摘要:在Cesium中展示大体量集中的三维模型需要进行渲染性能优化。Cesium原生方法效果不稳定，同时会降低渲染效果。为了尽可能避免该问题，提出相机状态变化期间高性能渲染机制，在相机状态变化期间停止加载图元，且仅在此期间采用会降低渲染效果但可提升性能的参数设置与算法，保证模型加载期间的渲染效果。同时提出基于堆的三维瓦片绘制命令限制方法，通过该方法可直接限制绘制命令数量，降低GPU计算量。实验证明，相机状态变化期间高性能渲染机制可行。在该机制中提升最大屏幕空间误差（max screen space error，MSSE）以及限制绘制命令对提升渲染性能的效果均显著优于降低分辨率比例（resolution scale，RS）。而限制绘制命令对渲染性能提升的稳定性优于提升MSSE。

Abstract: Rendering performance optimization is needed to display dense 3D models in Cesium requires improving the. However, the native approaches are unstable and will cause bad rendering results. To avoid this problem as much as possible, a mechanism is proposed in this paper to enable high-performance rendering when the camera state changes in which the camera states change pauses primitives loading, and applies parameter settings and algorithms that can improve rendering performance but may cause bad rendering results. Besides, this paper proposes a heap-based 3D tile draws command limitation approach, which can directly limit the number of draw commands and reduce the amount of GPU computation. The results prove that the mechanism of high-performance rendering when camera state changes are feasible. The mechanism outperforms the max screen space error (MSSE) increasing and the draw commands limiting, which excels reducing the resolution scale (RS) in improving rendering performance. Limiting the draw commands can ensure the stability of rendering performance compared with increasing MSSE.