Textures of RenderModels are black when using .NET 4.6 scripting runtime version

[JashanChittesh]

Since Unity 2017.1, there is an option in the Player Settings under "Other Settings" to switch from "Stable (.NET 3.5 Equivalent)" to "Experimental (.NET 4.6 Equivalent)". This mostly works really well - but apparently there is a change that causes the textures to load all black. It's very easy to reproduce when using one of the custom models with colorful textures (like the half-life one ;-) ). With 3.5 active, it works flawlessly. With 4.6, the controllers are all black. At first, I thought loading the custom models was the problem - but reviewing the loaded texture in Unity reveals that it's all black.

This could also be a bug in Unity's 4.6 implementation - I'll file a report with them, too.

[JashanChittesh]

Upon further investigation, I was able to fix this - the problem is that "char" behaves differently in the .NET 4.6 implementation than in the 3.5 implementation. Not sure why char was used but replacing it with ushort fixes the issue (that's in openvr_api.cs):

[StructLayout(LayoutKind.Sequential)] public struct RenderModel_TextureMap_t
{
	public ushort unWidth; // this was char before
	public ushort unHeight; // this was char before
	public IntPtr rubTextureMapData; // const uint8_t *
}
// This structure is for backwards binary compatibility on Linux and OSX only
[StructLayout(LayoutKind.Sequential, Pack = 4)] public struct RenderModel_TextureMap_t_Packed
{
	public ushort unWidth; // this was char before
	public ushort unHeight; // this was char before
	public IntPtr rubTextureMapData; // const uint8_t *
	public RenderModel_TextureMap_t_Packed(RenderModel_TextureMap_t unpacked)
	{
		this.unWidth = unpacked.unWidth;
		this.unHeight = unpacked.unHeight;
		this.rubTextureMapData = unpacked.rubTextureMapData;
	}
	public void Unpack(ref RenderModel_TextureMap_t unpacked)
	{
		unpacked.unWidth = this.unWidth; 
		unpacked.unHeight = this.unHeight;
		unpacked.rubTextureMapData = this.rubTextureMapData;
	}
}

[JashanChittesh]

This is fixed by Pull Request: #79

While fixing it, I saw that TriggerHapticPulse also uses char as parameter, so this may also be broken when .NET 4.6 is activated but I haven't tested this. EDIT: It seems like TriggerHapticPulse does not break. Still might be worth a consideration to change this to ushort. char seems like a misleading type here because it's not a char but a number.

[bddckr]

For more info see
ValveSoftware/openvr#638

(There's multiple others on the OpenVR repo, too. Example: ValveSoftware/openvr#469 (comment))

[zite]

Thanks for the report and fix guys. I've fixed this in the beta and will close when I merge beta to main. You can check it out on the releases page.