C++ QEglContext::config方法代码示例

void QVGEGLWindowSurfaceVGImage::beginPaint(QWidget *widget)
{
    QEglContext *context = ensureContext(widget);
    if (context) {
        if (recreateBackBuffer || backBufferSurface == EGL_NO_SURFACE) {
            // Create a VGImage object to act as the back buffer
            // for this window.  We have to create the VGImage with a
            // current context, so activate the main surface for the window.
            context->makeCurrent(mainSurface());
            recreateBackBuffer = false;
            if (backBufferSurface != EGL_NO_SURFACE) {
                eglDestroySurface(QEgl::display(), backBufferSurface);
                backBufferSurface = EGL_NO_SURFACE;
            }
            if (backBuffer != VG_INVALID_HANDLE) {
                vgDestroyImage(backBuffer);
            }
            VGImageFormat format = qt_vg_config_to_vg_format(context);
            backBuffer = vgCreateImage
                (format, size.width(), size.height(),
                 VG_IMAGE_QUALITY_FASTER);
            if (backBuffer != VG_INVALID_HANDLE) {
                // Create an EGL surface for rendering into the VGImage.
                backBufferSurface = eglCreatePbufferFromClientBuffer
                    (QEgl::display(), EGL_OPENVG_IMAGE,
                     (EGLClientBuffer)(backBuffer),
                     context->config(), NULL);
                if (backBufferSurface == EGL_NO_SURFACE) {
                    vgDestroyImage(backBuffer);
                    backBuffer = VG_INVALID_HANDLE;
                }
            }
        }
        if (backBufferSurface != EGL_NO_SURFACE)
            context->makeCurrent(backBufferSurface);
        else
            context->makeCurrent(mainSurface());
        isPaintingActive = true;
    }
}

QT_BEGIN_NAMESPACE

#ifdef EGL_BIND_TO_TEXTURE_RGBA
#define QGL_RENDER_TEXTURE 1
#else
#define QGL_RENDER_TEXTURE 0
#endif

bool QGLPixelBufferPrivate::init(const QSize &size, const QGLFormat &f, QGLWidget *shareWidget)
{
    // Create the EGL context.
    ctx = new QEglContext();
    ctx->setApi(QEgl::OpenGL);

    // Find the shared context.
    QEglContext *shareContext = 0;
    if (shareWidget && shareWidget->d_func()->glcx)
        shareContext = shareWidget->d_func()->glcx->d_func()->eglContext;

    // Choose an appropriate configuration.  We use the best format
    // we can find, even if it is greater than the requested format.
    // We try for a pbuffer that is capable of texture rendering if possible.
    textureFormat = EGL_NONE;
    if (shareContext) {
        // Use the same configuration as the widget we are sharing with.
        ctx->setConfig(shareContext->config());
#if QGL_RENDER_TEXTURE
        if (ctx->configAttrib(EGL_BIND_TO_TEXTURE_RGBA) == EGL_TRUE)
            textureFormat = EGL_TEXTURE_RGBA;
        else if (ctx->configAttrib(EGL_BIND_TO_TEXTURE_RGB) == EGL_TRUE)
            textureFormat = EGL_TEXTURE_RGB;
#endif
    } else {
        QEglProperties configProps;
        qt_eglproperties_set_glformat(configProps, f);
        configProps.setDeviceType(QInternal::Pbuffer);
        configProps.setRenderableType(ctx->api());
        bool ok = false;
#if QGL_RENDER_TEXTURE
        textureFormat = EGL_TEXTURE_RGBA;
        configProps.setValue(EGL_BIND_TO_TEXTURE_RGBA, EGL_TRUE);
        ok = ctx->chooseConfig(configProps, QEgl::BestPixelFormat);
        if (!ok) {
            // Try again with RGB texture rendering.
            textureFormat = EGL_TEXTURE_RGB;
            configProps.removeValue(EGL_BIND_TO_TEXTURE_RGBA);
            configProps.setValue(EGL_BIND_TO_TEXTURE_RGB, EGL_TRUE);
            ok = ctx->chooseConfig(configProps, QEgl::BestPixelFormat);
            if (!ok) {
                // One last try for a pbuffer with no texture rendering.
                configProps.removeValue(EGL_BIND_TO_TEXTURE_RGB);
                textureFormat = EGL_NONE;
            }
        }
#endif
        if (!ok) {
            if (!ctx->chooseConfig(configProps, QEgl::BestPixelFormat)) {
                delete ctx;
                ctx = 0;
                return false;
            }
        }
    }

    // Retrieve the actual format properties.
    qt_glformat_from_eglconfig(format, ctx->config());

    // Create the attributes needed for the pbuffer.
    QEglProperties attribs;
    attribs.setValue(EGL_WIDTH, size.width());
    attribs.setValue(EGL_HEIGHT, size.height());
#if QGL_RENDER_TEXTURE
    if (textureFormat != EGL_NONE) {
        attribs.setValue(EGL_TEXTURE_FORMAT, textureFormat);
        attribs.setValue(EGL_TEXTURE_TARGET, EGL_TEXTURE_2D);
    }
#endif

    // Create the pbuffer surface.
    pbuf = eglCreatePbufferSurface(ctx->display(), ctx->config(), attribs.properties());
#if QGL_RENDER_TEXTURE
    if (pbuf == EGL_NO_SURFACE && textureFormat != EGL_NONE) {
        // Try again with texture rendering disabled.
        textureFormat = EGL_NONE;
        attribs.removeValue(EGL_TEXTURE_FORMAT);
        attribs.removeValue(EGL_TEXTURE_TARGET);
        pbuf = eglCreatePbufferSurface(ctx->display(), ctx->config(), attribs.properties());
    }
#endif
    if (pbuf == EGL_NO_SURFACE) {
        qWarning() << "QGLPixelBufferPrivate::init(): Unable to create EGL pbuffer surface:" << QEgl::errorString();
        return false;
    }

    // Create a new context for the configuration.
    if (!ctx->createContext(shareContext)) {
        delete ctx;
        ctx = 0;
        return false;
    }
//.........这里部分代码省略.........