path: root/src/opengl/qgl_x11.cpp

/****************************************************************************
**
** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies).
** Contact: Qt Software Information (qt-info@nokia.com)
**
** This file is part of the QtOpenGL module of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:LGPL$
** No Commercial Usage
** This file contains pre-release code and may not be distributed.
** You may use this file in accordance with the terms and conditions
** contained in the either Technology Preview License Agreement or the
** Beta Release License Agreement.
**
** GNU Lesser General Public License Usage
** Alternatively, this file may be used under the terms of the GNU Lesser
** General Public License version 2.1 as published by the Free Software
** Foundation and appearing in the file LICENSE.LGPL included in the
** packaging of this file.  Please review the following information to
** ensure the GNU Lesser General Public License version 2.1 requirements
** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
**
** In addition, as a special exception, Nokia gives you certain
** additional rights. These rights are described in the Nokia Qt LGPL
** Exception version 1.0, included in the file LGPL_EXCEPTION.txt in this
** package.
**
** GNU General Public License Usage
** Alternatively, this file may be used under the terms of the GNU
** General Public License version 3.0 as published by the Free Software
** Foundation and appearing in the file LICENSE.GPL included in the
** packaging of this file.  Please review the following information to
** ensure the GNU General Public License version 3.0 requirements will be
** met: http://www.gnu.org/copyleft/gpl.html.
**
** If you are unsure which license is appropriate for your use, please
** contact the sales department at qt-sales@nokia.com.
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****************************************************************************/

#include "qgl.h"
#include "qgl_p.h"

#include "qmap.h"
#include "qapplication.h"
#include "qcolormap.h"
#include "qdesktopwidget.h"
#include "qpixmap.h"
#include "qhash.h"
#include "qlibrary.h"
#include "qdebug.h"
#include <private/qfontengine_ft_p.h>
#include <private/qt_x11_p.h>
#ifdef Q_OS_HPUX
// for GLXPBuffer
#include <private/qglpixelbuffer_p.h>
#endif

#define INT8  dummy_INT8
#define INT32 dummy_INT32
#include <GL/glx.h>
#undef  INT8
#undef  INT32
#include <X11/Xlib.h>
#include <X11/Xutil.h>
#include <X11/Xos.h>
#include <X11/Xatom.h>

#if defined(Q_OS_LINUX) || defined(Q_OS_BSD4)
#include <dlfcn.h>
#endif

QT_BEGIN_NAMESPACE

extern Drawable qt_x11Handle(const QPaintDevice *pd);
extern const QX11Info *qt_x11Info(const QPaintDevice *pd);

#ifndef GLX_ARB_multisample
#define GLX_SAMPLE_BUFFERS_ARB  100000
#define GLX_SAMPLES_ARB         100001
#endif

/*
  The qt_gl_choose_cmap function is internal and used by QGLWidget::setContext()
  and GLX (not Windows).  If the application can't find any sharable
  colormaps, it must at least create as few colormaps as possible.  The
  dictionary solution below ensures only one colormap is created per visual.
  Colormaps are also deleted when the application terminates.
*/

struct QCMapEntry {
    QCMapEntry();
    ~QCMapEntry();

    Colormap cmap;
    bool alloc;
    XStandardColormap scmap;
};

QCMapEntry::QCMapEntry()
{
    cmap = 0;
    alloc = false;
    scmap.colormap = 0;
}

QCMapEntry::~QCMapEntry()
{
    if (alloc)
        XFreeColormap(X11->display, cmap);
}
typedef QHash<int, QCMapEntry *> CMapEntryHash;
typedef QHash<int, QMap<int, QRgb> > GLCMapHash;
static bool mesa_gl = false;
static bool first_time = true;

static void cleanup_cmaps();

struct QGLCMapCleanupHandler {
    QGLCMapCleanupHandler() {
        cmap_hash = new CMapEntryHash;
        qglcmap_hash = new GLCMapHash;
    }
    ~QGLCMapCleanupHandler() {
        delete cmap_hash;
        delete qglcmap_hash;
    }
    CMapEntryHash *cmap_hash;
    GLCMapHash *qglcmap_hash;
};
Q_GLOBAL_STATIC(QGLCMapCleanupHandler, cmap_handler);

static void cleanup_cmaps()
{
    CMapEntryHash *hash = cmap_handler()->cmap_hash;
    QHash<int, QCMapEntry *>::ConstIterator it = hash->constBegin();
    while (it != hash->constEnd()) {
        delete it.value();
        ++it;
    }

    hash->clear();
    cmap_handler()->qglcmap_hash->clear();
}

Colormap qt_gl_choose_cmap(Display *dpy, XVisualInfo *vi)
{
    if (first_time) {
        const char *v = glXQueryServerString(dpy, vi->screen, GLX_VERSION);
        if (v)
            mesa_gl = (strstr(v, "Mesa") != 0);
        first_time = false;
    }

    CMapEntryHash *hash = cmap_handler()->cmap_hash;
    CMapEntryHash::ConstIterator it = hash->constFind((long) vi->visualid + (vi->screen * 256));
    if (it != hash->constEnd())
        return it.value()->cmap; // found colormap for visual

    if (vi->visualid ==
        XVisualIDFromVisual((Visual *) QX11Info::appVisual(vi->screen))) {
        // qDebug("Using x11AppColormap");
        return QX11Info::appColormap(vi->screen);
    }

    QCMapEntry *x = new QCMapEntry();

    XStandardColormap *c;
    int n, i;

    // qDebug("Choosing cmap for vID %0x", vi->visualid);

    if (mesa_gl) {                                // we're using MesaGL
        Atom hp_cmaps = XInternAtom(dpy, "_HP_RGB_SMOOTH_MAP_LIST", true);
        if (hp_cmaps && vi->visual->c_class == TrueColor && vi->depth == 8) {
            if (XGetRGBColormaps(dpy,RootWindow(dpy,vi->screen),&c,&n,
                                 hp_cmaps)) {
                i = 0;
                while (i < n && x->cmap == 0) {
                    if (c[i].visualid == vi->visual->visualid) {
                        x->cmap = c[i].colormap;
                        x->scmap = c[i];
                        //qDebug("Using HP_RGB scmap");

