/**
* Copyright 2013 JogAmp Community. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without modification, are
* permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice, this list of
* conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright notice, this list
* of conditions and the following disclaimer in the documentation and/or other materials
* provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY JogAmp Community ``AS IS'' AND ANY EXPRESS OR IMPLIED
* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
* FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL JogAmp Community OR
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
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*
* The views and conclusions contained in the software and documentation are those of the
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*/
package com.jogamp.opengl;
import com.jogamp.opengl.GLRendererQuirks;
/**
* Adds capabilities to set a shared {@link GLContext} directly or via an {@link GLAutoDrawable}.
* <p>
* Sharing of server-side OpenGL objects such as buffer objects, e.g. VBOs,
* and textures among OpenGL contexts is supported with this interface.
* </p>
* <p>
* A <i>master</i> {@link GLContext} is the {@link GLContext} which is created first.
* Subsequent shared {@link GLContext} w/ the <i>master</i> are referred as <i>slave</i> {@link GLContext}.
* </p>
* <p>
* Implementations of this interface control the <i>slave's</i> {@link GLContext} and {@link GLAutoDrawable} realization,
* i.e. the <i>slave</i> {@link GLAutoDrawable} will not be realized before their associated <i>master</i>.
* </p>
* <p>
* 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.
* </p>
* <h5><a name="lifecycle">Lifecycle Considerations</a></h5>
* <p>
* After shared objects are created on the <i>master</i>, the OpenGL pipeline
* might need to be synchronized w/ the <i>slaves</i>, e.g. via {@link GL#glFinish()}.
* At least this has been experienced w/ OSX 10.9.
* </p>
* <p>
* In general, destroying a <i>master</i> {@link GLContext} before their shared <i>slaves</i>
* 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 <code>com.jogamp.opengl.test.junit.jogl.acore.TestSharedContextVBOES2NEWT3</code> and similar.
* </p>
* <p>
* However, to avoid scenarios with buggy drivers, users <i>may not</i> destroy the
* <i>master</i> {@link GLContext} before its shared <i>slave</i> {@link GLContext} instances
* <i>as long as they are using them</i>.<br>
* Otherwise the OpenGL driver may crash w/ SIGSEGV, due to using already destroyed shared resources,
* if not handling the pending destruction of the latter!<br>
* Either proper lifecycle synchronization is implemented, e.g. by notifying the <i>slaves</i> about the loss of the shared resources,
* <i>or</i> the <i>slaves</i> validate whether the resources are still valid.
* </p>
* <p>
* 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 <i>master</i> of all shared <i>slave</i> {@link GLContext}.
* Since this <i>dummy instance</i> does not depend on any native windowing system, it can be controlled easily w/o being <i>in sight</i>.<br>
* Below code creates a {@link GLAutoDrawable} based on a <i>dummy GLDrawable</i>:
* <pre>
// 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 ..
* </pre>
* </p>
* <h5><a name="synchronization">GL Object Synchronization</a></h5>
* <p>
* Usually synchronization of shared GL objects should not be required, if the shared GL objects
* are created and immutable before concurrent usage.
* </p>
* <p>
* However, using drivers exposing {@link GLRendererQuirks#NeedSharedObjectSync} always
* require the user to synchronize access of shared GL objects.
* </p>
* <p>
* 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.
* </p>
* </p>
* <h5><a name="driverissues">Known Driver Issues</a></h5>
* <h7><a name="intelmesa">Intel's Mesa >= 9.1.2 Backend for [Sandybridge/Ivybridge] on GNU/Linux</a></h7>
* <p>
* <pre>
* 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
* </pre>
* 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.
* </p>
* <h7><a name="hisilicon">Hisilicon's Immersion.16 on Android</a></h7>
* <p>
* We failed to create a shared ES2 context on another thread.
* </p>
*/
public interface GLSharedContextSetter extends GLAutoDrawable {
/**
* Specifies an {@link GLContext OpenGL context}, which shall be shared by this {@link GLAutoDrawable}'s {@link GLContext}.
* <p>
* 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.
* </p>
* <p>
* A set <i>sharedContext</i> will block context creation, i.e. {@link GLAutoDrawable#initialization GLAutoDrawable initialization},
* as long it is not {@link GLContext#isCreated() created natively}.
* </p>
* <p>
* The <i>preferred method</i> of assigning a <i>shared context</i> is
* to {@link #setSharedAutoDrawable(GLAutoDrawable) set the shared GLAutoDrawable},
* since this method also takes the {@link GLEventListener}
* {@link GLAutoDrawable#areAllGLEventListenerInitialized() initialization into account}.
* </p>
* <p>
* See <a href="#lifecycle">Lifecycle Considerations</a>.
* </p>
*
* @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}.
* <p>
* 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.
* </p>
* <p>
* A set <i>sharedAutoDrawable</i> will block context creation, i.e. <a href="GLAutoDrawable.html#initialization">initialization</a>
* as long it's
* <ul>
* <li>{@link GLContext} is <code>null</code>, or</li>
* <li>{@link GLContext} has not been {@link GLContext#isCreated() created natively}, or</li>
* <li>{@link GLEventListener} are <i>not</i> {@link GLAutoDrawable#areAllGLEventListenerInitialized() completely initialized}</li>
* </ul>
* </p>
* <p>
* See <a href="#lifecycle">Lifecycle Considerations</a>.
* </p>
*
* @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;
}