/** @file
 *
 * VirtualBox OpenGL Cocoa Window System Helper implementation
 */

/*
 * Copyright (C) 2009 Oracle Corporation
 *
 * This file is part of VirtualBox Open Source Edition (OSE), as
 * available from http://www.virtualbox.org. This file is free software;
 * you can redistribute it and/or modify it under the terms of the GNU
 * General Public License (GPL) as published by the Free Software
 * Foundation, in version 2 as it comes in the "COPYING" file of the
 * VirtualBox OSE distribution. VirtualBox OSE is distributed in the
 * hope that it will be useful, but WITHOUT ANY WARRANTY of any kind.
 */

#include "renderspu_cocoa_helper.h"

#import <Cocoa/Cocoa.h>

#include "chromium.h" /* For the visual bits of chromium */

#include <iprt/thread.h>
#include <iprt/string.h>
#include <iprt/mem.h>
#include <iprt/time.h>

/*
 * How this works:
 * In general it is not so easy like on the other platforms, cause Cocoa
 * doesn't support any clipping of already painted stuff. In Mac OS X there is
 * the concept of translucent canvas's e.g. windows and there it is just
 * painted what should be visible to the user. Unfortunately this isn't the
 * concept of chromium. Therefor I reroute all OpenGL operation from the guest
 * to a frame buffer object (FBO). This is a OpenGL extension, which is
 * supported by all OS X versions we support (AFAIC tell). Of course the guest
 * doesn't know that and we have to make sure that the OpenGL state always is
 * in the right state to paint into the FBO and not to the front/back buffer.
 * Several functions below (like cocoaBindFramebufferEXT, cocoaGetIntegerv,
 * ...) doing this. When a swap or finish is triggered by the guest, the
 * content (which is already bound to an texture) is painted on the screen
 * within a separate OpenGL context. This allows the usage of the same
 * resources (texture ids, buffers ...) but at the same time having an
 * different internal OpenGL state. Another advantage is that we can paint a
 * thumbnail of the current output in a much more smaller (GPU accelerated
 * scale) version on a third context and use glReadPixels to get the actual
 * data. glReadPixels is a very slow operation, but as we just use a much more
 * smaller image, we can handle it (anyway this is only done 5 times per
 * second).
 *
 * Other things to know:
 * - If the guest request double buffering, we have to make sure there are two
 *   buffers. We use the same FBO with 2 color attachments. Also glDrawBuffer
 *   and glReadBuffer is intercepted to make sure it is painted/read to/from
 *   the correct buffers. On swap our buffers are swapped and not the
 *   front/back buffer.
 * - If the guest request a depth/stencil buffer, a combined render buffer for
 *   this is created.
 * - If the size of the guest OpenGL window changes, all FBO's, textures, ...
 *   need to be recreated.
 * - We need to track any changes to the parent window
 *   (create/destroy/move/resize). The various classes like OverlayHelperView,
 *   OverlayWindow, ... are there for.
 * - The HGCM service runs on a other thread than the Main GUI. Keeps this
 *   always in mind (see e.g. performSelectorOnMainThread in renderFBOToView)
 * - We make heavy use of late binding. We can not be sure that the GUI (or any
 *   other third party GUI), overwrite our NSOpenGLContext. So we always ask if
 *   this is our own one, before use. Really neat concept of Objective-C/Cocoa
 *   ;)
 */

/* Debug macros */
#define FBO 1 /* Disable this to see how the output is without the FBO in the middle of the processing chain. */
#if 0
#define SHOW_WINDOW_BACKGROUND 1 /* Define this to see the window background even if the window is clipped */
#define DEBUG_VERBOSE /* Define this to get some debug info about the messages flow. */
#endif

#ifdef DEBUG_poetzsch
#define DEBUG_MSG(text) \
    printf text
#else
#define DEBUG_MSG(text) \
    do {} while (0)
#endif

#ifdef DEBUG_VERBOSE
#define DEBUG_MSG_1(text) \
    DEBUG_MSG(text)
#else
#define DEBUG_MSG_1(text) \
    do {} while (0)
#endif

#ifdef DEBUG_poetzsch
#define CHECK_GL_ERROR()\
    do \
    { \
        checkGLError(__FILE__, __LINE__); \
    }while (0);

    static void checkGLError(char *file, int line)
    {
        GLenum g = glGetError();
        if (g != GL_NO_ERROR)
        {
            char *errStr;
            switch (g)
            {
                case GL_INVALID_ENUM:      errStr = RTStrDup("GL_INVALID_ENUM"); break;
                case GL_INVALID_VALUE:     errStr = RTStrDup("GL_INVALID_VALUE"); break;
                case GL_INVALID_OPERATION: errStr = RTStrDup("GL_INVALID_OPERATION"); break;
                case GL_STACK_OVERFLOW:    errStr = RTStrDup("GL_STACK_OVERFLOW"); break;
                case GL_STACK_UNDERFLOW:   errStr = RTStrDup("GL_STACK_UNDERFLOW"); break;
                case GL_OUT_OF_MEMORY:     errStr = RTStrDup("GL_OUT_OF_MEMORY"); break;
                case GL_TABLE_TOO_LARGE:   errStr = RTStrDup("GL_TABLE_TOO_LARGE"); break;
                default:                   errStr = RTStrDup("UNKNOWN"); break;
            }
            DEBUG_MSG(("%s:%d: glError %d (%s)\n", file, line, g, errStr));
            RTMemFree(errStr);
        }
    }
#else
#define CHECK_GL_ERROR()\
    do {} while (0)
#endif

#define GL_SAVE_STATE \
do \
{ \
    glPushAttrib(GL_ALL_ATTRIB_BITS); \
    glPushClientAttrib(GL_CLIENT_ALL_ATTRIB_BITS); \
    glMatrixMode(GL_PROJECTION); \
    glPushMatrix(); \
    glMatrixMode(GL_TEXTURE); \
    glPushMatrix(); \
    glMatrixMode(GL_COLOR); \
    glPushMatrix(); \
    glMatrixMode(GL_MODELVIEW); \
    glPushMatrix(); \
} \
while(0);

#define GL_RESTORE_STATE \
do \
{ \
    glMatrixMode(GL_MODELVIEW); \
    glPopMatrix(); \
    glMatrixMode(GL_COLOR); \
    glPopMatrix(); \
    glMatrixMode(GL_TEXTURE); \
    glPopMatrix(); \
    glMatrixMode(GL_PROJECTION); \
    glPopMatrix(); \
    glPopClientAttrib(); \
    glPopAttrib(); \
} \
while(0);

/* Custom OpenGL context class. This implementation doesn't allow to set a view
 * to the context, but save the view for later use. Also it saves a copy of the
 * pixel format used to create that context for later use. */
@interface OverlayOpenGLContext: NSOpenGLContext
{
@private
    NSOpenGLPixelFormat *m_pPixelFormat;
    NSView              *m_pView;
}
- (NSOpenGLPixelFormat*)openGLPixelFormat;
@end

@class DockOverlayView;

/* The custom view class. This is the main class of the cocoa OpenGL
 * implementation. It manages an frame buffer object for the rendering of the
 * guest applications. The guest applications render in this frame buffer which
 * is bind to an OpenGL texture. To display the guest content, an secondary
 * shared OpenGL context of the main OpenGL context is created. The secondary
 * context is marked as non opaque & the texture is displayed on an object
 * which is composed out of the several visible region rectangles. */
@interface OverlayView: NSView
{
@private
    NSView          *m_pParentView;
    NSWindow        *m_pOverlayWin;

    NSOpenGLContext *m_pGLCtx;
    NSOpenGLContext *m_pSharedGLCtx;
    RTTHREAD         mThread;

#ifdef FBO
    GLuint           m_FBOId;
    /* FBO handling */
    GLuint           m_FBOTexBackId;
    GLuint           m_FBOTexFrontId;
    GLuint           m_FBOAttBackId;
    GLuint           m_FBOAttFrontId;
    GLuint           m_FBODepthStencilPackedId;
    NSSize           m_FBOTexSize;

    bool             m_fFrontDrawing;
#endif

    /* The corresponding dock tile view of this OpenGL view & all helper
     * members. */
    DockOverlayView *m_DockTileView;

    GLuint           m_FBOThumbId;
    GLuint           m_FBOThumbTexId;
    GLfloat          m_FBOThumbScaleX;
    GLfloat          m_FBOThumbScaleY;
    uint64_t         m_uiDockUpdateTime;

    /* For clipping */
    GLint            m_cClipRects;
    GLint           *m_paClipRects;

    /* Position/Size tracking */
    NSPoint          m_Pos;
    NSSize           m_Size;

    /* This is necessary for clipping on the root window */
    NSPoint          m_RootShift;
}
- (id)initWithFrame:(NSRect)frame thread:(RTTHREAD)aThread parentView:(NSView*)pParentView;
- (void)setGLCtx:(NSOpenGLContext*)pCtx;
- (NSOpenGLContext*)glCtx;

- (void)setParentView: (NSView*)view;
- (NSView*)parentView;
- (void)setOverlayWin: (NSWindow*)win;
- (NSWindow*)overlayWin;

