public void renderViewPort(ViewPort vp, float tpf) {
        if (!vp.isEnabled()) {
            return;
        }        
        RenderPipeline pipeline = vp.getPipeline();
        if (pipeline == null) {
            pipeline = defaultPipeline;
        }
        PipelineContext context = pipeline.fetchPipelineContext(this);
        if (context == null) {
            throw new NullPointerException("Failed to fetch pipeline context.");
        }
        if (!context.startViewPortRender(this, vp)) {
            usedContexts.add(context);
        }
        if (!pipeline.hasRenderedThisFrame()) {
            usedPipelines.add(pipeline);
            pipeline.startRenderFrame(this);
        }
        pipeline.pipelineRender(this, context, vp, tpf);
        context.endViewPortRender(this, vp);
    }
Renders the {@link ViewPort} using the ViewPort's {@link RenderPipeline}.
<p>
If the ViewPort's RenderPipeline is null, the pipeline returned by
{@link #getPipeline()} is used instead.
<p>
If the ViewPort is disabled, no rendering will occur.

@param vp View port to render
@param tpf Time per frame value
jme3-core/src/main/java/com/jme3/renderer/RenderManager.java