qglframebufferobject.cpp

奇趣公司比较新的qt/emd版本

#endif

QGLFramebufferObject::QGLFramebufferObject(const QSize &size, GLenum target)
    : d_ptr(new QGLFramebufferObjectPrivate)
{
    Q_D(QGLFramebufferObject);
    d->init(size, NoAttachment, target, DEFAULT_FORMAT);
}


/*! \overload

    Constructs an OpenGL framebuffer object and binds a 2D GL texture
    to the buffer of the given \a width and \a height.

    \sa size(), texture()
*/
QGLFramebufferObject::QGLFramebufferObject(int width, int height, GLenum target)
    : d_ptr(new QGLFramebufferObjectPrivate)
{
    Q_D(QGLFramebufferObject);
    d->init(QSize(width, height), NoAttachment, target, DEFAULT_FORMAT);
}

/*! \overload

    Constructs an OpenGL framebuffer object and binds a texture to the
    buffer of the given \a width and \a height.

    The \a attachment parameter describes the depth/stencil buffer
    configuration, \a target the texture target and \a internal_format
    the internal texture format. The default texture target is \c
    GL_TEXTURE_2D, while the default internal format is \c GL_RGBA8.

    \sa size(), texture(), attachment()
*/
QGLFramebufferObject::QGLFramebufferObject(int width, int height, Attachment attachment,
                                           GLenum target, GLenum internal_format)
    : d_ptr(new QGLFramebufferObjectPrivate)
{
    Q_D(QGLFramebufferObject);
    d->init(QSize(width, height), attachment, target, internal_format);
}

/*! \overload

    Constructs an OpenGL framebuffer object and binds a texture to the
    buffer of the given \a size.

    The \a attachment parameter describes the depth/stencil buffer
    configuration, \a target the texture target and \a internal_format
    the internal texture format. The default texture target is \c
    GL_TEXTURE_2D, while the default internal format is \c GL_RGBA8.

    \sa size(), texture(), attachment()
*/
QGLFramebufferObject::QGLFramebufferObject(const QSize &size, Attachment attachment,
                                           GLenum target, GLenum internal_format)
    : d_ptr(new QGLFramebufferObjectPrivate)
{
    Q_D(QGLFramebufferObject);
    d->init(size, attachment, target, internal_format);
}



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

    Destroys the framebuffer object and frees any allocated resources.
*/
QGLFramebufferObject::~QGLFramebufferObject()
{
    Q_D(QGLFramebufferObject);
    QGL_FUNC_CONTEXT;

    if (isValid()
        && (d->ctx == QGLContext::currentContext()
            || qgl_share_reg()->checkSharing(d->ctx, QGLContext::currentContext())))
    {
        glDeleteTextures(1, &d->texture);
        if (d->depth_stencil_buffer)
            glDeleteRenderbuffersEXT(1, &d->depth_stencil_buffer);
        glDeleteFramebuffersEXT(1, &d->fbo);
    }
    delete d_ptr;
}

/*!
    \fn bool QGLFramebufferObject::isValid() const

    Returns true if the framebuffer object is valid.

    The framebuffer can become invalid if the initialization process
    fails, the user attaches an invalid buffer to the framebuffer
    object, or a non-power of 2 width/height is specified as the
    texture size if the texture target is \c{GL_TEXTURE_2D}.
*/
bool QGLFramebufferObject::isValid() const
{
    Q_D(const QGLFramebufferObject);
    return d->valid;
}

/*!
    \fn bool QGLFramebufferObject::bind()

    Switches rendering from the default, windowing system provided
    framebuffer to this framebuffer object.
    Returns true upon success, false otherwise.
*/
bool QGLFramebufferObject::bind()
{
    if (!isValid())
	return false;
    Q_D(QGLFramebufferObject);
    QGL_FUNC_CONTEXT;
    glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, d->fbo);
    d->valid = d->checkFramebufferStatus();
    return d->valid;
}

/*!
    \fn bool QGLFramebufferObject::release()

    Switches rendering back to the default, windowing system provided
    framebuffer.
    Returns true upon success, false otherwise.
*/
bool QGLFramebufferObject::release()
{
    if (!isValid())
	return false;
    Q_D(QGLFramebufferObject);
    QGL_FUNC_CONTEXT;
    glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, 0);
    d->valid = d->checkFramebufferStatus();
    return d->valid;
}