- (void)setPos:(NSPoint)pos;
- (NSPoint)pos;
- (void)setSize:(NSSize)size;
- (NSSize)size;
- (void)updateViewport;
- (void)reshape;

- (void)createFBO;
- (void)deleteFBO;

- (bool)isCurrentFBO;
- (void)updateFBO;
- (void)makeCurrentFBO;
- (void)swapFBO;
- (void)flushFBO;
- (void)stateInfo:(GLenum)pname withParams:(GLint*)params;
- (void)finishFBO;
- (void)bindFBO:(GLenum)target withFrameBuffer:(GLuint)framebuffer;
- (void)tryDraw;
- (void)renderFBOToView;
- (void)renderFBOToDockTile;

- (void)clearVisibleRegions;
- (void)setVisibleRegions:(GLint)cRects paRects:(GLint*)paRects;

- (NSView*)dockTileScreen;
- (void)reshapeDockTile;
@end

/* Helper view. This view is added as a sub view of the parent view to track
 * main window changes. Whenever the main window is changed (which happens on
 * fullscreen/seamless entry/exit) the overlay window is informed & can add
 * them self as a child window again. */
@class OverlayWindow;
@interface OverlayHelperView: NSView
{
@private
    OverlayWindow *m_pOverlayWindow;
}
-(id)initWithOverlayWindow:(OverlayWindow*)pOverlayWindow;
@end

/* Custom window class. This is the overlay window which contains our custom
 * NSView. Its a direct child of the Qt Main window. It marks its background
 * transparent & non opaque to make clipping possible. It also disable mouse
 * events and handle frame change events of the parent view. */
@interface OverlayWindow: NSWindow
{
@private
    NSView            *m_pParentView;
    OverlayView       *m_pOverlayView;
    OverlayHelperView *m_pOverlayHelperView;
    NSThread          *m_Thread;
}
- (id)initWithParentView:(NSView*)pParentView overlayView:(OverlayView*)pOverlayView;
- (void)parentWindowFrameChanged:(NSNotification *)note;
- (void)parentWindowChanged:(NSWindow*)pWindow;
@end

@interface DockOverlayView: NSView
{
    NSBitmapImageRep *m_ThumbBitmap;
    NSImage          *m_ThumbImage;
    NSLock           *m_Lock;
}
- (void)dealloc;
- (void)cleanup;
- (void)lock;
- (void)unlock;
- (void)setFrame:(NSRect)frame;
- (void)drawRect:(NSRect)aRect;
- (NSBitmapImageRep*)thumbBitmap;
- (NSImage*)thumbImage;
@end

@implementation DockOverlayView
- (id)init
{
    self = [super init];

    if (self)
    {
        /* We need a lock cause the thumb image could be accessed from the main
         * thread when someone is calling display on the dock tile & from the
         * OpenGL thread when the thumbnail is updated. */
        m_Lock = [[NSLock alloc] init];
    }

    return self;
}

- (void)dealloc
{
    [self cleanup];
    [m_Lock release];

    [super dealloc];
}

- (void)cleanup
{
    if (m_ThumbImage != nil)
    {
        [m_ThumbImage release];
        m_ThumbImage = nil;
    }
    if (m_ThumbBitmap != nil)
    {
        [m_ThumbBitmap release];
        m_ThumbBitmap = nil;
    }
}

- (void)lock
{
    [m_Lock lock];
}

- (void)unlock
{
    [m_Lock unlock];
}

- (void)setFrame:(NSRect)frame
{
    [super setFrame:frame];

    [self lock];
    [self cleanup];

    if (   frame.size.width > 0
        && frame.size.height > 0)
    {
        /* Create a buffer for our thumbnail image. Its in the size of this view. */
        m_ThumbBitmap = [[NSBitmapImageRep alloc] initWithBitmapDataPlanes:NULL
            pixelsWide:frame.size.width
            pixelsHigh:frame.size.height
            bitsPerSample:8
            samplesPerPixel:4
            hasAlpha:YES
            isPlanar:NO
            colorSpaceName:NSDeviceRGBColorSpace
            bitmapFormat:NSAlphaFirstBitmapFormat
            bytesPerRow:frame.size.width * 4
            bitsPerPixel:8 * 4];
        m_ThumbImage = [[NSImage alloc] initWithSize:[m_ThumbBitmap size]];
        [m_ThumbImage addRepresentation:m_ThumbBitmap];
    }
    [self unlock];
}

- (BOOL)isFlipped
{
    return YES;
}

- (void)drawRect:(NSRect)aRect
{
    NSRect frame;

    [self lock];
#ifdef SHOW_WINDOW_BACKGROUND
    [[NSColor colorWithCalibratedRed:1.0 green:0.0 blue:0.0 alpha:0.7] set];
    frame = [self frame];
    [NSBezierPath fillRect:NSMakeRect(0, 0, frame.size.width, frame.size.height)];
#endif /* SHOW_WINDOW_BACKGROUND */
    if (m_ThumbImage != nil)
        [m_ThumbImage drawAtPoint:NSMakePoint(0, 0) fromRect:NSZeroRect operation:NSCompositeSourceOver fraction:1.0];
    [self unlock];
}

- (NSBitmapImageRep*)thumbBitmap
{
    return m_ThumbBitmap;
}

- (NSImage*)thumbImage
{
    return m_ThumbImage;
}
@end

/********************************************************************************
*
* OverlayOpenGLContext class implementation
*
********************************************************************************/
@implementation OverlayOpenGLContext

-(id)initWithFormat:(NSOpenGLPixelFormat*)format shareContext:(NSOpenGLContext*)share
{
    m_pPixelFormat = NULL;
    m_pView = NULL;

    self = [super initWithFormat:format shareContext:share];
    if (self)
        m_pPixelFormat = format;

    DEBUG_MSG(("OCTX(%p): init OverlayOpenGLContext\n", (void*)self));

    return self;
}

- (void)dealloc
{
    DEBUG_MSG(("OCTX(%p): dealloc OverlayOpenGLContext\n", (void*)self));

    [m_pPixelFormat release];

    [super dealloc];
}

-(bool)isDoubleBuffer
{
    GLint val;
    [m_pPixelFormat getValues:&val forAttribute:NSOpenGLPFADoubleBuffer forVirtualScreen:0];
    return val == GL_TRUE ? YES : NO;
}

-(void)setView:(NSView*)view
{
    DEBUG_MSG(("OCTX(%p): setView: new view: %p\n", (void*)self, (void*)view));

#ifdef FBO
    m_pView = view;;
#else
    [super setView: view];
#endif
}

-(NSView*)view
{
#ifdef FBO
    return m_pView;
#else
    return [super view];
#endif
}

-(void)clearDrawable
{
    DEBUG_MSG(("OCTX(%p): clearDrawable\n", (void*)self));

    m_pView = NULL;;
    [super clearDrawable];
}

-(NSOpenGLPixelFormat*)openGLPixelFormat
{
    return m_pPixelFormat;
}

@end

/********************************************************************************
*
* OverlayHelperView class implementation
*
********************************************************************************/
@implementation OverlayHelperView

-(id)initWithOverlayWindow:(OverlayWindow*)pOverlayWindow
{
    self = [super initWithFrame:NSZeroRect];

    m_pOverlayWindow = pOverlayWindow;

    DEBUG_MSG(("OHVW(%p): init OverlayHelperView\n", (void*)self));

    return self;
}

-(void)viewDidMoveToWindow
{
    DEBUG_MSG(("OHVW(%p): viewDidMoveToWindow: new win: %p\n", (void*)self, (void*)[self window]));

    [m_pOverlayWindow parentWindowChanged:[self window]];
}

@end

/********************************************************************************
*
* OverlayWindow class implementation
*
********************************************************************************/
@implementation OverlayWindow

- (id)initWithParentView:(NSView*)pParentView overlayView:(OverlayView*)pOverlayView
{
    NSWindow *pParentWin = nil;

    if((self = [super initWithContentRect:NSZeroRect styleMask:NSBorderlessWindowMask backing:NSBackingStoreBuffered defer:NO]))
    {
        m_pParentView = pParentView;
        m_pOverlayView = pOverlayView;
        m_Thread = [NSThread currentThread];

        [m_pOverlayView setOverlayWin: self];

        m_pOverlayHelperView = [[OverlayHelperView alloc] initWithOverlayWindow:self];
        /* Add the helper view as a child of the parent view to get notifications */
        [pParentView addSubview:m_pOverlayHelperView];

        /* Make sure this window is transparent */
#ifdef SHOW_WINDOW_BACKGROUND
        /* For debugging */
        [self setBackgroundColor:[NSColor colorWithCalibratedRed:1.0 green:0.0 blue:0.0 alpha:0.7]];
#else
        [self setBackgroundColor:[NSColor clearColor]];
#endif
        [self setOpaque:NO];
        [self setAlphaValue:.999];
        /* Disable mouse events for this window */
        [self setIgnoresMouseEvents:YES];

        pParentWin = [m_pParentView window];

