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/*!

    \class QGLPixelBuffer

    \brief The QGLPixelBuffer class encapsulates an OpenGL pbuffer.

    \since 4.1

    \ingroup painting-3D

    Rendering into a pbuffer is normally done using full hardware

    acceleration. This can be significantly faster than rendering

    into a QPixmap.

    There are three approaches to using this class:

    \list 1

    \o \bold{We can draw into the pbuffer and convert it to a QImage

       using toImage().} This is normally much faster than calling

       QGLWidget::renderPixmap().

    \o \bold{We can draw into the pbuffer and copy the contents into

       an OpenGL texture using updateDynamicTexture().} This allows

       us to create dynamic textures and works on all systems

       with pbuffer support.

    \o \bold{On systems that support it, we can bind the pbuffer to

       an OpenGL texture.} The texture is then updated automatically

       when the pbuffer contents change, eliminating the need for

       additional copy operations. This is supported only on Windows

       and Mac OS X systems that provide the \c render_texture

       extension.

    \endlist

    Pbuffers are provided by the OpenGL \c pbuffer extension; call

    hasOpenGLPbuffer() to find out if the system provides pbuffers.

    \sa {opengl/pbuffers}{Pbuffers Example}

*/

#include <QtCore/qglobal.h>

#include <private/qpaintengineex_opengl2_p.h>

#endif

#include <qglpixelbuffer.h>

#include <private/qglpixelbuffer_p.h>

#include <qimage.h>

#ifndef QT_OPENGL_ES_2

#include <private/qpaintengine_opengl_p.h>

#endif

QT_BEGIN_NAMESPACE

#if !defined(QT_OPENGL_ES_2)

extern void qgl_cleanup_glyph_cache(QGLContext *);

#else

void qgl_cleanup_glyph_cache(QGLContext *) {}

#endif

extern QImage qt_gl_read_framebuffer(const QSize&, bool, bool);

QGLContext* QGLPBufferGLPaintDevice::context() const

{

    return pbuf->d_func()->qctx;

}

void QGLPBufferGLPaintDevice::endPaint() {

    glFlush();

    QGLPaintDevice::endPaint();

}

void QGLPBufferGLPaintDevice::setPBuffer(QGLPixelBuffer* pb)

{

    pbuf = pb;

}

void QGLPixelBufferPrivate::common_init(const QSize &size, const QGLFormat &format, QGLWidget *shareWidget)

{

    Q_Q(QGLPixelBuffer);

    if(init(size, format, shareWidget)) {

        req_size = size;

        req_format = format;

        req_shareWidget = shareWidget;

        invalid = false;

        qctx = new QGLContext(format);

        qctx->d_func()->sharing = (shareWidget != 0);

        if (shareWidget != 0 && shareWidget->d_func()->glcx) {

            QGLContextGroup::addShare(qctx, shareWidget->d_func()->glcx);

            shareWidget->d_func()->glcx->d_func()->sharing = true;

        }

        glDevice.setPBuffer(q);

        qctx->d_func()->paintDevice = q;

        qctx->d_func()->valid = true;

#if defined(Q_WS_WIN) && !defined(QT_OPENGL_ES)

        qctx->d_func()->dc = dc;

        qctx->d_func()->rc = ctx;

        qctx->d_func()->cx = ctx;

        qctx->d_func()->pbuf = (void *) pbuf;

        qctx->d_func()->vi = 0;

#elif defined(Q_WS_MAC)

        qctx->d_func()->cx = ctx;

        qctx->d_func()->vi = 0;

        qctx->d_func()->eglContext = ctx;

        qctx->d_func()->eglSurface = pbuf;

#endif

    }

}

/*!

    Constructs an OpenGL pbuffer of the given \a size. If no \a

    format is specified, the \l{QGLFormat::defaultFormat()}{default

    format} is used. If the \a shareWidget parameter points to a

    valid QGLWidget, the pbuffer will share its context with \a

    shareWidget.

    If you intend to bind this pbuffer as a dynamic texture, the width

    and height components of \c size must be powers of two (e.g., 512

    x 128).

    \sa size(), format()

*/

QGLPixelBuffer::QGLPixelBuffer(const QSize &size, const QGLFormat &format, QGLWidget *shareWidget)

    : d_ptr(new QGLPixelBufferPrivate(this))

{

    Q_D(QGLPixelBuffer);

    d->common_init(size, format, shareWidget);

}

/*! \overload

    Constructs an OpenGL pbuffer with the \a width and \a height. If

    no \a format is specified, the

    \l{QGLFormat::defaultFormat()}{default format} is used. If the \a

    shareWidget parameter points to a valid QGLWidget, the pbuffer

    will share its context with \a shareWidget.

    If you intend to bind this pbuffer as a dynamic texture, the width

    and height components of \c size must be powers of two (e.g., 512

    x 128).

