javax.media.opengl

Interface GLAutoDrawable

All Superinterfaces:

GLDrawable, NativeSurfaceHolder

All Known Subinterfaces:

AWTGLAutoDrawable, GLOffscreenAutoDrawable, GLOffscreenAutoDrawable.FBO, GLSharedContextSetter

All Known Implementing Classes:

GLCanvas, GLJPanel

public interface GLAutoDrawable
extends GLDrawable

A higher-level abstraction than GLDrawable which supplies an event based mechanism (GLEventListener) for performing OpenGL rendering. A GLAutoDrawable automatically creates a primary rendering context which is associated with the GLAutoDrawable for the lifetime of the object.

Since the GLContext makeCurrent implementation is synchronized, i.e. blocks if the context is current on another thread, the internal GLContext for the GLAutoDrawable can be used for the event based rendering mechanism and by end users directly.

GLAutoDrawable Initialization

The implementation shall initialize itself as soon as possible, which is only possible after the attached NativeSurface becomes visible and and is realized.
The following initialization sequence should be implemented:

• Create the GLDrawable with the requested GLCapabilities
• Notify GLDrawable to validate the GLCapabilities by calling setRealized(true).
• Create the new GLContext.
• Initialize all OpenGL resources by calling init(..) for all registered GLEventListeners. This can be done immediately, or with the followup display(..) call.
• Send a reshape event by calling reshape(..) for all registered GLEventListeners. This shall be done after the init(..) calls.

Note: The last to GLEventListener actions shall be also performed, when adding a new one to an already initialized GLAutoDrawable.

GLAutoDrawable Reconfiguration

Another implementation detail is the GLDrawable reconfiguration. One use case is where a window is being dragged to another screen with a different pixel configuration, ie GLCapabilities. The implementation shall be able to detect such cases in conjunction with the associated NativeSurface.
For example, AWT's Canvas 's getGraphicsConfiguration() is capable to determine a display device change. This is demonstrated within GLCanvas's and NEWT's AWTCanvas getGraphicsConfiguration() specialization. Another demonstration is NEWT's NativeWindow implementation on the Windows platform, which utilizes the native platform's MonitorFromWindow(HWND) function.
All OpenGL resources shall be regenerated, while the drawable's GLCapabilities has to be chosen again. The following protocol shall be satisfied.

• Controlled disposal:
• Dispose all OpenGL resources by calling dispose(..) for all registered GLEventListeners.
• Destroy the GLContext.
• Notify GLDrawable of the invalid state by calling setRealized(false).
• Controlled regeneration:
• Create the new GLDrawable with the requested GLCapabilities
• Notify GLDrawable to revalidate the GLCapabilities by calling setRealized(true).
• Create the new GLContext.
• Initialize all OpenGL resources by calling init(..) for all registered GLEventListeners. This can be done immediatly, or with the followup display(..) call.
• Send a reshape event by calling reshape(..) for all registered GLEventListeners. This shall be done after the init(..) calls.

Note: Current graphics driver keep the surface configuration for a given window, even if the window is moved to a monitor with a different pixel configuration, ie 32bpp to 16bpp. However, it is best to not assume such behavior and make your application comply with the above protocol.

Avoiding breakage with older applications and because of the situation mentioned above, the boolean system property jogl.screenchange.action will control the screen change action as follows:

    -Djogl.screenchange.action=false Disable the GLDrawable reconfiguration (the default)
    -Djogl.screenchange.action=true  Enable  the GLDrawable reconfiguration
    

GLAutoDrawable Locking

GLAutoDrawable implementations perform locking in the following order:

1. getUpstreamLock().lock()
2. GLDrawable.getNativeSurface().lockSurface()

and releases the locks accordingly:

1. GLDrawable.getNativeSurface().unlockSurface()
2. getUpstreamLock().unlock()

Above locking order is mandatory to guarantee atomicity of operation and to avoid race-conditions. A custom implementation or user applications requiring exclusive access shall follow the locking order. See:

• getUpstreamLock()
• invoke(boolean, GLRunnable)
• invoke(boolean, List)

Field Summary

Fields

Modifier and Type	Field and Description
static boolean	SCREEN_CHANGE_ACTION_ENABLED Flag reflecting whether the GLDrawable reconfiguration will be issued in case a screen device change occurred, e.g.

