Package javax.media.j3d
Class Billboard
java.lang.Object
javax.media.j3d.SceneGraphObject
javax.media.j3d.Node
javax.media.j3d.Leaf
javax.media.j3d.Behavior
javax.media.j3d.Billboard
The Billboard behavior node operates on the TransformGroup node
to cause the local +z axis of the TransformGroup to point at
the viewer's eye position. This is done regardless of the transforms
above the specified TransformGroup node in the scene graph.
If the alignment mode is ROTATE_ABOUT_AXIS, the rotation will be around the specified axis. If the alignment mode is ROTATE_ABOUT_POINT, the rotation will be about the specified point, with an additional rotation to align the +y axis of the TransformGroup with the +y axis in the View.
Note that in a multiple View system, the alignment is done to the primary View only.
Billboard nodes are ideal for drawing screen aligned-text or for drawing roughly-symmetrical objects. A typical use might consist of a quadrilateral that contains a texture of a tree.
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Field Summary
FieldsModifier and TypeFieldDescriptionstatic final int
Specifies that rotation should be about the specified axis.static final int
Specifies that rotation should be about the specified point and that the children's Y-axis should match the view object's Y-axis.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_LOCALE_READ, ALLOW_PARENT_READ, ALLOW_PICKABLE_READ, ALLOW_PICKABLE_WRITE, ENABLE_COLLISION_REPORTING, ENABLE_PICK_REPORTING
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Constructor Summary
ConstructorsConstructorDescriptionConstructs a Billboard node with default parameters.Constructs a Billboard node with default parameters that operates on the specified TransformGroup node.Billboard
(TransformGroup tg, int mode, javax.vecmath.Point3f point) Constructs a Billboard node with the specified rotation point and mode that operates on the specified TransformGroup node.Billboard
(TransformGroup tg, int mode, javax.vecmath.Vector3f axis) Constructs a Billboard node with the specified axis and mode that operates on the specified TransformGroup node. -
Method Summary
Modifier and TypeMethodDescriptioncloneNode
(boolean forceDuplicate) Creates a new instance of the node.void
getAlignmentAxis
(javax.vecmath.Vector3f axis) Gets the alignment axis and sets the parameter to this value.int
Gets the alignment mode.void
getRotationPoint
(javax.vecmath.Point3f point) Gets the rotation point and sets the parameter to this value.Returns a copy of the transformGroup associated with this Billboard.void
Initialize method that sets up initial wakeup criteria.void
processStimulus
(Enumeration criteria) Process stimulus method that computes appropriate transform.void
setAlignmentAxis
(float x, float y, float z) Sets the alignment axis.void
setAlignmentAxis
(javax.vecmath.Vector3f axis) Sets the alignment axis.void
setAlignmentMode
(int mode) Sets the alignment mode.void
setRotationPoint
(float x, float y, float z) Sets the rotation point.void
setRotationPoint
(javax.vecmath.Point3f point) Sets the rotation point.void
Sets the tranformGroup for this Billboard object.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 tocloneTree
.Methods inherited from class javax.media.j3d.Behavior
getEnable, getNumSchedulingIntervals, getSchedulingBoundingLeaf, getSchedulingBounds, getSchedulingInterval, getView, getWakeupCondition, postId, setEnable, setSchedulingBoundingLeaf, setSchedulingBounds, setSchedulingInterval, wakeupOn
Methods inherited from class javax.media.j3d.Node
cloneTree, cloneTree, cloneTree, cloneTree, cloneTree, cloneTree, duplicateNode, getBounds, getBoundsAutoCompute, getCollidable, getLocale, getLocalToVworld, getLocalToVworld, getParent, getPickable, setBounds, setBoundsAutoCompute, setCollidable, setPickable
Methods inherited from class javax.media.j3d.SceneGraphObject
clearCapability, clearCapabilityIsFrequent, duplicateSceneGraphObject, getCapability, getCapabilityIsFrequent, getName, getUserData, isCompiled, isLive, setCapability, setCapabilityIsFrequent, setName, setUserData, toString
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Field Details
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ROTATE_ABOUT_AXIS
public static final int ROTATE_ABOUT_AXISSpecifies that rotation should be about the specified axis.- See Also:
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ROTATE_ABOUT_POINT
public static final int ROTATE_ABOUT_POINTSpecifies that rotation should be about the specified point and that the children's Y-axis should match the view object's Y-axis.- See Also:
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Constructor Details
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Billboard
public Billboard()Constructs a Billboard node with default parameters. The default values are as follows:-
alignment mode : ROTATE_ABOUT_AXIS
alignment axis : Y-axis (0,1,0)
rotation point : (0,0,1)
target transform group: null
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Billboard
Constructs a Billboard node with default parameters that operates on the specified TransformGroup node. The default alignment mode is ROTATE_ABOUT_AXIS rotation with the axis pointing along the Y axis.- Parameters:
tg
- the TransformGroup node that this Billboard node operates upon
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Billboard
