Java tutorial
/* * Copyright 1997-2008 Sun Microsystems, Inc. All Rights Reserved. * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. * * This code is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License version 2 only, as * published by the Free Software Foundation. Sun designates this * particular file as subject to the "Classpath" exception as provided * by Sun in the LICENSE file that accompanied this code. * * This code 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 * version 2 for more details (a copy is included in the LICENSE file that * accompanied this code). * * You should have received a copy of the GNU General Public License version * 2 along with this work; if not, write to the Free Software Foundation, * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. * * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, * CA 95054 USA or visit www.sun.com if you need additional information or * have any questions. * */ package javax.media.j3d; import java.util.Enumeration; /** * TransparencyInterpolator behavior. This class defines a behavior * that modifies the transparency of its target TransparencyAttributes * object by linearly interpolating between a pair of specified * transparency values (using the value generated by the specified * Alpha object). * <P> * There are two forms of constructor to specify the * type of transparency interpolation. The first constructor takes * an Alpha and a TransparencyAttributes object and creates a transparency * interpolator that maps an Alpha value of 1.0 to a transparency * value of 1.0, and an Alpha value of 0.0 and maps it to a * transparency value of 0.0. The second constructor takes an Alpha, * a TransparencyAttributes object, a minimum transparency value and a * maximum transparency value. This constructor provides more * flexibility by specifying how the Alpha values are mapped * to the transparency values - an Alpha of 1.0 maps to the * maximum transparency value and an Alpha of 0.0 maps to the * minimum transparency value.<P> * * @see Alpha * @see TransparencyAttributes */ public class TransparencyInterpolator extends Interpolator { TransparencyAttributes target; float minimumTransparency; float maximumTransparency; // We can't use a boolean flag since it is possible // that after alpha change, this procedure only run // once at alpha.finish(). So the best way is to // detect alpha value change. private float prevAlphaValue = Float.NaN; private WakeupCriterion passiveWakeupCriterion = new WakeupOnElapsedFrames(0, true); // non-public, default constructor used by cloneNode TransparencyInterpolator() { } /** * Constructs a trivial transparency interpolator with a specified target, * a minimum transparency of 0.0f and a maximum transparency of 1.0f. * @param alpha the alpha object for this interpolator * @param target the TransparencyAttributes component object affected * by this interpolator */ public TransparencyInterpolator(Alpha alpha, TransparencyAttributes target) { super(alpha); this.target = target; this.minimumTransparency = 0.0f; this.maximumTransparency = 1.0f; } /** * Constructs a new transparency interpolator that varies the target * material's transparency between the two transparency values. * @param alpha the alpha object for this Interpolator * @param target the TransparencyAttributes component object affected * by this interpolator * @param minimumTransparency the starting transparency * @param maximumTransparency the ending transparency */ public TransparencyInterpolator(Alpha alpha, TransparencyAttributes target, float minimumTransparency, float maximumTransparency) { super(alpha); this.target = target; this.minimumTransparency = minimumTransparency; this.maximumTransparency = maximumTransparency; } /** * This method sets the minimumTransparency for this interpolator. * @param transparency the new minimum transparency */ public void setMinimumTransparency(float transparency) { this.minimumTransparency = transparency; } /** * This method retrieves this interpolator's minimumTransparency. * @return the interpolator's minimum transparency value */ public float getMinimumTransparency() { return this.minimumTransparency; } /** * This method sets the maximumTransparency for this interpolator. * @param transparency the new maximum transparency */ public void setMaximumTransparency(float transparency) { this.maximumTransparency = transparency; } /** * This method retrieves this interpolator's maximumTransparency. * @return the interpolator's maximal transparency vslue */ public float getMaximumTransparency() { return this.maximumTransparency; } /** * This method sets the target