Method Summary

Methods

Modifier and Type	Method and Description
void	addGLEventListener(GLEventListener listener) Adds the given listener to the end of this drawable queue.
void	addGLEventListener(int index, GLEventListener listener) Adds the given listener at the given index of this drawable queue.
boolean	areAllGLEventListenerInitialized() Returns true if all added GLEventListener are initialized, otherwise false.
GLContext	createContext(GLContext shareWith) Creates a new context for drawing to this drawable that will optionally share buffer objects, textures and other server-side OpenGL objects with the specified GLContext.
void	destroy() Destroys all resources associated with this GLAutoDrawable, inclusive the GLContext.
void	display() Causes OpenGL rendering to be performed for this GLAutoDrawable in the following order: Calling display(..) for all registered GLEventListeners.
GLEventListener	disposeGLEventListener(GLEventListener listener, boolean remove) Disposes the given listener via dispose(..) if it has been initialized and added to this queue.
void	flushGLRunnables() Flushes all enqueued GLRunnable of this GLAutoDrawable including notifying waiting executor.
GLAnimatorControl	getAnimator()
boolean	getAutoSwapBufferMode() Indicates whether automatic buffer swapping is enabled for this drawable.
GLContext	getContext() Returns the context associated with this drawable.
int	getContextCreationFlags()
GLDrawable	getDelegatedDrawable() If the implementation uses delegation, return the delegated GLDrawable instance, otherwise return this instance.
Thread	getExclusiveContextThread()
GL	getGL() Returns the GL pipeline object this GLAutoDrawable uses.
GLEventListener	getGLEventListener(int index) Returns the GLEventListener at the given index of this drawable queue.
int	getGLEventListenerCount() Returns the number of GLEventListener of this drawable queue.
boolean	getGLEventListenerInitState(GLEventListener listener) Retrieves whether the given listener is initialized or not.
RecursiveLock	getUpstreamLock() Returns the recursive lock object of the upstream widget to synchronize multithreaded access on top of NativeSurface.lockSurface().
Object	getUpstreamWidget() Method may return the upstream UI toolkit object holding this GLAutoDrawable instance, if exist.
boolean	invoke(boolean wait, GLRunnable glRunnable) Enqueues a one-shot GLRunnable, which will be executed within the next display() call after all registered GLEventListeners display(GLAutoDrawable) methods have been called.
boolean	invoke(boolean wait, List<GLRunnable> glRunnables) Extends invoke(boolean, GLRunnable) functionality allowing to inject a list of GLRunnables.
boolean	isThreadGLCapable() Indicates whether the current thread is capable of performing OpenGL-related work.
GLEventListener	removeGLEventListener(GLEventListener listener) Removes the given listener from this drawable queue.
void	setAnimator(GLAnimatorControl animatorControl) Registers the usage of an animator, an GLAnimatorControl implementation.
void	setAutoSwapBufferMode(boolean enable) Enables or disables automatic buffer swapping for this drawable.
GLContext	setContext(GLContext newCtx, boolean destroyPrevCtx) Associate the new context, newtCtx, to this auto-drawable.
void	setContextCreationFlags(int flags)
Thread	setExclusiveContextThread(Thread t) Dedicates this instance's GLContext to the given thread. The thread will exclusively claim the GLContext via display() and not release it until destroy() or setExclusiveContextThread(null) has been called.
GL	setGL(GL gl) Sets the GL pipeline object this GLAutoDrawable uses.
void	setGLEventListenerInitState(GLEventListener listener, boolean initialized) Sets the given listener's initialized state.

Methods inherited from interface javax.media.opengl.GLDrawable

getChosenGLCapabilities, getFactory, getGLProfile, getHandle, getNativeSurface, getRequestedGLCapabilities, getSurfaceHeight, getSurfaceWidth, isGLOriented, isRealized, setRealized, swapBuffers, toString

Field Detail

SCREEN_CHANGE_ACTION_ENABLED

static final boolean SCREEN_CHANGE_ACTION_ENABLED

Flag reflecting whether the GLDrawable reconfiguration will be issued in case a screen device change occurred, e.g. in a multihead environment, where you drag the window to another monitor.