        /* Initial set the position to the parents view top/left (Compiz fix). */
        [self setFrameOrigin:
            [pParentWin convertBaseToScreen:
                [m_pParentView convertPoint:NSZeroPoint toView:nil]]];

        /* Set the overlay view as our content view */
        [self setContentView:m_pOverlayView];

        /* Add ourself as a child to the parent views window. Note: this has to
         * be done last so that everything else is setup in
         * parentWindowChanged. */
        [pParentWin addChildWindow:self ordered:NSWindowAbove];
    }
    DEBUG_MSG(("OWIN(%p): init OverlayWindow\n", (void*)self));

    return self;
}

- (void)dealloc
{
    DEBUG_MSG(("OWIN(%p): dealloc OverlayWindow\n", (void*)self));

    [[NSNotificationCenter defaultCenter] removeObserver:self];

    [m_pOverlayHelperView removeFromSuperview];
    [m_pOverlayHelperView release];

    [super dealloc];
}

- (void)parentWindowFrameChanged:(NSNotification*)pNote
{
    DEBUG_MSG(("OWIN(%p): parentWindowFrameChanged\n", (void*)self));

    /* Reposition this window with the help of the OverlayView. Perform the
     * call in the OpenGL thread. */
    /*
    [m_pOverlayView performSelector:@selector(reshape) onThread:m_Thread withObject:nil waitUntilDone:YES];
    */

    [m_pOverlayView reshape];
}

- (void)parentWindowChanged:(NSWindow*)pWindow
{
    DEBUG_MSG(("OWIN(%p): parentWindowChanged\n", (void*)self));

    [[NSNotificationCenter defaultCenter] removeObserver:self];

    if(pWindow != nil)
    {
        /* Ask to get notifications when our parent window frame changes. */
        [[NSNotificationCenter defaultCenter]
            addObserver:self
            selector:@selector(parentWindowFrameChanged:)
            name:NSWindowDidResizeNotification
            object:pWindow];
        /* Add us self as child window */
        [pWindow addChildWindow:self ordered:NSWindowAbove];
        /* Reshape the overlay view after a short waiting time to let the main
         * window resize itself properly. */
        /*
        [m_pOverlayView performSelector:@selector(reshape) withObject:nil afterDelay:0.2];
        [NSTimer scheduledTimerWithTimeInterval:0.2 target:m_pOverlayView selector:@selector(reshape) userInfo:nil repeats:NO];
        */
        [m_pOverlayView reshape];
    }
}

@end

/********************************************************************************
*
* OverlayView class implementation
*
********************************************************************************/
@implementation OverlayView

- (id)initWithFrame:(NSRect)frame thread:(RTTHREAD)aThread parentView:(NSView*)pParentView
{
    m_pParentView             = pParentView;
    /* Make some reasonable defaults */
    m_pGLCtx                  = nil;
    m_pSharedGLCtx            = nil;
    mThread                   = aThread;
#ifdef FBO
    m_FBOId                   = 0;
    m_FBOTexBackId            = 0;
    m_FBOTexFrontId           = 0;
    m_FBOAttBackId            = GL_COLOR_ATTACHMENT0_EXT;
    m_FBOAttFrontId           = GL_COLOR_ATTACHMENT1_EXT;
    m_FBODepthStencilPackedId = 0;
    m_FBOTexSize              = NSZeroSize;
#endif
    m_FBOThumbId              = 0;
    m_FBOThumbTexId           = 0;
    m_cClipRects              = 0;
    m_paClipRects             = NULL;
    m_Pos                     = NSZeroPoint;
    m_Size                    = NSMakeSize(1, 1);
    m_RootShift               = NSZeroPoint;

    self = [super initWithFrame:frame];

    DEBUG_MSG(("OVIW(%p): init OverlayView\n", (void*)self));

    return self;
}

- (void)dealloc
{
    DEBUG_MSG(("OVIW(%p): dealloc OverlayView\n", (void*)self));

    [self deleteFBO];

    if (m_pGLCtx)
    {
        if ([m_pGLCtx view] == self)
            [m_pGLCtx clearDrawable];
    }
    if (m_pSharedGLCtx)
    {
        if ([m_pSharedGLCtx view] == self)
            [m_pSharedGLCtx clearDrawable];

        [m_pSharedGLCtx release];
    }

    [self clearVisibleRegions];

    [super dealloc];
}

- (void)drawRect:(NSRect)aRect
{
    /* Do nothing */
}

- (void)setGLCtx:(NSOpenGLContext*)pCtx
{
    DEBUG_MSG(("OVIW(%p): setGLCtx: new ctx: %p\n", (void*)self, (void*)pCtx));

    m_pGLCtx = pCtx;
}

- (NSOpenGLContext*)glCtx
{
    return m_pGLCtx;
}

- (NSView*)parentView
{
    return m_pParentView;
}

- (void)setParentView:(NSView*)pView
{
    DEBUG_MSG(("OVIW(%p): setParentView: new view: %p\n", (void*)self, (void*)pView));

    m_pParentView = pView;
}

- (void)setOverlayWin:(NSWindow*)pWin
{
    DEBUG_MSG(("OVIW(%p): setOverlayWin: new win: %p\n", (void*)self, (void*)pWin));

    m_pOverlayWin = pWin;
}

- (NSWindow*)overlayWin
{
    return m_pOverlayWin;
}

- (void)setPos:(NSPoint)pos
{
    DEBUG_MSG(("OVIW(%p): setPos: new pos: %d, %d\n", (void*)self, (int)pos.x, (int)pos.y));

    m_Pos = pos;

    [self reshape];
}

- (NSPoint)pos
{
    return m_Pos;
}

- (void)setSize:(NSSize)size
{
    m_Size = size;

#ifdef FBO
    if (m_FBOId)
    {
        DEBUG_MSG(("OVIW(%p): setSize: new size: %dx%d\n", (void*)self, (int)size.width, (int)size.height));
        [self reshape];
        [self updateFBO];
        /* have to rebind GL_TEXTURE_RECTANGLE_ARB as m_FBOTexId could be changed in updateFBO call */
        [self updateViewport];
    }
    else
#endif
    {
        DEBUG_MSG(("OVIW(%p): setSize (no FBO): new size: %dx%d\n", (void*)self, (int)size.width, (int)size.height));
        [self reshape];
        [self updateFBO];
    }
}

- (NSSize)size
{
    return m_Size;
}

- (void)updateViewport
{
    NSRect r;

    DEBUG_MSG(("OVIW(%p): updateViewport\n", (void*)self));

#ifdef FBO
    if (m_pSharedGLCtx)
    {
        /* Update the viewport for our OpenGL view */
        DEBUG_MSG(("OVIW(%p): makeCurrent (shared) %p\n", (void*)self, (void*)m_pSharedGLCtx));
        [m_pSharedGLCtx makeCurrentContext];
        [m_pSharedGLCtx update];

        r = [self frame];
        /* Setup all matrices */
        glMatrixMode(GL_PROJECTION);
        glLoadIdentity();
        glViewport(0, 0, r.size.width, r.size.height);
        glOrtho(0, r.size.width, 0, r.size.height, -1, 1);
        DEBUG_MSG_1(("OVIW(%p): frame[%i, %i, %i, %i]\n", (void*)self, (int)r.origin.x, (int)r.origin.x, (int)r.size.width, (int)r.size.height));
        DEBUG_MSG_1(("OVIW(%p): m_Pos(%i,%i) m_Size(%i,%i)\n", (void*)self, (int)m_Pos.x, (int)m_Pos.y, (int)m_Size.width, (int)m_Size.height));
        DEBUG_MSG_1(("OVIW(%p): m_RootShift(%i, %i)\n", (void*)self, (int)m_RootShift.x, (int)m_RootShift.y));
        glMatrixMode(GL_TEXTURE);
        glLoadIdentity();
        glMatrixMode(GL_MODELVIEW);
        glLoadIdentity();

        /* Clear background to transparent */
        glClearColor(0.0f, 0.0f, 0.0f, 0.0f);

        DEBUG_MSG(("OVIW(%p): makeCurrent (non shared) %p\n", (void*)self, (void*)m_pGLCtx));
        [m_pGLCtx makeCurrentContext];
    }
#endif
}

- (void)reshape
{
    NSRect parentFrame = NSZeroRect;
    NSPoint parentPos  = NSZeroPoint;
    NSPoint childPos   = NSZeroPoint;
    NSRect childFrame  = NSZeroRect;
    NSRect newFrame    = NSZeroRect;

    DEBUG_MSG(("OVIW(%p): reshape\n", (void*)self));

    /* Getting the right screen coordinates of the parents frame is a little bit
     * complicated. */
    parentFrame = [m_pParentView frame];
    parentPos = [[m_pParentView window] convertBaseToScreen:[[m_pParentView superview] convertPointToBase:NSMakePoint(parentFrame.origin.x, parentFrame.origin.y + parentFrame.size.height)]];
    parentFrame.origin.x = parentPos.x;
    parentFrame.origin.y = parentPos.y;