    \sa size(), format()

*/

QGLPixelBuffer::QGLPixelBuffer(int width, int height, const QGLFormat &format, QGLWidget *shareWidget)

    : d_ptr(new QGLPixelBufferPrivate(this))

{

    Q_D(QGLPixelBuffer);

    d->common_init(QSize(width, height), format, shareWidget);

}

/*! \fn QGLPixelBuffer::~QGLPixelBuffer()

    Destroys the pbuffer and frees any allocated resources.

*/

QGLPixelBuffer::~QGLPixelBuffer()

{

    Q_D(QGLPixelBuffer);

    // defined in qpaintengine_opengl.cpp

    QGLContext *current = const_cast<QGLContext *>(QGLContext::currentContext());

    if (current != d->qctx)

        makeCurrent();

    qgl_cleanup_glyph_cache(d->qctx);

    d->cleanup();

    delete d->qctx;

    if (current && current != d->qctx)

        current->makeCurrent();

}

/*! \fn bool QGLPixelBuffer::makeCurrent()

    Makes this pbuffer the current OpenGL rendering context. Returns

    true on success; otherwise returns false.

    \sa QGLContext::makeCurrent(), doneCurrent()

*/

bool QGLPixelBuffer::makeCurrent()

{

    Q_D(QGLPixelBuffer);

    if (d->invalid)

        return false;

    d->qctx->makeCurrent();

    return true;

}

/*! \fn bool QGLPixelBuffer::doneCurrent()

    Makes no context the current OpenGL context. Returns true on

    success; otherwise returns false.

*/

bool QGLPixelBuffer::doneCurrent()

{

    Q_D(QGLPixelBuffer);

    if (d->invalid)

        return false;

    d->qctx->doneCurrent();

    return true;

}

/*!

    Generates and binds a 2D GL texture that is the same size as the

    pbuffer, and returns the texture's ID. This can be used in

    conjunction with bindToDynamicTexture() and

    updateDynamicTexture().

    \sa size()

*/

GLuint QGLPixelBuffer::generateDynamicTexture() const

{

    Q_D(const QGLPixelBuffer);

    GLuint texture;

    glGenTextures(1, &texture);

    glBindTexture(GL_TEXTURE_2D, texture);

    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA8, d->req_size.width(), d->req_size.height(), 0, GL_RGBA, GL_FLOAT, 0);

    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);

    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);

    return texture;

}

#endif

/*! \fn bool QGLPixelBuffer::bindToDynamicTexture(GLuint texture_id)

    Binds the texture specified by \a texture_id to this pbuffer.

    Returns true on success; otherwise returns false.

    The texture must be of the same size and format as the pbuffer.

    To unbind the texture, call releaseFromDynamicTexture(). While

    the texture is bound, it is updated automatically when the

    pbuffer contents change, eliminating the need for additional copy

    operations.

    Example:

    \snippet doc/src/snippets/code/src_opengl_qglpixelbuffer.cpp 0

    \warning This function uses the \c {render_texture} extension,

    which is currently not supported under X11. An alternative that

    works on all systems (including X11) is to manually copy the

    pbuffer contents to a texture using updateDynamicTexture().

    \warning For the bindToDynamicTexture() call to succeed on the

    Mac OS X, the pbuffer needs a shared context, i.e. the

    QGLPixelBuffer must be created with a share widget.

    \sa generateDynamicTexture(), releaseFromDynamicTexture()

*/

/*! \fn void QGLPixelBuffer::releaseFromDynamicTexture()

    Releases the pbuffer from any previously bound texture.

    \sa bindToDynamicTexture()

*/

/*! \fn bool QGLPixelBuffer::hasOpenGLPbuffers()

    Returns true if the OpenGL \c pbuffer extension is present on

    this system; otherwise returns false.

*/

/*!

    Copies the pbuffer contents into the texture specified with \a

    texture_id.

    The texture must be of the same size and format as the pbuffer.

    Example:

    \snippet doc/src/snippets/code/src_opengl_qglpixelbuffer.cpp 1

    An alternative on Windows and Mac OS X systems that support the

    \c render_texture extension is to use bindToDynamicTexture() to

    get dynamic updates of the texture.

    \sa generateDynamicTexture(), bindToDynamicTexture()

*/

void QGLPixelBuffer::updateDynamicTexture(GLuint texture_id) const

{

    Q_D(const QGLPixelBuffer);

    if (d->invalid)

        return;

    glBindTexture(GL_TEXTURE_2D, texture_id);

#ifndef QT_OPENGL_ES

    glCopyTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA8, 0, 0, d->req_size.width(), d->req_size.height(), 0);

#else

    glCopyTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, 0, 0, d->req_size.width(), d->req_size.height(), 0);

#endif

}

#ifdef Q_MAC_COMPAT_GL_FUNCTIONS

void QGLPixelBuffer::updateDynamicTexture(QMacCompatGLuint texture_id) const

{

    updateDynamicTexture(GLuint(texture_id));

}

#endif

/*!

    Returns the size of the pbuffer.

