Skeletal Animation Optimization Using Mesh Shaders

Abstract: Background. In this thesis a novel method of skinning a mesh utilizing Nvidia’sTuring Mesh Shader pipeline is presented. Skinning a mesh is often performed with a Vertex Shader or a Compute Shader. By leveraging the strengths of the new pipeline it may be possible to further optimize the skinning process and increase performance, especially for more complex meshes. Objectives. The aim is to determine if the novel method is a suitable replacement for existing skinning implementations. The key metrics being studied is the total GPU frame time of the novel implementation in relation to the rest, and its total memory usage. Methods. Beyond the pre-existing implementations such as Vertex Shader skinning and Compute Shader skinning, two new methods using Mesh Shaders are implemented. The first implementation being a naive method that simply divides the mesh into meshlets and skins each meshlet in isolation. The proposed novel common influences method instead takes the skinning data, such as the joint influences of each vertex, into account when generating meshlets. The intention is to produce meshlets where all vertices are influenced by the same joints, allowing for information to be moved from a per vertex basis to a per meshlet basis. Allowing for fewer fetches to occur in the shader at run-time and potentially better performance. Results. The results indicate that utilizing Mesh Shaders results in approximately identical performance compared to Vertex Shader skinning, (which was observed to be the fastest of the previous implementations) with the novel implementation being marginally slower due to the increased number of meshlets generated. Mesh Shading has the potential to be faster if optimizations unique to the new shaders are employed. Despite producing more meshlets, the novel implementation is not significantly slower and is faster at processing individual meshlets compared to the naive approach. The novel Common Influences implementation spends between 15-22% less time processing each meshlet at run-time compared to the naive solution. Conclusions. Ultimately the unique capabilities of Mesh Shaders allow for potential performance increases to be had. The proposed novel Common Influences method shows promise due to it being faster on a per meshlet basis, but more work must be done in order to reduce the number of meshlets generated. The Mesh Shading pipeline is as of writing very new and there is a lot of potential for future work to further enhance and optimize the work presented in this thesis. More work must be done in order to make the meshlet generation more efficient so that the run-time workload is reduced as much as possible.