According to that presentation

By • December 11th, 2014

adaptive shading with Wolfenstein II

Nvidia’s RTX ray tracing acceleration stack might be getting the lion’s cheap Canada Goose share of press now that Battlefield V has helped debut the technology, but the Turing architecture is packed full of other fun tricks to help developers optimize the rendering performance of their applications. One of canada goose outlet reviews these is called variable rate shading, or VRS. This Turing capability allows graphics cards built with that architecture to put their shading power where it’s needed most in a frame, rather than shading every pixel naively. That naive approach might result in a canada goose jacket outlet graphics card “wasting” compute resources to arrive at the same result for each of a broad swath of uniformly canada Canada Goose Parka goose outlet in usa colored pixels, for just one example, or working to shade a finely detailed region of the screen that’s then blurred by motion.

An illustration of the pixel groupings possible with canada goose outlet Turing VRS, and how they might be applied to a scene. Source: Nvidia

To let shader power go where it’s needed most, VRS allows developers uk canada goose canada goose outlet store uk to subdivide a 3D canada goose outlet parka application’s screen space into a grid of 16×16 pixel regions (among other possible division techniques, ranging from as fine as canada goose outlet a per triangle division or, more logically, per object). According to Nvidia’s SIGGRAPH presentation on the canada goose topic, each of those 16×16 pixel regions can, in turn, have one of several shading rates applied to it, from the naive 1×1 grid that would typically be used canada goose outlet sale to shade every pixel in a scene today, to 2×2 groups of pixels for 1/4 rate shading, all the way out to a quite coarse set of 4×4 grids for 1/16 rate shading. According to that presentation, then, the canada goose factory sale parts of a scene that need the most detail can get it via 1×1 shading, while those that are the most uniform or the most likely canada goose clearance to be in motion can be shaded canada goose factory outlet at the lowest rates to save shader horsepower for the parts of the scene that need it.

This approach could prove most useful for VR, where foveated rendering demands the ability to subdivide the scene into different regions of rendering resolution, Canada Goose Online but it has other applications in traditional 3D graphics, as well. VRS and the variety of subdivisions of a scene it allows for are the foundation for a technique called content adaptive shading, or CAS. Here’s how it works, according to the Nvidia Turing architecture white paper:

In Content Adaptive Shading, shading rate is simply lowered by considering factors like spatial and temporal (across frames) color coherence. The desired shading rate for different parts of the next frame to be rendered are computed in a post processing step at the end of the current canada goose black friday sale frame. If the amount of detail in a particular region was relatively low (sky or a flat wall etc.), then the shading rate can be locally lowered in the next frame. The output of the post process analysis is a goose outlet canada texture specifying a shading rate per 16 x 16 tile, and this texture is used to drive shading rate in the next frame. A developer can implement content based shading rate reduction without modifying their existing pipeline, and with only small changes to their shaders.

Wolfenstein II: The New Colossus is the first game to implement CAS, and it is in fact the poster child for how the technique’s analysis canada goose outlet uk step works in the aforementioned white paper. Nvidia canada goose outlet online uk provides a visualized example of the result of its post processing analysis on a frame taken from the game’s good guys’ submarine, Evas Hammer.


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