Method Detail

getDelegatedDrawable

GLDrawable getDelegatedDrawable()

If the implementation uses delegation, return the delegated GLDrawable instance, otherwise return this instance.

getContext

GLContext getContext()

Returns the context associated with this drawable. The returned context will be synchronized. Don't rely on it's identity, the context may change.

setContext

GLContext setContext(GLContext newCtx,
                   boolean destroyPrevCtx)

Associate the new context, newtCtx, to this auto-drawable.

Remarks:

• The currently associated context will be destroyed if destroyPrevCtx is true, otherwise it will be disassociated from this auto-drawable via setGLDrawable(null, true); including glFinish().
• The new context will be associated with this auto-drawable via newCtx.setGLDrawable(drawable, true);.
• If the old context was current on this thread, it is being released after disassociating this auto-drawable.
• If the new context was current on this thread, it is being released before associating this auto-drawable and made current afterwards.
• Implementation may issue #makeCurrent() and #release() while drawable reassociation.
• The user shall take extra care of thread synchronization, i.e. lock the involved auto-drawable's upstream-locks and surfaces to avoid a race condition. See GLAutoDrawable Locking.

Parameters:

newCtx - the new context, maybe null for dis-association.

destroyPrevCtx - if true, destroy the previous context if exists

Returns:

the previous GLContext, maybe null

See Also:

GLContext.setGLDrawable(GLDrawable, boolean), GLContext.setGLReadDrawable(GLDrawable), GLDrawableHelper.switchContext(GLDrawable, GLContext, boolean, GLContext, int)

addGLEventListener

void addGLEventListener(GLEventListener listener)

Adds the given listener to the end of this drawable queue. The listeners are notified of events in the order of the queue.

The newly added listener's init(..) method will be called once before any other of it's callback methods. See getGLEventListenerInitState(GLEventListener) for details.

Parameters:

listener - The GLEventListener object to be inserted

addGLEventListener

void addGLEventListener(int index,
                      GLEventListener listener)
                        throws IndexOutOfBoundsException

Adds the given listener at the given index of this drawable queue. The listeners are notified of events in the order of the queue.

The newly added listener's init(..) method will be called once before any other of it's callback methods. See getGLEventListenerInitState(GLEventListener) for details.

Parameters:

index - Position where the listener will be inserted. Should be within (0 <= index && index <= size()). An index value of -1 is interpreted as the end of the list, size().

listener - The GLEventListener object to be inserted

Throws:

IndexOutOfBoundsException - If the index is not within (0 <= index && index <= size()), or -1

getGLEventListenerCount

int getGLEventListenerCount()

Returns the number of GLEventListener of this drawable queue.

Returns:

The number of GLEventListener objects of this drawable queue.

areAllGLEventListenerInitialized

boolean areAllGLEventListenerInitialized()

Returns true if all added GLEventListener are initialized, otherwise false.

Since:

2.2

getGLEventListener

GLEventListener getGLEventListener(int index)
                                   throws IndexOutOfBoundsException

Returns the GLEventListener at the given index of this drawable queue.

Parameters:

index - Position of the listener to be returned. Should be within (0 <= index && index < size()). An index value of -1 is interpreted as last listener, size()-1.

Returns:

The GLEventListener object at the given index.

Throws:

IndexOutOfBoundsException - If the index is not within (0 <= index && index < size()), or -1

getGLEventListenerInitState

boolean getGLEventListenerInitState(GLEventListener listener)

Retrieves whether the given listener is initialized or not.

After adding a GLEventListener it is marked uninitialized and added to a list of to be initialized GLEventListener. If such uninitialized GLEventListener's handler methods (reshape, display) are about to be invoked, it's init(..) method is invoked first. Afterwards the GLEventListener is marked initialized and removed from the list of to be initialized GLEventListener.

This methods returns the GLEventListener initialized state, i.e. returns false if it is included in the list of to be initialized GLEventListener, otherwise true.

