L16 images render as black until edit panel is open

[woelper]

Describe the bug
I suspect there is an issue with the texture / display of L16 images. It works if the edit panel is open and a Rgba8 operator is automatically added.

Tagging @B-LechCode for visibility.

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[B-LechCode]

Do you know the min and max pixel values in your L16 images?
I suppose the values are just too low?

[woelper]

Oh, that could be a possibility. I am testing Dicom support and they could be out of visual range. I am not sure, but even if that was the case I don't know if converting them to rgba8 would compress them into 8bit per channel so they become visible - not sure if image is doing anything along those lines. I can check that!

[B-LechCode]

Okay, I checked it up:
Using the edit panel sets the data type to 8 bit - that's why it works. As a workaround: change it to rgba32f if you need more dynamic range.
Using 16 Bit data with values up to 2^16-1 always results in a black rendering.

Will look more deeply into in the evening.

I think it's linked to the texture type. R16 is missing, so I used R16Uint

I suggest a 2 level fix:

1. Convert 16 Bit types to float in texture wrapper - we know that float is working fine (short term fix, will do it by this evening so you can carry on with dicom)
2. Add R16 type to notan and bring up a pull request to them (long term fix to save memory and cpu cycles)

I'm still kinda a newbie to rust. Is there an option to clone notan from github and use that source code directly to compile oculante with it? So I would have a good setup to test everything together :)