基于GPU Raycasting算法的矢量/栅格混合绘制研究

Hybrid rendering of polydata and volume based on GPU Raycasting

Raycasting体绘制算法由于成像质量高而被广泛应用于体数据的可视化,但当线、面表达的矢量数据和三维栅格表达的体数据同时绘制到同一场景时,由于绘制方法的差异会造成矢量和栅格数据空间遮挡关系不一致。在GPU实现Raycasting算法的基础上,通过矢量和栅格数据先后绘制,采用FBO离屏绘制等技术将矢量数据绘制到深度缓存纹理并在体绘制采样和融合中统一考虑矢栅颜色融合。实验结果表明,该算法在矢量数据非透明模式下能正确处理矢量栅格数据的混合绘制。

Raycasting algorithm is a widely applied volume rendering technique and can produce high quality image.Howe-ver,the algorithm is difficult to handle opaque/translucent volumes combined with polydata models defined by lines and surfaces in the same scene for the different process in traditional surface and volume rendering.To avoid errors in visibility at polydata-volume intersections,proposed GPU accelerated Raycasting algorithm and extended to handle scenes composed of both volume and polydata.Used FBO（framebuffer object） to render the polydata to intermediate textures and composited the resulting colors and opacities together in depth-sorted order in Raycasting process.Results show that the method can render opaque/translucent volumes composited with opaque polydata in the correct order.