Looking through the code, I cannot find a good way (or any way for that matter) to extract non-composited framebuffers. Specifically, I need to extract rendered billboards, polylines and points without any of the terrain or tiles around them. Afterwards I want to “apply” the rendered pixels onto a image taken with a camera.
The scene object (https://github.com/CesiumGS/cesium/blob/main/Source/Scene/Scene.js) has pre and post rendering events that I can easily hook into. I also have no problems with solutions that patch Cesium. I’m aware I’ll need to keep maintaining this “fork” afterwards.
The only documentation I could find on the inner workings of the rendering engine is this not very detailed blog post Graphics Tech in Cesium - The Graphics Stack – Cesium. The github wiki is quite old (over 6 years) and the referenced github issue is not of much help either.
Thank you for your time,
TL;DR: Any docs on how the rendering stack works and how to get data from the rendering passes?