TransparencyAttributes object * for this interpolator. * @param target the target TransparencyAttributes object */ public void setTarget(TransparencyAttributes target) { this.target = target; } /** * This method retrieves this interpolator's target reference. * @return the interpolator's target TransparencyAttributes object */ public TransparencyAttributes getTarget() { return target; } // The TransparencyInterpolator's initialize routine uses the default // initialization routine. /** * This method is invoked by the behavior scheduler every frame. It * maps the alpha value that corresponds to the current time into a * transparency value and updates the specified TransparencyAttributes * object with this new transparency value. * @param criteria an enumeration of the criteria that caused the * stimulus */ @Override public void processStimulus(Enumeration criteria) { // Handle stimulus WakeupCriterion criterion = passiveWakeupCriterion; if (alpha != null) { float value = alpha.value(); if (value != prevAlphaValue) { float val = (float) ((1.0 - value) * minimumTransparency + value * maximumTransparency); target.setTransparency(val); prevAlphaValue = value; } if (!alpha.finished() && !alpha.isPaused()) { criterion = defaultWakeupCriterion; } } wakeupOn(criterion); } /** * Used to create a new instance of the node. This routine is called * by <code>cloneTree</code> to duplicate the current node. * @param forceDuplicate when set to <code>true</code>, causes the * <code>duplicateOnCloneTree</code> flag to be ignored. When * <code>false</code>, the value of each node's * <code>duplicateOnCloneTree</code> variable determines whether * NodeComponent data is duplicated or copied. * * @see Node#cloneTree * @see Node#cloneNode * @see Node#duplicateNode * @see NodeComponent#setDuplicateOnCloneTree */ @Override public Node cloneNode(boolean forceDuplicate) { TransparencyInterpolator ti = new TransparencyInterpolator(); ti.duplicateNode(this, forceDuplicate); return ti; } /** * Copies all TransparencyInterpolator information from * <code>originalNode</code> into * the current node. This method is called from the * <code>cloneNode</code> method which is, in turn, called by the * <code>cloneTree</code> method.<P> * * @param originalNode the original node to duplicate. * @param forceDuplicate when set to <code>true</code>, causes the * <code>duplicateOnCloneTree</code> flag to be ignored. When * <code>false</code>, the value of each node's * <code>duplicateOnCloneTree</code> variable determines whether * NodeComponent data is duplicated or copied. * * @exception RestrictedAccessException if this object is part of a live * or compiled scenegraph. * * @see Node#duplicateNode * @see Node#cloneTree * @see NodeComponent#setDuplicateOnCloneTree */ @Override void duplicateAttributes(Node originalNode, boolean forceDuplicate) { super.duplicateAttributes(originalNode, forceDuplicate); TransparencyInterpolator ti = (TransparencyInterpolator) originalNode; setMinimumTransparency(ti.getMinimumTransparency()); setMaximumTransparency(ti.getMaximumTransparency()); // this reference will be updated in updateNodeReferences() setTarget(ti.getTarget()); } /** * Callback used to allow a node to check if any nodes referenced * by that node have been duplicated via a call to <code>cloneTree</code>. * This method is called by <code>cloneTree</code> after all nodes in * the sub-graph have been duplicated. The cloned Leaf node's method * will be called and the Leaf node can then look up any node references * by using the <code>getNewObjectReference</code> method found in the * <code>NodeReferenceTable</code> object. If a match is found, a * reference to the corresponding Node in the newly cloned sub-graph * is returned. If no corresponding reference is found, either a * DanglingReferenceException is thrown or a reference to the original * node is returned depending on the value of the * <code>allowDanglingReferences</code> parameter passed in the * <code>cloneTree</code> call. * <p> * NOTE: Applications should <i>not</i> call this method directly. * It should only be called by the cloneTree method. * * @param referenceTable a NodeReferenceTableObject that contains the * <code>getNewObjectReference</code> method needed to search for * new object instances. * @see NodeReferenceTable * @see Node#cloneTree * @see DanglingReferenceException */ @Override public void updateNodeReferences(NodeReferenceTable referenceTable) { super.updateNodeReferences(referenceTable); // check TransparencyAttributes NodeComponent nc = getTarget(); if (nc != null) { setTarget((TransparencyAttributes) referenceTable.getNewObjectReference(nc)); } } }