/*!
    \fn GLuint QGLFramebufferObject::texture() const

    Returns the texture id for the texture attached as the default
    rendering target in this framebuffer object. This texture id can
    be bound as a normal texture in your own GL code.
*/
GLuint QGLFramebufferObject::texture() const
{
    Q_D(const QGLFramebufferObject);
    return d->texture;
}

/*!
    \fn QSize QGLFramebufferObject::size() const

    Returns the size of the texture attached to this framebuffer
    object.
*/
QSize QGLFramebufferObject::size() const
{
    Q_D(const QGLFramebufferObject);
    return d->size;
}

/*!
    \fn QImage QGLFramebufferObject::toImage() const

    Returns the contents of this framebuffer object as a QImage.
*/
QImage QGLFramebufferObject::toImage() const
{
    Q_D(const QGLFramebufferObject);
    if (!d->valid)
        return QImage();

    const_cast<QGLFramebufferObject *>(this)->bind();
    QImage::Format image_format = QImage::Format_RGB32;
    if (d->ctx->format().alpha())
        image_format = QImage::Format_ARGB32_Premultiplied;
    QImage img(d->size, image_format);
    int w = d->size.width();
    int h = d->size.height();
    // ### fix the read format so that we don't have to do all the byte swapping
    glReadPixels(0, 0, d->size.width(), d->size.height(), GL_RGBA, GL_UNSIGNED_BYTE, img.bits());
    if (QSysInfo::ByteOrder == QSysInfo::BigEndian) {
	// OpenGL gives RGBA; Qt wants ARGB
	uint *p = (uint*)img.bits();
	uint *end = p + w*h;
	if (1) {
	    while (p < end) {
		uint a = *p << 24;
		*p = (*p >> 8) | a;
		p++;
	    }
	} else {
	    while (p < end) {
		*p = 0xFF000000 | (*p>>8);
		++p;
	    }
	}
    } else {
	// OpenGL gives ABGR (i.e. RGBA backwards); Qt wants ARGB
	img = img.rgbSwapped();
    }
    const_cast<QGLFramebufferObject *>(this)->release();
    return img.mirrored();
}

Q_GLOBAL_STATIC(QOpenGLPaintEngine, qt_buffer_paintengine)

/*! \reimp */
QPaintEngine *QGLFramebufferObject::paintEngine() const
{
    return qt_buffer_paintengine();
}

/*!
    \fn bool QGLFramebufferObject::hasOpenGLFramebufferObjects()

    Returns true if the OpenGL \c{GL_EXT_framebuffer_object} extension
    is present on this system; otherwise returns false.
*/
bool QGLFramebufferObject::hasOpenGLFramebufferObjects()
{
    QGLWidget dmy; // needed to detect and init the QGLExtensions object
    return (QGLExtensions::glExtensions & QGLExtensions::FramebufferObject);
}

extern int qt_defaultDpi();

/*! \reimp */
int QGLFramebufferObject::metric(PaintDeviceMetric metric) const
{
    Q_D(const QGLFramebufferObject);

    float dpmx = qt_defaultDpi()*100./2.54;
    float dpmy = qt_defaultDpi()*100./2.54;
    int w = d->size.width();
    int h = d->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 (int)(dpmx * 0.0254);

    case PdmDpiY:
        return (int)(dpmy * 0.0254);

    case PdmPhysicalDpiX:
        return (int)(dpmx * 0.0254);

    case PdmPhysicalDpiY:
        return (int)(dpmy * 0.0254);

    default:
        qWarning("QGLFramebufferObject::metric(), Unhandled metric type: %d.\n", metric);
        break;
    }
    return 0;
}

/*!
    \fn GLuint QGLFramebufferObject::handle() const

    Returns the GL framebuffer object handle for this framebuffer
    object (returned by the \c{glGenFrameBuffersEXT()} function). This
    handle can be used to attach new images or buffers to the
    framebuffer. The user is responsible for cleaning up and
    destroying these objects.
*/
GLuint QGLFramebufferObject::handle() const
{
    Q_D(const QGLFramebufferObject);
    return d->fbo;
}

/*! \fn int QGLFramebufferObject::devType() const

    \reimp
*/


/*!
    Returns the status of the depth and stencil buffers attached to
    this framebuffer object.
*/

QGLFramebufferObject::Attachment QGLFramebufferObject::attachment() const
{
    Q_D(const QGLFramebufferObject);
    if (d->valid)
        return d->fbo_attachment;
    return NoAttachment;
}