Parameters:

listener - the GLEventListener object to query it's initialized state.

setGLEventListenerInitState

void setGLEventListenerInitState(GLEventListener listener,
                               boolean initialized)

Sets the given listener's initialized state.

This methods allows manually setting the GLEventListener initialized state, i.e. adding it to, or removing it from the list of to be initialized GLEventListener. See getGLEventListenerInitState(GLEventListener) for details.

Warning: This method does not validate whether the given listener's is member of this drawable queue, i.e. added.

This method is only exposed to allow users full control over the GLEventListener's state and is usually not recommended to change.

One use case is moving a GLContext and their initialized GLEventListener from one GLAutoDrawable to another, where a subsequent init(..) call after adding it to the new owner is neither required nor desired. See swapGLContextAndAllGLEventListener(..).

Parameters:

listener - the GLEventListener object to perform a state change.

initialized - if true, mark the listener initialized, otherwise uninitialized.

disposeGLEventListener

GLEventListener disposeGLEventListener(GLEventListener listener,
                                     boolean remove)

Disposes the given listener via dispose(..) if it has been initialized and added to this queue.

If remove is true, the GLEventListener is removed from this drawable queue before disposal, otherwise marked uninitialized.

If an GLAnimatorControl is being attached and the current thread is different than the animator's thread, it is paused during the operation.

Note that this is an expensive operation, since dispose(..) is decorated by GLContext.makeCurrent() and GLContext.release().

Use removeGLEventListener(listener) instead if you just want to remove the listener and don't care about the disposal of the it's (OpenGL) resources.

Also note that this is done from within a particular drawable's GLEventListener handler (reshape, display, etc.), that it is not guaranteed that all other listeners will be evaluated properly during this update cycle.

Parameters:

listener - The GLEventListener object to be disposed and removed if remove is true

remove - pass true to have the listener removed from this drawable queue, otherwise pass false

Returns:

the disposed and/or removed GLEventListener, or null if no action was performed, i.e. listener was not added

removeGLEventListener

GLEventListener removeGLEventListener(GLEventListener listener)

Removes the given listener from this drawable queue.

This is an inexpensive operation, since the removed listener's dispose(..) method will not be called.

Use disposeGLEventListener(listener, true) instead to ensure disposal of the listener's (OpenGL) resources.

Note that if this is done from within a particular drawable's GLEventListener handler (reshape, display, etc.), that it is not guaranteed that all other listeners will be evaluated properly during this update cycle.

Parameters:

listener - The GLEventListener object to be removed

Returns:

the removed GLEventListener, or null if listener was not added

setAnimator

void setAnimator(GLAnimatorControl animatorControl)
                 throws GLException

Registers the usage of an animator, an GLAnimatorControl implementation. The animator will be queried whether it's animating, ie periodically issuing display() calls or not.

This method shall be called by an animator implementation only,
e.g. AnimatorBase.add(javax.media.opengl.GLAutoDrawable), passing it's control implementation,
and AnimatorBase.remove(javax.media.opengl.GLAutoDrawable), passing null.

Impacts display() and invoke(boolean, GLRunnable) semantics.

Parameters:

animatorControl - null reference indicates no animator is using this GLAutoDrawable,
a valid reference indicates an animator is using this GLAutoDrawable.

Throws:

GLException - if an animator is already registered.

See Also:

display(), invoke(boolean, GLRunnable), GLAnimatorControl

getAnimator

GLAnimatorControl getAnimator()

Returns:

the registered GLAnimatorControl implementation, using this GLAutoDrawable.

See Also:

setAnimator(javax.media.opengl.GLAnimatorControl), GLAnimatorControl

setExclusiveContextThread

Thread setExclusiveContextThread(Thread t)
                                 throws GLException

Dedicates this instance's GLContext to the given thread.
The thread will exclusively claim the GLContext via display() and not release it until destroy() or setExclusiveContextThread(null) has been called.

Default non-exclusive behavior is requested via setExclusiveContextThread(null), which will cause the next call of display() on the exclusive thread to release the GLContext. Only after it's async release, getExclusiveContextThread() will return null.

