1 files changed, 92 insertions, 0 deletions
diff --git a/src/main/java/com/jsyn/unitgen/SpectralIFFT.java b/src/main/java/com/jsyn/unitgen/SpectralIFFT.java
new file mode 100644
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+++ b/src/main/java/com/jsyn/unitgen/SpectralIFFT.java
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+/*
+ * Copyright 2013 Phil Burk, Mobileer Inc
+ *
+ * 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.data.SpectralWindow;
+import com.jsyn.data.Spectrum;
+import com.jsyn.ports.UnitOutputPort;
+import com.jsyn.ports.UnitSpectralInputPort;
+import com.softsynth.math.FourierMath;
+
+/**
+ * Periodically transform the input signal using an Inverse FFT.
+ * 
+ * @author Phil Burk (C) 2013 Mobileer Inc
+ * @version 016
+ * @see SpectralFFT
+ */
+public class SpectralIFFT extends UnitGenerator {
+    public UnitSpectralInputPort input;
+    public UnitOutputPort output;
+    private Spectrum localSpectrum;
+    private double[] buffer;
+    private int cursor;
+    private SpectralWindow window = RectangularWindow.getInstance();
+
+    /* Define Unit Ports used by connect() and set(). */
+    public SpectralIFFT() {
+        addPort(output = new UnitOutputPort());
+        addPort(input = new UnitSpectralInputPort("Input"));
+    }
+
+    @Override
+    public void generate(int start, int limit) {
+        double[] outputs = output.getValues();
+
+        if (buffer == null) {
+            if (input.isAvailable()) {
+                Spectrum spectrum = input.getSpectrum();
+                int size = spectrum.size();
+                localSpectrum = new Spectrum(size);
+                buffer = localSpectrum.getReal();
+                cursor = 0;
+            } else {
+                for (int i = start; i < limit; i++) {
+                    outputs[i] = 0.0;
+                }
+            }
+        }
+
+        if (buffer != null) {
+            for (int i = start; i < limit; i++) {
+                if (cursor == 0) {
+                    Spectrum spectrum = input.getSpectrum();
+                    spectrum.copyTo(localSpectrum);
+                    FourierMath.ifft(buffer.length, localSpectrum.getReal(),
+                            localSpectrum.getImaginary());
+                }
+
+                outputs[i] = buffer[cursor] * window.get(cursor);
+                cursor += 1;
+                if (cursor == buffer.length) {
+                    cursor = 0;
+                }
+            }
+        }
+    }
+
+    public SpectralWindow getWindow() {
+        return window;
+    }
+
+    /**
+     * Multiply output data by this window after doing the FFT. The default is a RectangularWindow.
+     */
+    public void setWindow(SpectralWindow window) {
+        this.window = window;
+    }
+}