/*
* Copyright (c) 2002-2008 LWJGL Project
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are
* met:
*
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* * 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.
*
* * Neither the name of 'LWJGL' nor the names of
* its contributors may be used to endorse or promote products derived
* from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "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 THE COPYRIGHT OWNER OR
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
* LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
package org.lwjgl.opengl;
import org.lwjgl.LWJGLException;
import org.lwjgl.LWJGLUtil;
import org.lwjgl.Sys;
import java.nio.ByteBuffer;
import java.nio.IntBuffer;
/**
* <p/>
* Context encapsulates an OpenGL context.
* <p/>
* <p/>
* This class is thread-safe.
*
* @author elias_naur <elias_naur@users.sourceforge.net>
* @version $Revision: 3332 $
* $Id: Context.java 3332 2010-04-20 18:21:05Z spasi $
*/
final class Context {
/** The platform specific implementation of context methods */
private final static ContextImplementation implementation;
/** The current Context */
private final static ThreadLocal current_context_local = new ThreadLocal();
/** Handle to the native GL rendering context */
private final ByteBuffer handle;
private final PeerInfo peer_info;
private final ContextAttribs contextAttribs;
private final boolean forwardCompatible;
/** Whether the context has been destroyed */
private boolean destroyed;
private boolean destroy_requested;
/** The thread that has this context current, or null. */
private Thread thread;
static {
Sys.initialize();
implementation = createImplementation();
}
private static ContextImplementation createImplementation() {
switch ( LWJGLUtil.getPlatform() ) {
case LWJGLUtil.PLATFORM_LINUX:
return new LinuxContextImplementation();
case LWJGLUtil.PLATFORM_WINDOWS:
return new WindowsContextImplementation();
case LWJGLUtil.PLATFORM_MACOSX:
return new MacOSXContextImplementation();
default:
throw new IllegalStateException("Unsupported platform");
}
}
PeerInfo getPeerInfo() {
return peer_info;
}
ContextAttribs getContextAttribs() {
return contextAttribs;
}
static Context getCurrentContext() {
return (Context)current_context_local.get();
}
/** Create a context with the specified peer info and shared context */
Context(PeerInfo peer_info, ContextAttribs attribs, Context shared_context) throws LWJGLException {
Context context_lock = shared_context != null ? shared_context : this;
// If shared_context is not null, synchronize on it to make sure it is not deleted
// while this context is created. Otherwise, simply synchronize on ourself to avoid NPE
synchronized ( context_lock ) {
if ( shared_context != null && shared_context.destroyed )
throw new IllegalArgumentException("Shared context is destroyed");
GLContext.loadOpenGLLibrary();
try {
this.peer_info = peer_info;
this.contextAttribs = attribs;
IntBuffer attribList;
if ( attribs != null ) {
attribList = attribs.getAttribList();
forwardCompatible = attribs.isForwardCompatible();
} else {
attribList = null;
forwardCompatible = false;
}
this.handle = implementation.create(peer_info, attribList, shared_context != null ? shared_context.handle : null);
} catch (LWJGLException e) {
GLContext.unloadOpenGLLibrary();
throw e;
}
}
}
/** Release the current context (if any). After this call, no context is current. */
public static void releaseCurrentContext() throws LWJGLException {
Context current_context = getCurrentContext();
if ( current_context != null ) {
implementation.releaseCurrentContext();
GLContext.useContext(null);
current_context_local.set(null);
synchronized ( current_context ) {
current_context.thread = null;
current_context.checkDestroy();
}
}
}
/**
* Release the context from its drawable. This is necessary on some platforms,
* like Mac OS X, where binding the context to a drawable and binding the context
* for rendering are two distinct actions and where calling releaseDrawable
* on every releaseCurrentContext results in artifacts.
*/
public synchronized void releaseDrawable() throws LWJGLException {
if ( destroyed )
throw new IllegalStateException("Context is destroyed");
implementation.releaseDrawable(getHandle());
}
/** Update the context. Should be called whenever it's drawable is moved or resized */
public synchronized void update() {
if ( destroyed )
throw new IllegalStateException("Context is destroyed");
implementation.update(getHandle());
}
/** Swap the buffers on the current context. Only valid for double-buffered contexts */
public static void swapBuffers() throws LWJGLException {
implementation.swapBuffers();
}
private boolean canAccess() {
return thread == null || Thread.currentThread() == thread;
}
private void checkAccess() {
if ( !canAccess() )
throw new IllegalStateException("From thread " + Thread.currentThread() + ": " + thread + " already has the context current");
}
/** Make the context current */
public synchronized void makeCurrent() throws LWJGLException {
checkAccess();
if ( destroyed )
throw new IllegalStateException("Context is destroyed");
thread = Thread.currentThread();
current_context_local.set(this);
implementation.makeCurrent(peer_info, handle);
GLContext.useContext(this, forwardCompatible);
}
ByteBuffer getHandle() {
return handle;
}
/** Query whether the context is current */
public synchronized boolean isCurrent() throws LWJGLException {
if ( destroyed )
throw new IllegalStateException("Context is destroyed");
return implementation.isCurrent(handle);
}
private void checkDestroy() {
if ( !destroyed && destroy_requested ) {
try {
releaseDrawable();
implementation.destroy(peer_info, handle);
destroyed = true;
thread = null;
GLContext.unloadOpenGLLibrary();
} catch (LWJGLException e) {
LWJGLUtil.log("Exception occurred while destroying context: " + e);
}
}
}
/**
* Set the buffer swap interval. This call is a best-attempt at changing
* the monitor swap interval, which is the minimum periodicity of color buffer swaps,
* measured in video frame periods, and is not guaranteed to be successful.
* <p/>
* A video frame period is the time required to display a full frame of video data.
*/
public static void setSwapInterval(int value) {
implementation.setSwapInterval(value);
}
/**
* Destroy the context. This method behaves the same as destroy() with the extra
* requirement that the context must be either current to the current thread or not
* current at all.
*/
public synchronized void forceDestroy() throws LWJGLException {
checkAccess();
destroy();
}
/**
* Request destruction of the Context. If the context is current, no context will be current after this call.
* The context is destroyed when no thread has it current.
*/
public synchronized void destroy() throws LWJGLException {
if ( destroyed )
return;
destroy_requested = true;
boolean was_current = isCurrent();
int error = GL11.GL_NO_ERROR;
if ( was_current ) {
if ( GLContext.getCapabilities() != null && GLContext.getCapabilities().OpenGL11 )
error = GL11.glGetError();
releaseCurrentContext();
}
checkDestroy();
if ( was_current && error != GL11.GL_NO_ERROR )
throw new OpenGLException(error);
}
}