Landform grid generating method being correlated with viewpoint and based on four-queue optimization

Abstract

The invention discloses a viewpoint-related four-queue optimization-based terrain mesh generating method, including: initializing the terrain meshes and four queues; recalculating error and updating the four queues; generating the terrain meshes by the four queues' driving triangles. It processes the original terrain data, can complete generating the terrain meshes within a limited time, and at the same time assure the quality of display picture. It uses the continuity between visual fields, can effectively control the number of triangles in the terrain meshes and adopts the four queues to drive the terrain meshes, only sequencing the meshing queues and combining queues, and when the viewpoint does not change greatly, the number of the terms in the meshing and combining queues is very small, thus reducing sequencing time, and enhancing the generating efficiency of the terrain meshes, so as to make real-time terrain ramble smoother and the display picture quality higher.

Description

Technical field [0001] The present invention relates to general image data processing or generation, and in particular to a method for generating a terrain grid based on four-line optimization related to viewpoints. technical background [0002] In order to realize real-time roaming of large-scale terrain, the terrain grid generated by the original terrain data must be simplified. The viewpoint-related terrain mesh simplification generation algorithm refers to the effective simplification of the terrain mesh under the current viewpoint according to a given error threshold, so that the simplified terrain triangle mesh and the original mesh are observed at a given viewpoint There is almost no difference in time. There are several ways to simplify the generation of terrain grids: [0003] 1. Bottom-up simplification generation method, that is, start from the bottom of the grid, merge the triangles that meet the conditions, until the triangle error meets the given threshold, see [Lin...

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Problems solved by technology

[0003] 1. Bottom-up layer-by-layer simplification generation method, that is, starting from the bottom layer of the grid, merging triangles that meet the conditions until the error of the triangles meets a given threshold, see [Linsdrom1996]PeterLindstrom, David Koller, William Ribarsky , Larry F. Hodges, Nick Faust, and Gregory Turner, "Real-time, Continuous Level of Detail Rendering of Height Fields," Proceedings of SIGGRAPH 96, 109-118., Simplification depends on the size of the terrain's finest resolution grid, Data that is relative to the entire terrain, both in terms of computation and storage, is not valid for large-scale terrains

[0004] 2. Gradual top-down refinement, the terrain grid is gradually subdivided and refined from the thickest triangle until the error of the triangle meets a given threshold, see [Linsdrom2001, 2002] (Peter Lindstrom and V.Pascucci, "Visualization of large terrains made easy," IEEE Visualization 2001, 363-370, Oct. 2001; Peter Lindstrom and V. Pascucci. "Terrain Simplification Simplified: A General Framework for View-Dependent Out-of-Core Visualization". IEEE Transaction on Visualization and Computer Graphics, 2002.), this method starts from the thickest two triangles in each frame, performs top-down subdivision, and cannot take advantage of the coherence between the viewing areas

The number of triangles can be determined according to the rendering ability. The ROAM algorithm guarantees the rendering at a fixed frame rate for the real-time terrain rendering system. However, in the real-time rendering process, each time the priority queue needs to be updated, the complexity is 0(nlogn), and the new Calculating priorities also consumes CPU time

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