## javax.media.opengl
Class GLDrawableFactory

    java.lang.Object
      javax.media.opengl.GLDrawableFactory

    public abstract class GLDrawableFactory

extends Object

Provides a virtual machine- and operating system-independent mechanism for creating `GLDrawable`s.

The `GLCapabilities` objects passed in to the various factory methods are used as a hint for the properties of the returned drawable. The default capabilities selection algorithm (equivalent to passing in a null `GLCapabilitiesChooser`) is described in `DefaultGLCapabilitiesChooser`. Sophisticated applications needing to change the selection algorithm may pass in their own `GLCapabilitiesChooser` which can select from the available pixel formats. The GLCapabilitiesChooser mechanism may not be supported by all implementations or on all platforms, in which case any passed GLCapabilitiesChooser will be ignored.

Because of the multithreaded nature of the Java platform's window system toolkit, it is typically not possible to immediately reject a given `GLCapabilities` as being unsupportable by either returning `null` from the creation routines or raising a `GLException`. The semantics of the rejection process are (unfortunately) left unspecified for now. The current implementation will cause a `GLException` to be raised during the first repaint of the `GLCanvas` or `GLJPanel` if the capabilities can not be met. Pbuffers are always created immediately and their creation will fail with a `GLException` if errors occur.

The concrete GLDrawableFactory subclass instantiated by `getFactory` can be changed by setting the system property `opengl.factory.class.name` to the fully-qualified name of the desired class.

Constructor Summary
`protected` `GLDrawableFactory()`

Method Summary
`abstract boolean` `canCreateExternalGLDrawable()` Returns true if it is possible to create an external GLDrawable object via `createExternalGLDrawable()`.
`abstract boolean` `canCreateGLPbuffer()` Returns true if it is possible to create a GLPbuffer.
`abstract AbstractGraphicsConfiguration` `chooseGraphicsConfiguration(GLCapabilities capabilities, GLCapabilitiesChooser chooser, AbstractGraphicsDevice device)` Selects a graphics configuration on the specified graphics device compatible with the supplied GLCapabilities.
`abstract GLContext` `createExternalGLContext()` Creates a GLContext object representing an existing OpenGL context in an external (third-party) OpenGL-based library.
`abstract GLDrawable` `createExternalGLDrawable()` Creates a `GLDrawable` object representing an existing OpenGL drawable in an external (third-party) OpenGL-based library.
`abstract GLPbuffer` `createGLPbuffer(GLCapabilities capabilities, GLCapabilitiesChooser chooser, int initialWidth, int initialHeight, GLContext shareWith)` Creates a GLPbuffer with the given capabilites and dimensions.
`static GLDrawableFactory` `getFactory()` Returns the sole GLDrawableFactory instance.
`abstract GLDrawable` `getGLDrawable(Object target, GLCapabilities capabilities, GLCapabilitiesChooser chooser)` Returns a GLDrawable that wraps a platform-specific window system object, such as an AWT or LCDUI Canvas.

Methods inherited from class java.lang.Object
`clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait`

Constructor Detail

### GLDrawableFactory

    protected GLDrawableFactory()

Method Detail

### getFactory

    public static GLDrawableFactory getFactory()

  Returns the sole GLDrawableFactory instance.

### chooseGraphicsConfiguration

    public abstract AbstractGraphicsConfiguration chooseGraphicsConfiguration(GLCapabilities capabilities,
                                                                              GLCapabilitiesChooser chooser,
                                                                              AbstractGraphicsDevice device)
                                                                       throws IllegalArgumentException,
                                                                              GLException

  Selects a graphics configuration on the specified graphics device compatible with the supplied GLCapabilities. This method is intended to be used by applications which do not use the supplied GLCanvas class but instead wrap their own Canvas or other window toolkit-specific object with a GLDrawable. Some platforms (specifically X11) require the graphics configuration to be specified when the window toolkit object is created. This method may return null on platforms on which the OpenGL pixel format selection process is performed later.

  The concrete data type of the passed graphics device and returned graphics configuration must be specified in the documentation binding this particular API to the underlying window toolkit. The Reference Implementation accepts `AWTGraphicsDevice` objects and returns `AWTGraphicsConfiguration` objects.

