Texture support for raw Mesh3D logging

[Wumpf]

What

Meshes can now be logged with optional texture coordinates and an optional albedo texture!

Vertex texture coordinates are straight forward, implemented as a new component, mostly to avoid semantic confusion (position2d on mesh?) and being able to call the coordinates uv.

The (albedo) texture itself got a bit messy: The original plan was to refer to a separately logged image and I believe that's still where we want to go. But this messes with some parts of the viewer so I made the decision to put a TensorData based field on the material. The main drawback of that is that now you can't inspect the texture separately and the format restrictions are quite tight (this is in part also due to the mesh renderer itself though, so that's deeper than just not using the Image archetype). I believe in the future the material should instead have an entity reference to specify where the texture comes from.
Another pretty bad sideffect from this is that if you have model with a bunch of meshes using the same texture several times, it will send this texture each time to the viewer since there's no way to "instance" this.

... but let's perfect not be the enemy of well-it-works-for-the-most-important-usecases-so-let's-ship-this!

Change: Texture is now a component, making a lot of things nicer

Checklist

• I have read and agree to Contributor Guide and the Code of Conduct
• I've included a screenshot or gif (if applicable)
• I have tested the web demo (if applicable):
  • Using newly built examples: app.rerun.io
  • Using examples from latest main build: app.rerun.io
  • Using full set of examples from nightly build: app.rerun.io
• The PR title and labels are set such as to maximize their usefulness for the next release's CHANGELOG

• PR Build Summary
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[github-actions]

Size changes

Name	main	4894/merge	Change
plots.rrd	1372.16 kiB	194.56 kiB	-85.82%

[teh-cmc]

I cannot compile the rust example:

$ cargo r -q -p raw_mesh
error[E0432]: unresolved imports `rerun::external::ecolor`, `rerun::external::re_memory`
  --> examples/rust/raw_mesh/src/main.rs:16:16
   |
16 |     external::{ecolor, re_log, re_memory::AccountingAllocator},
   |                ^^^^^^          ^^^^^^^^^ could not find `re_memory` in `external`
   |                |
   |                no `ecolor` in `external`

error[E0433]: failed to resolve: could not find `clap` in `rerun`
   --> examples/rust/raw_mesh/src/main.rs:126:19
    |
126 |     rerun: rerun::clap::RerunArgs,
    |                   ^^^^ could not find `clap` in `rerun`

error[E0425]: cannot find function `setup_native_logging` in crate `re_log`
   --> examples/rust/raw_mesh/src/main.rs:182:13
    |
182 |     re_log::setup_native_logging();
    |             ^^^^^^^^^^^^^^^^^^^^ not found in `re_log`

Some errors have detailed explanations: E0425, E0432, E0433.
For more information about an error, try `rustc --explain E0425`.
error: could not compile `raw_mesh` (bin "raw_mesh") due to 3 previous errors

[teh-cmc]

Python example works great but there are some issues in the data views.

In the outer data view, the material shows up as (empty):

In the data view of the material itself:

• The albedo_factor shows up as (empty) which is... weird? 🤔 what does it mean for an albedo factor to be empty?
• The texture shows its dimensions but there's no way to preview it. Any chance we can re-use the existing preview machinery for images/tensors?
  

[teh-cmc]

Why not do it for the rust example too?

[Wumpf]

I ran out of time and didn't see a quick & easy path towards that. Afaik the gltf loader doesn't load the image itself, so I need an extra path that loads the images from disk etc.

[teh-cmc]

Would be nice to update the screenshots in raw_mesh readmes (python & rust).

They look so sad right now as they rely on just the albedo factor, it's so much better looking now.

[Wumpf]

Would be nice to update the screenshots in raw_mesh readmes (python & rust).

Unfortunately I didn't update the Rust example (and apparently also broke it :/) though to upload the texture. Guess I shouldn't leave this business unfinished

[Wumpf]

The albedo_factor shows up as (empty) which is... weird? 🤔 what does it mean for an albedo factor to be empty?

Albedo factor showed like that before when it's null. Don't know what else to write there. Isn't (empty) what we usually show for null

The texture shows its dimensions but there's no way to preview it. Any chance we can re-use the existing preview machinery for images/tensors?

Yeah this sucks, but I found this really hard to fix that right now with the setup of the texture not being a Image archetype. See code comments & pr description. Again, this was outside my time budget

[teh-cmc]

Works great and I agree with everything you said 👍 🚢

[Wumpf]

Blocked by a crash in arrow when logging only a color and no image

[Wumpf]

Blocked by

• Crash on arrow2 when using component schema with optional color + optional tensordata #4971

[teh-cmc]

The fact that we cannot create a 2D view of the albedo texture when inspecting it because it is not in itself an entity is an interesting and extremely frustrating limitation of our current system.

I'll probably open an issue actually...