gecko/gfx/gl/GLContextProviderImpl.h

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 * Version: MPL 1.1/GPL 2.0/LGPL 2.1
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 * The contents of this file are subject to the Mozilla Public License Version
 * 1.1 (the "License"); you may not use this file except in compliance with
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 * License.
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 * The Initial Developer of the Original Code is Mozilla Foundation.
 * Portions created by the Initial Developer are Copyright (C) 2010
 * the Initial Developer. All Rights Reserved.
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 * Contributor(s):
 *   Bas Schouten <bschouten@mozilla.com>
 *   Matt Woodrow <mwoodrow@mozilla.com>
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#ifndef IN_GL_CONTEXT_PROVIDER_H
#error GLContextProviderImpl.h must only be included from GLContextProvider.h
#endif

#ifndef GL_CONTEXT_PROVIDER_NAME
#error GL_CONTEXT_PROVIDER_NAME not defined
#endif

class THEBES_API GL_CONTEXT_PROVIDER_NAME
{
public:
    typedef GLContext::ContextFlags ContextFlags;
    /**
     * Create a context that renders to the surface of the widget that is
     * passed in.  The context is always created with an RGB pixel format,
     * with no alpha, depth or stencil.  If any of those features are needed,
     * either use a framebuffer, or use CreateOffscreen.
     *
     * This context will attempt to share resources with all other window
     * contexts.  As such, it's critical that resources allocated that are not
     * needed by other contexts be deleted before the context is destroyed.
     *
     * The GetSharedContext() method will return non-null if sharing
     * was successful.
     *
     * Note: a context created for a widget /must not/ hold a strong
     * reference to the widget; otherwise a cycle can be created through
     * a GL layer manager.
     *
     * @param aWidget Widget whose surface to create a context for
     *
     * @return Context to use for the window
     */
    static already_AddRefed<GLContext>
    CreateForWindow(nsIWidget *aWidget);

    /**
     * Create a context for offscreen rendering.  The target of this
     * context should be treated as opaque -- it might be a FBO, or a
     * pbuffer, or some other construct.  Users of this GLContext
     * should not bind framebuffer 0 directly, and instead should bind
     * the framebuffer returned by GetOffscreenFBO().
     *
     * The offscreen context returned by this method will always have
     * the ability to be rendered into a context created by a window.
     * It might or might not share resources with the global context;
     * query GetSharedContext() for a non-null result to check.  If
     * resource sharing can be avoided on the target platform, it will
     * be, in order to isolate the offscreen context.
     *
     * @param aSize The initial size of this offscreen context.
     * @param aFormat The ContextFormat for this offscreen context.
     *
     * @return Context to use for offscreen rendering
     */
    static already_AddRefed<GLContext>
    CreateOffscreen(const gfxIntSize& aSize,
                    const ContextFormat& aFormat = ContextFormat::BasicRGBA32Format,
                    const ContextFlags aFlags = GLContext::ContextFlagsNone);

    /**
     * Try to create a GL context from native surface for arbitrary gfxASurface
     * If surface not compatible this will return NULL
     *
     * @param aSurface surface to create a context for
     *
     * @return Context to use for this surface
     */
    static already_AddRefed<GLContext>
    CreateForNativePixmapSurface(gfxASurface *aSurface);

    /**
     * Get a pointer to the global context, creating it if it doesn't exist.
     */
    static GLContext *
    GetGlobalContext();

    /**
     * Free any resources held by this Context Provider.
     */
    static void
    Shutdown();
};