* Sharing of server-side OpenGL objects such as buffer objects, e.g. VBOs, * and textures among OpenGL contexts is supported with this interface. *
** A master {@link GLContext} is the {@link GLContext} which is created first. * Subsequent shared {@link GLContext} w/ the master are referred as slave {@link GLContext}. *
** Implementations of this interface control the slave's {@link GLContext} and {@link GLAutoDrawable} realization, * i.e. the slave {@link GLAutoDrawable} will not be realized before their associated master. *
** Using the nearest or same {@link GLCapabilitiesImmutable#getVisualID(com.jogamp.nativewindow.VisualIDHolder.VIDType) visual ID} * or {@link GLCapabilitiesImmutable caps} across the shared {@link GLDrawable}s will yield best compatibility. *
** After shared objects are created on the master, the OpenGL pipeline * might need to be synchronized w/ the slaves, e.g. via {@link GL#glFinish()}. * At least this has been experienced w/ OSX 10.9. *
*
* In general, destroying a master {@link GLContext} before their shared slaves
* shall be permissible, i.e. the OpenGL driver needs to handle pending destruction of shared resources.
* This is confirmed to work properly on most platform/driver combinations,
* see unit test com.jogamp.opengl.test.junit.jogl.acore.TestSharedContextVBOES2NEWT3 and similar.
*
* However, to avoid scenarios with buggy drivers, users may not destroy the
* master {@link GLContext} before its shared slave {@link GLContext} instances
* as long as they are using them.
* Otherwise the OpenGL driver may crash w/ SIGSEGV, due to using already destroyed shared resources,
* if not handling the pending destruction of the latter!
* Either proper lifecycle synchronization is implemented, e.g. by notifying the slaves about the loss of the shared resources,
* or the slaves validate whether the resources are still valid.
*
* To simplify above lifecycle issues, one may use a {@link GLDrawableFactory#createDummyDrawable(com.jogamp.nativewindow.AbstractGraphicsDevice, boolean, GLCapabilitiesImmutable, GLCapabilitiesChooser) dummy}
* {@link GLDrawable} and it's {@link GLContext} as the master of all shared slave {@link GLContext}.
* Since this dummy instance does not depend on any native windowing system, it can be controlled easily w/o being in sight.
* Below code creates a {@link GLAutoDrawable} based on a dummy GLDrawable:
*
// GLProfile and GLCapabilities should be equal across all shared GL drawable/context.
final GLCapabilitiesImmutable caps = ... ;
final GLProfile glp = caps.getGLProfile();
..
final boolean createNewDevice = true; // use 'own' display device!
final GLAutoDrawable sharedDrawable = GLDrawableFactory.getFactory(glp).createDummyAutoDrawable(null, createNewDevice, caps, null);
sharedDrawable.display(); // triggers GLContext object creation and native realization.
...
// Later a shared 'slave' can be created e.g.:
GLWindow glad = GLWindow.create(caps); // or any other GLAutoDrawable supporting GLSharedContextSetter
glad.setSharedAutoDrawable(sharedDrawable);
glad.addGLEventListener(..);
glad.setVisible(true); // GLWindow creation ..
*
*
* * Usually synchronization of shared GL objects should not be required, if the shared GL objects * are created and immutable before concurrent usage. *
** However, using drivers exposing {@link GLRendererQuirks#NeedSharedObjectSync} always * require the user to synchronize access of shared GL objects. *
** Synchronization can be avoided if accessing the shared GL objects * exclusively via a queue or {@link com.jogamp.common.util.Ringbuffer Ringbuffer}, see GLMediaPlayerImpl as an example. *
* **
* Error: 'intel_do_flush_locked: No such file or directory' * JogAmp: https://jogamp.org/bugzilla/show_bug.cgi?id=873 * freedesktop.org: https://bugs.freedesktop.org/show_bug.cgi?id=41736#c8 ** Shared context seems not to be supported w/ lock-free bound X11 display connections * per OpenGL drawable/context. The error message above is thrown in this case. * Hence the driver bug renders shared context use w/ JOGL impossible. * *
* We failed to create a shared ES2 context on another thread. *
*/ public interface GLSharedContextSetter extends GLAutoDrawable { /** * Specifies an {@link GLContext OpenGL context}, which shall be shared by this {@link GLAutoDrawable}'s {@link GLContext}. ** Since the {@link GLDrawable drawable} and {@link GLContext context} is created * at {@link GLAutoDrawable#initialization GLAutoDrawable initialization} * this method shall be called beforehand to have any effect. *
** A set sharedContext will block context creation, i.e. {@link GLAutoDrawable#initialization GLAutoDrawable initialization}, * as long it is not {@link GLContext#isCreated() created natively}. *
** The preferred method of assigning a shared context is * to {@link #setSharedAutoDrawable(GLAutoDrawable) set the shared GLAutoDrawable}, * since this method also takes the {@link GLEventListener} * {@link GLAutoDrawable#areAllGLEventListenerInitialized() initialization into account}. *
** See Lifecycle Considerations. *
* * @param sharedContext The OpenGL context to be shared by this {@link GLAutoDrawable}'s {@link GLContext}. * @throws IllegalStateException if a {@link #setSharedContext(GLContext) shared GLContext} * or {@link #setSharedAutoDrawable(GLAutoDrawable) shared GLAutoDrawable} is already set, * the given sharedContext is null or equal to this {@link GLAutoDrawable}'s context. * @see #setSharedAutoDrawable(GLAutoDrawable) */ void setSharedContext(GLContext sharedContext) throws IllegalStateException; /** * Specifies an {@link GLAutoDrawable}, which {@link GLContext OpenGL context} shall be shared by this {@link GLAutoDrawable}'s {@link GLContext}. ** Since the {@link GLDrawable drawable} and {@link GLContext context} is created * at {@link GLAutoDrawable#initialization GLAutoDrawable initialization} * this method shall be called beforehand to have any effect. *
** A set sharedAutoDrawable will block context creation, i.e. initialization * as long it's *
null, or* See Lifecycle Considerations. *
* * @param sharedContext The GLAutoDrawable, which OpenGL context shall be shared by this {@link GLAutoDrawable}'s {@link GLContext}. * @throws IllegalStateException if a {@link #setSharedContext(GLContext) shared GLContext} * or {@link #setSharedAutoDrawable(GLAutoDrawable) shared GLAutoDrawable} is already set, * the given sharedAutoDrawable is null or equal to this GLAutoDrawable. * @see #setSharedContext(GLContext) */ void setSharedAutoDrawable(GLAutoDrawable sharedAutoDrawable) throws IllegalStateException; }