C++ QEglProperties::setPaintDeviceFormat方法代码示例

static QEglContext *createContext(QPaintDevice *device)
{
    QEglContext *context;

    // Create the context object and open the display.
    context = new QEglContext();
    context->setApi(QEgl::OpenVG);
    if (!context->openDisplay(device)) {
        delete context;
        return 0;
    }

    // Set the swap interval for the display.
    QByteArray interval = qgetenv("QT_VG_SWAP_INTERVAL");
    if (!interval.isEmpty())
        eglSwapInterval(context->display(), interval.toInt());
    else
        eglSwapInterval(context->display(), 1);

    // Choose an appropriate configuration for rendering into the device.
    QEglProperties configProps;
    configProps.setPaintDeviceFormat(device);
    int redSize = configProps.value(EGL_RED_SIZE);
    if (redSize == EGL_DONT_CARE || redSize == 0)
        configProps.setPixelFormat(QImage::Format_ARGB32);  // XXX
#ifndef QVG_SCISSOR_CLIP
    // If we are using the mask to clip, then explicitly request a mask.
    configProps.setValue(EGL_ALPHA_MASK_SIZE, 1);
#endif
#ifdef EGL_VG_ALPHA_FORMAT_PRE_BIT
    configProps.setValue(EGL_SURFACE_TYPE, EGL_WINDOW_BIT | EGL_PBUFFER_BIT |
                         EGL_VG_ALPHA_FORMAT_PRE_BIT);
    configProps.setRenderableType(QEgl::OpenVG);
    if (!context->chooseConfig(configProps)) {
        // Try again without the "pre" bit.
        configProps.setValue(EGL_SURFACE_TYPE, EGL_WINDOW_BIT | EGL_PBUFFER_BIT);
        if (!context->chooseConfig(configProps)) {
            delete context;
            return 0;
        }
    }
#else
    configProps.setValue(EGL_SURFACE_TYPE, EGL_WINDOW_BIT | EGL_PBUFFER_BIT);
    configProps.setRenderableType(QEgl::OpenVG);
    if (!context->chooseConfig(configProps)) {
        delete context;
        return 0;
    }
#endif

    // Construct a new EGL context for the selected configuration.
    if (!context->createContext()) {
        delete context;
        return 0;
    }

    return context;
}

static QEglContext *createContext(QPaintDevice *device)
{
    QEglContext *context;

    // Create the context object and open the display.
    context = new QEglContext();
    context->setApi(QEgl::OpenVG);

    // Set the swap interval for the display.
    QByteArray interval = qgetenv("QT_VG_SWAP_INTERVAL");
    if (!interval.isEmpty())
        eglSwapInterval(QEgl::display(), interval.toInt());
    else
        eglSwapInterval(QEgl::display(), 1);

#ifdef EGL_RENDERABLE_TYPE
    // Has the user specified an explicit EGL configuration to use?
    QByteArray configId = qgetenv("QT_VG_EGL_CONFIG");
    if (!configId.isEmpty()) {
        EGLint cfgId = configId.toInt();
        EGLint properties[] = {
            EGL_CONFIG_ID, cfgId,
            EGL_NONE
        };
        EGLint matching = 0;
        EGLConfig cfg;
        if (eglChooseConfig
                    (QEgl::display(), properties, &cfg, 1, &matching) &&
                matching > 0) {
            // Check that the selected configuration actually supports OpenVG
            // and then create the context with it.
            EGLint id = 0;
            EGLint type = 0;
            eglGetConfigAttrib
                (QEgl::display(), cfg, EGL_CONFIG_ID, &id);
            eglGetConfigAttrib
                (QEgl::display(), cfg, EGL_RENDERABLE_TYPE, &type);
            if (cfgId == id && (type & EGL_OPENVG_BIT) != 0) {
                context->setConfig(cfg);
                if (!context->createContext()) {
                    delete context;
                    return 0;
                }
                return context;
            } else {
                qWarning("QT_VG_EGL_CONFIG: %d is not a valid OpenVG configuration", int(cfgId));
            }
        }
    }
#endif

    // Choose an appropriate configuration for rendering into the device.
    QEglProperties configProps;
    configProps.setPaintDeviceFormat(device);
    int redSize = configProps.value(EGL_RED_SIZE);
    if (redSize == EGL_DONT_CARE || redSize == 0)
        configProps.setPixelFormat(QImage::Format_ARGB32);  // XXX
#ifndef QVG_SCISSOR_CLIP
    // If we are using the mask to clip, then explicitly request a mask.
    configProps.setValue(EGL_ALPHA_MASK_SIZE, 1);
#endif
#ifdef EGL_VG_ALPHA_FORMAT_PRE_BIT
    configProps.setValue(EGL_SURFACE_TYPE, EGL_WINDOW_BIT |
                         EGL_VG_ALPHA_FORMAT_PRE_BIT);
    configProps.setRenderableType(QEgl::OpenVG);
    if (!context->chooseConfig(configProps)) {
        // Try again without the "pre" bit.
        configProps.setValue(EGL_SURFACE_TYPE, EGL_WINDOW_BIT);
        if (!context->chooseConfig(configProps)) {
            delete context;
            return 0;
        }
    }
#else
    configProps.setValue(EGL_SURFACE_TYPE, EGL_WINDOW_BIT);
    configProps.setRenderableType(QEgl::OpenVG);
    if (!context->chooseConfig(configProps)) {
        delete context;
        return 0;
    }
#endif