    /* Calculate the new screen coordinates of the overlay window. */
    childPos = NSMakePoint(m_Pos.x, m_Pos.y + m_Size.height);
    childPos = [[m_pParentView window] convertBaseToScreen:[[m_pParentView superview] convertPointToBase:childPos]];

    /* Make a frame out of it. */
    childFrame = NSMakeRect(childPos.x, childPos.y, m_Size.width, m_Size.height);

    /* We have to make sure that the overlay window will not be displayed out
     * of the parent window. So intersect both frames & use the result as the new
     * frame for the window. */
    newFrame = NSIntersectionRect(parentFrame, childFrame);

    /* Later we have to correct the texture position in the case the window is
     * out of the parents window frame. So save the shift values for later use. */
    if (parentFrame.origin.x > childFrame.origin.x)
        m_RootShift.x = parentFrame.origin.x - childFrame.origin.x;
    else
        m_RootShift.x = 0;
    if (parentFrame.origin.y > childFrame.origin.y)
        m_RootShift.y = parentFrame.origin.y - childFrame.origin.y;
    else
        m_RootShift.y = 0;

    /*
    NSScrollView *pScrollView = [[[m_pParentView window] contentView] enclosingScrollView];
    if (pScrollView)
    {
        NSRect scrollRect = [pScrollView documentVisibleRect];
        NSRect scrollRect = [m_pParentView visibleRect];
        printf ("sc rect: %d %d %d %d\n", (int) scrollRect.origin.x,(int) scrollRect.origin.y,(int) scrollRect.size.width,(int) scrollRect.size.height);
        NSRect b = [[m_pParentView superview] bounds];
        printf ("bound rect: %d %d %d %d\n", (int) b.origin.x,(int) b.origin.y,(int) b.size.width,(int) b.size.height);
        newFrame.origin.x += scrollRect.origin.x;
        newFrame.origin.y += scrollRect.origin.y;
    }
    */

    /* Set the new frame. */
    [[self window] setFrame:newFrame display:YES];

    /* Inform the dock tile view as well */
    [self reshapeDockTile];

    /* Make sure the context is updated according */
    [self updateViewport];
}

- (void)createFBO
{
    GLint   oldTexId         = 0;
    GLint   oldFBId          = 0;
    NSView *pDockScreen      = nil;
    GLint   maxTexSize       = 0;
    GLfloat imageAspectRatio = 0;
    GLint   filter           = GL_NEAREST;

    [self deleteFBO];

#ifdef FBO
    DEBUG_MSG(("OVIW(%p): createFBO\n", (void*)self));

    glGetIntegerv(GL_TEXTURE_BINDING_RECTANGLE_ARB, &oldTexId);
    glGetIntegerv(GL_FRAMEBUFFER_BINDING_EXT, &oldFBId);

    /* If not previously setup generate IDs for FBO and its associated texture. */
    if (!m_FBOId)
    {
        /* Make sure the framebuffer extension is supported */
        const GLubyte* strExt;
        GLboolean isFBO;
        /* Get the extension name string. It is a space-delimited list of the
         * OpenGL extensions that are supported by the current renderer. */
        strExt = glGetString(GL_EXTENSIONS);
        isFBO = gluCheckExtension((const GLubyte*)"GL_EXT_framebuffer_object", strExt);
        if (!isFBO)
        {
            DEBUG_MSG(("Your system does not support the GL_EXT_framebuffer_object extension\n"));
        }
        isFBO = gluCheckExtension((const GLubyte*)"GL_EXT_framebuffer_blit", strExt);
        if (!isFBO)
        {
            DEBUG_MSG(("Your system does not support the GL_EXT_framebuffer_blit extension\n"));
        }

        /* Create FBO object */
        glGenFramebuffersEXT(1, &m_FBOId);
        /* & the texture as well the depth/stencil render buffer */
        glGenTextures(1, &m_FBOTexBackId);
        glGenTextures(1, &m_FBOTexFrontId);
        DEBUG_MSG(("OVIW(%p): gen numbers: FBOId=%d FBOTexBackId=%d FBOTexFrontId=%d\n", (void*)self, m_FBOId, m_FBOTexBackId, m_FBOTexFrontId));

        glGenRenderbuffersEXT(1, &m_FBODepthStencilPackedId);
    }

    m_FBOTexSize = m_Size;
    /* Bind to FBO */
    glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, m_FBOId);

    /*
    glEnable(GL_TEXTURE_RECTANGLE_ARB);
     */

    imageAspectRatio = m_FBOTexSize.width / m_FBOTexSize.height;

    /* Sanity check against maximum OpenGL texture size. If bigger adjust to
     * maximum possible size while maintain the aspect ratio. */
    glGetIntegerv(GL_MAX_TEXTURE_SIZE, &maxTexSize);
    if (m_FBOTexSize.width > maxTexSize || m_FBOTexSize.height > maxTexSize)
    {
        filter = GL_LINEAR;
        if (imageAspectRatio > 1)
        {
            m_FBOTexSize.width = maxTexSize;
            m_FBOTexSize.height = maxTexSize / imageAspectRatio;
        }
        else
        {
            m_FBOTexSize.width = maxTexSize * imageAspectRatio;
            m_FBOTexSize.height = maxTexSize;
        }
    }

    DEBUG_MSG(("OVIW(%p): tex size is: %dx%d\n", (void*)self, (int)m_FBOTexSize.width, (int)m_FBOTexSize.height));

    /* Initialize FBO Textures */
    /* The GPUs like the GL_BGRA / GL_UNSIGNED_INT_8_8_8_8_REV combination
     * others are also valid, but might incur a costly software translation. */
    glBindTexture(GL_TEXTURE_RECTANGLE_ARB, m_FBOTexBackId);
    glTexImage2D(GL_TEXTURE_RECTANGLE_ARB, 0, GL_RGB, m_FBOTexSize.width, m_FBOTexSize.height, 0, GL_BGRA, GL_UNSIGNED_INT_8_8_8_8_REV, NULL);
    glBindTexture(GL_TEXTURE_RECTANGLE_ARB, m_FBOTexFrontId);
    glTexImage2D(GL_TEXTURE_RECTANGLE_ARB, 0, GL_RGB, m_FBOTexSize.width, m_FBOTexSize.height, 0, GL_BGRA, GL_UNSIGNED_INT_8_8_8_8_REV, NULL);

    /* Now attach the textures to the FBO as its color destinations */
    glFramebufferTexture2DEXT(GL_FRAMEBUFFER_EXT, m_FBOAttBackId,  GL_TEXTURE_RECTANGLE_ARB, m_FBOTexBackId, 0);
    glFramebufferTexture2DEXT(GL_FRAMEBUFFER_EXT, m_FBOAttFrontId, GL_TEXTURE_RECTANGLE_ARB, m_FBOTexFrontId, 0);

    glBindRenderbufferEXT(GL_RENDERBUFFER_EXT, m_FBODepthStencilPackedId);
    glRenderbufferStorageEXT(GL_RENDERBUFFER_EXT, GL_DEPTH_COMPONENT, m_FBOTexSize.width, m_FBOTexSize.height);
    glFramebufferRenderbufferEXT(GL_FRAMEBUFFER_EXT, GL_DEPTH_ATTACHMENT_EXT, GL_RENDERBUFFER_EXT, m_FBODepthStencilPackedId);

    /* Bind the FBOs for reading and drawing. */
    glBindFramebufferEXT(GL_READ_FRAMEBUFFER_EXT, m_FBOId);
    glBindFramebufferEXT(GL_DRAW_FRAMEBUFFER_EXT, m_FBOId);

    /* Explicitly clear the textures otherwise they would contain old memory stuff. */
    glDrawBuffer(m_FBOAttBackId);
    glClear(GL_COLOR_BUFFER_BIT);
    glDrawBuffer(m_FBOAttFrontId);
    glClear(GL_COLOR_BUFFER_BIT);

    /* Now initially reading/drawing to the back buffer. */
    glReadBuffer(m_FBOAttBackId);
    glDrawBuffer(m_FBOAttBackId);

    /* Make sure the FBO was created successfully. */
    if (GL_FRAMEBUFFER_COMPLETE_EXT != glCheckFramebufferStatusEXT(GL_FRAMEBUFFER_EXT))
        DEBUG_MSG(("OVIW(%p): Framebuffer Object creation or update failed!\n", (void*)self));

//    glBindRenderbufferEXT(GL_RENDERBUFFER_EXT, 0);
    glBindTexture(GL_TEXTURE_RECTANGLE_ARB, oldTexId);
    glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, (GLuint)oldFBId ? (GLuint)oldFBId : m_FBOId);

    /* Is there a dock tile preview enabled in the GUI? If so setup a
     * additional thumbnail view for the dock tile. */
    pDockScreen = [self dockTileScreen];
    if (pDockScreen)
    {
        if (!m_FBOThumbId)
        {
            glGenFramebuffersEXT(1, &m_FBOThumbId);
            glGenTextures(1, &m_FBOThumbTexId);
        }

        glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, m_FBOThumbId);
        /* Initialize FBO Texture */
        glBindTexture(GL_TEXTURE_RECTANGLE_ARB, m_FBOThumbTexId);
        glTexParameteri(GL_TEXTURE_RECTANGLE_ARB, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
        glTexParameteri(GL_TEXTURE_RECTANGLE_ARB, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
        glTexParameteri(GL_TEXTURE_RECTANGLE_ARB, GL_TEXTURE_WRAP_S, GL_CLAMP);
        glTexParameteri(GL_TEXTURE_RECTANGLE_ARB, GL_TEXTURE_WRAP_T, GL_CLAMP);

