javax.media.j3d
Class PointLight

java.lang.Object
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  +--javax.media.j3d.SceneGraphObject
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        +--javax.media.j3d.Node
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              +--javax.media.j3d.Leaf
                    |
                    +--javax.media.j3d.Light
                          |
                          +--javax.media.j3d.PointLight

Direct Known Subclasses:

SpotLight

public class PointLight

extends Light

The PointLight object specifies an attenuated light source at a fixed point in space that radiates light equally in all directions away from the light source. PointLight has the same attributes as a Light node, with the addition of location and attenuation parameters.

A point light contributes to diffuse and specular reflections, which in turn depend on the orientation and position of a surface. A point light does not contribute to ambient reflections.

A PointLight is attenuated by multiplying the contribution of the light by an attenuation factor. The attenuation factor causes the the PointLight's brightness to decrease as distance from the light source increases. A PointLight's attenuation factor contains three values:

• Constant attenuation
• Linear attenuation
• Quadratic attenuation

A PointLight is attenuated by the reciprocal of the sum of:

The constant attenuation factor
The Linear attenuation factor times the distance between the light and the vertex being illuminated
The quadratic attenuation factor times the square of the distance between the light and the vertex

By default, the constant attenuation value is 1 and the other two values are 0, resulting in no attenuation.

Field Summary

static int	ALLOW_ATTENUATION_READ Specifies that this PointLight node allows reading its attenuation information.
static int	ALLOW_ATTENUATION_WRITE Specifies that this PointLight node allows writing its attenuation information.
static int	ALLOW_POSITION_READ Specifies that this PointLight node allows reading its position information.
static int	ALLOW_POSITION_WRITE Specifies that this PointLight node allows writing its position information.

Fields inherited from class javax.media.j3d.Light

ALLOW_COLOR_READ, ALLOW_COLOR_WRITE, ALLOW_INFLUENCING_BOUNDS_READ, ALLOW_INFLUENCING_BOUNDS_WRITE, ALLOW_SCOPE_READ, ALLOW_SCOPE_WRITE, ALLOW_STATE_READ, ALLOW_STATE_WRITE

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

PointLight()
Constructs a PointLight node with default parameters.

PointLight(boolean lightOn, Color3f color, Point3f position, Point3f attenuation)
Constructs and initializes a point light.

PointLight(Color3f color, Point3f position, Point3f attenuation)
Constructs and initializes a point light.

Method Summary

Node	cloneNode(boolean forceDuplicate) Used to create a new instance of the node.
void	getAttenuation(Point3f attenuation) Gets this Light's current attenuation values and places it in the parameter specified.
void	getPosition(Point3f position) Gets this Light's current position and places it in the parameter specified.
void	setAttenuation(float constant, float linear, float quadratic) Sets this Light's current attenuation values and places it in the parameter specified.
void	setAttenuation(Point3f attenuation) Sets this Light's current attenuation values and places it in the parameter specified.
void	setPosition(float x, float y, float z) Set light position.
void	setPosition(Point3f position) Set light position.

Methods inherited from class javax.media.j3d.Light

addScope, getAllScopes, getColor, getEnable, getInfluencingBoundingLeaf, getInfluencingBounds, getScope, insertScope, numScopes, removeScope, setColor, setEnable, setInfluencingBoundingLeaf, setInfluencingBounds, setScope, updateNodeReferences

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

Field Detail

ALLOW_POSITION_READ

public static final int ALLOW_POSITION_READ

Specifies that this PointLight node allows reading its position information.

ALLOW_POSITION_WRITE

public static final int ALLOW_POSITION_WRITE

Specifies that this PointLight node allows writing its position information.

ALLOW_ATTENUATION_READ

public static final int ALLOW_ATTENUATION_READ

Specifies that this PointLight node allows reading its attenuation information.

ALLOW_ATTENUATION_WRITE

public static final int ALLOW_ATTENUATION_WRITE

Specifies that this PointLight node allows writing its attenuation information.

Constructor Detail

PointLight

public PointLight()

Constructs a PointLight node with default parameters. The default values are as follows:

position : (0,0,0)
attenuation : (1,0,0)

PointLight

public PointLight(Color3f color,
                  Point3f position,
                  Point3f attenuation)

Constructs and initializes a point light.

Parameters:

color - the color of the light source

position - the position of the light in three-space

attenuation - the attenutation (constant, linear, quadratic) of the light

PointLight

public PointLight(boolean lightOn,
                  Color3f color,
                  Point3f position,
                  Point3f attenuation)

Constructs and initializes a point light.

Parameters:

lightOn - flag indicating whether this light is on or off

color - the color of the light source

position - the position of the light in three-space

attenuation - the attenuation (constant, linear, quadratic) of the light

Method Detail

setPosition

public void setPosition(Point3f position)

Set light position.

Parameters:

position - the new position

Throws:

CapabilityNotSetException - if appropriate capability is not set and this object is part of live or compiled scene graph

setPosition

public void setPosition(float x,
                        float y,
                        float z)

Set light position.

Parameters:

x - the new X position

y - the new Y position

z - the new Z position

Throws:

CapabilityNotSetException - if appropriate capability is not set and this object is part of live or compiled scene graph

getPosition

public void getPosition(Point3f position)

Gets this Light's current position and places it in the parameter specified.

Parameters:

position - the vector that will receive this node's position

Throws:

CapabilityNotSetException - if appropriate capability is not set and this object is part of live or compiled scene graph

setAttenuation

public void setAttenuation(Point3f attenuation)

Sets this Light's current attenuation values and places it in the parameter specified.

Parameters:

attenuation - the vector that will receive the attenuation values

Throws:

CapabilityNotSetException - if appropriate capability is not set and this object is part of live or compiled scene graph

setAttenuation

public void setAttenuation(float constant,
                           float linear,
                           float quadratic)

Sets this Light's current attenuation values and places it in the parameter specified.

Parameters:

constant - the light's constant attenuation

linear - the light's linear attenuation

quadratic - the light's quadratic attenuation

Throws:

CapabilityNotSetException - if appropriate capability is not set and this object is part of live or compiled scene graph

getAttenuation

public void getAttenuation(Point3f attenuation)

Gets this Light's current attenuation values and places it in the parameter specified.

Parameters:

attenuation - the vector that will receive the attenuation values

Throws:

CapabilityNotSetException - if appropriate capability is not set and this object is part of live or compiled scene graph

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)