To release a previous made exclusive thread, a user issues setExclusiveContextThread(null) and may poll getExclusiveContextThread() until it returns null, while the exclusive thread is still running.

Note: Setting a new exclusive thread without properly releasing a previous one will throw an GLException.

Note: Utilizing this feature w/ AWT could lead to an AWT-EDT deadlock, depending on the AWT implementation. Hence it is advised not to use it with native AWT GLAutoDrawable like GLCanvas.

One scenario could be to dedicate the context to the animator thread and spare redundant context switches, see AnimatorBase.setExclusiveContext(boolean).

Parameters:

t - the exclusive thread to claim the context, or null for default operation.

Returns:

previous exclusive context thread

Throws:

GLException - If an exclusive thread is still active but a new one is attempted to be set

See Also:

AnimatorBase.setExclusiveContext(boolean)

getExclusiveContextThread

Thread getExclusiveContextThread()

See Also:

setExclusiveContextThread(Thread)

invoke

boolean invoke(boolean wait,
             GLRunnable glRunnable)
               throws IllegalStateException

Enqueues a one-shot GLRunnable, which will be executed within the next display() call after all registered GLEventListeners display(GLAutoDrawable) methods have been called.

If no GLAnimatorControl is animating (default),
or if the current thread is the animator thread,
a display() call is issued after enqueue the GLRunnable, hence the GLRunnable will be executed right away.

If an animator is running,
no explicit display() call is issued, allowing the animator to perform at due time.

If wait is true the call blocks until the glRunnable has been executed by the animator, otherwise the method returns immediately.

If wait is true and GLDrawable.isRealized() returns false or getContext() returns null, the call is ignored and returns false.
This helps avoiding deadlocking the caller.

The internal queue of GLRunnable's is being flushed with destroy() where all blocked callers are being notified.

To avoid a deadlock situation which causes an IllegalStateException one should avoid issuing invoke while this GLAutoDrawable is being locked.
Detected deadlock situations throwing an IllegalStateException are:

• Animator is running on another thread and waiting and is locked on current thread, but is not GL-Thread
• No Animator is running on another thread and is locked on current thread, but is not GL-Thread

Parameters:

wait - if true block until execution of glRunnable is finished, otherwise return immediately w/o waiting

glRunnable - the GLRunnable to execute within display()

Returns:

true if the GLRunnable has been processed or queued, otherwise false.

Throws:

IllegalStateException - in case of a detected deadlock situation ahead, see above.

See Also:

setAnimator(GLAnimatorControl), display(), GLRunnable, invoke(boolean, List), flushGLRunnables()

invoke

boolean invoke(boolean wait,
             List<GLRunnable> glRunnables)
               throws IllegalStateException

Extends invoke(boolean, GLRunnable) functionality allowing to inject a list of GLRunnables.

Parameters:

wait - if true block until execution of the last glRunnable is finished, otherwise return immediately w/o waiting

glRunnables - the GLRunnables to execute within display()

Returns:

true if the GLRunnables has been processed or queued, otherwise false.

Throws:

IllegalStateException - in case of a detected deadlock situation ahead, see invoke(boolean, GLRunnable).

See Also:

invoke(boolean, GLRunnable), flushGLRunnables()

flushGLRunnables

void flushGLRunnables()

Flushes all enqueued GLRunnable of this GLAutoDrawable including notifying waiting executor.

The executor which might have been blocked until notified will be unblocked and all tasks removed from the queue.

Since:

2.2

See Also:

invoke(boolean, GLRunnable)

destroy

void destroy()

Destroys all resources associated with this GLAutoDrawable, inclusive the GLContext. If a window is attached to it's implementation, it shall be closed. Causes disposing of all OpenGL resources by calling dispose(..) for all registered GLEventListeners. Called automatically by the window system toolkit upon receiving a destroy notification. This routine may be called manually.

display

void display()

Causes OpenGL rendering to be performed for this GLAutoDrawable in the following order:

• Calling display(..) for all registered GLEventListeners.
• Executes all one-shot GLRunnable, enqueued via invoke(boolean, GLRunnable).