        /* The GPUs like the GL_BGRA / GL_UNSIGNED_INT_8_8_8_8_REV combination
         * others are also valid, but might incur a costly software translation. */
        glTexImage2D(GL_TEXTURE_RECTANGLE_ARB, 0, GL_RGB, m_FBOTexSize.width * m_FBOThumbScaleX, m_FBOTexSize.height * m_FBOThumbScaleY, 0, GL_BGRA, GL_UNSIGNED_INT_8_8_8_8_REV, NULL);

        /* Now attach texture to the FBO as its color destination */
        glFramebufferTexture2DEXT(GL_FRAMEBUFFER_EXT, GL_COLOR_ATTACHMENT0_EXT, GL_TEXTURE_RECTANGLE_ARB, m_FBOThumbTexId, 0);

        /* Make sure the FBO was created successfully. */
        if (GL_FRAMEBUFFER_COMPLETE_EXT != glCheckFramebufferStatusEXT(GL_FRAMEBUFFER_EXT))
            DEBUG_MSG(("OVIW(%p): Framebuffer \"Thumb\" Object creation or update failed!\n", (void*)self));

        glBindTexture(GL_TEXTURE_RECTANGLE_ARB, oldTexId);
        glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, (GLuint)oldFBId ? (GLuint)oldFBId : m_FBOId);

        m_DockTileView = [[DockOverlayView alloc] init];
        [self reshapeDockTile];
        [pDockScreen addSubview:m_DockTileView];
    }

    /* Initialize with one big visual region over the full size */
    [self clearVisibleRegions];
    m_cClipRects = 1;
    m_paClipRects = (GLint*)RTMemAlloc(sizeof(GLint) * 4);
    m_paClipRects[0] = 0;
    m_paClipRects[1] = 0;
    m_paClipRects[2] = m_FBOTexSize.width;
    m_paClipRects[3] = m_FBOTexSize.height;
#endif
}

- (void)deleteFBO
{
    DEBUG_MSG(("OVIW(%p): deleteFBO\n", (void*)self));

    if (m_pSharedGLCtx)
    {
        DEBUG_MSG(("OVIW(%p): makeCurrent (shared) %p\n", (void*)self, (void*)m_pSharedGLCtx));
        [m_pSharedGLCtx makeCurrentContext];
        [m_pSharedGLCtx update];

        glEnable(GL_TEXTURE_RECTANGLE_ARB);
        glBindTexture(GL_TEXTURE_RECTANGLE_ARB, 0);
    }

    if (m_pGLCtx)
    {
        DEBUG_MSG(("OVIW(%p): makeCurrent (non shared) %p\n", (void*)self, (void*)m_pGLCtx));
        [m_pGLCtx makeCurrentContext];

#ifdef FBO
        if (m_FBODepthStencilPackedId > 0)
        {
            glDeleteRenderbuffersEXT(1, &m_FBODepthStencilPackedId);
            m_FBODepthStencilPackedId = 0;
        }
        if (m_FBOTexBackId > 0)
        {
            glDeleteTextures(1, &m_FBOTexBackId);
            m_FBOTexBackId = 0;
        }
        if (m_FBOTexFrontId > 0)
        {
            glDeleteTextures(1, &m_FBOTexFrontId);
            m_FBOTexFrontId = 0;
        }
        if (m_FBOId > 0)
        {
            if ([self isCurrentFBO])
                glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, 0);

            glDeleteFramebuffersEXT(1, &m_FBOId);
            m_FBOId = 0;
        }
#endif
    }

    if (m_DockTileView != nil)
    {
        [m_DockTileView removeFromSuperview];
        [m_DockTileView release];
        m_DockTileView = nil;
    }
}

- (void)updateFBO
{
    DEBUG_MSG(("OVIW(%p): updateFBO\n", (void*)self));

    [self makeCurrentFBO];

    if (m_pGLCtx)
    {
#ifdef FBO
        glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, 0);
        [self createFBO];
        glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, m_FBOId);
#endif
        [m_pGLCtx update];
    }
}

- (void)makeCurrentFBO
{
    DEBUG_MSG(("OVIW(%p): makeCurrentFBO\n", (void*)self));

#ifdef FBO
    DEBUG_MSG(("OVIW(%p): FBOId=%d CTX=%p\n", (void*)self, m_FBOId, (void*)m_pGLCtx));
    if([NSOpenGLContext currentContext] != 0)
        glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, m_FBOId);
#endif
    if (m_pGLCtx)
    {
        if ([m_pGLCtx view] != self)
        {
            /* We change the active view, so flush first */
            if([NSOpenGLContext currentContext] != 0)
                glFlush();
            [m_pGLCtx setView: self];
            CHECK_GL_ERROR();
        }
        /*
        if ([NSOpenGLContext currentContext] != m_pGLCtx)
        */
        {
            [m_pGLCtx makeCurrentContext];
            CHECK_GL_ERROR();
            /*
            [m_pGLCtx update];
            */
        }
    }
#ifdef FBO
    glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, m_FBOId);
#endif
}

- (bool)isCurrentFBO
{
#ifdef FBO
    GLint curFBOId = 0;

    glGetIntegerv(GL_FRAMEBUFFER_BINDING_EXT, &curFBOId);
    DEBUG_MSG_1(("OVIW(%p): isCurrentFBO: curFBOId=%d FBOId=%d\n", (void*)self, curFBOId, m_FBOId));
    return (GLuint)curFBOId == m_FBOId;
#else
    return false;
#endif
}

- (void)tryDraw
{
    if ([self lockFocusIfCanDraw])
    {
        [self renderFBOToView];
        [self unlockFocus];
    }
}

- (void)swapFBO
{
    GLint sw     = 0;
    GLint readFBOId = 0;
    GLint drawFBOId = 0;
    GLint readId = 0;
    GLint drawId = 0;

    DEBUG_MSG(("OVIW(%p): swapFBO\n", (void*)self));

#ifdef FBO
    /* Don't use flush buffers cause we are using FBOs here! */

    /* Before we swap make sure everything is done (This is really
     * important. Don't remove.) */
    glFlush();

    /* Fetch the current used read and draw buffers. */
    glGetIntegerv(GL_READ_FRAMEBUFFER_BINDING, &readFBOId);
    glGetIntegerv(GL_DRAW_FRAMEBUFFER_BINDING, &drawFBOId);
    glGetIntegerv(GL_READ_BUFFER, &readId);
    glGetIntegerv(GL_DRAW_BUFFER, &drawId);

    /* Do the swapping of our internal ids */
    sw              = m_FBOTexFrontId;
    m_FBOTexFrontId = m_FBOTexBackId;
    m_FBOTexBackId  = sw;
    sw              = m_FBOAttFrontId;
    m_FBOAttFrontId = m_FBOAttBackId;
    m_FBOAttBackId  = sw;

    DEBUG_MSG_1(("read FBO: %d draw FBO: %d readId: %d drawId: %d\n", readFBOId, drawFBOId, readId, drawId));
    /* We also have to swap the real ids on the current context. */
    if ((GLuint)readFBOId == m_FBOId)
    {
        if ((GLuint)readId == m_FBOAttFrontId)
            glReadBuffer(m_FBOAttBackId);
        if ((GLuint)readId == m_FBOAttBackId)
            glReadBuffer(m_FBOAttFrontId);
    }
    if ((GLuint)drawFBOId == m_FBOId)
    {
        if ((GLuint)drawId == m_FBOAttFrontId)
            glDrawBuffer(m_FBOAttBackId);
        if ((GLuint)drawId == m_FBOAttBackId)
            glDrawBuffer(m_FBOAttFrontId);
    }

    [self tryDraw];
#else
    [m_pGLCtx flushBuffer];
#endif
}

- (void)flushFBO
{
    GLint drawId = 0;
    GLint FBOId  = 0;

    DEBUG_MSG(("OVIW(%p): flushFBO\n", (void*)self));

    glFlush();
#ifdef FBO
    /* If at any time OpenGl operations where done in the front buffer, we need
     * to reflect this in the FBO as well. This is something which on real
     * hardware happens and unfortunately some applications rely on it (grrr ... Compiz). */
    if (   m_fFrontDrawing
        && [self isCurrentFBO])
    {
        /* Only reset if we aren't currently front. */
        glGetIntegerv(GL_DRAW_FRAMEBUFFER_BINDING, &FBOId);
        glGetIntegerv(GL_DRAW_BUFFER, &drawId);
        if (!(   (GLuint)FBOId  == m_FBOId
              && (GLuint)drawId == m_FBOAttFrontId))
            m_fFrontDrawing = false;
        [self tryDraw];
    }
#endif
}

