【摘要】 在体绘制过程中,为了给物质表面加入材质(光照和纹理)来提高结果的可读性,提出一种带材质的体绘制算法.通过引入2D球面光照贴图,用纹理映射替代了GPU中复杂的光照模型计算;利用物质表面单位法向量索引球面光照贴图中对应点的颜色信息,从而给物体表面赋予各种材质属性;并结合基于3D纹理的GPU光线投射算法完成绘制.实验结果表明,该算法简单易行,在增强可视化效果的同时使得绘制的效率也得到提升.更多还原

【Abstract】 Object surface with material(lighting and texture) can be used to enhance the perception of volume rendering.In this paper,we introduce a 2D sphere illumination map,which is computed offline and used in the run time to simplify GPU shading computation to texture lookups.Color of the corresponding point in the sphere map is indexed by the normalized normal vector of the object surface,thus assigning material to the surface.This method can be simply applied to GPU-based 3D texture ray-casting algorithm.The results show the implementation permits both visual effect enhancement and efficiency improvement.更多还原