qglpixelbuffer.rar_The Class

/*! \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> #if !defined(QT_OPENGL_ES_1) #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; #elif (defined(Q_WS_X11) && defined(QT_NO_EGL)) 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; #elif !defined(QT_NO_EGL) 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() */ #if (defined(Q_WS_X11) || defined(Q_WS_WIN)) && defined(QT_NO_EGL) 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