gov.nasa.worldwind.util
Class TextureAtlasElement

java.lang.Object
  gov.nasa.worldwind.util.TextureAtlasElement

All Implemented Interfaces:

Disposable

Direct Known Subclasses:

AbstractTacticalSymbol.IconAtlasElement

public class TextureAtlasElement
extends Object
implements Disposable

Represents a texture defined by a sub-image within a TextureAtlas.

TextureAtlasElement performs lazy retrieval and loading of its image source into its texture atlas. This loads the image source and adds it to the atlas only when the load(gov.nasa.worldwind.render.DrawContext) method is called. If the image source is a BufferedImage it is added to the atlas immediately when load is called. If the image source is a local file or a remote stream (URL), retrieval and loading is performed on a separate thread from the EDT.

Nested Class Summary

protected static class

TextureAtlasElement.RequestTask RequestTask is an implementation of the Runnable interface who's run method retrieves and loads this element's image source.

Field Summary

protected TextureAtlas	atlas Indicates the texture atlas this element belongs to.
protected BufferedImage	image The BufferedImage created as the image source is read.
protected boolean	imageInitializationFailed Indicates that image initialization failed.
protected Object	imageSource Indicates the original image source associated with this element.
protected PropertyChangeListener	listener The object to notify when the image is eventually loaded in memory.

Constructor Summary

TextureAtlasElement(TextureAtlas atlas, Object imageSource)
Creates a new texture atlas element with the specified atlas and image source.

Method Summary

protected boolean	addAtlasImage() Adds this element's image source into its texture atlas.
protected Runnable	createRequestTask() Returns an object that implements the Runnable interface, and who's run method retrieves and loads this element's image source.
void	dispose() Removes this element's image from its texture atlas and disposes of this element's image resource.
boolean	equals(Object o) Indicates whether another texture atlas element is equivalent to this one.
protected BufferedImage	getImage() Indicates the image created as the image source is read.
Object	getImageSource() Indicates the original image source associated with this element.
Dimension	getSize() Returns the image dimensions associated with this texture atlas element.
TextureCoords	getTexCoords() Returns the OpenGL texture coordinates associated this texture atlas element.
TextureAtlas	getTextureAtlas() Indicates the texture atlas this element belongs to.
int	hashCode() Returns the hash code for this texture atlas element's image source.
protected boolean	isBufferedImageSource() Indicates whether this element's image source is a BufferedImage.
boolean	isImageInitializationFailed() Indicates whether this element's image failed to load.
boolean	load(DrawContext dc) Loads this element's image and adds it to the texture atlas.
protected boolean	loadImage() Loads this element's image source into its image property.
protected void	notifyImageLoaded() Notifies this texture atlas element's listener that image loading has completed.
protected BufferedImage	readImage(URL fileUrl) Reads and returns the specified image URL as a BufferedImage.
protected boolean	requestImage(DrawContext dc) Requests that this element's image source be loaded into its texture atlas.
protected void	setImage(BufferedImage image) Specifies the image created as the image source is read.
String	toString() Returns the string representation of this texture atlas element's image source.

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Field Detail

atlas

protected TextureAtlas atlas

Indicates the texture atlas this element belongs to. Specified during construction.

image

protected volatile BufferedImage image

The BufferedImage created as the image source is read. This intermediate field is necessary because the image source is read on a non-EDT thread, but changes to the texture atlas must be performed on the EDT. This is set to null once the image is loaded into the texture atlas. This field is volatile in order to synchronize atomic access among threads. This field is not used if the image source is BufferedImage.

imageInitializationFailed

protected boolean imageInitializationFailed

Indicates that image initialization failed. This element should not be used if true. Initially false.

imageSource

protected Object imageSource

Indicates the original image source associated with this element. Specified during construction.

listener

protected PropertyChangeListener listener

The object to notify when the image is eventually loaded in memory. This is either the current layer or the layer list at the time the image source is requested. The latter is used when the image source is requested during ordered rendering mode, in which case the current layer is null. This set to null once the image is loaded into the texture atlas.

Constructor Detail

TextureAtlasElement

public TextureAtlasElement(TextureAtlas atlas,
                           Object imageSource)

Creates a new texture atlas element with the specified atlas and image source.

Parameters:

atlas - the texture atlas this element belongs to.

imageSource - a general image source. The source type may be one of the following:

• a URL
• an InputStream
• a File
• a String containing a valid URL description or a file or resource name available on the classpath.

Throws:

IllegalArgumentException - if either the atlas or the image source is null.

Method Detail

addAtlasImage

protected boolean addAtlasImage()

Adds this element's image source into its texture atlas. This throws an exception if this element's image source is not loaded and stored in the image property.

