QGLContext Class Reference

#include <qgl.h>

Collaboration diagram for QGLContext:

[legend]List of all members.

---

Detailed Description

The QGLContext class encapsulates an OpenGL rendering context.

An OpenGL OpenGL is a trademark of Silicon Graphics, Inc. in the United States and other countries. rendering context is a complete set of OpenGL state variables.

The context's format is set in the constructor or later with setFormat(). The format options that are actually set are returned by format(); the options you asked for are returned by requestedFormat(). Note that after a QGLContext object has been constructed, the actual OpenGL context must be created by explicitly calling the create() function. The makeCurrent() function makes this context the current rendering context. You can make no context current using doneCurrent(). The reset() function will reset the context and make it invalid.

You can examine properties of the context with, e.g. isValid(), isSharing(), initialized(), windowCreated() and overlayTransparentColor().

If you're using double buffering you can swap the screen contents with the off-screen buffer using swapBuffers().

Please note that QGLContext is not thread safe.

Definition at line 211 of file qgl.h.

Public Member Functions
	QGLContext (const QGLFormat &format, QPaintDevice *device)
	QGLContext (const QGLFormat &format)
virtual	~QGLContext ()
virtual bool	create (const QGLContext *shareContext=0)
bool	isValid () const
bool	isSharing () const
void	reset ()
QGLFormat	format () const
QGLFormat	requestedFormat () const
void	setFormat (const QGLFormat &format)
virtual void	makeCurrent ()
virtual void	doneCurrent ()
virtual void	swapBuffers () const
GLuint	bindTexture (const QImage &image, GLenum target=GL_TEXTURE_2D, GLint format=GL_RGBA)
GLuint	bindTexture (const QPixmap &pixmap, GLenum target=GL_TEXTURE_2D, GLint format=GL_RGBA)
GLuint	bindTexture (const QString &fileName)
void	deleteTexture (GLuint tx_id)
void *	getProcAddress (const QString &proc) const
QPaintDevice *	device () const
QColor	overlayTransparentColor () const
Static Public Member Functions
static void	setTextureCacheLimit (int size)
static int	textureCacheLimit ()
static const QGLContext *	currentContext ()
Protected Member Functions
virtual bool	chooseContext (const QGLContext *shareContext=0)
bool	deviceIsPixmap () const
bool	windowCreated () const
void	setWindowCreated (bool on)
bool	initialized () const
void	setInitialized (bool on)
void	generateFontDisplayLists (const QFont &fnt, int listBase)
uint	colorIndex (const QColor &c) const
void	setValid (bool valid)
void	setDevice (QPaintDevice *pDev)
Static Protected Attributes
static QGLContext *	currentCtx
Private Attributes
QGLContextPrivate *	d_ptr
Friends
class	QGLPixelBuffer
class	QGLPixelBufferPrivate
class	QGLWidget
class	QGLDrawable
class	QGLWidgetPrivate
class	QGLGlyphCache
class	QOpenGLPaintEngine
class	QOpenGLPaintEnginePrivate

---

Constructor & Destructor Documentation

QGLContext::QGLContext	(	const QGLFormat &	format,
		QPaintDevice *	device
	)

Constructs an OpenGL context for the given paint device, which can be a widget or a pixmap. The format specifies several display options for the context.

If the underlying OpenGL/Window system cannot satisfy all the features requested in format, the nearest subset of features will be used. After creation, the format() method will return the actual format obtained.

Note that after a QGLContext object has been constructed, create() must be called explicitly to create the actual OpenGL context. The context will be {isValid()}{invalid} if it was not possible to obtain a GL context at all.

Definition at line 1408 of file qgl.cpp.

References d, d_ptr, device(), and format().

{
    d_ptr = new QGLContextPrivate(this);
    Q_D(QGLContext);
    d->init(device, format);
}

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QGLContext::QGLContext

(

const QGLFormat &

format

)

Constructs an OpenGL context with the given format which specifies several display options for the context.

If the underlying OpenGL/Window system cannot satisfy all the features requested in format, the nearest subset of features will be used. After creation, the format() method will return the actual format obtained.

Note that after a QGLContext object has been constructed, create() must be called explicitly to create the actual OpenGL context. The context will be {isValid()}{invalid} if it was not possible to obtain a GL context at all.

