Virtual Deferred Rendering

In this paper the virtual deferred algorithm is introduced, which combines the benefits of virtual texturing and deferred rendering in order to minimize the bandwidth consumption in rasterized based rendering. The proposed algorithm improves the performance of rendering by minimizing the number of expensive memory accesses such as texture fetches, which are usually the main catalysts for performance bottlenecks in real-time rendering. State of the art deferred rendering methods employ geometry buffers in order to avoid evaluating the lighting equation for occluded primitives. The problem with these methods is that they either fill the geometry buffers in linear complexity in texture fetches or that they draw the geometry multiple times. The proposed method almost completely decouples texture fetching from visibility determination without using multiple geometry passes. The only exceptions are geometry altering texture fetches. The virtual deferred rendering algorithm utilizes a single rasterization based rendering pass, saving only geometric information in the geometry buffer, without using any texture fetches. The algorithm then uses a compute shader and virtual texturing based rendering pipeline, which guarantees constant complexity in texture fetches without further geometry processing. The proposed method also benefits from the streaming properties of virtual texturing, making it ideal for large, streamed scenes.