3DMark has incorporated a new mesh shader test as a part of its DirectX 12 Ultimate tests. The tool can assist in game development by showing how mesh shading can boost framerates versus traditional geometry culling. As new features like ray tracing become more widely adopted and compute programming increases, developers are sure to want new techniques to recoup lost frames for visual quality.
Mesh shaders introduce a new approach to geometry processing that simplifies the graphics pipeline while also giving developers more flexibility and control.
In 3D graphics, a mesh is the set of vertices, edges, and faces that define the shape of an object. In current graphics pipelines, all the geometry data in a mesh must be processed sequentially before any further steps can be taken. This can be a significant performance bottleneck.
Mesh shaders replace the old approach with a new model that brings the power, flexibility, and control of a compute programming model to the geometry pipeline.
Mesh shaders can process small sections of a mesh, called meshlets, in parallel with a much greater degree of flexibility and control.
Amplification shaders, another new part of the mesh shader pipeline, are especially useful for culling, as they can efficiently determine which meshlets are visible before shading. An amplification shader can cull nonvisible meshlets far more efficiently than the traditional methods.
The new test works by creating a baseline using the traditional geometry culling technique. Then, there’s a second pass using mesh shading to compare the two. It also has an interactive mode allowing users to switch between timelines and examine LOD (level of detail) for each meshlet. Raja Koduri shared an image of the mesh-shading test running on Intel’s new Xe HPG GPU yesterday.