updateVertexPositions too slow to use for real-time animation loops

I'm wondering if I'm using the updateVertexPositions and userCallback correctly. Currently I'm getting around 260 ms/f (4 FPS) when I update the positions of a mesh with 262,144 faces inside the draw loop callback.

If I run a similar animation in the libigl viewer I'm getting 19.9 ms/f (50 FPS). In that scenario I'm using set_vertices and callback_pre_draw.

Here's a video screenshot on my intel macbook pro running catalina:

https://user-images.githubusercontent.com/2241689/147182765-78b15f28-a1ce-4fc6-abf0-f6b44af2728e.mov

( Turning off the polyscope groundplane doesn't seem to change anything. I'm guessing the slowdown is happening in updateVertexPositions)

从绘制循环中使用的 updateVertexPositions 和 userCallback 入口点开始，并将它们的行为与 libigl 的 set_vertices 和 callback_pre_draw 路径进行比较。在报告的 macOS 配置上对 262,144 面动画进行性能分析，以确定帧时间差异的来源。完成的标准是明确原因和正确用法，并提供可复现的性能比较或记录在案的限制。