Persistent Grid Mapping: A GPU-based Framework for Interactive Terrain Rendering

In this paper we present the Persistent Grid Mapping (PGM), a novel framework for interactive terrain rendering that provides a screen-uniform tessellation of terrains in a view-dependent manner. The persistent grid, which covers the entire screen, is triangulated with respect to the rendering capabilities of the graphics hardware and cached in video memory. The GPU maps each vertex of the persistent grid onto the terrain. Such perspective mapping of the persistent grid remeshes the visible region of the terrain in a view-dependent manner with local adaptivity. Our algorithm maintains multiple levels of the elevation and color maps to achieve a faithful sampling of the viewed region. The rendered mesh ensures the absence of cracks and degenerated triangles that may cause the appearance of visual artifacts. In addition, an out-of-core support is provided to enable the rendering of large terrains that exceed the size of texture memory. PGM algorithm provides high quality images at steady frame rates.