public void applyViewPort(ViewPort vp) {
        renderer.setFrameBuffer(vp.getOutputFrameBuffer());
        setCamera(vp.getCamera(), false);
        if (vp.isClearDepth() || vp.isClearColor() || vp.isClearStencil()) {
            if (vp.isClearColor()) {
                renderer.setBackgroundColor(vp.getBackgroundColor());
            }
            renderer.clearBuffers(vp.isClearColor(), vp.isClearDepth(), vp.isClearStencil());
        }
    }
Applies the ViewPort's Camera and FrameBuffer in preparation
for rendering.

@param vp
jme3-core/src/main/java/com/jme3/renderer/RenderManager.java