public void setOutputFrameBuffer(FrameBuffer out) {
        this.out = out;
    }
Sets the output framebuffer for the ViewPort.

<p>The output framebuffer specifies where the scenes attached
to this ViewPort are rendered to. By default, this is <code>null</code>,
which indicates the scenes are rendered to the display window.

@param out The framebuffer to render scenes to, or null if to render
    to the screen.
jme3-core/src/main/java/com/jme3/renderer/ViewPort.java