + { + gain = State->Early.PanGain[l][c]; + if(fabsf(gain) > GAIN_SILENCE_THRESHOLD) + { + for(i = 0;i < todo;i++) + SamplesOut[c][index+i] += gain*early[i][l]; + } + gain = State->Late.PanGain[l][c]; + if(fabsf(gain) > GAIN_SILENCE_THRESHOLD) + { + for(i = 0;i < todo;i++) + SamplesOut[c][index+i] += gain*late[i][l]; + } + } + } + + index += todo; + } +} + +static ALvoid ALreverbState_process(ALreverbState *State, ALuint SamplesToDo, const ALfloat (*restrict SamplesIn)[BUFFERSIZE], ALfloat (*restrict SamplesOut)[BUFFERSIZE], ALuint NumChannels) +{ + if(State->IsEax) + ALreverbState_processEax(State, SamplesToDo, SamplesIn[0], SamplesOut, NumChannels); + else + ALreverbState_processStandard(State, SamplesToDo, SamplesIn[0], SamplesOut, NumChannels); +} typedef struct ALreverbStateFactory { |