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diff --git a/src/libnoiseforjava/module/Blend.java b/src/libnoiseforjava/module/Blend.java
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+/*
+ * Copyright (C) 2003, 2004 Jason Bevins (original libnoise code)
+ * Copyright  2010 Thomas J. Hodge (java port of libnoise)
+ * 
+ * This file is part of libnoiseforjava.
+ * 
+ * libnoiseforjava is a Java port of the C++ library libnoise, which may be found at 
+ * http://libnoise.sourceforge.net/.  libnoise was developed by Jason Bevins, who may be 
+ * contacted at [email protected] (for great email, take off every 'zig').
+ * Porting to Java was done by Thomas Hodge, who may be contacted at
+ * [email protected] (remove every 'zag').
+ * 
+ * libnoiseforjava is free software: you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the Free Software
+ * Foundation, either version 3 of the License, or (at your option) any later version.
+ * 
+ * libnoiseforjava is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more details.
+ * 
+ * You should have received a copy of the GNU General Public License along with
+ * libnoiseforjava.  If not, see <http://www.gnu.org/licenses/>.
+ * 
+ */
+
+package libnoiseforjava.module;
+
+import libnoiseforjava.Interp;
+import libnoiseforjava.exception.ExceptionInvalidParam;
+
+public class Blend extends ModuleBase
+{
+   /// Noise module that outputs a weighted blend of the output values from
+   /// two source modules given the output value supplied by a control module.
+   ///
+   /// Unlike most other noise modules, the index value assigned to a source
+   /// module determines its role in the blending operation:
+   /// - Source module 0 outputs one of the
+   ///   values to blend.
+   /// - Source module 1 outputs one of the
+   ///   values to blend.
+   /// - Source module 2 is known as the <i>control
+   ///   module</i>.  The control module determines the weight of the
+   ///   blending operation.  Negative values weigh the blend towards the
+   ///   output value from the source module with an index value of 0.
+   ///   Positive values weigh the blend towards the output value from the
+   ///   source module with an index value of 1.
+   ///
+   /// An application can pass the control module to the setControlModule()
+   /// method instead of the setSourceModule() method.  This may make the
+   /// application code easier to read.
+   ///
+   /// This noise module uses linear interpolation to perform the blending
+   /// operation.
+   ///
+   /// This noise module requires three source modules.
+
+   public Blend (ModuleBase sourceModuleOne, ModuleBase sourceModuleTwo,
+         ModuleBase sourceModuleThree) throws ExceptionInvalidParam
+   {
+      super(3);
+      setSourceModule(0, sourceModuleOne);
+      setSourceModule(1, sourceModuleTwo);
+      setSourceModule(2, sourceModuleThree);
+   }
+
+   public double getValue (double x, double y, double z)
+   {
+      assert (sourceModules[0] != null);
+      assert (sourceModules[1] != null);
+      assert (sourceModules[2] != null);
+
+      double v0 = sourceModules[0].getValue (x, y, z);
+      double v1 = sourceModules[1].getValue (x, y, z);
+      double alpha = (sourceModules[2].getValue (x, y, z) + 1.0) / 2.0;
+
+      return Interp.linearInterp (v0, v1, alpha);
+   }
+}