    // Construct a new EGL context for the selected configuration.
    if (!context->createContext()) {
        delete context;
        return 0;
    }

    return context;
}

// Chooses the EGL config and creates the EGL context
bool QGLContext::chooseContext(const QGLContext* shareContext) // almost same as in qgl_x11egl.cpp
{
    Q_D(QGLContext);

    if (!device())
        return false;

    int devType = device()->devType();

    if ((devType != QInternal::Widget) && (devType != QInternal::Pbuffer)) {
        qWarning("WARNING: Creating a QGLContext not supported on device type %d", devType);
        return false;
    }

    // Get the display and initialize it.
    if (d->eglContext == 0) {
        d->eglContext = new QEglContext();
        d->ownsEglContext = true;
        d->eglContext->setApi(QEgl::OpenGL);

        if (d->glFormat.samples() == EGL_DONT_CARE) {
            // Allow apps to override ability to use multisampling by setting an environment variable. Eg:
            //   qputenv("QT_SYMBIAN_DISABLE_GL_MULTISAMPLE", "1");
            // Added to allow camera app to start with limited memory.
            if (!QSymbianGraphicsSystemEx::hasBCM2727() && !qgetenv("QT_SYMBIAN_DISABLE_GL_MULTISAMPLE").toInt()) {
                // Most likely we have hw support for multisampling
                // so let's enable it.
                d->glFormat.setSampleBuffers(1);
                d->glFormat.setSamples(4);
            } else {
                d->glFormat.setSampleBuffers(0);
                d->glFormat.setSamples(0);
            }
        }

	    // If the device is a widget with WA_TranslucentBackground set, make sure the glFormat
        // has the alpha channel option set:
        if (devType == QInternal::Widget) {
            QWidget* widget = static_cast<QWidget*>(device());
            if (widget->testAttribute(Qt::WA_TranslucentBackground))
                d->glFormat.setAlpha(true);
        }

        // Construct the configuration we need for this surface.
        QEglProperties configProps;
        configProps.setDeviceType(devType);
        configProps.setPaintDeviceFormat(device());
        configProps.setRenderableType(QEgl::OpenGL);
        configProps.setValue(EGL_SURFACE_TYPE, EGL_WINDOW_BIT|EGL_SWAP_BEHAVIOR_PRESERVED_BIT);

        qt_eglproperties_set_glformat(configProps, d->glFormat);

        if (!d->eglContext->chooseConfig(configProps, QEgl::BestPixelFormat)) {
            delete d->eglContext;
            d->eglContext = 0;
            return false;
        }

        // Create a new context for the configuration.
        QEglContext* eglSharedContext = shareContext ? shareContext->d_func()->eglContext : 0;
        if (!d->eglContext->createContext(eglSharedContext)) {
            delete d->eglContext;
            d->eglContext = 0;
            return false;
        }
        d->sharing = d->eglContext->isSharing();
        if (d->sharing && shareContext)
            const_cast<QGLContext *>(shareContext)->d_func()->sharing = true;
	}

    // Inform the higher layers about the actual format properties
    qt_glformat_from_eglconfig(d->glFormat, d->eglContext->config());

    // Do don't create the EGLSurface for everything.
    //    QWidget - yes, create the EGLSurface and store it in QGLContextPrivate::eglSurface
    //    QGLWidget - yes, create the EGLSurface and store it in QGLContextPrivate::eglSurface
    //    QGLPixelBuffer - no, it creates the surface itself and stores it in QGLPixelBufferPrivate::pbuf

    if (devType == QInternal::Widget) {
        if (d->eglSurface != EGL_NO_SURFACE)
            eglDestroySurface(d->eglContext->display(), d->eglSurface);

        d->eglSurface = QEgl::createSurface(device(), d->eglContext->config());

        eglGetError();  // Clear error state first.

#ifdef QGL_NO_PRESERVED_SWAP
        eglSurfaceAttrib(QEgl::display(), d->eglSurface,
                EGL_SWAP_BEHAVIOR, EGL_BUFFER_DESTROYED);

        if (eglGetError() != EGL_SUCCESS)
            qWarning("QGLContext: could not enable destroyed swap behaviour");
#else
        eglSurfaceAttrib(QEgl::display(), d->eglSurface,
                EGL_SWAP_BEHAVIOR, EGL_BUFFER_PRESERVED);

        if (eglGetError() != EGL_SUCCESS)
            qWarning("QGLContext: could not enable preserved swap behaviour");
#endif
//.........这里部分代码省略.........