Seamless patches for GPU-based terrain rendering

In this paper we present a novel approach for interactive rendering of large terrain datasets which is based on subdividing the terrain into rectangular patches at different resolutions. Each patch is represented by four triangular tiles which can be at different resolutions; and four strips which are used to stitch the four tiles in a seamless manner. As a result, our scheme maintains resolution changes within patches and not across patches. At runtime, the terrain patches are used to construct a level of detail based on view-parameters. The selected level of detail only includes the layout of the patches and the resolutions at boundary edges. Since adjacent patches agree on the resolution of common edges, the resulted mesh does not include any cracks or degenerate triangles. The GPU generates the meshes of the patches by using scaled instances of cached tiles and assigning elevation for each vertex from the cached textures. Our algorithm manages to achieve quality images at high frame rates while providing seamless transition between different levels of detail.