基于反射阴影图的间接光照绘制改进算法

Improved Algorithm for Rendering Indirect Illumination Based on Reflective Shadow Maps

提出了基于反射阴影图的间接光照绘制改进算法。利用间接光照变化平滑的特点对低空间分辨率间接光照的计算结果进行插值得到高分辨率间接光照的结果。由于边界区域间接光照的变化是高频的,必须对边界和非边界区域分别计算。利用可视场景点的几何属性图,检测场景中几何对象的边界,将可视场景区域分为边界区域和非边界区域。边界区域的间接光照在高分辨率下直接计算,其它区域则由低分辨率的间接光照结果插值得来,最后使用自适应区域滤波方法对高分辨率间接光照的结果进行滤波得到最终间接光照结果。实验结果表明,相比于原始的基于反射阴影图的间接光照绘制算法,本算法显著提高了绘制效率,并通过设置插值分辨率阈值来增强算法的适应性。

In this paper,an advanced algorithm based on reflective shadow maps (RSM) for rendering indirect illumina-tion is proposed. Due to the fact that indirect illumination changes smoothly,high-resolution indirect illumination can be calculated by interpolating the low-resolution results. However, the indirect illumination in regions of boundary changes sharply;thus the visible regions of scenes should be divided into areas of boundary and non-boundary via detection for the boundary of 3D objects with help of geometric attribute maps. The indirect illumination in the areas of boundary is computed directly, while others can be interpolated by low-resolution results. Finally, adaptive region filtering is used to smoothen the high-resolution indirect illumination results obtained by interpolation operations mentioned above. Exper-imental result shows that our algorithm is faster than the original RSM-based one. Its adaptability can be controlled by the interpolation resolution threshold.