org.j3d.aviatrix3d
Class Viewpoint

java.lang.Object
  org.j3d.aviatrix3d.SceneGraphObject
      org.j3d.aviatrix3d.Node
          org.j3d.aviatrix3d.Leaf
              org.j3d.aviatrix3d.Viewpoint

All Implemented Interfaces:

java.lang.Comparable, Cullable, EnvironmentCullable, ObjectRenderable, Renderable

public class Viewpoint
extends Leaf
implements ObjectRenderable, EnvironmentCullable

A viewpoint into the scene.

Viewpoints have their own implicit directional light (a headlight) that is controlled separately to the normal in-scenegraph lights. Lights are scoped by default and thus having the viewpoint also have a light following it around is a pain to deal with, you can select on directly on the viewpoint itself. This light is always pointing down the Z axis in the local coordinate system.

In addition to the headlight, a separate ambient light colour may be provided. Although this is provided, note that whether it has any effect is dependent on whether lighting is enabled on the object being rendered.

2D Scenes

Since a 2D scene does not have any form of lighting enabled, this class mostly acts as a placeholder to position where the view is located in a 2D frame of reference. By modifying the pixel transformations above this viewpoint, you can effect a 2D scrolling effect. All the other effects of this node are ignored.

Version:

$Revision: 1.25 $

Author:

Justin Couch

Field Summary

Fields inherited from class org.j3d.aviatrix3d.Node

bounds, implicitBounds, INVALID_BOUNDS, parent

Fields inherited from class org.j3d.aviatrix3d.SceneGraphObject

alive, LISTENER_SET_TIMING_ERR_PROP, updateHandler

Constructor Summary

Viewpoint()
The default constructor where the headlight is implicitly turned off, and the default light type is directional.

Method Summary

int	compareTo(java.lang.Object o) Compares this object with the specified object for order.
int	compareTo(Viewpoint vp) Compares this object with the specified object for order.
boolean	equals(java.lang.Object o) Compare this object for equality to the given object.
boolean	equals(Viewpoint vp) Compares this object with the specified object to check for equivalence.
Cullable	getCullableParent() Get the parent cullable of this instance.
void	getGlobalAmbientColor(float[] col) Retrieve the current colour value from the light.
Renderable	getRenderable() Get the renderable that represents the environment node rendering.
boolean	isDirectionalLight() Get the current state of the headlight type.
boolean	isGlobalAmbientLightEnabled() Get the current state of the global ambient light usage.
boolean	isHeadlightEnabled() Get the current state of the headlight usage.
protected void	markBoundsDirty() Mark this node as having dirty bounds due to one of it's children having their bounds changed.
void	postRender(javax.media.opengl.GL gl)
void	render(javax.media.opengl.GL gl) This method is called to render this node.
void	setGlobalAmbientColor(float[] col) Set the ambient colour to the new value.
void	setGlobalAmbientLightEnabled(boolean state) Turn the global ambient lighting setting on or off.
void	setHeadlightEnabled(boolean state) Turn the local headlight on/off.
void	setHeadlightType(boolean state) Change the style of the headlight between directional and spot types.

Methods inherited from class org.j3d.aviatrix3d.Node

boundsChanged, checkForCyclicParent, getBounds, getParent, recomputeBounds, removeParent, requestBoundsUpdate, setBounds, setParent, updateBounds, updateParentBounds

Methods inherited from class org.j3d.aviatrix3d.SceneGraphObject

checkForCyclicChild, dataChanged, getAppUpdateWriteTimingMessage, getBoundsWriteTimingMessage, getDataWriteTimingMessage, getUserData, isLive, setLive, setUpdateHandler, setUserData

Methods inherited from class java.lang.Object

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

Constructor Detail

Viewpoint

public Viewpoint()

The default constructor where the headlight is implicitly turned off, and the default light type is directional.

Method Detail

getCullableParent

public Cullable getCullableParent()

Get the parent cullable of this instance.

Specified by:

getCullableParent in interface EnvironmentCullable

Returns:

The parent instance

getRenderable

public Renderable getRenderable()

Get the renderable that represents the environment node rendering.

