Add examples for orthographic and perspective zoom #15092

bas-ie · 2024-09-08T07:29:30Z

Objective

Add examples for zooming (and orbiting) orthographic and perspective cameras.

I'm pretty green with 3D, so please treat with suspicion! I note that if/when #15075 is merged, .scale will go away so this example uses .scaling_mode.

Closes #2580

examples/3d/orthographic_zoom.rs

examples/3d/perspective_zoom.rs

examples/3d/orthographic_zoom.rs

alice-i-cecile

A few notes, but overall I really like these examples. Very actionable and relevant, with clear code.

bas-ie · 2024-09-09T00:19:36Z

BTW I've seen both, but do we have a standard for choosing "instructions on the screen as UI" vs "instructions in an info! in the terminal output"?

alice-i-cecile · 2024-09-09T00:22:38Z

Moderate preference for instructions on screen, especially if it's not going to interfere with the example otherwise.

alice-i-cecile · 2024-09-09T01:27:33Z

Fantastic, thank you :)

janhohenheim

Reviewed only one example, but the comments apply to both.
I like that these examples exist, but there are some things in here that are a bit suboptimal when using the examples as a general learning resource, which a lot of beginners do. I'd like to showcase best practices a bit more if possible.

examples/3d/perspective_zoom.rs

janhohenheim · 2024-09-09T01:49:18Z

examples/3d/perspective_zoom.rs

@@ -0,0 +1,125 @@
+//! Shows how to zoom and orbit a perspective projection camera.


Could you cross-reference this and the first person view model example? Both feature perspective zoom.

examples/3d/perspective_zoom.rs

janhohenheim

I'm not entirely convinced that this should be two separate examples instead of one. Would it complicate the logic a lot if you added a toggle between the two modes when pressing space?

Cargo.toml

bas-ie · 2024-09-09T05:37:15Z

Would it complicate the logic a lot if you added a toggle between the two modes when pressing space?

TBH, I did think there was an awful lot of repetition. Let's see what it looks like as a combined effort.

bas-ie · 2024-09-09T10:58:48Z

@janhohenheim How do we feel about this? I don't know if I've just muddied the waters, but at least everything is in one place... 🤔

Will clean up last bits and pieces tomorrow, otherwise I will be pitchin' and yawin' in my sleep.

janhohenheim

Looks pretty good now! Minor naming suggestion and we are good to go once you did your edits. Approving already :)

janhohenheim · 2024-09-09T11:04:47Z

examples/README.md

@@ -255,6 +255,7 @@ Example | Description
 --- | ---
 [2D top-down camera](../examples/camera/2d_top_down_camera.rs) | A 2D top-down camera smoothly following player movements
 [First person view model](../examples/camera/first_person_view_model.rs) | A first-person camera that uses a world model and a view model with different field of views (FOV)
+[Projection Zoom](../examples/camera/projection_zoom.rs) | Shows how to zoom and orbit orthographic and perspective projection cameras.


I quite like the orbit showcase. I don't think we had that before :)
Maybe rename the file to orbit_and_projection_zoom, with the example name changing accordingly?

janhohenheim · 2024-09-09T11:08:55Z

@richchurcher I'd also be happy if we split this into an example that showed the projection scaling on a static scene (e.g. our fox model) without any movement controls, and one example that only showed the orbit. That would probably be cleaner, but I'll leave the choice to you :)

alice-i-cecile · 2024-09-09T16:26:29Z

The merge train waits for no man 🚋 Seriously though, I think this is good enough to merge, but do feel free to tweak it in follow-ups.

alice-i-cecile · 2024-09-09T16:57:22Z

Ah, this needs revision following #15073 <3

bas-ie · 2024-09-09T22:09:03Z

The train stops for no-one! I'll revise in a sec.

bas-ie · 2024-09-09T23:20:10Z

Does some kind person want to expand a tiny bit on into_inner vs deref_mut? lol

alice-i-cecile · 2024-09-09T23:27:04Z

into_inner is a function that turns Mut<T> into &mut T. @janhohenheim got it confused with deref_mut, which didn't compile here. The ultimate goal was just a style nit to avoid the &mut * pattern which can be ugly to read. CI was failing so I checked out your PR locally and fixed it before pushing to your branch :)

bas-ie · 2024-09-09T23:56:52Z

Thanks! I'll split the example in a separate PR.

# Objective As previously discussed, split camera zoom and orbiting examples to keep things less cluttered. See discussion on #15092 for context.