javax.media.opengl

Interface GLDrawable

All Known Subinterfaces:

AWTGLAutoDrawable, GLAutoDrawable, GLFBODrawable, GLFBODrawable.Resizeable, GLOffscreenAutoDrawable, GLOffscreenAutoDrawable.FBO, GLPbuffer, GLSharedContextSetter

All Known Implementing Classes:

jogamp.opengl.GLAutoDrawableBase, GLAutoDrawableDelegate, GLCanvas, GLCanvas, GLJPanel, GLWindow

public interface GLDrawable

An abstraction for an OpenGL rendering target. A GLDrawable's primary functionality is to create OpenGL contexts which can be used to perform rendering. A GLDrawable does not automatically create an OpenGL context, but all implementations of GLAutoDrawable do so upon creation.

Method Summary

Methods

Modifier and Type	Method and Description
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.
GLCapabilitiesImmutable	getChosenGLCapabilities() Fetches the GLCapabilitiesImmutable corresponding to the chosen OpenGL capabilities (pixel format / visual / GLProfile) for this drawable. On some platforms, the pixel format is not directly associated with the drawable; a best attempt is made to return a reasonable value in this case.
GLDrawableFactory	getFactory() Return the GLDrawableFactory being used to create this instance.
GLProfile	getGLProfile() Fetches the GLProfile for this drawable.
long	getHandle() Returns the GL drawable handle, guaranteed to be valid after realization and while it's surface is being locked.
int	getHeight() Returns the current height of this GLDrawable.
NativeSurface	getNativeSurface() Returns the underlying native surface which surface handle represents this OpenGL drawable's native resource.
int	getWidth() Returns the current width of this GLDrawable.
boolean	isGLOriented() Returns true if the drawable is rendered in OpenGL's coordinate system, origin at bottom left.
boolean	isRealized() Returns true if this drawable is realized, otherwise true.
void	setRealized(boolean realized) Indicates to GLDrawable implementations whether the underlying surface has been created and can be drawn into.
void	swapBuffers() Swaps the front and back buffers of this drawable.
String	toString()

Method Detail

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.

setRealized

void setRealized(boolean realized)

Indicates to GLDrawable implementations whether the underlying surface has been created and can be drawn into.

If realized, the drawable handle may become valid while it's surface is being locked.

End users do not need to call this method; it is not necessary to call setRealized on a GLAutoDrawable as these perform the appropriate calls on their underlying GLDrawables internally.

Developers implementing new OpenGL components for various window toolkits need to call this method against GLDrawables obtained from the GLDrawableFactory via the GLDrawableFactory.createGLDrawable(NativeSurface) method. It must typically be called with an argument of true when the component associated with the GLDrawable is realized and with an argument of false just before the component is unrealized. For the AWT, this means calling setRealized(true) in the addNotify method and with an argument of false in the removeNotify method.

GLDrawable implementations should handle multiple cycles of setRealized(true) / setRealized(false) calls. Most, if not all, Java window toolkits have a persistent object associated with a given component, regardless of whether that component is currently realized. The GLDrawable object associated with a particular component is intended to be similarly persistent. A GLDrawable is intended to be created for a given component when it is constructed and live as long as that component. setRealized allows the GLDrawable to re-initialize and destroy any associated resources as the component becomes realized and unrealized, respectively.

With an argument of true, the minimum implementation shall call NativeSurface's lockSurface() and if successful:

• Update the GLCapabilities, which are associated with the attached NativeSurface's AbstractGraphicsConfiguration.
• Release the lock with NativeSurface's unlockSurface().

This is important since NativeSurface's lockSurface() ensures resolving the window/surface handles, and the drawable's GLCapabilities might have changed.

Calling this method has no other effects. For example, if removeNotify is called on a Canvas implementation for which a GLDrawable has been created, it is also necessary to destroy all OpenGL contexts associated with that GLDrawable. This is not done automatically by the implementation.

See Also:

isRealized(), getHandle(), NativeSurface.lockSurface()

isRealized

boolean isRealized()

Returns true if this drawable is realized, otherwise true.

A drawable can be realized and unrealized via setRealized(boolean).

See Also:

setRealized(boolean)

getWidth

int getWidth()

Returns the current width of this GLDrawable.

getHeight

int getHeight()

Returns the current height of this GLDrawable.

isGLOriented

boolean isGLOriented()

Returns true if the drawable is rendered in OpenGL's coordinate system, origin at bottom left. Otherwise returns false, i.e. origin at top left.

Default impl. is true, i.e. OpenGL coordinate system.

Currently only MS-Windows bitmap offscreen drawable uses a non OpenGL orientation and hence returns false.
This removes the need of a vertical flip when used in AWT or Windows applications.

swapBuffers

void swapBuffers()
                 throws GLException

Swaps the front and back buffers of this drawable. For GLAutoDrawable implementations, when automatic buffer swapping is enabled (as is the default), this method is called automatically and should not be called by the end user.

Throws:

GLException

getChosenGLCapabilities

GLCapabilitiesImmutable getChosenGLCapabilities()

Fetches the GLCapabilitiesImmutable corresponding to the chosen OpenGL capabilities (pixel format / visual / GLProfile) for this drawable.
On some platforms, the pixel format is not directly associated with the drawable; a best attempt is made to return a reasonable value in this case.
This object shall be directly associated to the attached NativeSurface's AbstractGraphicsConfiguration, and if changes are necessary, they should reflect those as well.

Returns:

The immutable queried instance.

getGLProfile

GLProfile getGLProfile()

Fetches the GLProfile for this drawable. Returns the GLProfile object, no copy.

getNativeSurface

NativeSurface getNativeSurface()

Returns the underlying native surface which surface handle represents this OpenGL drawable's native resource.

See Also:

getHandle()

getHandle

long getHandle()

Returns the GL drawable handle, guaranteed to be valid after realization and while it's surface is being locked.

It is usually identical to the underlying windowing toolkit surface's handle or an intermediate layer to suite GL, e.g. an EGL surface.

On EGL it is represented by the EGLSurface.
On X11/GLX it is represented by either the Window XID, GLXPixmap, or GLXPbuffer.
On Windows it is represented by the HDC, which may change with each NativeSurface.lockSurface().

See Also:

setRealized(boolean), NativeSurface.lockSurface(), NativeSurface.unlockSurface()

getFactory

GLDrawableFactory getFactory()

Return the GLDrawableFactory being used to create this instance.

toString

String toString()

Overrides:

toString in class Object