Add height fog to bevy_city by mate-h · Pull Request #23776 · bevyengine/bevy

mate-h · 2026-04-12T20:50:14Z

Objective

Add height fog to bevy_city

Solution

update the bevy_city package

alice-i-cecile · 2026-04-12T22:17:00Z

Can you say a bit more about why we should do this?

I think it looks nice, but I want to understand how this fits into the bigger vision for this.

mate-h · 2026-04-12T23:59:37Z

Good question let me add a bit more context. Initially the question came up when I was gathering some feedback from a crate author in the bevy ecosystem. They created a create called https://docs.rs/crate/bevy_exponential_height_fog.
From their feedback what I could gather is that it wasn't entirely obvious how to use Bevy's atmosphere APIs to create this effect. So having this in bevy_city we could point newcomers to this as a common use case for height fog but is physically based volumetric rendering.
Later on @IceSentry had asked me to include this in the bevy_city example since it helps to establish some depth in the scene and a better scale. It is visually better than simple depth based fog. And in a future version we can also include shadow map sampling for this to get volumetric light shafts that the city buildings leave.

Co-authored-by: Alice Cecile <alice.i.cecile@gmail.com>

alice-i-cecile

Much improved! Thanks.

ecoskey · 2026-04-13T19:13:28Z

+    // Koschmieder relation to calculate the extinction coefficient for the medium in m^-1 units.
+    let beta_ext = (3.912 / HAZE_VISIBILITY_KM) * 1e-3;


Could be nice to link to further reading here but not blocking.

Co-authored-by: Emerson Coskey <emerson@coskey.dev>

# Objective - Add height fog to bevy_city ## Solution - update the bevy_city package <img width="1915" height="1098" alt="Screenshot 2026-04-12 at 1 49 22 PM" src="https://github.com/user-attachments/assets/61127e59-cab8-4e2e-b9c3-b32edbef6c03" /> <img width="1919" height="1113" alt="Screenshot 2026-04-12 at 1 48 56 PM" src="https://github.com/user-attachments/assets/dd08fd00-988e-4a00-a670-1e425e5633dc" /> --------- Co-authored-by: Alice Cecile <alice.i.cecile@gmail.com> Co-authored-by: Emerson Coskey <emerson@coskey.dev>

mate-h added 2 commits March 31, 2026 19:59

Add height fog to bevy city

a96cc59

Merge branch 'main' into m/bevy-city-fog

e03115d

alice-i-cecile added A-Rendering Drawing game state to the screen C-Examples An addition or correction to our examples C-Benchmarks Stress tests and benchmarks used to measure how fast things are S-Needs-Review Needs reviewer attention (from anyone!) to move forward labels Apr 12, 2026

github-project-automation bot added this to Rendering Apr 12, 2026

github-project-automation bot moved this to Needs SME Triage in Rendering Apr 12, 2026

alice-i-cecile added X-Contentious There are nontrivial implications that should be thought through D-Straightforward Simple bug fixes and API improvements, docs, test and examples labels Apr 12, 2026

mate-h requested a review from IceSentry April 13, 2026 00:00