中文摘要：

针对传统软阴影绘制算法在面对大规模三维场景时绘制效率较低的问题，文章基于四叉树加速结构的阴影图构建，研究了邻域节点的搜索方法和遍历顺序的选择方法，提出了一种基于四叉树的百分比近邻软阴影算法。实验结果表明，与传统算法相比，该方法能够有效提高大规模三维场景的软阴影绘制效率，且性能稳定，可以渲染出高质量的软阴影效果。

英文摘要：

In order to overcome the problems of low efficiency of the traditional soft shadow rendering algorithm in the face of large scale 3D scene, in this paper, an acceleration structure based on the quad tree was built for shadow map of 3D scene, the method for searching neighbor node and the method for selecting traversal sequence was studied, and a percentage closer soft shadow algorithm based on quad tree was proposed. The experimental results indicated that, compared with the traditional algorithm, the proposed algorithm could effectively improve the soft shadow rendering efficiency of large scale 3D scene, and the performance was stable, the high quality soft shadows could be rendered.