- (void)finishFBO
{
    DEBUG_MSG(("OVIW(%p): finishFBO\n", (void*)self));

    glFinish();
#ifdef FBO
    if ([self isCurrentFBO])
        [self tryDraw];
#endif
}

- (void)stateInfo:(GLenum)pname withParams:(GLint*)params
{
    GLint test;
//    DEBUG_MSG_1(("StateInfo requested: %d\n", pname));

    glGetIntegerv(pname, params);
#ifdef FBO
    switch(pname)
    {
        case GL_FRAMEBUFFER_BINDING_EXT:
        case GL_READ_FRAMEBUFFER_BINDING:
        case GL_READ_FRAMEBUFFER_EXT:
        case GL_DRAW_FRAMEBUFFER_EXT:
        {
            if ((GLuint)*params == m_FBOId)
                *params = 0;
            break;
        }
        case GL_READ_BUFFER:
        {
            glGetIntegerv(GL_READ_FRAMEBUFFER_BINDING, &test);
            if ((GLuint)test == m_FBOId)
            {
                if ((GLuint)*params == m_FBOAttFrontId)
                    *params = GL_FRONT;
                else
                    if ((GLuint)*params == m_FBOAttBackId)
                        *params = GL_BACK;
            }
            break;
        }
        case GL_DRAW_BUFFER:
        {
            glGetIntegerv(GL_DRAW_FRAMEBUFFER_BINDING, &test);
            if ((GLuint)test == m_FBOId)
            {
                if ((GLuint)*params == m_FBOAttFrontId)
                    *params = GL_FRONT;
                else
                    if ((GLuint)*params == m_FBOAttBackId)
                        *params = GL_BACK;
            }
            break;
        }
    }
#endif
}

- (void)readBuffer:(GLenum)mode
{
#ifdef FBO
    /*
    if ([self isCurrentFBO])
    */
    {
        if (mode == GL_FRONT)
        {
            glBindFramebufferEXT(GL_READ_FRAMEBUFFER_EXT, m_FBOId);
            glReadBuffer(m_FBOAttFrontId);
        }
        else if (mode == GL_BACK)
        {
            glBindFramebufferEXT(GL_READ_FRAMEBUFFER_EXT, m_FBOId);
            glReadBuffer(m_FBOAttBackId);
        }
        else
            glReadBuffer(mode);
    }
#else
    glReadBuffer(mode);
#endif
}

- (void)drawBuffer:(GLenum)mode
{
#ifdef FBO
    /*
    if ([self isCurrentFBO])
    */
    {
        if (mode == GL_FRONT)
        {
            DEBUG_MSG(("OVIW(%p): front\n", (void*)self));
            glBindFramebufferEXT(GL_DRAW_FRAMEBUFFER_EXT, m_FBOId);
            glDrawBuffer(m_FBOAttFrontId);
            m_fFrontDrawing = true;
        }
        else if (mode == GL_BACK)
        {
            DEBUG_MSG(("OVIW(%p): back\n", (void*)self));
            glBindFramebufferEXT(GL_DRAW_FRAMEBUFFER_EXT, m_FBOId);
            glDrawBuffer(m_FBOAttBackId);
        }
        else
        {
            DEBUG_MSG(("OVIW(%p): other: %d\n", (void*)self, mode));
            glDrawBuffer(mode);
        }
    }
#else
    glDrawBuffer(mode);
#endif
}

- (void)bindFBO:(GLenum)target withFrameBuffer:(GLuint)framebuffer
{
#ifdef FBO
    if (framebuffer != 0)
        glBindFramebufferEXT(target, framebuffer);
    else
        glBindFramebufferEXT(target, m_FBOId);
#else
    glBindFramebufferEXT(target, framebuffer);
#endif
}

- (void)renderFBOToView
{
    GLint opaque       = 0;
    GLint i            = 0;
    GLint oldReadFBOId = 0;
    GLint oldDrawFBOId = 0;
    GLint oldReadId    = 0;
    GLint oldDrawId    = 0;

    DEBUG_MSG(("OVIW(%p): renderFBOToView\n", (void*)self));

#ifdef FBO

    /* Fetch the current used read and draw buffers. */
    glGetIntegerv(GL_READ_FRAMEBUFFER_BINDING_EXT, &oldReadFBOId);
    glGetIntegerv(GL_DRAW_FRAMEBUFFER_BINDING_EXT, &oldDrawFBOId);
    glGetIntegerv(GL_READ_BUFFER, &oldReadId);
    glGetIntegerv(GL_DRAW_BUFFER, &oldDrawId);

    if (!m_pSharedGLCtx)
    {
        /* Create a shared context out of the main context. Use the same pixel format. */
        m_pSharedGLCtx = [[NSOpenGLContext alloc] initWithFormat:[(OverlayOpenGLContext*)m_pGLCtx openGLPixelFormat] shareContext:m_pGLCtx];

        /* Set the new context as non opaque */
        [m_pSharedGLCtx setValues:&opaque forParameter:NSOpenGLCPSurfaceOpacity];
        /* Set this view as the drawable for the new context */
        [m_pSharedGLCtx setView: self];
        [self updateViewport];
    }

    if (m_pSharedGLCtx)
    {
        NSRect r = [self frame];
        DEBUG_MSG(("OVIW(%p): rF2V frame: [%i, %i, %i, %i]\n", (void*)self, (int)r.origin.x, (int)r.origin.y, (int)r.size.width, (int)r.size.height));

        if (m_FBOTexFrontId > 0)
        {
            if ([m_pSharedGLCtx view] != self)
            {
                DEBUG_MSG(("OVIW(%p): not current view of shared ctx! Switching ...\n", (void*)self));
                [m_pSharedGLCtx setView: self];
                [self updateViewport];
            }

            [m_pSharedGLCtx makeCurrentContext];

            glBindFramebufferEXT(GL_READ_FRAMEBUFFER_EXT, m_FBOId);
            glReadBuffer(m_FBOAttFrontId);
            glBindFramebufferEXT(GL_DRAW_FRAMEBUFFER_EXT, 0);
            glDrawBuffer(GL_BACK);

            /* Render FBO content to the dock tile when necessary. */
            [self renderFBOToDockTile];

#if 1 /* Set to 0 to see the docktile instead of the real output */
            /* Clear background to transparent */
            glClear(GL_COLOR_BUFFER_BIT);

            /* Blit the content of the FBO to the screen. */
            for (i = 0; i < m_cClipRects; ++i)
            {
                GLint x1 = m_paClipRects[4*i];
                GLint y1 = r.size.height - m_paClipRects[4*i+1];
                GLint x2 = m_paClipRects[4*i+2];
                GLint y2 = r.size.height - m_paClipRects[4*i+3];
                glBlitFramebufferEXT(x1, y1 + m_RootShift.y, x2, y2 + m_RootShift.y,
                                     x1 - m_RootShift.x, y1, x2 - m_RootShift.x, y2,
                                     GL_COLOR_BUFFER_BIT, GL_NEAREST);
            }
#endif
            /*
            glFinish();
            */
            glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, 0);
            [m_pSharedGLCtx flushBuffer];

            [m_pGLCtx makeCurrentContext];
            /* Reset to previous buffer bindings. */
            glBindFramebufferEXT(GL_READ_FRAMEBUFFER_EXT, oldReadFBOId);
            glReadBuffer(oldReadId);
            glBindFramebufferEXT(GL_DRAW_FRAMEBUFFER_EXT, oldDrawFBOId);
            glDrawBuffer(oldDrawId);
        }
    }
#else
    [m_pGLCtx flushBuffer];
#endif
}

- (void)renderFBOToDockTile
{
    NSRect r        = [self frame];
    NSRect rr       = NSZeroRect;
    GLint i         = 0;
    NSDockTile *pDT = nil;

#ifdef FBO
    if (   m_FBOThumbId
        && m_FBOThumbTexId
        && [m_DockTileView thumbBitmap] != nil)
    {
        /* Only update after at least 200 ms, cause glReadPixels is
         * heavy performance wise. */
        uint64_t uiNewTime = RTTimeMilliTS();
        if (uiNewTime - m_uiDockUpdateTime > 200)
        {
            m_uiDockUpdateTime = uiNewTime;
#if 0
            /* todo: check this for optimization */
            glBindTexture(GL_TEXTURE_RECTANGLE_ARB, myTextureName);
            glTexParameteri(GL_TEXTURE_RECTANGLE_ARB, GL_TEXTURE_STORAGE_HINT_APPLE,
                            GL_STORAGE_SHARED_APPLE);
            glPixelStorei(GL_UNPACK_CLIENT_STORAGE_APPLE, GL_TRUE);
            glTexImage2D(GL_TEXTURE_RECTANGLE_ARB, 0, GL_RGBA,
                         sizex, sizey, 0, GL_BGRA,
                         GL_UNSIGNED_INT_8_8_8_8_REV, myImagePtr);
            glCopyTexSubImage2D(GL_TEXTURE_RECTANGLE_ARB,
                                0, 0, 0, 0, 0, image_width, image_height);
            glFlush();
            /* Do other work processing here, using a double or triple buffer */
            glGetTexImage(GL_TEXTURE_RECTANGLE_ARB, 0, GL_BGRA,
                          GL_UNSIGNED_INT_8_8_8_8_REV, pixels);
#endif
            /* Clear background to transparent */
            glClear(GL_COLOR_BUFFER_BIT);