                    }
                    i++;
                }
                XFree((char *)c);
            }
        }
    }
    if (!x->cmap) {
        if (XGetRGBColormaps(dpy,RootWindow(dpy,vi->screen),&c,&n,
                             XA_RGB_DEFAULT_MAP)) {
            for (int i = 0; i < n && x->cmap == 0; ++i) {
                if (!c[i].red_max ||
                    !c[i].green_max ||
                    !c[i].blue_max ||
                    !c[i].red_mult ||
                    !c[i].green_mult ||
                    !c[i].blue_mult)
                    continue; // invalid stdcmap
                if (c[i].visualid == vi->visualid) {
                    x->cmap = c[i].colormap;
                    x->scmap = c[i];
                    //qDebug("Using RGB_DEFAULT scmap");
                }
            }
            XFree((char *)c);
        }
    }
    if (!x->cmap) {                                // no shared cmap found
        x->cmap = XCreateColormap(dpy, RootWindow(dpy,vi->screen), vi->visual,
                                  AllocNone);
        x->alloc = true;
        // qDebug("Allocating cmap");
    }

    // colormap hash should be cleanup only when the QApplication dtor is called
    if (hash->isEmpty())
        qAddPostRoutine(cleanup_cmaps);

    // associate cmap with visualid
    hash->insert((long) vi->visualid + (vi->screen * 256), x);
    return x->cmap;
}

struct QTransColor
{
    VisualID vis;
    int screen;
    long color;
};

static QVector<QTransColor> trans_colors;
static int trans_colors_init = false;

static void find_trans_colors()
{
    struct OverlayProp {
        long  visual;
        long  type;
        long  value;
        long  layer;
    };

    trans_colors_init = true;

    Display* appDisplay = X11->display;

    int scr;
    int lastsize = 0;
    for (scr = 0; scr < ScreenCount(appDisplay); scr++) {
        QWidget* rootWin = QApplication::desktop()->screen(scr);
        if (!rootWin)
            return;                                        // Should not happen
        Atom overlayVisualsAtom = XInternAtom(appDisplay,
                                               "SERVER_OVERLAY_VISUALS", True);
        if (overlayVisualsAtom == XNone)
            return;                                        // Server has no overlays

        Atom actualType;
        int actualFormat;
        ulong nItems;
        ulong bytesAfter;
        unsigned char *retval = 0;
        int res = XGetWindowProperty(appDisplay, rootWin->winId(),
                                      overlayVisualsAtom, 0, 10000, False,
                                      overlayVisualsAtom, &actualType,
                                      &actualFormat, &nItems, &bytesAfter,
                                      &retval);

        if (res != Success || actualType != overlayVisualsAtom
             || actualFormat != 32 || nItems < 4 || !retval)
            return;                                        // Error reading property

        OverlayProp *overlayProps = (OverlayProp *)retval;

        int numProps = nItems / 4;
        trans_colors.resize(lastsize + numProps);
        int j = lastsize;
        for (int i = 0; i < numProps; i++) {
            if (overlayProps[i].type == 1) {
                trans_colors[j].vis = (VisualID)overlayProps[i].visual;
                trans_colors[j].screen = scr;
                trans_colors[j].color = (int)overlayProps[i].value;
                j++;
            }
        }
        XFree(overlayProps);
        lastsize = j;
        trans_colors.resize(lastsize);
    }
}

/*****************************************************************************
  QGLFormat UNIX/GLX-specific code
 *****************************************************************************/

bool QGLFormat::hasOpenGL()
{
    return glXQueryExtension(X11->display, 0, 0) != 0;
}


bool QGLFormat::hasOpenGLOverlays()
{
    if (!trans_colors_init)
        find_trans_colors();
    return trans_colors.size() > 0;
}

/*****************************************************************************
  QGLContext UNIX/GLX-specific code
 *****************************************************************************/

bool QGLContext::chooseContext(const QGLContext* shareContext)
{
    Q_D(QGLContext);
    const QX11Info *xinfo = qt_x11Info(d->paintDevice);

    Display* disp = xinfo->display();
    d->vi = chooseVisual();
    if (!d->vi)
        return false;

    if (deviceIsPixmap() &&
         (((XVisualInfo*)d->vi)->depth != xinfo->depth() ||
          ((XVisualInfo*)d->vi)->screen != xinfo->screen()))
    {
        XFree(d->vi);
        XVisualInfo appVisInfo;
        memset(&appVisInfo, 0, sizeof(XVisualInfo));
        appVisInfo.visualid = XVisualIDFromVisual((Visual *) xinfo->visual());
        appVisInfo.screen = xinfo->screen();
        int nvis;
        d->vi = XGetVisualInfo(disp, VisualIDMask | VisualScreenMask, &appVisInfo, &nvis);
        if (!d->vi)
            return false;

        int useGL;
        glXGetConfig(disp, (XVisualInfo*)d->vi, GLX_USE_GL, &useGL);
        if (!useGL)
            return false;        //# Chickening out already...
    }
    int res;
    glXGetConfig(disp, (XVisualInfo*)d->vi, GLX_LEVEL, &res);
    d->glFormat.setPlane(res);
    glXGetConfig(disp, (XVisualInfo*)d->vi, GLX_DOUBLEBUFFER, &res);
    d->glFormat.setDoubleBuffer(res);
    glXGetConfig(disp, (XVisualInfo*)d->vi, GLX_DEPTH_SIZE, &res);
    d->glFormat.setDepth(res);
    if (d->glFormat.depth())
        d->glFormat.setDepthBufferSize(res);
    glXGetConfig(disp, (XVisualInfo*)d->vi, GLX_RGBA, &res);
    d->glFormat.setRgba(res);
    glXGetConfig(disp, (XVisualInfo*)d->vi, GLX_RED_SIZE, &res);
    d->glFormat.setRedBufferSize(res);
    glXGetConfig(disp, (XVisualInfo*)d->vi, GLX_GREEN_SIZE, &res);
    d->glFormat.setGreenBufferSize(res);
    glXGetConfig(disp, (XVisualInfo*)d->vi, GLX_BLUE_SIZE, &res);
    d->glFormat.setBlueBufferSize(res);
    glXGetConfig(disp, (XVisualInfo*)d->vi, GLX_ALPHA_SIZE, &res);
    d->glFormat.setAlpha(res);
    if (d->glFormat.alpha())
        d->glFormat.setAlphaBufferSize(res);
    glXGetConfig(disp, (XVisualInfo*)d->vi, GLX_ACCUM_RED_SIZE, &res);
    d->glFormat.setAccum(res);
    if (d->glFormat.accum())
        d->glFormat.setAccumBufferSize(res);
    glXGetConfig(disp, (XVisualInfo*)d->vi, GLX_STENCIL_SIZE, &res);
    d->glFormat.setStencil(res);
    if (d->glFormat.stencil())
        d->glFormat.setStencilBufferSize(res);
    glXGetConfig(disp, (XVisualInfo*)d->vi, GLX_STEREO, &res);
    d->glFormat.setStereo(res);
    glXGetConfig(disp, (XVisualInfo*)d->vi, GLX_SAMPLE_BUFFERS_ARB, &res);
    d->glFormat.setSampleBuffers(res);
    if (d->glFormat.sampleBuffers()) {
        glXGetConfig(disp, (XVisualInfo*)d->vi, GLX_SAMPLES_ARB, &res);
        d->glFormat.setSamples(res);
    }

