GetMirrorTextureGL() always returns VRCompositorError_InvalidTexture.

[LibreVR]

I'm not sure how I'm supposed to use this function, as it always seems to return a VRCompositorError_InvalidTexture error and triggers a GL_INVALID_OPERATION error internally:

GL_INVALID_OPERATION error generated. Invalid format.

[LibreVR]

Am I supposed to initialize the texture myself instead of expecting GetMirrorTextureGL() to initialize the shared texture for me? If so, what are the criteria for the size and format of this texture?

[tjhorner]

@JoeLudwig @aleiby Apologies for the ping, but it looks like this issue still exists in the latest version of SteamVR. Documentation is scarce, and I've tried every possible thing to get this method working, but it refuses to! It also looks like others are having the same issue (see #1410). I've even resorted to decompiling vrclient_x64.dll to see why it could be giving out InvalidTexture errors (😅), but with no luck.

Some guidance here would be greatly appreciated 🙏

If it's helpful, here's how I'm using it at the moment: https://github.com/OVRTools/OVRSharp/blob/b98c57943eb87827da8494d6ac67f878636bdfbb/OVRSharp.Graphics.OpenGL/OpenGLCompositor.cs#L26-L31

It seems nearly the same as how the person in #1410 is using it.