May be called periodically by a running GLAnimatorControl implementation,
which must register itself with setAnimator(javax.media.opengl.GLAnimatorControl).

Called automatically by the window system toolkit upon receiving a repaint() request,
except an GLAnimatorControl implementation GLAnimatorControl.isAnimating().

This routine may also be called manually for better control over the rendering process. It is legal to call another GLAutoDrawable's display method from within the display(..) callback.

In case of a new generated OpenGL context, the implementation shall call init(..) for all registered GLEventListeners before making the actual display(..) calls, in case this has not been done yet.

See Also:

setAnimator(javax.media.opengl.GLAnimatorControl)

setAutoSwapBufferMode

void setAutoSwapBufferMode(boolean enable)

Enables or disables automatic buffer swapping for this drawable. By default this property is set to true; when true, after all GLEventListeners have been called for a display() event, the front and back buffers are swapped, displaying the results of the render. When disabled, the user is responsible for calling GLDrawable.swapBuffers(..) manually.

getAutoSwapBufferMode

boolean getAutoSwapBufferMode()

Indicates whether automatic buffer swapping is enabled for this drawable. See setAutoSwapBufferMode(boolean).

setContextCreationFlags

void setContextCreationFlags(int flags)

Parameters:

flags - Additional context creation flags.

See Also:

GLContext.setContextCreationFlags(int), GLContext.enableGLDebugMessage(boolean)

getContextCreationFlags

int getContextCreationFlags()

Returns:

Additional context creation flags

createContext

GLContext createContext(GLContext shareWith)

Creates a new context for drawing to this drawable that will optionally share buffer objects, textures and other server-side OpenGL objects with the specified GLContext.

The GLContext share need not be associated with this GLDrawable and may be null if sharing of display lists and other objects is not desired. See the note in the overview documentation on context sharing.

This GLAutoDrawable implementation holds it's own GLContext reference, thus created a GLContext using this methods won't replace it implicitly. To replace or set this GLAutoDrawable's GLContext you need to call setContext(GLContext, boolean).

The GLAutoDrawable implementation shall also set the context creation flags as customized w/ setContextCreationFlags(int).

Specified by:

createContext in interface GLDrawable

getGL

GL getGL()

Returns the GL pipeline object this GLAutoDrawable uses. If this method is called outside of the GLEventListener's callback methods (init, display, etc.) it may return null. Users should not rely on the identity of the returned GL object; for example, users should not maintain a hash table with the GL object as the key. Additionally, the GL object should not be cached in client code, but should be re-fetched from the GLAutoDrawable at the beginning of each call to init, display, etc.

setGL

GL setGL(GL gl)

Sets the GL pipeline object this GLAutoDrawable uses. This should only be called from within the GLEventListener's callback methods, and usually only from within the init() method, in order to install a composable pipeline. See the JOGL demos for examples.

Returns:

the set GL pipeline or null if not successful

getUpstreamWidget

Object getUpstreamWidget()

Method may return the upstream UI toolkit object holding this GLAutoDrawable instance, if exist.

Currently known Java UI toolkits and it's known return types are:

Toolkit	GLAutoDrawable Implementation	~	Return Type of getUpstreamWidget()
NEWT	com.jogamp.newt.opengl.GLWindow	has a	com.jogamp.newt.Window
SWT	com.jogamp.opengl.swt.GLCanvas	is a	org.eclipse.swt.widgets.Canvas
AWT	GLCanvas	is a	Canvas
AWT	GLJPanel	is a	JPanel

However, the result may be other object types than the listed above due to new supported toolkits.

This method may also return null if no UI toolkit is being used, as common for offscreen rendering.

getUpstreamLock

RecursiveLock getUpstreamLock()

Returns the recursive lock object of the upstream widget to synchronize multithreaded access on top of NativeSurface.lockSurface().

See GLAutoDrawable Locking.

Since:

2.2

isThreadGLCapable

boolean isThreadGLCapable()

Indicates whether the current thread is capable of performing OpenGL-related work.

Implementation utilizes this knowledge to determine whether display() performs the OpenGL commands on the current thread directly or spawns them on the dedicated OpenGL thread.

Since:

2.2