多重散射的天空光照效果建模与实时绘制

依据大气散射的物理原理，提出了一种考虑多重散射的天空光照效果建 模与实时绘制方法。该方法首先以太阳和天空光作为光源建立了多重散射的天空光照效果模 型，然后综合多种大气粒子密度, 采用合理的分段采样策略，对天空颜色模型的积分进行简 化，以减少积分近似计算所带来的误差；通过对简化后的模型进行分析提出了采用二维纹理 与三维纹理对光学深度预计算的方法，避免了运行时计算光学深度积分的问题；最后该算法 在GPU 的片段处理器上执行，实现了天空光照效果模型的实时绘制，可以满足各种实时应 用需求。

Modeling and Real-time Rendering of Sky Illumination EffectsTaking Account of Multiple Scattering

This paper presents a method of modeling and real-time rendering of the sky illumination effects taking account of multiple scattering with atmospheric scattering based on physical models. Firstly, with the sun and the sky as light sources, the model of the sky illumination effects taking account of multiple scattering is built. Then a reasonable segmented sampling strategy based on a variety of atmospheric particle densities is adopted to simplify the integral of the sky color model to reduce the integral approximation calculation error. By analyzing the simplified model, the pre-computed 2D texture and 3D texture for optical depth are proposed to avoid a run-time calculation of optical depth. Finally, the algorithm is executed on the fragment processor of GPU so that the sky illumination effects taking account of multiple scattering are rendered with high frame rate for real-time applications.