See also:

format(), isValid()

Definition at line 1431 of file qgl.cpp.

References d, d_ptr, and format().

{
    d_ptr = new QGLContextPrivate(this);
    Q_D(QGLContext);
    d->init(0, format);
}

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QGLContext::~QGLContext

(

)

[virtual]

Destroys the OpenGL context and frees its resources.

Definition at line 1442 of file qgl.cpp.

References QList< T >::at(), d, i, key, QCache< Key, T >::keys(), QCache< Key, T >::object(), qt_image_cleanup_hook, qt_pixmap_cleanup_hook, qt_tex_cache, QCache< Key, T >::remove(), reset(), QCache< Key, T >::size(), and QList< T >::size().

{
    Q_D(QGLContext);
    // remove any textures cached in this context
    if (qt_tex_cache) {
        QList<QString> keys = qt_tex_cache->keys();
        for (int i = 0; i < keys.size(); ++i) {
            const QString &key = keys.at(i);
            if (qt_tex_cache->object(key)->context == this)
                qt_tex_cache->remove(key);
        }
        // ### thread safety
        if (qt_tex_cache->size() == 0) {
            qt_pixmap_cleanup_hook = 0;
            qt_image_cleanup_hook = 0;
            delete qt_tex_cache;
            qt_tex_cache = 0;
        }
    }

    reset();
    delete d;
}

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---

Member Function Documentation

bool QGLContext::create

(

const QGLContext *

shareContext = 0

)

[virtual]

Creates the GL context. Returns true if it was successful in creating a valid GL rendering context on the paint device specified in the constructor; otherwise returns false (i.e. the context is invalid).

After successful creation, format() returns the set of features of the created GL rendering context.

If shareContext points to a valid QGLContext, this method will try to establish OpenGL display list sharing between this context and the shareContext. Note that this may fail if the two contexts have different formats. Use isSharing() to see if sharing succeeded.

Warning:

Implementation note: initialization of C++ class members usually takes place in the class constructor. QGLContext is an exception because it must be simple to customize. The virtual functions chooseContext() (and chooseVisual() for X11) can be reimplemented in a subclass to select a particular context. The problem is that virtual functions are not properly called during construction (even though this is correct C++) because C++ constructs class hierarchies from the bottom up. For this reason we need a create() function.

See also:

chooseContext(), format(), isValid()

Definition at line 2036 of file qgl.cpp.

References QGLShareRegister::addShare(), chooseContext(), d, qgl_share_reg(), and reset().

{
    Q_D(QGLContext);
    reset();
    d->valid = chooseContext(shareContext);
    if (d->sharing)  // ok, we managed to share
        qgl_share_reg()->addShare(this, shareContext);
    return d->valid;
}

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bool QGLContext::isValid

(

)

const

Returns true if a GL rendering context has been successfully created; otherwise returns false.

Definition at line 2046 of file qgl.cpp.

References d.

Referenced by chooseContext(), colorIndex(), overlayTransparentColor(), and setDevice().

{
    Q_D(const QGLContext);
    return d->valid;
}

bool QGLContext::isSharing

(

)

const

Returns true if this context is sharing its GL context with another QGLContext, otherwise false is returned. Note that context sharing might not be supported between contexts with different formats.

Definition at line 2058 of file qgl.cpp.

References d.

Referenced by QGLTexture::~QGLTexture().

{
    Q_D(const QGLContext);
    return d->sharing;
}

void QGLContext::reset

(

)

Resets the context and makes it invalid.

See also:

create(), isValid()

Definition at line 587 of file qgl_x11.cpp.

References d, QX11Info::display(), doneCurrent(), qgl_share_reg(), qt_x11Info(), and QGLShareRegister::removeShare().

Referenced by create(), setDevice(), setFormat(), and ~QGLContext().

{
    Q_D(QGLContext);
    if (!d->valid)
        return;
    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);
}

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QGLFormat QGLContext::format

(

)

const

Returns the frame buffer format that was obtained (this may be a subset of what was requested).

See also:

requestedFormat()

Definition at line 2064 of file qgl.cpp.

References d.