    Bool direct = format().directRendering() ? True : False;

    if (shareContext &&
         (!shareContext->isValid() || !shareContext->d_func()->cx)) {
            qWarning("QGLContext::chooseContext(): Cannot share with invalid context");
            shareContext = 0;
    }

    // 1. Sharing between rgba and color-index will give wrong colors.
    // 2. Contexts cannot be shared btw. direct/non-direct renderers.
    // 3. Pixmaps cannot share contexts that are set up for direct rendering.
    // 4. If the contexts are not created on the same screen, they can't be shared

    if (shareContext
        && (format().rgba() != shareContext->format().rgba()
            || (deviceIsPixmap() && glXIsDirect(disp, (GLXContext)shareContext->d_func()->cx))
            || (shareContext->d_func()->screen != xinfo->screen())))
    {
        shareContext = 0;
    }

    d->cx = 0;
    if (shareContext) {
        d->cx = glXCreateContext(disp, (XVisualInfo *)d->vi,
                               (GLXContext)shareContext->d_func()->cx, direct);
        d->screen = ((XVisualInfo*)d->vi)->screen;
        if (d->cx) {
            QGLContext *share = const_cast<QGLContext *>(shareContext);
            d->sharing = true;
            share->d_func()->sharing = true;
        }
    }
    if (!d->cx) {
        d->cx = glXCreateContext(disp, (XVisualInfo *)d->vi, NULL, direct);
        d->screen = ((XVisualInfo*)d->vi)->screen;
    }
    if (!d->cx)
        return false;
    d->glFormat.setDirectRendering(glXIsDirect(disp, (GLXContext)d->cx));
    if (deviceIsPixmap()) {
#if defined(GLX_MESA_pixmap_colormap) && defined(QGL_USE_MESA_EXT)
        d->gpm = glXCreateGLXPixmapMESA(disp, (XVisualInfo *)d->vi,
                                        qt_x11Handle(d->paintDevice),
                                        qt_gl_choose_cmap(disp, (XVisualInfo *)d->vi));
#else
        d->gpm = (quint32)glXCreateGLXPixmap(disp, (XVisualInfo *)d->vi,
                                              qt_x11Handle(d->paintDevice));
#endif
        if (!d->gpm)
            return false;
    }
    QString glxExt = QString(QLatin1String(glXGetClientString(QX11Info::display(), GLX_EXTENSIONS)));
    if (glxExt.contains(QLatin1String("GLX_SGI_video_sync"))) {
        if (d->glFormat.swapInterval() == -1)
            d->glFormat.setSwapInterval(0);
    } else {
        d->glFormat.setSwapInterval(-1);
    }
    return true;
}


/*!
  \bold{X11 only:} This virtual function tries to find a
  visual that matches the format, reducing the demands if the original
  request cannot be met.

  The algorithm for reducing the demands of the format is quite
  simple-minded, so override this method in your subclass if your
  application has spcific requirements on visual selection.

  \sa chooseContext()
*/

void *QGLContext::chooseVisual()
{
    Q_D(QGLContext);
    static const int bufDepths[] = { 8, 4, 2, 1 };        // Try 16, 12 also?
    //todo: if pixmap, also make sure that vi->depth == pixmap->depth
    void* vis = 0;
    int i = 0;
    bool fail = false;
    QGLFormat fmt = format();
    bool tryDouble = !fmt.doubleBuffer();  // Some GL impl's only have double
    bool triedDouble = false;
    bool triedSample = false;
    if (fmt.sampleBuffers())
        fmt.setSampleBuffers(QGLExtensions::glExtensions & QGLExtensions::SampleBuffers);
    while(!fail && !(vis = tryVisual(fmt, bufDepths[i]))) {
        if (!fmt.rgba() && bufDepths[i] > 1) {
            i++;
            continue;
        }
        if (tryDouble) {
            fmt.setDoubleBuffer(true);
            tryDouble = false;
            triedDouble = true;
            continue;
        } else if (triedDouble) {
            fmt.setDoubleBuffer(false);
            triedDouble = false;
        }
        if (!triedSample && fmt.sampleBuffers()) {
            fmt.setSampleBuffers(false);
            triedSample = true;
            continue;
        }
        if (fmt.stereo()) {
            fmt.setStereo(false);
            continue;
        }
        if (fmt.accum()) {
            fmt.setAccum(false);
            continue;
        }
        if (fmt.stencil()) {
            fmt.setStencil(false);
            continue;
        }
        if (fmt.alpha()) {
            fmt.setAlpha(false);
            continue;
        }
        if (fmt.depth()) {
            fmt.setDepth(false);
            continue;
        }
        if (fmt.doubleBuffer()) {
            fmt.setDoubleBuffer(false);
            continue;
        }
        fail = true;
    }
    d->glFormat = fmt;
    return vis;
}


/*!
  \internal

  \bold{X11 only:} This virtual function chooses a visual
  that matches the OpenGL \link format() format\endlink. Reimplement this
  function in a subclass if you need a custom visual.

