实时软影映射算法能够使用一张阴影映射图绘制出复杂动态场景的真实的软影效果。结合物体空间和图像空间的算法,提出一种在物体空间中提取面光源轮廓边的方法;然后利用面光源轮廓边的属性,提出一个在图像空间中确定轮廓边像素走向的方法;最后反投影拟合的轮廓边计算最终的几何可见性。实验结果表明,本文算法减少了提取轮廓边的消耗,提高了绘制效率;增加了拟合轮廓边的精度,提高了绘制效果。

Real-time soft shadow algorithms can render convincing soft shadows on complex and dynamic scenes with a single shadow map. In this paper, we propose a hybrid rendering method, which extracts edges for area light in object space and determines the edge pixel’s direction in image space. Then, we use the Hierarchical Edge Map to compute the visibility. The results show, the cost of silhouette extracting is reduced and the rendering performance is improved. Furthermore, the accuracy of the contour and the shadow quality are both enhanced.