javax.media.j3d
Class PositionPathInterpolator

java.lang.Object
  |
  +--javax.media.j3d.SceneGraphObject
        |
        +--javax.media.j3d.Node
              |
              +--javax.media.j3d.Leaf
                    |
                    +--javax.media.j3d.Behavior
                          |
                          +--javax.media.j3d.Interpolator
                                |
                                +--javax.media.j3d.PathInterpolator
                                      |
                                      +--javax.media.j3d.PositionPathInterpolator

public class PositionPathInterpolator

extends PathInterpolator

PositionPathInterpolator behavior. This class defines a behavior that modifies the translational component of its target TransformGroup by linearly interpolating among a series of predefined knot/position pairs (using the value generated by the specified Alpha object). The interpolated position is used to generate a translation transform in the local coordinate system of this interpolator. The first knot must have a value of 0.0. The last knot must have a value of 1.0. An intermediate knot with index k must have a value strictly greater than any knot with index less than k.

Fields inherited from class javax.media.j3d.PathInterpolator

currentInterpolationValue, currentKnotIndex

Fields inherited from class javax.media.j3d.Interpolator

defaultWakeupCriterion

Fields inherited from class javax.media.j3d.Node

ALLOW_AUTO_COMPUTE_BOUNDS_READ, ALLOW_AUTO_COMPUTE_BOUNDS_WRITE, ALLOW_BOUNDS_READ, ALLOW_BOUNDS_WRITE, ALLOW_COLLIDABLE_READ, ALLOW_COLLIDABLE_WRITE, ALLOW_LOCAL_TO_VWORLD_READ, ALLOW_PICKABLE_READ, ALLOW_PICKABLE_WRITE, ENABLE_COLLISION_REPORTING, ENABLE_PICK_REPORTING

Constructor Summary

PositionPathInterpolator(Alpha alpha, TransformGroup target, Transform3D axisOfTranslation, float[] knots, Point3f[] positions)
Constructs a new PositionPathInterpolator that varies the transform of the target TransformGroup.

Method Summary

Node	cloneNode(boolean forceDuplicate) Used to create a new instance of the node.
Transform3D	getAxisOfTranslation() Retrieves this interpolator's axis of translation.
void	getPosition(int index, Point3f position) Retrieves the position value at the specified index.
void	getPositions(Point3f[] positions) Copies the array of position values from this interpolator into the specified array.
TransformGroup	getTarget() Retrieves this interpolator's target TransformGroup reference.
void	processStimulus(java.util.Enumeration criteria) This method is invoked by the behavior scheduler every frame.
void	setAxisOfTranslation(Transform3D axisOfTranslation) Sets the axis of translation for the interpolator.
void	setPathArrays(float[] knots, Point3f[] positions) Replaces the existing arrays of knot values and position values with the specified arrays.
void	setPosition(int index, Point3f position) Sets the position at the specified index for this interpolator.
void	setTarget(TransformGroup target) Sets the target TransformGroup for this interpolator.
void	updateNodeReferences(NodeReferenceTable referenceTable) Callback used to allow a node to check if any scene graph objects referenced by that node have been duplicated via a call to cloneTree.

Methods inherited from class javax.media.j3d.PathInterpolator

computePathInterpolation, getArrayLengths, getKnot, getKnots, setKnot, setKnots

Methods inherited from class javax.media.j3d.Interpolator

getAlpha, initialize, setAlpha

Methods inherited from class javax.media.j3d.Behavior

getEnable, getSchedulingBoundingLeaf, getSchedulingBounds, getView, postId, setEnable, setSchedulingBoundingLeaf, setSchedulingBounds, wakeupOn

Methods inherited from class javax.media.j3d.Node

cloneTree, cloneTree, cloneTree, cloneTree, cloneTree, cloneTree, duplicateNode, getBounds, getBoundsAutoCompute, getCollidable, getLocalToVworld, getLocalToVworld, getParent, getPickable, setBounds, setBoundsAutoCompute, setCollidable, setPickable

Methods inherited from class javax.media.j3d.SceneGraphObject

clearCapability, duplicateSceneGraphObject, getCapability, getUserData, isCompiled, isLive, setCapability, setUserData

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

PositionPathInterpolator

public PositionPathInterpolator(Alpha alpha,
                                TransformGroup target,
                                Transform3D axisOfTranslation,
                                float[] knots,
                                Point3f[] positions)

Constructs a new PositionPathInterpolator that varies the transform of the target TransformGroup.

