/*8
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* Make a donation http://sourceforge.net/donate/index.php?group_id=98797
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* Microcrowd.com
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*
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* Contact Josh DeFord jdeford@microcrowd.com
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*/
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package com.microcrowd.loader.java3d.max3ds.chunks;
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import java.util.ArrayList;
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import java.util.List;
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import javax.vecmath.Quat4f;
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import javax.vecmath.Vector3f;
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import com.microcrowd.loader.java3d.max3ds.ChunkChopper;
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/**
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* Extracts the rotation information from the 3ds file.
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* Rotations occur about a pivot at a position within
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* a local coordinate system. The rotation information
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* is provided to the KeyFramerInfoChunk which then converts
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* it to a global coordinate system and applies animation
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* information.
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* {@see KeyFramerInfoChunk} for more information about using
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* animations from a 3ds file
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*/
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public class RotationChunk extends Chunk
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{
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/**
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* String that will be used as a data object in the transform that the
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* RotationInterpolator will be a child of so it may be look up later.
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**/
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public static String ROTATION_TAG = "ROTATION_INTERPOLATOR";
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/**
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* Loads the quaternion for a rotation of a shape
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* and notifies mesh info chunk.
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*
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* @param chopper the ChunkChopper containing the state of the parser.
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*/
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public void loadData(ChunkChopper chopper)
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{
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int flags = chopper.getUnsignedShort();
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chopper.getLong();
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int numKeys = chopper.getUnsignedInt();
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Quat4f previousQuat = null;
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List quats = new ArrayList();
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for(int i =0; i < numKeys; i++)
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{
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long frameNumber = chopper.getUnsignedInt();//Part of the track header
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int accelerationData = chopper.getUnsignedShort();//Part of the track header
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getSplineTerms(accelerationData, chopper);//Part of the track header
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float angle = chopper.getFloat();
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Vector3f vector = chopper.getVector();
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Quat4f quat = getQuaternion(vector, angle);
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if(previousQuat != null) {
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quat.mul(previousQuat, quat);
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}
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previousQuat = quat;
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quats.add(quat);
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if(i==0)
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{
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chopper.getKeyFramer().setRotation(quat);
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}
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}
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chopper.getKeyFramer().setOrientationKeys(quats);
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}
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/**
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* This only reads the spline data and should be part
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* of the track header when it gets invented.
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* @param chopper an integer representing the bits that
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* determine which of the five possible spline terms are present in the
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* data and should be read.
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* @param chopper what to read the data from
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* The possible spline values are are
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* <ol>
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* <li> Tension
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* <li> Continuity
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* <li> Bias
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* <li> EaseTo
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* <li> EaseFrom
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* </ol>
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*/
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private void getSplineTerms(final int accelerationData, ChunkChopper chopper)
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{
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int bits = accelerationData;
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for(int i=0; i < 5; i++)
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{
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bits = bits >>> i;
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if((bits & 1) == 1)
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{
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chopper.getFloat();
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}
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}
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}
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/**
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* This converts a 3ds angle and axis to
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* a quaternion rotation. Successive
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* rotations are relative to the first so each
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* rotation must be made absolute by multiplying
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* it with its predecessor
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*/
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public Quat4f getQuaternion(Vector3f axis, float angle)
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{
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float sinA = (float)(java.lang.Math.sin(angle/2.0f));
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float cosA = (float)(java.lang.Math.cos(angle/2.0f));
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return new Quat4f(axis.x * sinA, axis.y * sinA, axis.z * sinA, cosA);
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}
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}
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