  \sa chooseContext()
*/

void *QGLContext::tryVisual(const QGLFormat& f, int bufDepth)
{
    Q_D(QGLContext);
    int spec[40];
    int i = 0;
    spec[i++] = GLX_LEVEL;
    spec[i++] = f.plane();
    const QX11Info *xinfo = qt_x11Info(d->paintDevice);

#if defined(GLX_VERSION_1_1) && defined(GLX_EXT_visual_info)
    static bool useTranspExt = false;
    static bool useTranspExtChecked = false;
    if (f.plane() && !useTranspExtChecked && d->paintDevice) {
        QByteArray estr(glXQueryExtensionsString(xinfo->display(), xinfo->screen()));
        useTranspExt = estr.contains("GLX_EXT_visual_info");
        //# (A bit simplistic; that could theoretically be a substring)
        if (useTranspExt) {
            QByteArray cstr(glXGetClientString(xinfo->display(), GLX_VENDOR));
            useTranspExt = !cstr.contains("Xi Graphics"); // bug workaround
            if (useTranspExt) {
                // bug workaround - some systems (eg. FireGL) refuses to return an overlay
                // visual if the GLX_TRANSPARENT_TYPE_EXT attribute is specified, even if
                // the implementation supports transparent overlays
                int tmpSpec[] = { GLX_LEVEL, f.plane(), GLX_TRANSPARENT_TYPE_EXT,
                                  f.rgba() ? GLX_TRANSPARENT_RGB_EXT : GLX_TRANSPARENT_INDEX_EXT,
                                  XNone };
                XVisualInfo * vinf = glXChooseVisual(xinfo->display(), xinfo->screen(), tmpSpec);
                if (!vinf) {
                    useTranspExt = false;
                }
            }
        }

        useTranspExtChecked = true;
    }
    if (f.plane() && useTranspExt) {
        // Required to avoid non-transparent overlay visual(!) on some systems
        spec[i++] = GLX_TRANSPARENT_TYPE_EXT;
        spec[i++] = f.rgba() ? GLX_TRANSPARENT_RGB_EXT : GLX_TRANSPARENT_INDEX_EXT;
    }
#endif

    if (f.doubleBuffer())
        spec[i++] = GLX_DOUBLEBUFFER;
    if (f.depth()) {
        spec[i++] = GLX_DEPTH_SIZE;
        spec[i++] = f.depthBufferSize() == -1 ? 1 : f.depthBufferSize();
    }
    if (f.stereo()) {
        spec[i++] = GLX_STEREO;
    }
    if (f.stencil()) {
        spec[i++] = GLX_STENCIL_SIZE;
        spec[i++] = f.stencilBufferSize() == -1 ? 1 : f.stencilBufferSize();
    }
    if (f.rgba()) {
        spec[i++] = GLX_RGBA;
        spec[i++] = GLX_RED_SIZE;
        spec[i++] = f.redBufferSize() == -1 ? 1 : f.redBufferSize();
        spec[i++] = GLX_GREEN_SIZE;
        spec[i++] = f.greenBufferSize() == -1 ? 1 : f.greenBufferSize();
        spec[i++] = GLX_BLUE_SIZE;
        spec[i++] = f.blueBufferSize() == -1 ? 1 : f.blueBufferSize();
        if (f.alpha()) {
            spec[i++] = GLX_ALPHA_SIZE;
            spec[i++] = f.alphaBufferSize() == -1 ? 1 : f.alphaBufferSize();
        }
        if (f.accum()) {
            spec[i++] = GLX_ACCUM_RED_SIZE;
            spec[i++] = f.accumBufferSize() == -1 ? 1 : f.accumBufferSize();
            spec[i++] = GLX_ACCUM_GREEN_SIZE;
            spec[i++] = f.accumBufferSize() == -1 ? 1 : f.accumBufferSize();
            spec[i++] = GLX_ACCUM_BLUE_SIZE;
            spec[i++] = f.accumBufferSize() == -1 ? 1 : f.accumBufferSize();
            if (f.alpha()) {
                spec[i++] = GLX_ACCUM_ALPHA_SIZE;
                spec[i++] = f.accumBufferSize() == -1 ? 1 : f.accumBufferSize();
            }
        }
    } else {
        spec[i++] = GLX_BUFFER_SIZE;
        spec[i++] = bufDepth;
    }

    if (f.sampleBuffers()) {
        spec[i++] = GLX_SAMPLE_BUFFERS_ARB;
        spec[i++] = 1;
        spec[i++] = GLX_SAMPLES_ARB;
        spec[i++] = f.samples() == -1 ? 4 : f.samples();
    }

    spec[i] = XNone;
    return glXChooseVisual(xinfo->display(), xinfo->screen(), spec);
}


void QGLContext::reset()
{
    Q_D(QGLContext);
    if (!d->valid)
        return;
    d->cleanup();
    const QX11Info *xinfo = qt_x11Info(d->paintDevice);
    doneCurrent();
    if (d->gpm)
        glXDestroyGLXPixmap(xinfo->display(), (GLXPixmap)d->gpm);
    d->gpm = 0;
    glXDestroyContext(xinfo->display(), (GLXContext)d->cx);
    if (d->vi)
        XFree(d->vi);
    d->vi = 0;
    d->cx = 0;
    d->crWin = false;
    d->sharing = false;
    d->valid = false;
    d->transpColor = QColor();
    d->initDone = false;
    qgl_share_reg()->removeShare(this);
}


void QGLContext::makeCurrent()
{
    Q_D(QGLContext);
    if (!d->valid) {
        qWarning("QGLContext::makeCurrent(): Cannot make invalid context current.");
        return;
    }
    const QX11Info *xinfo = qt_x11Info(d->paintDevice);
    bool ok = true;
    if (d->paintDevice->devType() == QInternal::Pixmap) {
        ok = glXMakeCurrent(xinfo->display(), (GLXPixmap)d->gpm, (GLXContext)d->cx);
    } else if (d->paintDevice->devType() == QInternal::Pbuffer) {
        ok = glXMakeCurrent(xinfo->display(), (GLXPbuffer)d->pbuf, (GLXContext)d->cx);
    } else if (d->paintDevice->devType() == QInternal::Widget) {
        ok = glXMakeCurrent(xinfo->display(), ((QWidget *)d->paintDevice)->winId(), (GLXContext)d->cx);
    }
    if (!ok)
        qWarning("QGLContext::makeCurrent(): Failed.");

    if (ok) {
        if (!qgl_context_storage.hasLocalData() && QThread::currentThread())
            qgl_context_storage.setLocalData(new QGLThreadContext);
        if (qgl_context_storage.hasLocalData())
            qgl_context_storage.localData()->context = this;
        currentCtx = this;
    }
}

void QGLContext::doneCurrent()
{
    Q_D(QGLContext);
    glXMakeCurrent(qt_x11Info(d->paintDevice)->display(), 0, 0);
    if (qgl_context_storage.hasLocalData())
        qgl_context_storage.localData()->context = 0;
    currentCtx = 0;
}