Constructs a Billboard node with the specified axis and mode that operates on the specified TransformGroup node. The specified axis must not be parallel to the Z axis--(0,0,z) for any value of z. It is not possible for the +Z axis to point at the viewer's eye position by rotating about itself. The target transform will be set to the identity if the axis is (0,0,z).- Parameters:
tg
- the TransformGroup node that this Billboard node operates uponmode
- alignment mode, one of ROTATE_ABOUT_AXIS or ROTATE_ABOUT_POINTaxis
- the ray about which the billboard rotates
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Billboard
Constructs a Billboard node with the specified rotation point and mode that operates on the specified TransformGroup node.- Parameters:
tg
- the TransformGroup node that this Billboard node operates uponmode
- alignment mode, one of ROTATE_ABOUT_AXIS or ROTATE_ABOUT_POINTpoint
- the position about which the billboard rotates
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Method Details
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setAlignmentMode
public void setAlignmentMode(int mode) Sets the alignment mode.- Parameters:
mode
- one of: ROTATE_ABOUT_AXIS or ROTATE_ABOUT_POINT
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getAlignmentMode
public int getAlignmentMode()Gets the alignment mode.- Returns:
- one of: ROTATE_ABOUT_AXIS or ROTATE_ABOUT_POINT
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setAlignmentAxis
public void setAlignmentAxis(javax.vecmath.Vector3f axis) Sets the alignment axis. The specified axis must not be parallel to the Z axis--(0,0,z) for any value of z. It is not possible for the +Z axis to point at the viewer's eye position by rotating about itself. The target transform will be set to the identity if the axis is (0,0,z).- Parameters:
axis
- the ray about which the billboard rotates
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setAlignmentAxis
public void setAlignmentAxis(float x, float y, float z) Sets the alignment axis. The specified axis must not be parallel to the Z axis--(0,0,z) for any value of z. It is not possible for the +Z axis to point at the viewer's eye position by rotating about itself. The target transform will be set to the identity if the axis is (0,0,z).- Parameters:
x
- the x component of the ray about which the billboard rotatesy
- the y component of the ray about which the billboard rotatesz
- the z component of the ray about which the billboard rotates
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getAlignmentAxis
public void getAlignmentAxis(javax.vecmath.Vector3f axis) Gets the alignment axis and sets the parameter to this value.- Parameters:
axis
- the vector that will contain the ray about which the billboard rotates
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setRotationPoint
public void setRotationPoint(javax.vecmath.Point3f point) Sets the rotation point.- Parameters:
point
- the point about which the billboard rotates
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setRotationPoint
public void setRotationPoint(float x, float y, float z) Sets the rotation point.- Parameters:
x
- the x component of the point about which the billboard rotatesy
- the y component of the point about which the billboard rotatesz
- the z component of the point about which the billboard rotates
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getRotationPoint
public void getRotationPoint(javax.vecmath.Point3f point) Gets the rotation point and sets the parameter to this value.- Parameters:
point
- the position the Billboard rotates about
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setTarget
Sets the tranformGroup for this Billboard object.- Parameters:
tg
- the transformGroup node which replaces the current transformGroup node for this Billboard
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getTarget
Returns a copy of the transformGroup associated with this Billboard.- Returns:
- the TranformGroup for this Billboard
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initialize
public void initialize()Initialize method that sets up initial wakeup criteria.- Specified by:
initialize
in classBehavior
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processStimulus
Process stimulus method that computes appropriate transform.- Specified by:
processStimulus
in classBehavior
- Parameters:
criteria
- an enumeration of the criteria that caused the stimulus
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cloneNode
Creates a new instance of the node. This routine is called bycloneTree
to duplicate the current node. -
updateNodeReferences
Callback used to allow a node to check if any scene graph objects referenced by that node have been duplicated via a call tocloneTree
. This method is called bycloneTree
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 thegetNewObjectReference
method found in theNodeReferenceTable
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 theallowDanglingReferences
parameter passed in thecloneTree
call.NOTE: Applications should not call this method directly. It should only be called by the cloneTree method.
- Overrides:
updateNodeReferences
in classBehavior
- Parameters:
referenceTable
- a NodeReferenceTableObject that contains thegetNewObjectReference
method needed to search for new object instances.- See Also:
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