Diploma and Master Theses (authored and supervised):
"Improved Persistent Grid Mapping";
Supervisor: E. Gröller;
Institute of Visual Computing & Human-Centered Technology,
final examination: 2019-11-19.
We propose a novel heightmap-based terrain rendering algorithm that enhances the Persistent Grid Mapping (PGM) method. As in the underlying method, we cache a regular triangulated grid in video memory and use the GPU to project the mesh onto the ground plane each frame anew. Each vertex in the grid is then displaced according to the sampled heightmap value along the ground plane´s normal vector. The perspective mapping of the grid results in a view-dependent, continuous level-of-detail approximation of the terrain dataset. PGM is a simple and elegant terrain rendering algorithm, however, as the camera hovers over the terrain, projected vertex positions slide over the terrain. This leads to the underlying static terrain surface changing shape slightly from frame to frame. We address these swimming artifacts by introducing four improvements: tailoring the projected grid, which pushes most otherwise culled vertices back into the view frustum, redistributing grid vertices according to an importance function for more faithful mipmap selection when sampling the heightmap, local terrain edge search for vertices within a certain proximity to the camera, and exploiting temporal coherence between frames. While our algorithm cannot guarantee a maximum screen-space error, it nevertheless reduces PGM´s inherent temporal aliasing artifacts considerably.
Electronic version of the publication:
Created from the Publication Database of the Vienna University of Technology.