A reinterpreted-texture strategy for rendering point symbols based on graphics processing unit

Abstract

ABSTRACT The increasing demands of presenting large numbers of points in maps have promoted the progress of rendering point symbols in GPUs. Although the drawing efficiency issue can be handled with texture mapping methods, the rendering quality problem due to the fixed resolution that affects map renders’ visual experiences remains. The method of directly drawing vector paths of a point symbol can be used to satisfy the sharper effect of point symbols. However, it requires high memory cost and affects the drawing efficiency. This paper proposes a point symbol rendering method using the idea of reinterpreted textures. The rendering data used in this method are based on vectors to achieve refined results. Vector properties of symbols are encoded and organized into the texture structure with specific layout schemes. In the rendering phase, an instanced pipeline is launched to accept the texture and decode the required attributes. The proposed method takes advantage of fast access and continuity of textures while retaining geometric transformations. These features allow all symbols to be drawn in one single draw call and rotated or scaled arbitrarily. Experiments on drawing quality and efficiency demonstrate that the proposed method achieves fast and stable performance while maintaining the rendering quality.