*/

QSize QGLPixelBuffer::size() const

{

    Q_D(const QGLPixelBuffer);

    return d->req_size;

}

/*!

    Returns the contents of the pbuffer as a QImage.

*/

QImage QGLPixelBuffer::toImage() const

{

    Q_D(const QGLPixelBuffer);

    if (d->invalid)

        return QImage();

    const_cast<QGLPixelBuffer *>(this)->makeCurrent();

    return qt_gl_read_framebuffer(d->req_size, d->format.alpha(), true);

}

/*!

    Returns the native pbuffer handle.

*/

Qt::HANDLE QGLPixelBuffer::handle() const

{

    Q_D(const QGLPixelBuffer);

    if (d->invalid)

        return 0;

    return (Qt::HANDLE) d->pbuf;

}

/*!

    Returns true if this pbuffer is valid; otherwise returns false.

*/

bool QGLPixelBuffer::isValid() const

{

    Q_D(const QGLPixelBuffer);

    return !d->invalid;

}

Q_GLOBAL_STATIC(QGL2PaintEngineEx, qt_buffer_2_engine)

#endif

#ifndef QT_OPENGL_ES_2

Q_GLOBAL_STATIC(QOpenGLPaintEngine, qt_buffer_engine)

#endif

/*! \reimp */

QPaintEngine *QGLPixelBuffer::paintEngine() const

{

    return qt_buffer_engine();

#elif defined(QT_OPENGL_ES_2)

    return qt_buffer_2_engine();

#else

    if (qt_gl_preferGL2Engine())

        return qt_buffer_2_engine();

    else

        return qt_buffer_engine();

#endif

}

extern int qt_defaultDpiX();

extern int qt_defaultDpiY();

/*! \reimp */

int QGLPixelBuffer::metric(PaintDeviceMetric metric) const

{

    Q_D(const QGLPixelBuffer);

    float dpmx = qt_defaultDpiX()*100./2.54;

    float dpmy = qt_defaultDpiY()*100./2.54;

    int w = d->req_size.width();

    int h = d->req_size.height();

    switch (metric) {

    case PdmWidth:

        return w;

    case PdmHeight:

        return h;

    case PdmWidthMM:

        return qRound(w * 1000 / dpmx);

    case PdmHeightMM:

        return qRound(h * 1000 / dpmy);

    case PdmNumColors:

        return 0;

    case PdmDepth:

        return 32;//d->depth;

    case PdmDpiX:

        return qRound(dpmx * 0.0254);

    case PdmDpiY:

        return qRound(dpmy * 0.0254);

    case PdmPhysicalDpiX:

        return qRound(dpmx * 0.0254);

    case PdmPhysicalDpiY:

        return qRound(dpmy * 0.0254);

    default:

        qWarning("QGLPixelBuffer::metric(), Unhandled metric type: %d\n", metric);

        break;

    }

    return 0;

}

/*!

    Generates and binds a 2D GL texture to the current context, based

    on \a image. The generated texture id is returned and can be used

    in later glBindTexture() calls.

    The \a target parameter specifies the texture target.

    Equivalent to calling QGLContext::bindTexture().

    \sa deleteTexture()

*/

GLuint QGLPixelBuffer::bindTexture(const QImage &image, GLenum target)

{

    Q_D(QGLPixelBuffer);

#ifndef QT_OPENGL_ES

    return d->qctx->bindTexture(image, target, GLint(GL_RGBA8));

#else

    return d->qctx->bindTexture(image, target, GL_RGBA);

#endif

}

#ifdef Q_MAC_COMPAT_GL_FUNCTIONS

/*! \internal */

GLuint QGLPixelBuffer::bindTexture(const QImage &image, QMacCompatGLenum target)

{

    Q_D(QGLPixelBuffer);

    return d->qctx->bindTexture(image, target, QMacCompatGLint(GL_RGBA8));

}

#endif

/*! \overload

    Generates and binds a 2D GL texture based on \a pixmap.

    Equivalent to calling QGLContext::bindTexture().

    \sa deleteTexture()

*/

GLuint QGLPixelBuffer::bindTexture(const QPixmap &pixmap, GLenum target)

{

    Q_D(QGLPixelBuffer);

#ifndef QT_OPENGL_ES

    return d->qctx->bindTexture(pixmap, target, GLint(GL_RGBA8));

#else

    return d->qctx->bindTexture(pixmap, target, GL_RGBA);

#endif

}

#ifdef Q_MAC_COMPAT_GL_FUNCTIONS

/*! \internal */

GLuint QGLPixelBuffer::bindTexture(const QPixmap &pixmap, QMacCompatGLenum target)

{

    Q_D(QGLPixelBuffer);

    return d->qctx->bindTexture(pixmap, target, QMacCompatGLint(GL_RGBA8));

}

#endif

/*! \overload

    Reads the DirectDrawSurface (DDS) compressed file \a fileName and

    generates a 2D GL texture from it.

    Equivalent to calling QGLContext::bindTexture().

    \sa deleteTexture()