Referenced by chooseContext(), colorIndex(), QGLDrawable::format(), QGLWidgetPrivate::init(), QGLWidget::qglClearColor(), QGLWidget::qglColor(), QGLContext(), and setFormat().

{
    Q_D(const QGLContext);
    return d->glFormat;
}

QGLFormat QGLContext::requestedFormat

(

)

const

Returns the frame buffer format that was originally requested in the constructor or setFormat().

See also:

format()

Definition at line 2070 of file qgl.cpp.

References d.

{
    Q_D(const QGLContext);
    return d->reqFormat;
}

void QGLContext::setFormat

(

const QGLFormat &

format

)

Sets a format for this context. The context is reset.

Call create() to create a new GL context that tries to match the new format.

    QGLContext *cx;
    //  ...
    QGLFormat f;
    f.setStereo(true);
    cx->setFormat(f);
    if (!cx->create())
        exit(); // no OpenGL support, or cannot render on the specified paintdevice
    if (!cx->format().stereo())
        exit(); // could not create stereo context

See also:

format(), reset(), create()

Definition at line 1878 of file qgl.cpp.

References d, format(), and reset().

{
    Q_D(QGLContext);
    reset();
    d->glFormat = d->reqFormat = format;
}

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void QGLContext::makeCurrent

(

)

[virtual]

Makes this context the current OpenGL rendering context. All GL functions you call operate on this context until another context is made current.

In some very rare cases the underlying call may fail. If this occurs an error message is output to stderr.

Definition at line 611 of file qgl_x11.cpp.

References currentCtx, QThread::currentThread(), d, deviceIsPixmap(), QX11Info::display(), qgl_context_storage, qt_x11Info(), and qWarning().

Referenced by QGLWidget::renderPixmap(), and QGLPixelBuffer::~QGLPixelBuffer().

{
    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 (deviceIsPixmap())
        ok = glXMakeCurrent(xinfo->display(), (GLXPixmap)d->gpm, (GLXContext)d->cx);

    else
        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;
    }
}

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void QGLContext::doneCurrent

(

)

[virtual]

Makes no GL context the current context. Normally, you do not need to call this function; QGLContext calls it as necessary.

Definition at line 639 of file qgl_x11.cpp.

References currentCtx, d, QX11Info::display(), qgl_context_storage, and qt_x11Info().

Referenced by QGLWidget::renderPixmap(), and reset().

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

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void QGLContext::swapBuffers

(

)

const [virtual]

Swaps the screen contents with an off-screen buffer. Only works if the context is in double buffer mode.

See also:

QGLFormat::setDoubleBuffer()

Definition at line 649 of file qgl_x11.cpp.

References d, deviceIsPixmap(), QX11Info::display(), and qt_x11Info().

{
    Q_D(const QGLContext);
    if (!d->valid)
        return;
    if (!deviceIsPixmap())
        glXSwapBuffers(qt_x11Info(d->paintDevice)->display(),
                       static_cast<QWidget *>(d->paintDevice)->winId());
}

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GLuint QGLContext::bindTexture	(	const QImage &	image,
		GLenum	target = GL_TEXTURE_2D,
		GLint	format = GL_RGBA
	)

Generates and binds a 2D GL texture to the current context, based on image. The generated texture id is returned and can be used in later glBindTexture() calls.

The target parameter specifies the texture target. The default target is GL_TEXTURE_2D.

The format parameter sets the internal format for the texture. The default format is GL_RGBA8.

If the GL implementation supports the GL_SGIS_generate_mipmap extension, mipmaps will be automatically generated for the texture. Mipmap generation is only supported for the GL_TEXTURE_2D target.

The texture that is generated is cached, so multiple calls to bindTexture() with the same QImage will return the same texture id.

See also:

deleteTexture()

Definition at line 1774 of file qgl.cpp.

References d, and image.

{
    Q_D(QGLContext);
    return d->bindTexture(image, target, format, false);
}

GLuint QGLContext::bindTexture	(	const QPixmap &	pixmap,
		GLenum	target = GL_TEXTURE_2D,
		GLint	format = GL_RGBA
	)

This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts. Generates and binds a 2D GL texture based on pixmap.

Definition at line 1784 of file qgl.cpp.

References d.

