Dan and I are writing a chapter for GPU Pro 4, A WebGL Globe Rendering Pipeline, that describes a few of the rendering techniques we developed for Cesium. We’d be happy to have a few folks review it. Please contact me if you are interested. From the introduction:
We present a WebGL globe rendering pipeline that integrates with hierarchical levels of detail (HLOD) algorithms used to manage high resolution imagery streamed from standard map servers, such as Esri or OpenStreetMap. Our pipeline uses screen-space techniques, including filling cracks between adjacent tiles with different LODs with a masked Gaussian~blur; filling holes in the north and south pole with masking and ray casting; and avoiding depth fighting with vector data overlaid on the globe by rendering a depth plane.