void QGLContext::swapBuffers() const
{
    Q_D(const QGLContext);
    if (!d->valid)
        return;
    if (!deviceIsPixmap()) {
        int interval = d->glFormat.swapInterval();
        if (interval > 0) {
            typedef int (*qt_glXGetVideoSyncSGI)(uint *);
            typedef int (*qt_glXWaitVideoSyncSGI)(int, int, uint *);
            static qt_glXGetVideoSyncSGI glXGetVideoSyncSGI = 0;
            static qt_glXWaitVideoSyncSGI glXWaitVideoSyncSGI = 0;
            static bool resolved = false;
            if (!resolved) {
                QString glxExt = QString(QLatin1String(glXGetClientString(QX11Info::display(), GLX_EXTENSIONS)));
                if (glxExt.contains(QLatin1String("GLX_SGI_video_sync"))) {
#if defined(Q_OS_LINUX) || defined(Q_OS_BSD4)
                    void *handle = dlopen(NULL, RTLD_LAZY);
                    if (handle) {
                        glXGetVideoSyncSGI = (qt_glXGetVideoSyncSGI) dlsym(handle, "glXGetVideoSyncSGI");
                        glXWaitVideoSyncSGI = (qt_glXWaitVideoSyncSGI) dlsym(handle, "glXWaitVideoSyncSGI");
                        dlclose(handle);
                    }
                    if (!glXGetVideoSyncSGI)
#endif
                    {
                        extern const QString qt_gl_library_name();
                        QLibrary lib(qt_gl_library_name());
                        glXGetVideoSyncSGI = (qt_glXGetVideoSyncSGI) lib.resolve("glXGetVideoSyncSGI");
                        glXWaitVideoSyncSGI = (qt_glXWaitVideoSyncSGI) lib.resolve("glXWaitVideoSyncSGI");
                    }
                }
                resolved = true;
            }
            if (glXGetVideoSyncSGI && glXWaitVideoSyncSGI) {
                uint counter;
                if (!glXGetVideoSyncSGI(&counter))
                    glXWaitVideoSyncSGI(interval + 1, (counter + interval) % (interval + 1), &counter);
            }
        }
        glXSwapBuffers(qt_x11Info(d->paintDevice)->display(),
                       static_cast<QWidget *>(d->paintDevice)->winId());
    }
}

QColor QGLContext::overlayTransparentColor() const
{
    if (isValid())
        return Qt::transparent;
    return QColor();                // Invalid color
}

static uint qt_transparent_pixel(VisualID id, int screen)
{
    for (int i = 0; i < trans_colors.size(); i++) {
        if (trans_colors[i].vis == id && trans_colors[i].screen == screen)
            return trans_colors[i].color;
    }
    return 0;
}

uint QGLContext::colorIndex(const QColor& c) const
{
    Q_D(const QGLContext);
    int screen = ((XVisualInfo *)d->vi)->screen;
    QColormap colmap = QColormap::instance(screen);
    if (isValid()) {
        if (format().plane() && c == Qt::transparent) {
            return qt_transparent_pixel(((XVisualInfo *)d->vi)->visualid,
                                        ((XVisualInfo *)d->vi)->screen);
        }
        if (((XVisualInfo*)d->vi)->visualid ==
             XVisualIDFromVisual((Visual *) QX11Info::appVisual(screen)))
            return colmap.pixel(c);                // We're using QColor's cmap

        XVisualInfo *info = (XVisualInfo *) d->vi;
        CMapEntryHash *hash = cmap_handler()->cmap_hash;
        CMapEntryHash::ConstIterator it = hash->constFind(long(info->visualid)
                + (info->screen * 256));
        QCMapEntry *x = 0;
        if (it != hash->constEnd())
            x = it.value();
        if (x && !x->alloc) {                // It's a standard colormap
            int rf = (int)(((float)c.red() * (x->scmap.red_max+1))/256.0);
            int gf = (int)(((float)c.green() * (x->scmap.green_max+1))/256.0);
            int bf = (int)(((float)c.blue() * (x->scmap.blue_max+1))/256.0);
            uint p = x->scmap.base_pixel
                     + (rf * x->scmap.red_mult)
                     + (gf * x->scmap.green_mult)
                     + (bf * x->scmap.blue_mult);
            return p;
        } else {
            QMap<int, QRgb> &cmap = (*cmap_handler()->qglcmap_hash)[(long)info->visualid];

            // already in the map?
            QRgb target = c.rgb();
            QMap<int, QRgb>::Iterator it = cmap.begin();
            for (; it != cmap.end(); ++it) {
                if ((*it) == target)
                    return it.key();
            }

            // need to alloc color
            unsigned long plane_mask[2];
            unsigned long color_map_entry;
            if (!XAllocColorCells (QX11Info::display(), x->cmap, true, plane_mask, 0,
                                   &color_map_entry, 1))
                return colmap.pixel(c);

            XColor col;
            col.flags = DoRed | DoGreen | DoBlue;
            col.pixel = color_map_entry;
            col.red   = (ushort)((qRed(c.rgb()) / 255.0) * 65535.0 + 0.5);
            col.green = (ushort)((qGreen(c.rgb()) / 255.0) * 65535.0 + 0.5);
            col.blue  = (ushort)((qBlue(c.rgb()) / 255.0) * 65535.0 + 0.5);
            XStoreColor(QX11Info::display(), x->cmap, &col);

            cmap.insert(color_map_entry, target);
            return color_map_entry;
        }
    }
    return 0;
}

#ifndef QT_NO_FONTCONFIG
/*! \internal
    This is basically a substitute for glxUseXFont() which can only
    handle XLFD fonts. This version relies on freetype to render the
    glyphs, but it works with all fonts that fontconfig provides - both
    antialiased and aliased bitmap and outline fonts.
*/
static void qgl_use_font(QFontEngineFT *engine, int first, int count, int listBase)
{
    GLfloat color[4];
    glGetFloatv(GL_CURRENT_COLOR, color);

    // save the pixel unpack state
    GLint gl_swapbytes, gl_lsbfirst, gl_rowlength, gl_skiprows, gl_skippixels, gl_alignment;
    glGetIntegerv (GL_UNPACK_SWAP_BYTES, &gl_swapbytes);
    glGetIntegerv (GL_UNPACK_LSB_FIRST, &gl_lsbfirst);
    glGetIntegerv (GL_UNPACK_ROW_LENGTH, &gl_rowlength);
    glGetIntegerv (GL_UNPACK_SKIP_ROWS, &gl_skiprows);
    glGetIntegerv (GL_UNPACK_SKIP_PIXELS, &gl_skippixels);
    glGetIntegerv (GL_UNPACK_ALIGNMENT, &gl_alignment);

    glPixelStorei(GL_UNPACK_SWAP_BYTES, GL_FALSE);
    glPixelStorei(GL_UNPACK_LSB_FIRST, GL_FALSE);
    glPixelStorei(GL_UNPACK_ROW_LENGTH, 0);
    glPixelStorei(GL_UNPACK_SKIP_ROWS, 0);
    glPixelStorei(GL_UNPACK_SKIP_PIXELS, 0);
    glPixelStorei(GL_UNPACK_ALIGNMENT, 1);

    const bool antialiased = engine->drawAntialiased();
    FT_Face face = engine->lockFace();