{
    Q_D(QGLContext);
    return d->bindTexture(pixmap, target, format, false);
}

GLuint QGLContext::bindTexture

(

const QString &

fileName

)

This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts. Reads the DirectDrawSurface (DDS) compressed file fileName and generates a 2D GL texture from it.

Only the DXT1, DXT3 and DXT5 DDS formats are supported.

Note that this will only work if the implementation supports the GL_ARB_texture_compression and GL_EXT_texture_compression_s3tc extensions.

See also:

deleteTexture()

Definition at line 1479 of file qgl.cpp.

References QFile::close(), FOURCC_DXT1, FOURCC_DXT3, FOURCC_DXT5, GL_COMPRESSED_RGBA_S3TC_DXT1_EXT, GL_COMPRESSED_RGBA_S3TC_DXT3_EXT, GL_COMPRESSED_RGBA_S3TC_DXT5_EXT, GLenum, h, i, QCache< Key, T >::insert(), int, key, QCache< Key, T >::object(), QFile::open(), qt_tex_cache, qt_tex_cache_limit, qWarning(), QIODevice::read(), QIODevice::ReadOnly, QFile::seek(), size, and w.

{
    if (!qt_glCompressedTexImage2DARB) {
        qWarning("QGLContext::bindTexture(): The GL implementation does not support texture"
                 "compression extensions.");
        return 0;
    }

    if (!qt_tex_cache)
        qt_tex_cache = new QGLTextureCache(qt_tex_cache_limit);

    QString key(fileName);
    QGLTexture *texture = qt_tex_cache->object(key);

    if (texture && texture->context == this) {
        glBindTexture(GL_TEXTURE_2D, texture->id);
        return texture->id;
    }

    QFile f(fileName);
    f.open(QIODevice::ReadOnly);

    char tag[4];
    f.read(&tag[0], 4);
    if (strncmp(tag,"DDS ", 4) != 0) {
        qWarning("QGLContext::bindTexture(): not a DDS image file.");
        return 0;
    }

    DDSFormat ddsHeader;
    f.read((char *) &ddsHeader, sizeof(DDSFormat));

    if (!ddsHeader.dwLinearSize) {
        qWarning("QGLContext::bindTexture() DDS image size is not valid.");
        return 0;
    }

    int factor = 4;
    int bufferSize = 0;
    int blockSize = 16;
    GLenum format;

    switch(ddsHeader.ddsPixelFormat.dwFourCC) {
    case FOURCC_DXT1:
        format = GL_COMPRESSED_RGBA_S3TC_DXT1_EXT;
        factor = 2;
        blockSize = 8;
        break;
    case FOURCC_DXT3:
        format = GL_COMPRESSED_RGBA_S3TC_DXT3_EXT;
        break;
    case FOURCC_DXT5:
        format = GL_COMPRESSED_RGBA_S3TC_DXT5_EXT;
        break;
    default:
        qWarning("QGLContext::bindTexture() DDS image format not supported.");
        return 0;
    }

    if (ddsHeader.dwMipMapCount > 1)
        bufferSize = ddsHeader.dwLinearSize * factor;
    else
        bufferSize = ddsHeader.dwLinearSize;

    GLubyte *pixels = (GLubyte *) malloc(bufferSize*sizeof(GLubyte));
    f.seek(ddsHeader.dwSize + 4);
    f.read((char *) pixels, bufferSize);
    f.close();

    GLuint tx_id;
    glGenTextures(1, &tx_id);
    glBindTexture(GL_TEXTURE_2D, tx_id);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);

    int size;
    int offset = 0;
    int w = ddsHeader.dwWidth;
    int h = ddsHeader.dwHeight;

    // load mip-maps
    for(int i = 0; i < (int) ddsHeader.dwMipMapCount; ++i) {
        if (w == 0) w = 1;
        if (h == 0) h = 1;

        size = ((w+3)/4) * ((h+3)/4) * blockSize;
        qt_glCompressedTexImage2DARB(GL_TEXTURE_2D, i, format, w, h, 0,
                                     size, pixels + offset);
        offset += size;

        // half size for each mip-map level
        w = w/2;
        h = h/2;
    }

    free(pixels);

    int cost = bufferSize/1024;
    qt_tex_cache->insert(key, new QGLTexture(this, tx_id, 0), cost);
    return tx_id;
}

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void QGLContext::deleteTexture

(

GLuint

id

)

Removes the texture identified by id from the texture cache. If the context is not shared by any other QGLContext, glDeleteTextures() will be called to delete the texture from the context.

