Research On Real-time Drawing Of 3D Terrain Based Dynamic Multi-resolution

Based on the adaptive quad tree,a dynamic multi-resolution terrain model is set up,which not only meets the need of the real-time rendering of terrain, but also ensure the fidelity of the actual geographical environment, and then which achieves the true representation of terrain. Finally, in the VC++ platform the simplified dynamic model of multi-resolution terrain is established by using the OpenGL library and the construction and texture rendering of the realistic 3d terrain in the scene is realized.This article includes the following aspects:(1) A dynamic multi-resolution terrain model is mainly study based on the adaptive quad tree. Applying the visual volume clipping and the terrain block achieves the organization and real-time dynamic scheduling of the DEM data. The T-cracks generated in the quad tree model is eliminated by setting up a function which checks the situation of the adjacent blocks'division and resets the value to the relevant nodes.(2)The nodes evaluation function for the model is analyzed. According to the terrain roughness, viewpoint position, gaze direction and visual sensitivity and other decision factors, the more detailed static and dynamic errors of the terrain model is evaluated.(3) The method of the multi-resolution texture quad tree and constructing the pyramid model are improved, which can quickly determine the multi-resolution texture image that is consistent with the geometry level of the details, and then achieves the real-time optimization in the drawing process.