Curvature-Driven Normal Interpolation for Shading Applications

摘要

Systems and methods for performing shading operations of a three-dimensional model, such as a three-dimensional model of a geographic area, are provided. According to aspects of the present disclosure, shading operations can be performed based on a curvature of the polygon mesh such that smooth surfaces still appear smooth after shading and such that sharp edges still appear sharp after shading. In particular, a curvature-driven normal is used for shading operations that takes into account the local curvature of the polygon mesh. A curvature factor can be obtained for each vertex in the polygon mesh. The curvature factor for each vertex can be a scalar value that describes the degree of local curvature in the mesh polygons connected at the vertex. The curvature-driven normal for each fragment can be determined based on the curvature factors associated with the vertices in the polygon mesh.

主权项

1. A computer-implemented method of rendering a three-dimensional model, the method comprising:
accessing, by one or more computing devices, a polygon mesh representing geometry of the three-dimensional model, the polygon mesh comprising a mesh polygon and a vertex; obtaining, by the one or more computing devices, a curvature factor for the vertex of the polygon mesh, the curvature factor for the vertex indicative of a local curvature of the polygon mesh at the vertex; obtaining, by the one or more computing devices, a curvature-driven normal for a fragment of the polygon mesh located on the mesh polygon, the curvature-driven normal determined based at least in part on a face normal associated with the fragment, an interpolated vertex normal associated with the fragment and the curvature factor determined for the vertex; and performing, by the one or more computing devices, a shading operation using the curvature-driven normal; wherein a contribution of the face normal relative to the interpolated vertex normal in determination of the curvature-driven normal is based at least in part on the curvature factor.