Thank you very much. In fact, in my project, I also used a single equirectangular texture, and maybe a 360 video. I want to realize that in the interior of the skybox, I can replace anything inside with decals, like a painting in a museum, and so on, so that I can reduce the number of equirectangular textures and change the scene.
In the past, my idea was that the user would select four points with the mouse and then create a mesh (plane) to map on it. We did, but I found that the scenarios for this approach were limited. Because there’s no guarantee that all four points are in one plane (except on the surface of the cube), and there’s no way to have more complex shapes. Even the decals used now can not be replaced by any shape, and there is also the trouble of texture UV. Do you have any good ideas?
（The description of the application scenario can be seen here：Texture of a polygon ）