            rr = [m_DockTileView frame];

            for (i = 0; i < m_cClipRects; ++i)
            {
                GLint x1 = m_paClipRects[4*i];
                GLint y1 = r.size.height - m_paClipRects[4*i+1];
                GLint x2 = m_paClipRects[4*i+2];
                GLint y2 = r.size.height - m_paClipRects[4*i+3];

                glBlitFramebufferEXT(x1, y1 + m_RootShift.y, x2, y2 + m_RootShift.y,
                                     x1 * m_FBOThumbScaleX, y1 * m_FBOThumbScaleY, x2 * m_FBOThumbScaleX, y2 * m_FBOThumbScaleY,
                                     GL_COLOR_BUFFER_BIT, GL_LINEAR);
            }
            glFinish();

            glBindFramebufferEXT(GL_READ_FRAMEBUFFER_EXT, 0);
            glReadBuffer(GL_BACK);
            /* Here the magic of reading the FBO content in our own buffer
             * happens. We have to lock this access, in the case the dock
             * is updated currently. */
            [m_DockTileView lock];
            glReadPixels(0, 0, rr.size.width, rr.size.height,
                         GL_BGRA,
                         GL_UNSIGNED_INT_8_8_8_8,
                         [[m_DockTileView thumbBitmap] bitmapData]);
            [m_DockTileView unlock];

            glBindFramebufferEXT(GL_READ_FRAMEBUFFER_EXT, m_FBOId);
            glReadBuffer(m_FBOAttFrontId);

            pDT = [[NSApplication sharedApplication] dockTile];

            /* Send a display message to the dock tile in the main thread */
            [[[NSApplication sharedApplication] dockTile] performSelectorOnMainThread:@selector(display) withObject:nil waitUntilDone:NO];

        }
    }
#endif
}

- (void)clearVisibleRegions
{
    if(m_paClipRects)
    {
        RTMemFree(m_paClipRects);
        m_paClipRects = NULL;
    }
    m_cClipRects = 0;
}

- (void)setVisibleRegions:(GLint)cRects paRects:(GLint*)paRects
{
    DEBUG_MSG_1(("OVIW(%p): setVisibleRegions: cRects=%d\n", (void*)self, cRects));

    [self clearVisibleRegions];

    if (cRects > 0)
    {
#ifdef DEBUG_poetzsch
        int i =0;
        for (i = 0; i < cRects; ++i)
            DEBUG_MSG_1(("OVIW(%p): setVisibleRegions: %d - %d %d %d %d\n", (void*)self, i, paRects[i * 4], paRects[i * 4 + 1], paRects[i * 4 + 2], paRects[i * 4 + 3]));
#endif

        m_paClipRects = (GLint*)RTMemAlloc(sizeof(GLint) * 4 * cRects);
        m_cClipRects = cRects;
        memcpy(m_paClipRects, paRects, sizeof(GLint) * 4 * cRects);
    }
    else
        [self tryDraw];
}

- (NSView*)dockTileScreen
{
    NSView *contentView = [[[NSApplication sharedApplication] dockTile] contentView];
    NSView *screenContent = nil;
    /* First try the new variant which checks if this window is within the
       screen which is previewed in the dock. */
    if ([contentView respondsToSelector:@selector(screenContentWithParentView:)])
         screenContent = [contentView performSelector:@selector(screenContentWithParentView:) withObject:(id)m_pParentView];
    /* If it fails, fall back to the old variant (VBox...) */
    else if ([contentView respondsToSelector:@selector(screenContent)])
         screenContent = [contentView performSelector:@selector(screenContent)];
    return screenContent;
}

- (void)reshapeDockTile
{
    NSRect newFrame = NSZeroRect;

    NSView *pView = [self dockTileScreen];
    if (pView != nil)
    {
        NSRect dockFrame = [pView frame];
        NSRect parentFrame = [m_pParentView frame];

        m_FBOThumbScaleX = (float)dockFrame.size.width / parentFrame.size.width;
        m_FBOThumbScaleY = (float)dockFrame.size.height / parentFrame.size.height;
        newFrame = NSMakeRect((int)(m_Pos.x * m_FBOThumbScaleX), (int)(dockFrame.size.height - (m_Pos.y + m_Size.height - m_RootShift.y) * m_FBOThumbScaleY), (int)(m_Size.width * m_FBOThumbScaleX), (int)(m_Size.height * m_FBOThumbScaleY));
        /*
        NSRect newFrame = NSMakeRect ((int)roundf(m_Pos.x * m_FBOThumbScaleX), (int)roundf(dockFrame.size.height - (m_Pos.y + m_Size.height) * m_FBOThumbScaleY), (int)roundf(m_Size.width * m_FBOThumbScaleX), (int)roundf(m_Size.height * m_FBOThumbScaleY));
        NSRect newFrame = NSMakeRect ((m_Pos.x * m_FBOThumbScaleX), (dockFrame.size.height - (m_Pos.y + m_Size.height) * m_FBOThumbScaleY), (m_Size.width * m_FBOThumbScaleX), (m_Size.height * m_FBOThumbScaleY));
        printf ("%f %f %f %f - %f %f\n", newFrame.origin.x, newFrame.origin.y, newFrame.size.width, newFrame.size.height, m_Size.height, m_FBOThumbScaleY);
        */
        [m_DockTileView setFrame: newFrame];
    }
}

@end

/********************************************************************************
*
* OpenGL context management
*
********************************************************************************/
void cocoaGLCtxCreate(NativeNSOpenGLContextRef *ppCtx, GLbitfield fVisParams)
{
    NSOpenGLPixelFormat *pFmt = nil;

    NSAutoreleasePool *pPool = [[NSAutoreleasePool alloc] init];

    NSOpenGLPixelFormatAttribute attribs[24] =
    {
        NSOpenGLPFAWindow,
        NSOpenGLPFAAccelerated,
        NSOpenGLPFAColorSize, (NSOpenGLPixelFormatAttribute)24
    };

    int i = 4;

    if (fVisParams & CR_ALPHA_BIT)
    {
        DEBUG_MSG(("CR_ALPHA_BIT requested\n"));
        attribs[i++] = NSOpenGLPFAAlphaSize;
        attribs[i++] = 8;
    }
    if (fVisParams & CR_DEPTH_BIT)
    {
        DEBUG_MSG(("CR_DEPTH_BIT requested\n"));
        attribs[i++] = NSOpenGLPFADepthSize;
        attribs[i++] = 24;
    }
    if (fVisParams & CR_STENCIL_BIT)
    {
        DEBUG_MSG(("CR_STENCIL_BIT requested\n"));
        attribs[i++] = NSOpenGLPFAStencilSize;
        attribs[i++] = 8;
    }
    if (fVisParams & CR_ACCUM_BIT)
    {
        DEBUG_MSG(("CR_ACCUM_BIT requested\n"));
        attribs[i++] = NSOpenGLPFAAccumSize;
        if (fVisParams & CR_ALPHA_BIT)
            attribs[i++] = 32;
        else
            attribs[i++] = 24;
    }
    if (fVisParams & CR_MULTISAMPLE_BIT)
    {
        DEBUG_MSG(("CR_MULTISAMPLE_BIT requested\n"));
        attribs[i++] = NSOpenGLPFASampleBuffers;
        attribs[i++] = 1;
        attribs[i++] = NSOpenGLPFASamples;
        attribs[i++] = 4;
    }
    if (fVisParams & CR_DOUBLE_BIT)
    {
        DEBUG_MSG(("CR_DOUBLE_BIT requested\n"));
        attribs[i++] = NSOpenGLPFADoubleBuffer;
    }
    if (fVisParams & CR_STEREO_BIT)
    {
        /* We don't support that.
        DEBUG_MSG(("CR_STEREO_BIT requested\n"));
        attribs[i++] = NSOpenGLPFAStereo;
        */
    }

    /* Mark the end */
    attribs[i++] = 0;

    /* Choose a pixel format */
    pFmt = [[NSOpenGLPixelFormat alloc] initWithAttributes:attribs];

    if (pFmt)
    {
        *ppCtx = [[OverlayOpenGLContext alloc] initWithFormat:pFmt shareContext:nil];

        /* Enable multi threaded OpenGL engine */
        /*
        CGLContextObj cglCtx = [*ppCtx CGLContextObj];
        CGLError err = CGLEnable(cglCtx, kCGLCEMPEngine);
        if (err != kCGLNoError)
            printf ("Couldn't enable MT OpenGL engine!\n");
        */

        DEBUG_MSG(("New context %X\n", (uint)*ppCtx));
    }

    [pPool release];
}

void cocoaGLCtxDestroy(NativeNSOpenGLContextRef pCtx)
{
    NSAutoreleasePool *pPool = [[NSAutoreleasePool alloc] init];

