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/*
* Copyright 2022 Phil Burk
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.jsyn.unitgen;
import com.jsyn.ports.UnitInputPort;
import com.jsyn.ports.UnitOutputPort;
/**
* Simulate reverberation in a room using a MultiTapDelay to model the early reflections
* and a PlateReverb to provide diffusion.
*
* @author (C) 2022 Phil Burk, Mobileer Inc
* @see MultiTapDelay
* @see PlateReverb
*/
public class RoomReverb extends Circuit {
private static final double SIZE_SCALER_MIN = 0.05;
private static final double SIZE_SCALER_MAX = 5.0;
private static final int[] kPositions = {
10, 197, 401,
521, 733, 1117,
1481, 2731, 4177,
6073, 7927, 9463};
// Gains based on attenuation in air after a pre-delay.
// See spreadsheet MiscSynthCalculations
private static final float[] kGains = {
0.1840f, -0.1543f, -0.1311f,
0.1205f, -0.1054f, -0.0859f,
-0.0731f, -0.0484f, 0.0347f,
0.0254f, 0.0201f, -0.0171f};
/**
* Mono input.
*/
public UnitInputPort input;
/** Pre-delay time in milliseconds. */
public UnitInputPort preDelayMillis;
/**
* Approximate time in seconds to decay by -60 dB.
*/
public UnitInputPort time;
/**
* Damping factor for the feedback filters.
* Must be <= 1.0. Default is 0.5.
*/
public UnitInputPort damping;
/**
* Amount of multi-tap delay in the output mix.
* Must be between 0.0 and 1.0.
*/
public UnitInputPort multiTap;
/**
* Amount of diffusion in the output mix.
* Must be between 0.0 and 1.0.
*/
public UnitInputPort diffusion;
/**
* Stereo output.
*/
public UnitOutputPort output;
private final PlateReverb mPlateReverb;
private final MultiTapDelay mMultiTapDelay;
private final RoomReverbMixer mRoomReverbMixer;
/**
* Construct a RoomReverb with a default size of 1.0.
*/
public RoomReverb() {
this(1.0);
}
/**
* The size parameter scales the allocated size.
* A value of 1.0 is the default.
* At low values the reverb will sound more metallic, like a comb filter.
* At larger values it will have longer echos.
*
* The size value will be clipped between 0.05 and 5.0.
*
* @param size adjust internal delay sizes
*/
public RoomReverb(double size) {
size = Math.max(SIZE_SCALER_MIN, Math.min(SIZE_SCALER_MAX, size));
int[] positions = new int[kPositions.length];
for (int tap = 0; tap < kPositions.length; tap++) {
positions[tap] = (int) (kPositions[tap] * size);
}
add(mMultiTapDelay = new MultiTapDelay(positions, kGains,
(int)(4000 * size) /* preDelayFrames */)); // roughly 80 msec max
add(mPlateReverb = new PlateReverb(1.0));
add(mRoomReverbMixer = new RoomReverbMixer());
mMultiTapDelay.output.connect(mPlateReverb.input);
mMultiTapDelay.output.connect(mRoomReverbMixer.multiTapInput);
mPlateReverb.output.connect(0, mRoomReverbMixer.diffusionInput, 0);
mPlateReverb.output.connect(1, mRoomReverbMixer.diffusionInput, 1);
// Assign ports
input = mMultiTapDelay.input;
addPort(input);
preDelayMillis = mMultiTapDelay.preDelayMillis;
addPort(preDelayMillis);
time = mPlateReverb.time;
addPort(time);
damping = mPlateReverb.damping;
addPort(damping);
multiTap = mRoomReverbMixer.multiTapGain;
addPort(multiTap);
diffusion = mRoomReverbMixer.diffusionGain;
addPort(diffusion);
output = mRoomReverbMixer.output;
addPort(output);
}
// Custom mixer for room reverb.
// This is faster than multiple small unit generators.
static class RoomReverbMixer extends UnitGenerator {
public UnitInputPort multiTapInput;
public UnitInputPort diffusionInput;
public UnitInputPort multiTapGain;
public UnitInputPort diffusionGain;
public UnitOutputPort output;
/* Define Unit Ports used by connect() and set(). */
public RoomReverbMixer() {
addPort(multiTapInput = new UnitInputPort("MultiTapInput"));
addPort(diffusionInput = new UnitInputPort(2,"DiffusionInput"));
addPort(multiTapGain = new UnitInputPort("MultiTap"));
addPort(diffusionGain = new UnitInputPort(2,"Diffusion"));
multiTapGain.setup(0.0, 1.0, 1.0);
diffusionGain.setup(0.0, 1.0, 1.0);
addPort(output = new UnitOutputPort(2,"Output"));
}
@Override
public void generate(int start, int limit) {
double[] multiTapInputs = multiTapInput.getValues();
double[] diffusionInputs0 = diffusionInput.getValues(0);
double[] diffusionInputs1 = diffusionInput.getValues(1);
double multiTapGainValue = multiTapGain.getValues()[start];
double diffusionGainValue = diffusionGain.getValues()[start];
double[] outputs0 = output.getValues(0);
double[] outputs1 = output.getValues(1);
for (int i = start; i < limit; i++) {
double multiTapScaled = multiTapInputs[i] * multiTapGainValue;
outputs0[i] = multiTapScaled + (diffusionInputs0[i] * diffusionGainValue);
outputs1[i] = multiTapScaled + (diffusionInputs1[i] * diffusionGainValue);
}
}
}
}
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