| Contour line as an effective tool for analyzing spatial phenomena is one of the most important object in 3D observation system,which needs efficient rendering.With the continuous expansion of the scope of work in the field of seismic exploration,the number of control points up to the level of tens of millions.How to achieve real-time and efficient fusion rendering of large-scale 3D terrain and large amount of contour line has become an industry difficulty.Based on the existing computer hardware conditions and visualization technology,this thesis proposes a method of using GPU dynamic control pipeline technology to achieve 3D terrain and contour line fusion rendering and attributes editing.The main research contents are as follows.(1)Based on GPU programming technology,combined with scene view and terrain multi-resolution structure to achieve elevation texture generation and organization scheduling method.(2)A high speed and fast interpolation method based on GPU for the elevation of contour points is realized.This method uses the elevation texture and the control point coordinates as the input object,and writes the interpolation algorithm in the shader to acquire the real-time elevation of the control point in parallel.(3)A color value calculation method based on GPU when contours are associated with scene color code is designed.This method achieves efficient calculation of contour colors by passing the color code into the GPU memory in the form of a specific one-dimensional array and using the shader function written by GLSL.(4)An improved polygon approximation algorithm is proposed.The algorithm is used to dynamically set the error threshold for polygon approximation according to the terrain distribution,so that the contour labels are evenly and effectively displayed.Based on the actual project,this thesis designs and implements the application system of 3D terrain and contour fusion rendering.The practice shows that the technology is feasible and has good effect. |
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