Merge pull request #2365 from malfet:dont-use-VLA

    ogl::render(arr, idx, ogl::TRIANGLES);

    float f[params.frameSize.width*params.frameSize.height];

    float pixels[params.frameSize.width*params.frameSize.height][3];

    glReadPixels(0, 0, params.frameSize.width, params.frameSize.height, GL_DEPTH_COMPONENT, GL_FLOAT, &f[0]);

    glReadPixels(0, 0, params.frameSize.width, params.frameSize.height, GL_RGB, GL_FLOAT, &pixels[0][0]);

    Mat depthData(params.frameSize.height, params.frameSize.width, CV_32F);

    Mat shadeData(params.frameSize.height, params.frameSize.width, CV_32FC3);

    glReadPixels(0, 0, params.frameSize.width, params.frameSize.height, GL_DEPTH_COMPONENT, GL_FLOAT, depthData.ptr());

    glReadPixels(0, 0, params.frameSize.width, params.frameSize.height, GL_RGB, GL_FLOAT, shadeData.ptr());

    // linearise depth

    for(int i = 0; i < params.frameSize.width*params.frameSize.height; i++)

    for(auto it = depthData.begin<float>(); it != depthData.end<float>(); ++it)

    {

        f[i] = farZ * nearZ / (f[i]*(nearZ - farZ) + farZ);

        *it = farZ * nearZ / ((*it)*(nearZ - farZ) + farZ);

        if(f[i] >= farZ)

            f[i] = std::numeric_limits<float>::quiet_NaN();

        if(*it >= farZ)

            *it = std::numeric_limits<float>::quiet_NaN();

    }

    if(depthImage.needed()) {

        Mat depthData(params.frameSize.height, params.frameSize.width, CV_32F, f);

        depthData.copyTo(depthImage);

    }

    if(shadedImage.needed()) {

        Mat shadeData(params.frameSize.height, params.frameSize.width, CV_32FC3, pixels);

        shadeData.copyTo(shadedImage);

    }

#else