Vrtk: Unity 2018.1.0b12: Can't create empty Texture (not allowed, needs to be subclass)

[BlackDragonBE]

This line causes projects to fail compilation:

https://github.com/thestonefox/VRTK/blob/e43089a4dbefba55af2716d22de31458e0b615ca/Assets/VRTK/Scripts/Interactions/Highlighters/VRTK_MaterialColorSwapHighlighter.cs#L152

This can be fixed by replacing the line above with:

renderer.material.SetTexture("_MainTex", new Texture2D(0,0));

Cheers!

[kristianpd]

This is addressed in https://github.com/thestonefox/VRTK/pull/1730

[thestonefox]

@kristianpd I wonder if the proposed fix of new Texture2D(0,0) is actually better than Texture2D.whiteTexture

Then at least the new texture should be garbage collected in scope.

Thoughts?

[kristianpd]

I assumed Texture2D.whiteTexture would be a shared texture already in
memory as opposed t created at call time. Wouldn't that texture be around
for the entire run anyway? Are we assuming it created it the first time
it's called then keeps it around forever? I didn't expect a leaked
reference on every call.

On Fri, Apr 6, 2018, 5:20 AM The Stonefox [e-mail] wrote:

@kristianpd https://github.com/kristianpd I wonder if the proposed fix
of new Texture2D(0,0) is actually better than Texture2D.whiteTexture

Then at least the new texture should be garbage collected in scope.

Thoughts?

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[thestonefox]

I'm trying to look through the new c# reference code and struggling to see where they define Texture2D.whiteTexture

here maybe?

https://github.com/Unity-Technologies/UnityCsReference/blob/11bcfd801fccd2a52b09bb6fd636c1ddcc9f1705/Runtime/Export/Texture.bindings.cs#L56

[kristianpd]

I assumed that Texture2D.whiteTexture would be a 1x1 (ish) white pixel. Since it's a class attribute, I was under the impression it would be garbage collected as part of Texture2D's internals and assumed it was a reference to a single texture in memory.

If it was creating a new texture every time, wouldn't the old ones be GC'd when the new material texture is set and no longer referencing the object? If it is a shared texture then I would assume nothing is going to be cleaning it up for as long as unity is running. If it is a new instance of a texture, no longer referencing it via the material texture should allow it to be GC'd, no?

Am I missing something obvious here?

[thestonefox]

You may be totally right, it would just be nice to know what Unity is doing!

Have you ever seen what they do with Camera.main? it will blow your mind :p

[bddckr]

GC is of no interest: A texture(2D) is a unity object and as such you need to call Destroy on it.

The actual asset of the texture is unloaded with a call to that method Unity has to unload unused assets.

The recompiled source shows all the methods of interest (texture getters and constructors) are just calling into their native C++ layer, so can't see what it's doing. Docs don't tell anything either.

Quick test would be to just access .whiteTexture in an update method and keep looking at the GPU/Rendering profiler in the Editor - one of them lists the number of textures in use.

I'd expect that one to not increase, but the constructor call to create multiple textures except when you call Destroy on them.

[thestonefox]

Can confirm Texture2D.whiteTexture does not increase texture count whereas new Texture2D does.

Texture2D text = new Texture2D(0, 0);

vs

Texture2D text = Texture2D.whiteTexture;

so whiteTexture is the solution imho

[kristianpd]

Cool, TIL. I'll update the PR