opened
Compynerd255
username_0
The [IVRSystem::GetHiddenAreaMesh](https://github.com/ValveSoftware/openvr/wiki/IVRSystem::GetHiddenAreaMesh) method is documented to return a **HiddenAreaMesh_t** that simply contains a pointer to a list of vertices and an indicated number of triangles. Could you please post more information to the wiki as to what the format of that list of vertices is (i.e. is it 3-vectors or 4-vectors, is it a triangle list or a triangle strip, does it need to be transformed or projected, can it change during program execution, etc.)?
GetHiddenAreaMesh does not specify mesh format
issue
created
jrbudda
username_1
It's a list of 2d triangles. There should be 20 triangles reported. That's 60 vertices and 2 coordinates per vertex so 120 individual values in the format x1, y1, x2, y2, x3, y3 ... etc
comment
created
L-P
username_2
As this issue is the only documentation I found on the subject, let me expand
it a bit:

As of today (IVRSystem_017 with a HTC Vive), `GetHiddenAreaMesh` returns 78
vertices **in the [0-1] range**. (0,0) is bottom-left.

The rest can be inferred from the definition of `HiddenAreaMesh_t`.
The comments on `GetHiddenAreaMesh` does not match the definition but match the
functionality.
comment
created
jorjic
username_3
There's a C# example of converting the `HmdVector2_t pVertexData` into a Unity mesh.
https://github.com/ValveSoftware/openvr/blob/4c85abcb7f7f1f02adaf3812018c99fc593bc341/samples/unity_teleport_sample/Assets/SteamVR/Scripts/SteamVR_Utils.cs#L390

It's also worth checking out that Ogre3D has mentioned Valve's hidden area mesh in this blogpost: 
[https://www.ogre3d.org/2019/09/22/improvements-in-vr-morph-animations-moving-to-github-and-ci](https://www.ogre3d.org/2019/09/22/improvements-in-vr-morph-animations-moving-to-github-and-ci)
comment