Vega中云的仿真方法

比较了飞行视景仿真中几种常用的云模拟方法，分析了Windows平台上Vega中仿真天空和云的局限，提出了一种在Vega中基于非物理模型的模拟方法。该方法采用粒子系统实现，粒子为带纹理的多边形，并使用分段抛物线与随机量的叠加作为粒子运动方程。云层由大量粒子系统组成，并采用与视点相关的层次技术对场景中的各个粒子系统的粒子数量进行动态管理以减少计算量。最后给出了在Vega中的实现方法。

Cloud Simulation in Vega

After comparing 5 cloud simulation methods in flight visual simulation, a non-physically based method in Vega was presented. This method was based on particle system. All the Particles were rendered by textured polygons, and moved along broken parabolas. Cloud-space was made up of plentiful particle systems, and to reduce the computation, an observer-related technology was used to manage the quantity of particles dynamically.