    /*
    [pCtx release];
    */

    [pPool release];
}

/********************************************************************************
*
* View management
*
********************************************************************************/
void cocoaViewCreate(NativeNSViewRef *ppView, NativeNSViewRef pParentView, GLbitfield fVisParams)
{
    NSAutoreleasePool *pPool = [[NSAutoreleasePool alloc] init];

    /* Create our worker view */
    OverlayView* pView = [[OverlayView alloc] initWithFrame:NSZeroRect thread:RTThreadSelf() parentView:pParentView];

    if (pView)
    {
        /* We need a real window as container for the view */
        [[OverlayWindow alloc] initWithParentView:pParentView overlayView:pView];
        /* Return the freshly created overlay view */
        *ppView = pView;
    }

    [pPool release];
}

void cocoaViewReparent(NativeNSViewRef pView, NativeNSViewRef pParentView)
{
    NSAutoreleasePool *pPool = [[NSAutoreleasePool alloc] init];

    OverlayView* pOView = (OverlayView*)pView;

    if (pOView)
    {
        /* Make sure the window is removed from any previous parent window. */
        if ([[pOView overlayWin] parentWindow] != nil)
        {
            [[[pOView overlayWin] parentWindow] removeChildWindow:[pOView overlayWin]];
        }

        /* Set the new parent view */
        [pOView setParentView: pParentView];

        /* Add the overlay window as a child to the new parent window */
        if (pParentView != nil)
        {
            [[pParentView window] addChildWindow:[pOView overlayWin] ordered:NSWindowAbove];
            [pOView createFBO];
        }
    }

    [pPool release];
}

void cocoaViewDestroy(NativeNSViewRef pView)
{
    NSWindow *pWin = nil;

    NSAutoreleasePool *pPool = [[NSAutoreleasePool alloc] init];

    /* Hide the view early */
    [pView setHidden: YES];

    pWin = [pView window];
    [[NSNotificationCenter defaultCenter] removeObserver:pWin];
    [pWin setContentView: nil];
    [[pWin parentWindow] removeChildWindow: pWin];
    /*
    a = [pWin retainCount];
    for (; a > 1; --a)
        [pWin performSelector:@selector(release)]
    */
    [pWin performSelectorOnMainThread:@selector(release) withObject:nil waitUntilDone:YES];
    /*
    [pWin release];
    */

    /* There seems to be a bug in the performSelector method which is called in
     * parentWindowChanged above. The object is retained but not released. This
     * results in an unbalanced reference count, which is here manually
     * decremented. */
    /*
    a = [pView retainCount];
    for (; a > 1; --a)
    */
    [pView performSelectorOnMainThread:@selector(release) withObject:nil waitUntilDone:YES];
    /*
    [pView release];
    */

    [pPool release];
}

void cocoaViewShow(NativeNSViewRef pView, GLboolean fShowIt)
{
    NSAutoreleasePool *pPool = [[NSAutoreleasePool alloc] init];

    [pView setHidden: fShowIt==GL_TRUE?NO:YES];

    [pPool release];
}

void cocoaViewDisplay(NativeNSViewRef pView)
{
    NSAutoreleasePool *pPool = [[NSAutoreleasePool alloc] init];

    DEBUG_MSG_1(("cocoaViewDisplay %p\n", (void*)pView));
    [(OverlayView*)pView swapFBO];

    [pPool release];

}

void cocoaViewSetPosition(NativeNSViewRef pView, NativeNSViewRef pParentView, int x, int y)
{
    NSAutoreleasePool *pPool = [[NSAutoreleasePool alloc] init];

    [(OverlayView*)pView setPos:NSMakePoint(x, y)];

    [pPool release];
}

void cocoaViewSetSize(NativeNSViewRef pView, int w, int h)
{
    NSAutoreleasePool *pPool = [[NSAutoreleasePool alloc] init];

    [(OverlayView*)pView setSize:NSMakeSize(w, h)];

    [pPool release];
}

void cocoaViewGetGeometry(NativeNSViewRef pView, int *pX, int *pY, int *pW, int *pH)
{
    NSAutoreleasePool *pPool = [[NSAutoreleasePool alloc] init];

    NSRect frame = [[pView window] frame];
    *pX = frame.origin.x;
    *pY = frame.origin.y;
    *pW = frame.size.width;
    *pH = frame.size.height;

    [pPool release];
}

void cocoaViewMakeCurrentContext(NativeNSViewRef pView, NativeNSOpenGLContextRef pCtx)
{
    NSAutoreleasePool *pPool = [[NSAutoreleasePool alloc] init];

    DEBUG_MSG(("cocoaViewMakeCurrentContext(%p, %p)\n", (void*)pView, (void*)pCtx));

    [(OverlayView*)pView setGLCtx:pCtx];
    [(OverlayView*)pView makeCurrentFBO];

    [pPool release];
}

void cocoaViewSetVisibleRegion(NativeNSViewRef pView, GLint cRects, GLint* paRects)
{
    NSAutoreleasePool *pPool = [[NSAutoreleasePool alloc] init];

    [(OverlayView*)pView setVisibleRegions:cRects paRects:paRects];

    [pPool release];
}

/********************************************************************************
*
* Additional OpenGL wrapper
*
********************************************************************************/
static void performSelectorOnView(SEL selector)
{
    NSOpenGLContext *pCtx = [NSOpenGLContext currentContext];

    if (pCtx)
    {
        NSView *pView = [pCtx view];
        if (pView)
        {
            if ([pView respondsToSelector:selector])
                [pView performSelector:selector];
        }
    }
}

static void performSelectorOnViewOneArg(SEL selector, id arg1)
{
    NSOpenGLContext *pCtx = [NSOpenGLContext currentContext];

    if (pCtx)
    {
        NSView *pView = [pCtx view];
        if (pView)
        {
            if ([pView respondsToSelector:selector])
                [pView performSelector:selector withObject:arg1];
        }
    }
}

static void performSelectorOnViewTwoArgs(SEL selector, id arg1, id arg2)
{
    NSOpenGLContext *pCtx = [NSOpenGLContext currentContext];

    if (pCtx)
    {
        NSView *pView = [pCtx view];
        if (pView)
        {
            if ([pView respondsToSelector:selector])
                [pView performSelector:selector withObject:arg1 withObject:arg2];
        }
    }
}

void cocoaFlush(void)
{
    NSOpenGLContext *pCtx = nil;

    NSAutoreleasePool *pPool = [[NSAutoreleasePool alloc] init];

    DEBUG_MSG_1(("glFlush called\n"));

    performSelectorOnView(@selector(flushFBO));

    [pPool release];
}

void cocoaFinish(void)
{
    NSAutoreleasePool *pPool = [[NSAutoreleasePool alloc] init];

    DEBUG_MSG_1(("glFinish called\n"));

    performSelectorOnView(@selector(finishFBO));

    [pPool release];
}

void cocoaBindFramebufferEXT(GLenum target, GLuint framebuffer)
{
    NSAutoreleasePool *pPool = [[NSAutoreleasePool alloc] init];

    DEBUG_MSG_1(("glBindFramebufferEXT called target: %d  fb: %d\n", target, framebuffer));

    performSelectorOnViewTwoArgs(@selector(bindFBO:withFrameBuffer:), (id)target, (id)framebuffer);

    [pPool release];
}

void cocoaCopyPixels(GLint x, GLint y, GLsizei width, GLsizei height, GLenum type)
{
    NSAutoreleasePool *pPool = [[NSAutoreleasePool alloc] init];
    GLbitfield mask = GL_COLOR_BUFFER_BIT;

    DEBUG_MSG_1(("glCopyPixels called: %d,%d-%dx%d type: %d\n", x, y, width, height, type));

#ifdef FBO
    if (type == GL_DEPTH)
        mask = GL_DEPTH_BUFFER_BIT;
    else if (type == GL_STENCIL)
        mask = GL_STENCIL_BUFFER_BIT;
    glBlitFramebufferEXT(x, y, x + width, y + height, x, y, x + width, y + height, mask, GL_NEAREST);
#else
    glCopyPixels(x, y, width, height, type);
#endif

    [pPool release];
}

void cocoaGetIntegerv(GLenum pname, GLint *params)
{
    NSAutoreleasePool *pPool = [[NSAutoreleasePool alloc] init];

//    DEBUG_MSG_1(("getIntergerv called: %d\n", pname));

    performSelectorOnViewTwoArgs(@selector(stateInfo:withParams:), (id)pname, (id)params);

    [pPool release];
}

void cocoaReadBuffer(GLenum mode)
{
    NSAutoreleasePool *pPool = [[NSAutoreleasePool alloc] init];

    DEBUG_MSG_1(("glReadBuffer called: %d\n", mode));

    performSelectorOnViewOneArg(@selector(readBuffer:), (id)mode);

    [pPool release];
}

void cocoaDrawBuffer(GLenum mode)
{
    NSAutoreleasePool *pPool = [[NSAutoreleasePool alloc] init];

    DEBUG_MSG_1(("glDrawBuffer called: %d\n", mode));

    performSelectorOnViewOneArg(@selector(drawBuffer:), (id)mode);

    [pPool release];
}

