path: root/src/classes/javax/media/opengl/GLDrawableFactory.java

/*
 * Copyright (c) 2003 Sun Microsystems, Inc. All Rights Reserved.
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 * - Redistribution of source code must retain the above copyright
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 * contributors may be used to endorse or promote products derived from
 * this software without specific prior written permission.
 * 
 * This software is provided "AS IS," without a warranty of any kind. ALL
 * EXPRESS OR IMPLIED CONDITIONS, REPRESENTATIONS AND WARRANTIES,
 * INCLUDING ANY IMPLIED WARRANTY OF MERCHANTABILITY, FITNESS FOR A
 * PARTICULAR PURPOSE OR NON-INFRINGEMENT, ARE HEREBY EXCLUDED. SUN
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 * You acknowledge that this software is not designed or intended for use
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 * Sun gratefully acknowledges that this software was originally authored
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 */

package javax.media.opengl;

import java.security.*;
import com.sun.opengl.impl.*;

/** <P> Provides a virtual machine- and operating system-independent
    mechanism for creating {@link GLDrawable}s. </P>

    <P> The {@link javax.media.opengl.GLCapabilities} objects passed in to the
    various factory methods are used as a hint for the properties of
    the returned drawable. The default capabilities selection
    algorithm (equivalent to passing in a null {@link
    GLCapabilitiesChooser}) is described in {@link
    DefaultGLCapabilitiesChooser}. Sophisticated applications needing
    to change the selection algorithm may pass in their own {@link
    GLCapabilitiesChooser} which can select from the available pixel
    formats. </P>

    <P> Because of the multithreaded nature of the Java platform's
    window system toolkit, it is typically not possible to immediately
    reject a given {@link GLCapabilities} as being unsupportable by
    either returning <code>null</code> from the creation routines or
    raising a {@link GLException}. The semantics of the rejection
    process are (unfortunately) left unspecified for now. The current
    implementation will cause a {@link GLException} to be raised
    during the first repaint of the {@link GLCanvas} or {@link
    GLJPanel} if the capabilities can not be met. Pbuffers are always
    created immediately and their creation will fail with a {@link
    GLException} if errors occur. </P>

    <P> The concrete GLDrawableFactory subclass instantiated by {@link
    #getFactory getFactory} can be changed by setting the system
    property <code>opengl.factory.class.name</code> to the
    fully-qualified name of the desired class. </P>
*/

public abstract class GLDrawableFactory {
  private static GLDrawableFactory factory;

  protected GLDrawableFactory() {}

  /** Returns the sole GLDrawableFactory instance. */
  public static GLDrawableFactory getFactory() {
    if (factory == null) {
      try {
        String factoryClassName =
          (String) AccessController.doPrivileged(new PrivilegedAction() {
              public Object run() {
                return System.getProperty("opengl.factory.class.name");
              }
            });
        String osName = System.getProperty("os.name");
        String osNameLowerCase = osName.toLowerCase();
        Class factoryClass = null;

        // Because there are some complications with generating all
        // platforms' Java glue code on all platforms (among them that we
        // would have to include jawt.h and jawt_md.h in the jogl
        // sources, which we currently don't have to do) we break the only
        // static dependencies with platform-specific code here using reflection.

        if (factoryClassName != null) {
          factoryClass = Class.forName(factoryClassName);
        } else if (osNameLowerCase.startsWith("wind")) {
          factoryClass = Class.forName("com.sun.opengl.impl.windows.WindowsGLDrawableFactory");
        } else if (osNameLowerCase.startsWith("mac os x")) {
          factoryClass = Class.forName("com.sun.opengl.impl.macosx.MacOSXGLDrawableFactory");
        } else {
          // Assume Linux, Solaris, etc. Should probably test for these explicitly.
          factoryClass = Class.forName("com.sun.opengl.impl.x11.X11GLDrawableFactory");
        }

        if (factoryClass == null) {
          throw new GLException("OS " + osName + " not yet supported");
        }

        factory = (GLDrawableFactory) factoryClass.newInstance();
      } catch (Exception e) {
        throw new GLException(e);
      }
    }

    return factory;
  }

  /**
   * <P> Selects a graphics configuration on the specified graphics
   * device compatible with the supplied GLCapabilities. This method
   * is intended to be used by applications which do not use the
   * supplied GLCanvas class but instead wrap their own Canvas or
   * other window toolkit-specific object with a GLDrawable. Some
   * platforms (specifically X11) require the graphics configuration
   * to be specified when the window toolkit object is created. This
   * method returns null on platforms on which the OpenGL pixel format
   * selection process is performed later. </P>
   *
   * <P> The concrete data type of the passed graphics device and
   * returned graphics configuration must be specified in the
   * documentation binding this particular API to the underlying
   * window toolkit. The Reference Implementation accepts {@link
   * AWTGraphicsDevice AWTGraphicsDevice} objects and returns {@link
   * AWTGraphicsConfiguration AWTGraphicsConfiguration} objects.
   *
   * @see java.awt.Canvas#Canvas(java.awt.GraphicsConfiguration) */
  public abstract AbstractGraphicsConfiguration
    chooseGraphicsConfiguration(GLCapabilities capabilities,
                                GLCapabilitiesChooser chooser,
                                AbstractGraphicsDevice device);