See also:

bindTexture()

Definition at line 1798 of file qgl.cpp.

References QList< T >::at(), i, QCache< Key, T >::keys(), QCache< Key, T >::object(), qt_tex_cache, QCache< Key, T >::remove(), and QList< T >::size().

{
    if (!qt_tex_cache)
        return;

    QList<QString> keys = qt_tex_cache->keys();
    for (int i = 0; i < keys.size(); ++i) {
        QGLTexture *tex = qt_tex_cache->object(keys.at(i));
        if (tex->id == id && tex->context == this) {
            qt_tex_cache->remove(keys.at(i));
            break;
        }
    }
}

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void QGLContext::setTextureCacheLimit

(

int

size

)

[static]

This function sets the limit for the texture cache to size, expressed in kilobytes.

By default, the cache limit is approximately 64 MB.

See also:

textureCacheLimit()

Definition at line 1821 of file qgl.cpp.

References qt_tex_cache, qt_tex_cache_limit, and QCache< Key, T >::setMaxCost().

{
    qt_tex_cache_limit = size;
    if (qt_tex_cache)
        qt_tex_cache->setMaxCost(qt_tex_cache_limit);
}

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int QGLContext::textureCacheLimit

(

)

[static]

Returns the current texture cache limit in kilobytes.

See also:

setTextureCacheLimit()

Definition at line 1833 of file qgl.cpp.

References qt_tex_cache_limit.

{
    return qt_tex_cache_limit;
}

void * QGLContext::getProcAddress

(

const QString &

proc

)

const

Returns a function pointer to the GL extension function passed in proc. 0 is returned if a pointer to the function could not be obtained.

Definition at line 884 of file qgl_x11.cpp.

References QString::contains(), QByteArray::data(), QX11Info::display(), and QString::toLatin1().

Referenced by QGLExtensions::init_extensions().

{
    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"))) {
            QLibrary lib(QLatin1String("GL"));
            glXGetProcAddressARB = (qt_glXGetProcAddressARB) lib.resolve("glXGetProcAddressARB");
        }
        resolved = true;
    }
    if (!glXGetProcAddressARB)
        return 0;
    return glXGetProcAddressARB(reinterpret_cast<const GLubyte *>(proc.toLatin1().data()));
}

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QPaintDevice * QGLContext::device

(

)

const

Returns the paint device set for this context.

See also:

QGLContext::QGLContext()

Definition at line 2076 of file qgl.cpp.

References d.

Referenced by QGLWidgetPrivate::initContext(), QGLContext(), and QGLWidget::setContext().

{
    Q_D(const QGLContext);
    return d->paintDevice;
}

QColor QGLContext::overlayTransparentColor

(

)

const

If this context is a valid context in an overlay plane, returns the plane's transparent color. Otherwise returns an invalid color.

The returned color's pixel value is the index of the transparent color in the colormap of the overlay plane. (Naturally, the color's RGB values are meaningless.)

The returned QColor object will generally work as expected only when passed as the argument to QGLWidget::qglColor() or QGLWidget::qglClearColor(). Under certain circumstances it can also be used to draw transparent graphics with a QPainter. See the examples/opengl/overlay_x11 example for details.

Definition at line 659 of file qgl_x11.cpp.

References b, choose_cmap(), d, QX11Info::display(), find_trans_colors(), g, int, isValid(), qRgb(), qt_x11Info(), and trans_colors.

Referenced by colorIndex(), and QGLOverlayWidget::initializeGL().

