Joakim Lilja
As video games get more and more demanding together with screen resolutions continuing to increase, new methods to render video games at high frame rates are needed. Variable Rate Shading is a technique currently available on Nvidia's Turing architecture and Intel Gen11 hardware. Variable Rate Shading makes it possible to pick a shading rate during rendering and shade a group of pixels instead of individually, ultimately speeding up the pipeline. A drawback of Variable Rate Shading is that the image quality often degrades by producing a pixelated look. The work in this paper aims to reduce the pixelated look of particle effects rendered through Variable Rate Shading by implementing and evaluating four different post-processing filters. A qualitative evaluation in the form of a user study took place to evaluate the work subjectively. Structural Similarity Index was another qualitative method used to evaluate the image quality objectively. Also, a quantitative evaluation was performed to measure how the render times vary. All Variable Rate Shading solutions were compared against a traditional method that was used in the industry for effectively rendering particles. Findings showed that when using 2x2 shading rate, two of the solutions presented in this paper have better image quality than the traditional method and close to, but not equally good time performance for both 1080p and 4K resolution. 4x4 shading rate has more specific use cases such as smoke that consists of similar color over the entire effect or if 4K resolution is used. Using 4K resolution makes 4x4 shading rate potentially useful as the render times were the fastest together with having an acceptable aesthetic look, while for 1080p resolution, it was not recommended. In conclusion, as video games are vastly different, an artist might be best suited to decide which implementation is best and how essential the reduction in render times are. Variable Rate Shading can be used to reduce render times and keep an appealing visual look.