Specified by:

getRenderable in interface EnvironmentCullable

Returns:

The renderable responsible for this node

render

public void render(javax.media.opengl.GL gl)

This method is called to render this node. All openGL commands needed to render the node should be executed. Any transformations needed should be added to the transformation stack premultiplied. This method must be re-entrant as it can be called from multiple places at once.

Specified by:

render in interface ObjectRenderable

Parameters:

gl - The gl context to draw with

postRender

public void postRender(javax.media.opengl.GL gl)

Specified by:

postRender in interface ObjectRenderable

markBoundsDirty

protected void markBoundsDirty()

Mark this node as having dirty bounds due to one of it's children having their bounds changed.

Overrides:

markBoundsDirty in class Node

compareTo

public int compareTo(java.lang.Object o)
              throws java.lang.ClassCastException

Compares this object with the specified object for order. Returns a negative integer, zero, or a positive integer as this object is less than, equal to, or greater than the specified object.

Specified by:

compareTo in interface java.lang.Comparable

Parameters:

o - The objec to be compared

Returns:

-1, 0 or 1 depending on order

Throws:

java.lang.ClassCastException - The specified object's type prevents it from being compared to this Object

equals

public boolean equals(java.lang.Object o)

Compare this object for equality to the given object.

Specified by:

equals in interface Renderable

Overrides:

equals in class java.lang.Object

Parameters:

o - The object to be compared

Returns:

True if these represent the same values

isHeadlightEnabled

public boolean isHeadlightEnabled()

Get the current state of the headlight usage.

Returns:

true if the headlight is currently active

setHeadlightEnabled

public void setHeadlightEnabled(boolean state)
                         throws InvalidWriteTimingException

Turn the local headlight on/off.

Parameters:

state - true to turn the light on

Throws:

InvalidWriteTimingException - An attempt was made to write outside of the NodeUpdateListener data changed callback method

setGlobalAmbientLightEnabled

public void setGlobalAmbientLightEnabled(boolean state)
                                  throws InvalidWriteTimingException

Turn the global ambient lighting setting on or off.

Parameters:

state - true to turn the light on

Throws:

InvalidWriteTimingException - An attempt was made to write outside of the NodeUpdateListener data changed callback method

isGlobalAmbientLightEnabled

public boolean isGlobalAmbientLightEnabled()

Get the current state of the global ambient light usage.

Returns:

true if the ambient light is currently active

setGlobalAmbientColor

public void setGlobalAmbientColor(float[] col)
                           throws java.lang.IllegalArgumentException,
                                  InvalidWriteTimingException

Set the ambient colour to the new value. Colour must be in the range [0, 1] otherwise an exception is generated.

Parameters:

col - The new colour value to use

Throws:

java.lang.IllegalArgumentException - The colour value is out of range

InvalidWriteTimingException - An attempt was made to write outside of the NodeUpdateListener data changed callback method

getGlobalAmbientColor

public void getGlobalAmbientColor(float[] col)

Retrieve the current colour value from the light.

Parameters:

col - An array to copy the colour value into

isDirectionalLight

public boolean isDirectionalLight()

Get the current state of the headlight type.

Returns:

true if the headlight is currently a directional light

setHeadlightType

public void setHeadlightType(boolean state)
                      throws InvalidWriteTimingException

Change the style of the headlight between directional and spot types.

Parameters:

state - true to turn the light to directional, false for spot

Throws:

InvalidWriteTimingException - An attempt was made to write outside of the NodeUpdateListener data changed callback method

compareTo

public int compareTo(Viewpoint vp)

Compares this object with the specified object for order. Returns a negative integer, zero, or a positive integer as this object is less than, equal to, or greater than the specified object.

Parameters:

vp - The argument instance to be compared

Returns:

-1, 0 or 1 depending on order

equals

public boolean equals(Viewpoint vp)

Compares this object with the specified object to check for equivalence.

Parameters:

vp - The viewpoint instance to be compared

Returns:

true if the objects represent identical values