  /**
   * Returns a GLDrawable that wraps a platform-specific window system
   * object, such as an AWT or LCDUI Canvas. On platforms which
   * support it, selects a pixel format compatible with the supplied
   * GLCapabilities, or if the passed GLCapabilities object is null,
   * uses a default set of capabilities. On these platforms, uses
   * either the supplied GLCapabilitiesChooser object, or if the
   * passed GLCapabilitiesChooser object is null, uses a
   * DefaultGLCapabilitiesChooser instance.
   *
   * @throws IllegalArgumentException if the passed target is either
   *         null or its data type is not supported by this GLDrawableFactory.
   * @throws GLException if any window system-specific errors caused
   *         the creation of the GLDrawable to fail.
   */
  public abstract GLDrawable getGLDrawable(Object target,
                                           GLCapabilities capabilities,
                                           GLCapabilitiesChooser chooser)
    throws IllegalArgumentException, GLException;
  
  //----------------------------------------------------------------------
  // Methods to create high-level objects

  /**
   * Returns true if it is possible to create a GLPbuffer. Some older
   * graphics cards do not have this capability.
   */
  public abstract boolean canCreateGLPbuffer();

  /**
   * Creates a GLPbuffer with the given capabilites and dimensions.
   */
  public abstract GLPbuffer createGLPbuffer(GLCapabilities capabilities,
                                            int initialWidth,
                                            int initialHeight,
                                            GLContext shareWith);

  //----------------------------------------------------------------------
  // Methods for interacting with third-party OpenGL libraries

  /**
   * <P> Creates a GLContext object representing an existing OpenGL
   * context in an external (third-party) OpenGL-based library. This
   * GLContext object may be used to draw into this preexisting
   * context using its {@link GL} and {@link
   * javax.media.opengl.glu.GLU} objects. New contexts created through
   * {@link GLDrawable}s may share textures and display lists with
   * this external context. </P>
   *
   * <P> The underlying OpenGL context must be current on the current
   * thread at the time this method is called. The user is responsible
   * for the maintenance of the underlying OpenGL context; calls to
   * <code>makeCurrent</code> and <code>release</code> on the returned
   * GLContext object have no effect. If the underlying OpenGL context
   * is destroyed, the <code>destroy</code> method should be called on
   * the <code>GLContext</code>. A new <code>GLContext</code> object
   * should be created for each newly-created underlying OpenGL
   * context.
   */
  public abstract GLContext createExternalGLContext();

  /**
   * Returns true if it is possible to create an external GLDrawable
   * object via {@link #createExternalGLDrawable}.
   */
  public abstract boolean canCreateExternalGLDrawable();

  /**
   * <P> Creates a {@link GLDrawable} object representing an existing
   * OpenGL drawable in an external (third-party) OpenGL-based
   * library. This GLDrawable object may be used to create new,
   * fully-functional {@link GLContext}s on the OpenGL drawable. This
   * is useful when interoperating with a third-party OpenGL-based
   * library and it is essential to not perturb the state of the
   * library's existing context, even to the point of not sharing
   * textures or display lists with that context. </P>
   *
   * <P> An underlying OpenGL context must be current on the desired
   * drawable and the current thread at the time this method is
   * called. The user is responsible for the maintenance of the
   * underlying drawable. If one or more contexts are created on the
   * drawable using {@link GLDrawable#createContext}, and the drawable
   * is deleted by the third-party library, the user is responsible
   * for calling {@link GLContext#destroy} on these contexts. </P>
   *
   * <P> Calls to <code>setSize</code>, <code>getWidth</code> and
   * <code>getHeight</code> are illegal on the returned GLDrawable. If
   * these operations are required by the user, they must be performed
   * by the third-party library. </P>
   *
   * <P> It is legal to create both an external GLContext and
   * GLDrawable representing the same third-party OpenGL entities.
   * This can be used, for example, to query current state information
   * using the external GLContext and then create and set up new
   * GLContexts using the external GLDrawable. </P>
   *
   * <P> This functionality may not be available on all platforms and
   * {@link #canCreateExternalGLDrawable} should be called first to
   * see if it is present. For example, on X11 platforms, this API
   * requires the presence of GLX 1.3 or later.
   */
  public abstract GLDrawable createExternalGLDrawable();
}