  Throws:
    `IllegalArgumentException` - if the data type of the passed AbstractGraphicsDevice is not supported by this GLDrawableFactory.
    `GLException` - if any window system-specific errors caused the selection of the graphics configuration to fail.
  See Also:
    `Canvas.Canvas(java.awt.GraphicsConfiguration)`

### getGLDrawable

    public abstract GLDrawable getGLDrawable(Object target,
                                             GLCapabilities capabilities,
                                             GLCapabilitiesChooser chooser)
                                      throws IllegalArgumentException,
                                             GLException

  Returns a GLDrawable that wraps a platform-specific window system object, such as an AWT or LCDUI Canvas. On platforms which support it, selects a pixel format compatible with the supplied GLCapabilities, or if the passed GLCapabilities object is null, uses a default set of capabilities. On these platforms, uses either the supplied GLCapabilitiesChooser object, or if the passed GLCapabilitiesChooser object is null, uses a DefaultGLCapabilitiesChooser instance.

  Throws:
    `IllegalArgumentException` - if the passed target is either null or its data type is not supported by this GLDrawableFactory.
    `GLException` - if any window system-specific errors caused the creation of the GLDrawable to fail.

### canCreateGLPbuffer

    public abstract boolean canCreateGLPbuffer()

  Returns true if it is possible to create a GLPbuffer. Some older graphics cards do not have this capability.

### createGLPbuffer

    public abstract GLPbuffer createGLPbuffer(GLCapabilities capabilities,
                                              GLCapabilitiesChooser chooser,
                                              int initialWidth,
                                              int initialHeight,
                                              GLContext shareWith)
                                       throws GLException

  Creates a GLPbuffer with the given capabilites and dimensions.

  See the note in the overview documentation on context sharing.

  Throws:
    `GLException` - if any window system-specific errors caused the creation of the GLPbuffer to fail.

### createExternalGLContext

    public abstract GLContext createExternalGLContext()
                                               throws GLException

  Creates a GLContext object representing an existing OpenGL context in an external (third-party) OpenGL-based library. This GLContext object may be used to draw into this preexisting context using its `GL` and `GLU` objects. New contexts created through `GLDrawable`s may share textures and display lists with this external context.

  The underlying OpenGL context must be current on the current thread at the time this method is called. The user is responsible for the maintenance of the underlying OpenGL context; calls to `makeCurrent` and `release` on the returned GLContext object have no effect. If the underlying OpenGL context is destroyed, the `destroy` method should be called on the `GLContext`. A new `GLContext` object should be created for each newly-created underlying OpenGL context.

  Throws:
    `GLException` - if any window system-specific errors caused the creation of the external GLContext to fail.

### canCreateExternalGLDrawable

    public abstract boolean canCreateExternalGLDrawable()

  Returns true if it is possible to create an external GLDrawable object via `createExternalGLDrawable()`.

### createExternalGLDrawable

    public abstract GLDrawable createExternalGLDrawable()
                                                 throws GLException

  Creates a `GLDrawable` object representing an existing OpenGL drawable in an external (third-party) OpenGL-based library. This GLDrawable object may be used to create new, fully-functional `GLContext`s on the OpenGL drawable. This is useful when interoperating with a third-party OpenGL-based library and it is essential to not perturb the state of the library's existing context, even to the point of not sharing textures or display lists with that context.

  An underlying OpenGL context must be current on the desired drawable and the current thread at the time this method is called. The user is responsible for the maintenance of the underlying drawable. If one or more contexts are created on the drawable using `GLDrawable.createContext(javax.media.opengl.GLContext)`, and the drawable is deleted by the third-party library, the user is responsible for calling `GLContext.destroy()` on these contexts.

  Calls to `setSize`, `getWidth` and `getHeight` are illegal on the returned GLDrawable. If these operations are required by the user, they must be performed by the third-party library.

  It is legal to create both an external GLContext and GLDrawable representing the same third-party OpenGL entities. This can be used, for example, to query current state information using the external GLContext and then create and set up new GLContexts using the external GLDrawable.

  This functionality may not be available on all platforms and `canCreateExternalGLDrawable()` should be called first to see if it is present. For example, on X11 platforms, this API requires the presence of GLX 1.3 or later.

  Throws:
    `GLException` - if any window system-specific errors caused the creation of the external GLDrawable to fail.

Copyright 2005 Sun Microsystems, Inc. All rights reserved. Use is subject to license terms.