At the top of the **DrawScene** function,author wrote this:
    //Clear our backbuffer
    float bgColor[4] = { (0.0f, 0.0f, 0.0f, 0.0f) };
    d3d11DevCon->ClearRenderTargetView(renderTargetView, bgColor); 
i try to change the elements which in **bgColor** array,like that:
    float bgColor[4] = { (0.0f, 1.0f, 0.0f, 0.0f) };
but it doesn't work,i tried a lot of different changes,still the same.
i wonder know why!thanks!