在实时的虚拟场景渲染中, 为减少阴影图算法由分辨率不足导致的阴影走样, 提出了利用并行线性扫描的混合分辨率阴影图算法。首先, 从光源视角生成高分辨率阴影图, 利用并行线性扫描算法对深度均值差进行计算和分析, 自底向上的合并纹素, 建立纹素之间的索引关系并讨论混合分辨率阴影图的存储。在渲染阶段, 利用混合分辨率阴影图进行深度测试, 绘制实时的反走样阴影。实验表明, 与标准阴影图相比, 混合分辨率阴影图能提高20%以上的重要区域分辨率, 明显改善阴影边界锯齿走样, 使Dragon等模型的计算时间减少9%~18%。经实际应用验证, 混合分辨率阴影图是一种有效的实时阴影绘制算法, 可有效减少阴影图算法的走样。

In order to reduce the aliasing artifact due to the finite resolution of shadow mapping in real-time rendering, we propose a hybrid-resolution shadow map based on a parallel line-sweep algorithm. First, our method generates a high-resolution depth map from light′s view, and analysizes the mean difference of depth using parallel line-sweep algorithm with threads and kernels. Then this method merges the texels from bottom to top to establish indexes for the texels and discusses the storage methods. At rendering pass, our method renders shadows in real time using the hybrid-resolution shadow map for occluder detection. Experimental results indicate that our algorithm improves the resolution of boundaries′ area over 20% compared with standard shadow mapping and reduces the time consumption about 9%-18% running by Dragon model. Verified by practical application, the hybrid-resolution shadow mapping is an effective real-time shadow rendering algorithm, which can effectively reduce the aliasing artifact.