真实感天空的实时渲染

Realistic sky rendering In real-time

提出一种实现真实感天空实时渲染的高效方法。首先利用基于分析的天空模型实现天空的光照计算，该模型充分考虑了天空的昼夜变化，并对夜空中特有的各类光源如月球、星体、黄道光和气辉等进行分析；其次通过色调重现实现天空的真实感渲染，通过对暗视效果的模拟进一步提高夜空渲染的真实感；最后给出基于观察窗口的天空几何模型和银河系、星体的渲染方法，并通过图形处理器（GPU）实现上述算法的实时渲染。该方法适用于室外场景的渲染，并已成功应用于某直升机飞行模拟器中。

This paper presents an effective method to render realistic sky in real-time. sky light computation is achieved by using the analytic sky model, in which day account and light sources at night such as moonlight, It is described below： and night changes are Firstly, a taken into starlight, zodiacal light and airglow are analyzed. Secondly, tone reproduction is employed to render realistic sky. The scotopic phenomenon is simulated to further get the night rendering realistic. Finally, the viewport-based sky geometry model and the rendering method for galaxy and stars are presented. The real-time rendering for the above algorithms was achieved by a graphics processing unit （GPU）. The proposed method is suitable for rendering of outdoor scenery, which has been applied to a helicopter flight simulator successfully.