    // start generating font glyphs
    for (int i = first; i < count; ++i) {
        int list = listBase + i;
        GLfloat x0, y0, dx, dy;

        FT_Error err;

        err = FT_Load_Glyph(face, FT_Get_Char_Index(face, i), FT_LOAD_DEFAULT);
        if (err) {
            qDebug("failed loading glyph %d from font", i);
            Q_ASSERT(!err);
        }
        err = FT_Render_Glyph(face->glyph, (antialiased ? FT_RENDER_MODE_NORMAL
                                            : FT_RENDER_MODE_MONO));
        if (err) {
            qDebug("failed rendering glyph %d from font", i);
            Q_ASSERT(!err);
        }

        FT_Bitmap bm = face->glyph->bitmap;
        x0 = face->glyph->metrics.horiBearingX >> 6;
        y0 = (face->glyph->metrics.height - face->glyph->metrics.horiBearingY) >> 6;
        dx = face->glyph->metrics.horiAdvance >> 6;
        dy = 0;
        int sz = bm.pitch * bm.rows;
        uint *aa_glyph = 0;
        uchar *ua_glyph = 0;

        if (antialiased)
            aa_glyph = new uint[sz];
        else
            ua_glyph = new uchar[sz];

        // convert to GL format
        for (int y = 0; y < bm.rows; ++y) {
            for (int x = 0; x < bm.pitch; ++x) {
                int c1 = y*bm.pitch + x;
                int c2 = (bm.rows - y - 1) > 0 ? (bm.rows-y-1)*bm.pitch + x : x;
                if (antialiased) {
                    aa_glyph[c1] = (int(color[0]*255) << 24)
                                   | (int(color[1]*255) << 16)
                                   | (int(color[2]*255) << 8) | bm.buffer[c2];
                } else {
                    ua_glyph[c1] = bm.buffer[c2];
                }
            }
        }

        glNewList(list, GL_COMPILE);
        if (antialiased) {
            // calling glBitmap() is just a trick to move the current
            // raster pos, since glGet*() won't work in display lists
            glBitmap(0, 0, 0, 0, x0, -y0, 0);
            glDrawPixels(bm.pitch, bm.rows, GL_RGBA, GL_UNSIGNED_INT_8_8_8_8, aa_glyph);
            glBitmap(0, 0, 0, 0, dx-x0, y0, 0);
        } else {
            glBitmap(bm.pitch*8, bm.rows, -x0, y0, dx, dy, ua_glyph);
        }
        glEndList();
        antialiased ? delete[] aa_glyph : delete[] ua_glyph;
    }

    engine->unlockFace();

    // restore pixel unpack settings
    glPixelStorei(GL_UNPACK_SWAP_BYTES, gl_swapbytes);
    glPixelStorei(GL_UNPACK_LSB_FIRST, gl_lsbfirst);
    glPixelStorei(GL_UNPACK_ROW_LENGTH, gl_rowlength);
    glPixelStorei(GL_UNPACK_SKIP_ROWS, gl_skiprows);
    glPixelStorei(GL_UNPACK_SKIP_PIXELS, gl_skippixels);
    glPixelStorei(GL_UNPACK_ALIGNMENT, gl_alignment);
}
#endif

#undef d
void QGLContext::generateFontDisplayLists(const QFont & fnt, int listBase)
{
    QFont f(fnt);
    QFontEngine *engine = f.d->engineForScript(QUnicodeTables::Common);

    if (engine->type() == QFontEngine::Multi)
        engine = static_cast<QFontEngineMulti *>(engine)->engine(0);
#ifndef QT_NO_FONTCONFIG
    if(engine->type() == QFontEngine::Freetype) {
        qgl_use_font(static_cast<QFontEngineFT *>(engine), 0, 256, listBase);
        return;
    }
#endif
    // glXUseXFont() only works with XLFD font structures and a few GL
    // drivers crash if 0 is passed as the font handle
    f.setStyleStrategy(QFont::OpenGLCompatible);
    if (f.handle() && engine->type() == QFontEngine::XLFD)
        glXUseXFont(static_cast<Font>(f.handle()), 0, 256, listBase);
}

void *QGLContext::getProcAddress(const QString &proc) const
{
    typedef void *(*qt_glXGetProcAddressARB)(const GLubyte *);
    static qt_glXGetProcAddressARB glXGetProcAddressARB = 0;
    static bool resolved = false;

    if (resolved && !glXGetProcAddressARB)
        return 0;
    if (!glXGetProcAddressARB) {
        QString glxExt = QString(QLatin1String(glXGetClientString(QX11Info::display(), GLX_EXTENSIONS)));
        if (glxExt.contains(QLatin1String("GLX_ARB_get_proc_address"))) {
#if defined(Q_OS_LINUX) || defined(Q_OS_BSD4)
            void *handle = dlopen(NULL, RTLD_LAZY);
            if (handle) {
                glXGetProcAddressARB = (qt_glXGetProcAddressARB) dlsym(handle, "glXGetProcAddressARB");
                dlclose(handle);
            }
            if (!glXGetProcAddressARB)
#endif
            {
                extern const QString qt_gl_library_name();
                QLibrary lib(qt_gl_library_name());
                glXGetProcAddressARB = (qt_glXGetProcAddressARB) lib.resolve("glXGetProcAddressARB");
            }
        }
        resolved = true;
    }
    if (!glXGetProcAddressARB)
        return 0;
    return glXGetProcAddressARB(reinterpret_cast<const GLubyte *>(proc.toLatin1().data()));
}

/*****************************************************************************
  QGLOverlayWidget (Internal overlay class for X11)
 *****************************************************************************/

class QGLOverlayWidget : public QGLWidget
{
    Q_OBJECT
public:
    QGLOverlayWidget(const QGLFormat& format, QGLWidget* parent, const QGLWidget* shareWidget=0);

protected:
    void                initializeGL();
    void                paintGL();
    void                resizeGL(int w, int h);
    bool                x11Event(XEvent *e) { return realWidget->x11Event(e); }

private:
    QGLWidget*                realWidget;

private:
    Q_DISABLE_COPY(QGLOverlayWidget)
};