{
    Q_D(const QGLContext);
    if (isValid()) {
        if (!trans_colors_init)
            find_trans_colors();

        VisualID myVisualId = ((XVisualInfo*)d->vi)->visualid;
        int myScreen = ((XVisualInfo*)d->vi)->screen;
        for (int i = 0; i < (int)trans_colors.size(); i++) {
            if (trans_colors[i].vis == myVisualId &&
                 trans_colors[i].screen == myScreen) {
                XColor col;
                col.pixel = trans_colors[i].color;
                col.red = col.green = col.blue = 0;
                col.flags = 0;
                Display *dpy = qt_x11Info(d->paintDevice)->display();
                if (col.pixel > (uint) ((XVisualInfo *)d->vi)->colormap_size - 1)
                    col.pixel = ((XVisualInfo *)d->vi)->colormap_size - 1;
                XQueryColor(dpy, choose_cmap(dpy, (XVisualInfo *) d->vi), &col);
                uchar r = (uchar)((col.red / 65535.0) * 255.0 + 0.5);
                uchar g = (uchar)((col.green / 65535.0) * 255.0 + 0.5);
                uchar b = (uchar)((col.blue / 65535.0) * 255.0 + 0.5);
                return QColor(qRgb(r,g,b));
            }
        }
    }
    return QColor();                // Invalid color
}

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const QGLContext * QGLContext::currentContext

(

)

[static]

Returns the current context, i.e. the context to which any OpenGL commands will currently be directed. Returns 0 if no context is current.

See also:

makeCurrent()

Definition at line 2114 of file qgl.cpp.

References qgl_context_storage.

Referenced by QGLDrawable::bindTexture(), QGLDrawable::context(), QGLDrawable::format(), QGLFramebufferObjectPrivate::init(), QGLWidget::qglClearColor(), QGLWidget::qglColor(), and QGLPixelBuffer::~QGLPixelBuffer().

{
    if (qgl_context_storage.hasLocalData())
        return qgl_context_storage.localData()->context;
    return 0;
}

bool QGLContext::chooseContext

(

const QGLContext *

shareContext = 0

)

[protected, virtual]

This semi-internal function is called by create(). It creates a system-dependent OpenGL handle that matches the format() of shareContext as closely as possible, returning true if successful or false if a suitable handle could not be found.

On Windows, it calls the virtual function choosePixelFormat(), which finds a matching pixel format identifier. On X11, it calls the virtual function chooseVisual() which finds an appropriate X visual. On other platforms it may work differently.

Definition at line 290 of file qgl_x11.cpp.

References choose_cmap(), d, QX11Info::depth(), deviceIsPixmap(), QGLFormat::directRendering(), QX11Info::display(), format(), GLX_SAMPLE_BUFFERS_ARB, GLX_SAMPLES_ARB, isValid(), NULL, qt_x11Handle(), qt_x11Info(), qWarning(), QGLFormat::rgba(), QX11Info::screen(), and QX11Info::visual().

Referenced by create().

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

    d->cx = 0;
    if (shareContext) {
        d->cx = glXCreateContext(disp, (XVisualInfo *)d->vi,
                               (GLXContext)shareContext->d_func()->cx, direct);
        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);
    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),
                                        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;
    }
    return true;
}

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bool QGLContext::deviceIsPixmap

(

)

const [protected]

Returns true if the paint device of this context is a pixmap; otherwise returns false.

Definition at line 2082 of file qgl.cpp.

References d, and QInternal::Pixmap.

Referenced by chooseContext(), makeCurrent(), QGLWidget::setContext(), and swapBuffers().

{
    Q_D(const QGLContext);
    return d->paintDevice->devType() == QInternal::Pixmap;
}

bool QGLContext::windowCreated

(

)

const [protected]

Returns true if a window has been created for this context; otherwise returns false.

See also:

setWindowCreated()

Definition at line 2089 of file qgl.cpp.

References d.

Referenced by QGLWidget::setContext().

{
    Q_D(const QGLContext);
    return d->crWin;
}

void QGLContext::setWindowCreated

(

bool

on

)

[protected]

If on is true the context has had a window created for it. If on is false no window has been created for the context.

See also:

windowCreated()

Definition at line 2096 of file qgl.cpp.

References d.

{
    Q_D(QGLContext);
    d->crWin = on;
}

bool QGLContext::initialized

(

)

const [protected]

Returns true if this context has been initialized, i.e. if QGLWidget::initializeGL() has been performed on it; otherwise returns false.

See also:

setInitialized()

Definition at line 2102 of file qgl.cpp.

References d.

Referenced by QGLWidgetPrivate::renderCxPm().