Parameters:

alpha - the alpha object for this interpolator

target - the TransformGroup node affected by this translator

axisOfTranslation - the transform that defines the local coordinate system in which this interpolator operates

knots - an array of knot values that specify interpolation points.

positions - an array of position values at the knots.

Throws:

java.lang.IllegalArgumentException - if the lengths of the knots and positions arrays are not the same.

Method Detail

setPosition

public void setPosition(int index,
                        Point3f position)

Sets the position at the specified index for this interpolator.

Parameters:

index - the index of the position to be changed

position - the new position at the index

getPosition

public void getPosition(int index,
                        Point3f position)

Retrieves the position value at the specified index.

Parameters:

index - the index of the value requested

position - the variable to receive the position value at the specified index

setPathArrays

public void setPathArrays(float[] knots,
                          Point3f[] positions)

Replaces the existing arrays of knot values and position values with the specified arrays. The arrays of knots and positions are copied into this interpolator object.

Parameters:

knots - a new array of knot values that specify interpolation points

positions - a new array of position values at the knots

Throws:

java.lang.IllegalArgumentException - if the lengths of the knots and positions arrays are not the same.

Since:

Java 3D 1.2

getPositions

public void getPositions(Point3f[] positions)

Copies the array of position values from this interpolator into the specified array. The array must be large enough to hold all of the positions. The individual array elements must be allocated by the caller.

Parameters:

positions - array that will receive the positions

Since:

Java 3D 1.2

setAxisOfTranslation

public void setAxisOfTranslation(Transform3D axisOfTranslation)

Sets the axis of translation for the interpolator.

Parameters:

axisOfTranslation - transform that defines the local coordinate system in which this interpolator operates

getAxisOfTranslation

public Transform3D getAxisOfTranslation()

Retrieves this interpolator's axis of translation.

Returns:

the interpolator's axis of translation

setTarget

public void setTarget(TransformGroup target)

Sets the target TransformGroup for this interpolator.

Parameters:

target - the target TransformGroup

getTarget

public TransformGroup getTarget()

Retrieves this interpolator's target TransformGroup reference.

Returns:

the interpolator's target TransformGroup

processStimulus

public void processStimulus(java.util.Enumeration criteria)

This method is invoked by the behavior scheduler every frame. It maps the alpha value that corresponds to the current time into a translation value, computes a transform based on this value, and updates the specified TransformGroup node with this new transform.

Overrides:

processStimulus in class Behavior

Parameters:

criteria - an enumeration of WakeupCriterion that have triggered

cloneNode

public Node cloneNode(boolean forceDuplicate)

Used to create a new instance of the node. This routine is called by cloneTree to duplicate the current node.

Overrides:

cloneNode in class Node

Parameters:

forceDuplicate - when set to true, causes the duplicateOnCloneTree flag to be ignored. When false, the value of each node's duplicateOnCloneTree variable determines whether NodeComponent data is duplicated or copied.

See Also:

Node.cloneTree(), Node.cloneNode(boolean), Node.duplicateNode(javax.media.j3d.Node, boolean), NodeComponent.setDuplicateOnCloneTree(boolean)

updateNodeReferences

public void updateNodeReferences(NodeReferenceTable referenceTable)

Callback used to allow a node to check if any scene graph objects referenced by that node have been duplicated via a call to cloneTree. This method is called by cloneTree 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 object references by using the getNewObjectReference method found in the NodeReferenceTable object. If a match is found, a reference to the corresponding object 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 object is returned depending on the value of the allowDanglingReferences parameter passed in the cloneTree call.

NOTE: Applications should not call this method directly. It should only be called by the cloneTree method.

Overrides:

updateNodeReferences in class Behavior

Parameters:

referenceTable - a NodeReferenceTableObject that contains the getNewObjectReference method needed to search for new object instances.

See Also:

NodeReferenceTable, Node.cloneTree(), DanglingReferenceException