QGLOverlayWidget::QGLOverlayWidget(const QGLFormat& format, QGLWidget* parent,
                                   const QGLWidget* shareWidget)
    : QGLWidget(format, parent, shareWidget ? shareWidget->d_func()->olw : 0)
{
    setAttribute(Qt::WA_X11OpenGLOverlay);
    realWidget = parent;
}



void QGLOverlayWidget::initializeGL()
{
    QColor transparentColor = context()->overlayTransparentColor();
    if (transparentColor.isValid())
        qglClearColor(transparentColor);
    else
        qWarning("QGLOverlayWidget::initializeGL(): Could not get transparent color");
    realWidget->initializeOverlayGL();
}


void QGLOverlayWidget::resizeGL(int w, int h)
{
    glViewport(0, 0, w, h);
    realWidget->resizeOverlayGL(w, h);
}


void QGLOverlayWidget::paintGL()
{
    realWidget->paintOverlayGL();
}

#undef Bool
QT_BEGIN_INCLUDE_NAMESPACE
#include "qgl_x11.moc"
QT_END_INCLUDE_NAMESPACE

/*****************************************************************************
  QGLWidget UNIX/GLX-specific code
 *****************************************************************************/
void QGLWidgetPrivate::init(QGLContext *context, const QGLWidget *shareWidget)
{
    Q_Q(QGLWidget);
    initContext(context, shareWidget);
    olw = 0;

    if (q->isValid() && context->format().hasOverlay()) {
        QString olwName = q->objectName();
        olwName += QLatin1String("-QGL_internal_overlay_widget");
        olw = new QGLOverlayWidget(QGLFormat::defaultOverlayFormat(), q, shareWidget);
        olw->setObjectName(olwName);
        if (olw->isValid()) {
            olw->setAutoBufferSwap(false);
            olw->setFocusProxy(q);
        }
        else {
            delete olw;
            olw = 0;
            glcx->d_func()->glFormat.setOverlay(false);
        }
    }
}

bool QGLWidgetPrivate::renderCxPm(QPixmap* pm)
{
    Q_Q(QGLWidget);
    if (((XVisualInfo*)glcx->d_func()->vi)->depth != pm->depth())
        return false;

    GLXPixmap glPm;
#if defined(GLX_MESA_pixmap_colormap) && defined(QGL_USE_MESA_EXT)
    glPm = glXCreateGLXPixmapMESA(X11->display,
                                   (XVisualInfo*)glcx->vi,
                                   (Pixmap)pm->handle(),
                                   qt_gl_choose_cmap(pm->X11->display,
                                                (XVisualInfo*)glcx->vi));
#else
    glPm = (quint32)glXCreateGLXPixmap(X11->display,
                                         (XVisualInfo*)glcx->d_func()->vi,
                                         (Pixmap)pm->handle());
#endif

    if (!glXMakeCurrent(X11->display, glPm, (GLXContext)glcx->d_func()->cx)) {
        glXDestroyGLXPixmap(X11->display, glPm);
        return false;
    }

    glDrawBuffer(GL_FRONT);
    if (!glcx->initialized())
        q->glInit();
    q->resizeGL(pm->width(), pm->height());
    q->paintGL();
    glFlush();
    q->makeCurrent();
    glXDestroyGLXPixmap(X11->display, glPm);
    q->resizeGL(q->width(), q->height());
    return true;
}

/*! \internal
  Free up any allocated colormaps. This fn is only called for
  top-level widgets.
*/
void QGLWidgetPrivate::cleanupColormaps()
{
    if (!cmap.handle()) {
        return;
    } else {
        XFreeColormap(X11->display, (Colormap) cmap.handle());
        cmap.setHandle(0);
    }
}

void QGLWidget::setMouseTracking(bool enable)
{
    Q_D(QGLWidget);
    if (d->olw)
        d->olw->setMouseTracking(enable);
    QWidget::setMouseTracking(enable);
}


void QGLWidget::resizeEvent(QResizeEvent *)
{
    Q_D(QGLWidget);
    if (!isValid())
        return;
    makeCurrent();
    if (!d->glcx->initialized())
        glInit();
    glXWaitX();
    resizeGL(width(), height());
    if (d->olw)
        d->olw->setGeometry(rect());
}

const QGLContext* QGLWidget::overlayContext() const
{
    Q_D(const QGLWidget);
    if (d->olw)
        return d->olw->context();
    else
        return 0;
}


void QGLWidget::makeOverlayCurrent()
{
    Q_D(QGLWidget);
    if (d->olw)
        d->olw->makeCurrent();
}


void QGLWidget::updateOverlayGL()
{
    Q_D(QGLWidget);
    if (d->olw)
        d->olw->updateGL();
}

/*!
    \internal

    Sets a new QGLContext, \a context, for this QGLWidget, using the
    shared context, \a shareContext. If \a deleteOldContext is true,
    the original context is deleted; otherwise it is overridden.
*/
void QGLWidget::setContext(QGLContext *context,
                            const QGLContext* shareContext,
                            bool deleteOldContext)
{
    Q_D(QGLWidget);
    if (context == 0) {
        qWarning("QGLWidget::setContext: Cannot set null context");
        return;
    }
    if (!context->deviceIsPixmap() && context->device() != this) {
        qWarning("QGLWidget::setContext: Context must refer to this widget");
        return;
    }

    if (d->glcx)
        d->glcx->doneCurrent();
    QGLContext* oldcx = d->glcx;
    d->glcx = context;


    if (parentWidget()) {
        // force creation of delay-created widgets
        parentWidget()->winId();
        if (parentWidget()->x11Info().screen() != x11Info().screen())
            d_func()->xinfo = parentWidget()->d_func()->xinfo;
    }

    bool createFailed = false;
    if (!d->glcx->isValid()) {
        if (!d->glcx->create(shareContext ? shareContext : oldcx))
            createFailed = true;
    }
    if (createFailed) {
        if (deleteOldContext)
            delete oldcx;
        return;
    }

    if (d->glcx->windowCreated() || d->glcx->deviceIsPixmap()) {
        if (deleteOldContext)
            delete oldcx;
        return;
    }

    bool visible = isVisible();
    if (visible)
        hide();

    XVisualInfo *vi = (XVisualInfo*)d->glcx->d_func()->vi;
    XSetWindowAttributes a;