{
    Q_D(const QGLContext);
    return d->initDone;
}

void QGLContext::setInitialized

(

bool

on

)

[protected]

If on is true the context has been initialized, i.e. QGLContext::setInitialized() has been called on it. If on is false the context has not been initialized.

See also:

initialized()

Definition at line 2108 of file qgl.cpp.

References d.

{
    Q_D(QGLContext);
    d->initDone = on;
}

void QGLContext::generateFontDisplayLists	(	const QFont &	font,
		int	listBase
	)			[protected]

Generates a set of 256 display lists for the 256 first characters in the font font. The first list will start at index listBase.

See also:

QGLWidget::renderText()

Definition at line 859 of file qgl_x11.cpp.

References QUnicodeTables::Common, QFont::d, QFontPrivate::engineForScript(), QFontEngine::Freetype, QFont::handle(), QFontEngine::Multi, QFont::OpenGLCompatible, qgl_use_font(), QFont::setStyleStrategy(), QFontEngine::type(), and QFontEngine::XLFD.

{
    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);
}

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uint QGLContext::colorIndex

(

const QColor &

c

)

const [protected]

Definition at line 690 of file qgl_x11.cpp.

References QX11Info::appVisual(), QMap< Key, T >::begin(), c, d, QX11Info::display(), QMap< Key, T >::end(), format(), info, QMap< Key, T >::insert(), QColormap::instance(), int, isValid(), overlayTransparentColor(), p, QColormap::pixel(), qBlue(), qGreen(), qRed(), QRgb, QHash< Key, T >::const_iterator::value(), and x.

Referenced by QGLWidget::qglClearColor(), and QGLWidget::qglColor().

{
    Q_D(const QGLContext);
    int screen = ((XVisualInfo *)d->vi)->screen;
    QColormap colmap = QColormap::instance(screen);
    if (isValid()) {
        if (format().plane()
             && colmap.pixel(c) == colmap.pixel(overlayTransparentColor()))
            return colmap.pixel(c);                // Special; don't look-up
        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;
}

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void QGLContext::setValid

(

bool

valid

)

[protected]

Definition at line 2052 of file qgl.cpp.

References d.

{
    Q_D(QGLContext);
    d->valid = valid;
}

void QGLContext::setDevice

(

QPaintDevice *

pDev

)

[protected]

Definition at line 1888 of file qgl.cpp.

References d, isValid(), QInternal::Pbuffer, QInternal::Pixmap, qWarning(), reset(), and QInternal::Widget.

Referenced by QGLWidgetPrivate::initContext().

{
    Q_D(QGLContext);
    if (isValid())
        reset();
    d->paintDevice = pDev;
    if (d->paintDevice && (d->paintDevice->devType() != QInternal::Widget
                           && d->paintDevice->devType() != QInternal::Pixmap
                           && d->paintDevice->devType() != QInternal::Pbuffer)) {
        qWarning("QGLContext: Unsupported paint device type");
    }
}

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---

Friends And Related Function Documentation

friend class QGLPixelBuffer [friend]

Definition at line 282 of file qgl.h.

friend class QGLPixelBufferPrivate [friend]

Definition at line 283 of file qgl.h.

friend class QGLWidget [friend]

Definition at line 284 of file qgl.h.

friend class QGLDrawable [friend]

Definition at line 285 of file qgl.h.

friend class QGLWidgetPrivate [friend]

Definition at line 286 of file qgl.h.

friend class QGLGlyphCache [friend]

Definition at line 287 of file qgl.h.

friend class QOpenGLPaintEngine [friend]

Definition at line 288 of file qgl.h.

friend class QOpenGLPaintEnginePrivate [friend]

Definition at line 289 of file qgl.h.

---

Member Data Documentation

QGLContext * QGLContext::currentCtx [static, protected]

Definition at line 277 of file qgl.h.

Referenced by doneCurrent(), and makeCurrent().

QGLContextPrivate* QGLContext::d_ptr [private]

Definition at line 280 of file qgl.h.

Referenced by QGLContext().

---

The documentation for this class was generated from the following files:

• src/opengl/qgl.h
• src/opengl/qgl.cpp
• src/opengl/qgl_x11.cpp

---