Returns:

true if this element's image is successfully added to the texture atlas, and false otherwise.

createRequestTask

protected Runnable createRequestTask()

Returns an object that implements the Runnable interface, and who's run method retrieves and loads this element's image source.

Returns:

a new request task that retrieves and loads this element's image source.

dispose

public void dispose()

Removes this element's image from its texture atlas and disposes of this element's image resource. This does nothing if this element's image has not yet been loaded.

Specified by:

dispose in interface Disposable

equals

public boolean equals(Object o)

Indicates whether another texture atlas element is equivalent to this one. This tests equality using the image source of each element.

Overrides:

equals in class Object

Parameters:

o - the object to test.

Returns:

true if the specified object is a TextureAtlasElement and its image source is equivalent to this element's image source, otherwise false.

getImage

protected BufferedImage getImage()

Indicates the image created as the image source is read.

Returns:

this element's image.

See Also:

setImage(java.awt.image.BufferedImage)

getImageSource

public Object getImageSource()

Indicates the original image source associated with this element.

Returns:

this element's image source.

getSize

public Dimension getSize()

Returns the image dimensions associated with this texture atlas element. Always call load before calling this method to ensure that the element is loaded into its texture atlas.

Returns:

the image dimensions associated with this texture atlas element, or null if this texture atlas element has not yet loaded or has failed to load.

See Also:

load(gov.nasa.worldwind.render.DrawContext)

getTexCoords

public TextureCoords getTexCoords()

Returns the OpenGL texture coordinates associated this texture atlas element. Always call load before calling this method to ensure that the element is loaded into its texture atlas.

The returned texture coordinates can change any time an element is added or removed from this element's texture atlas, and therefore should not be cached unless the caller has explicit knowledge of when this element's texture atlas has changed.

Returns:

the OpenGL texture coordinates corresponding this texture atlas element, or null if this texture atlas element has not yet loaded or has failed to load.

See Also:

load(gov.nasa.worldwind.render.DrawContext)

getTextureAtlas

public TextureAtlas getTextureAtlas()

Indicates the texture atlas this element belongs to.

Returns:

this element's texture atlas.

hashCode

public int hashCode()

Returns the hash code for this texture atlas element's image source.

Overrides:

hashCode in class Object

isBufferedImageSource

protected boolean isBufferedImageSource()

Indicates whether this element's image source is a BufferedImage.

Returns:

true if this element's image source is a BufferedImage, and false otherwise.

isImageInitializationFailed

public boolean isImageInitializationFailed()

Indicates whether this element's image failed to load. This element should not be used if true.

Returns:

true if this element's image failed to load, and false otherwise.

load

public boolean load(DrawContext dc)

Loads this element's image and adds it to the texture atlas. If the image is not yet loaded this initiates image source retrieval in a separate thread. This does nothing if the texture atlas already contains this element, or if this element's image failed to load in an earlier attempt.

Parameters:

dc - the current draw context. Used to generate a repaint event when the image source retrieval completes.

Returns:

true if this element's image is successfully loaded and added to the texture atlas, otherwise false.

loadImage

protected boolean loadImage()

Loads this element's image source into its image property. If the image source is a remote resource, this initiates a request for it and returns null.

Returns:

true if the image source has been loaded successfully, and false otherwise.

notifyImageLoaded

protected void notifyImageLoaded()

Notifies this texture atlas element's listener that image loading has completed. This does nothing if this texture atlas element has no listener.

readImage

protected BufferedImage readImage(URL fileUrl)

Reads and returns the specified image URL as a BufferedImage.

Parameters:

fileUrl - the image URL to read.

Returns:

the image URL as a BufferedImage, or null if the image could not be read.

requestImage

protected boolean requestImage(DrawContext dc)

Requests that this element's image source be loaded into its texture atlas. If the image source is a BufferedImage, this immediately loads it into the texture atlas and returns true. Otherwise, this initiates the retrieval of this element's image source in a separate thread and returns false. Once the image source is retrieved, a subsequent invocation of this method loads it into the texture atlas and returns true.

Parameters:

dc - the current draw context. Used to generate a repaint event when the image source retrieval completes.

Returns:

true if this element's image is loaded into the texture atlas, and false otherwise.

setImage

protected void setImage(BufferedImage image)

Specifies the image created as the image source is read. This intermediate field is necessary because the image source is read on a non-EDT thread, but changes to the texture atlas must be performed on the EDT. This field is volatile in order to synchronize atomic access among threads.

Parameters:

image - this element's image.

toString

public String toString()

Returns the string representation of this texture atlas element's image source.

Overrides:

toString in class Object