利用形状因子采样的实时全局光照绘制

Form-Factor Sampling Based Real-Time Global Illumination

为了对物体表面材质进行实时编辑,提出一种动态光照和任意视点条件下的实时全局光照算法.该算法预计算各面片的形状因子,并存储其中较大的形状因子值和相应的面片号,这些面片是光照贡献最大的面片.一次间接光照利用这些面片计算,并用亮度补偿策略增加计算精度,而二次及多次间接光照则用近似公式估算,整个光照计算过程在GPU中完成.实验结果表明,文中算法在视点改变、光照改变和材质改变情况下,对静态场景能获得逼真的实时全局光照绘制效果.

We present a method for real-time computation of global illumination in dynamic light scenes based on approximate indirect illumination.In the pre-computation process,Form-factors are obtained for each surface,and only the largest ones are preserved for rendering.During the rendering,while the One-bounce indirect illumination is calculated by only considering the surfaces with these preserved large factor-former as light sources,multiple-bounce indirect illumination is simply approximated by average reflective intensity.The accuracy of one-bounce indirect illumination is further increased by brightness compensation algorithm.The whole indirect illumination computation is implemented in GPU,and the memory requirement is small.The experiments have shown we can change the light or view point,and even the BRDF of the scene in real time.