    QColormap colmap = QColormap::instance(vi->screen);
    a.colormap = qt_gl_choose_cmap(QX11Info::display(), vi);        // find best colormap
    a.background_pixel = colmap.pixel(palette().color(backgroundRole()));
    a.border_pixel = colmap.pixel(Qt::black);
    Window p = RootWindow(X11->display, vi->screen);
    if (parentWidget())
        p = parentWidget()->winId();

    Window w = XCreateWindow(X11->display, p, x(), y(), width(), height(),
                              0, vi->depth, InputOutput, vi->visual,
                              CWBackPixel|CWBorderPixel|CWColormap, &a);
    Window *cmw;
    Window *cmwret;
    int count;
    if (XGetWMColormapWindows(X11->display, window()->winId(),
                                &cmwret, &count)) {
        cmw = new Window[count+1];
        memcpy((char *)cmw, (char *)cmwret, sizeof(Window)*count);
        XFree((char *)cmwret);
        int i;
        for (i=0; i<count; i++) {
            if (cmw[i] == winId()) {                // replace old window
                cmw[i] = w;
                break;
            }
        }
        if (i >= count)                        // append new window
            cmw[count++] = w;
    } else {
        count = 1;
        cmw = new Window[count];
        cmw[0] = w;
    }

#if defined(GLX_MESA_release_buffers) && defined(QGL_USE_MESA_EXT)
    if (oldcx && oldcx->windowCreated())
        glXReleaseBuffersMESA(X11->display, winId());
#endif
    if (deleteOldContext)
        delete oldcx;
    oldcx = 0;

    if (testAttribute(Qt::WA_WState_Created))
        create(w);
    else
        d->createWinId(w);
    XSetWMColormapWindows(X11->display, window()->winId(), cmw, count);
    delete [] cmw;

    // calling QWidget::create() will always result in a new paint
    // engine being created - get rid of it and replace it with our
    // own

    if (visible)
        show();
    XFlush(X11->display);
    d->glcx->setWindowCreated(true);
}

const QGLColormap & QGLWidget::colormap() const
{
    Q_D(const QGLWidget);
    return d->cmap;
}

/*\internal
  Store color values in the given colormap.
*/
static void qStoreColors(QWidget * tlw, Colormap cmap,
                          const QGLColormap & cols)
{
    Q_UNUSED(tlw);
    XColor c;
    QRgb color;

    for (int i = 0; i < cols.size(); i++) {
        color = cols.entryRgb(i);
        c.pixel = i;
        c.red   = (ushort)((qRed(color) / 255.0) * 65535.0 + 0.5);
        c.green = (ushort)((qGreen(color) / 255.0) * 65535.0 + 0.5);
        c.blue  = (ushort)((qBlue(color) / 255.0) * 65535.0 + 0.5);
        c.flags = DoRed | DoGreen | DoBlue;
        XStoreColor(X11->display, cmap, &c);
    }
}

/*\internal
  Check whether the given visual supports dynamic colormaps or not.
*/
static bool qCanAllocColors(QWidget * w)
{
    bool validVisual = false;
    int  numVisuals;
    long mask;
    XVisualInfo templ;
    XVisualInfo * visuals;
    VisualID id = XVisualIDFromVisual((Visual *) w->window()->x11Info().visual());

    mask = VisualScreenMask;
    templ.screen = w->x11Info().screen();
    visuals = XGetVisualInfo(X11->display, mask, &templ, &numVisuals);

    for (int i = 0; i < numVisuals; i++) {
        if (visuals[i].visualid == id) {
            switch (visuals[i].c_class) {
                case TrueColor:
                case StaticColor:
                case StaticGray:
                case XGrayScale:
                    validVisual = false;
                    break;
                case DirectColor:
                case PseudoColor:
                    validVisual = true;
                    break;
            }
            break;
        }
    }
    XFree(visuals);

    if (!validVisual)
        return false;
    return true;
}


void QGLWidget::setColormap(const QGLColormap & c)
{
    Q_D(QGLWidget);
    QWidget * tlw = window(); // must return a valid widget

    d->cmap = c;
    if (!d->cmap.handle())
        return;

    if (!qCanAllocColors(this)) {
        qWarning("QGLWidget::setColormap: Cannot create a read/write "
                  "colormap for this visual");
        return;
    }

    // If the child GL widget is not of the same visual class as the
    // toplevel widget we will get in trouble..
    Window wid = tlw->winId();
    Visual * vis = (Visual *) tlw->x11Info().visual();;
    VisualID cvId = XVisualIDFromVisual((Visual *) x11Info().visual());
    VisualID tvId = XVisualIDFromVisual((Visual *) tlw->x11Info().visual());
    if (cvId != tvId) {
        wid = winId();
        vis = (Visual *) x11Info().visual();
    }

    if (!d->cmap.handle()) // allocate a cmap if necessary
        d->cmap.setHandle(XCreateColormap(X11->display, wid, vis, AllocAll));

    qStoreColors(this, (Colormap) d->cmap.handle(), c);
    XSetWindowColormap(X11->display, wid, (Colormap) d->cmap.handle());

    // tell the wm that this window has a special colormap
    Window * cmw;
    Window * cmwret;
    int count;
    if (XGetWMColormapWindows(X11->display, tlw->winId(), &cmwret, &count))
    {
        cmw = new Window[count+1];
        memcpy((char *) cmw, (char *) cmwret, sizeof(Window) * count);
        XFree((char *) cmwret);
        int i;
        for (i = 0; i < count; i++) {
            if (cmw[i] == winId()) {
                break;
            }
        }
        if (i >= count)   // append new window only if not in the list
            cmw[count++] = winId();
    } else {
        count = 1;
        cmw = new Window[count];
        cmw[0] = winId();
    }
    XSetWMColormapWindows(X11->display, tlw->winId(), cmw, count);
    delete [] cmw;
}

void QGLExtensions::init()
{
    static bool init_done = false;

    if (init_done)
        return;
    init_done = true;

    QGLWidget dmy;
    dmy.makeCurrent();
    init_extensions();

    // nvidia 9x.xx unix drivers contain a bug which requires us to call glFinish before releasing an fbo
    // to avoid painting artifacts
    const QByteArray versionString(reinterpret_cast<const char*>(glGetString(GL_VERSION)));
    const int pos = versionString.indexOf("NVIDIA");
    if (pos >= 0) {
        const float nvidiaDriverVersion = versionString.mid(pos + strlen("NVIDIA")).toFloat();
        nvidiaFboNeedsFinish = nvidiaDriverVersion >= 90.0 && nvidiaDriverVersion < 100.0;
    }
}

QT_END_NAMESPACE