A parallelized screen-based method for rendering polylines and polygons on terrain surfaces

Two dimensional (2D) vector features, when rendered on terrain as reference or highlight features, can improve the intelligibility of three dimensional (3D) scenes. This research proposes a new screen-space based method to render solid color 2D polylines and polygons on terrain. Using the z-buffer value and window coordinates in screen space, a pixel's spatial extent in real world coordinates can be calculated. The pixel's color is changed, if its spatial extent intersects with a polyline or polygon feature, to reflect the fact that there is a polyline going through or a polygon covering the pixel. Compared to other existing methods, our method eliminates undesirable rendering artifacts. A parallel computing schema was proposed and implemented as well to improve rendering performance.