Shadows by Neptilo · Pull Request #2691 · iTowns/itowns

Neptilo · 2026-01-30T11:21:12Z

Description

Integrate shadows separately from the "realistic lighting" mode. Add UI to control date/time in one example. The Sun position is defined from the date and shared between the shadow rendering and the "realistic lighting", if enabled.

Motivation and Context

Visualizing shadows can be useful to view illumination of buildings or simply to make the rendering more realistic.
Fixes #1825

Screenshots (if appropriate)

Neptilo · 2026-01-30T15:03:12Z

packages/Main/src/Core/Prefab/Globe/SkyManager.ts

+    private readonly scene: THREE.Scene;
+    private readonly composer: EffectComposer;
+    private readonly fog: THREE.Fog;
+    private readonly view: View;


I'd like to add _ before all private members but it will mess up the diff, so maybe it's better to wait for a first review

gchoqueux

Nice feature.
I mainly added architectural comments to simplify the code and increase its robustness.

There is also an integration of THREE.js passes; I think this logic should be integrated into the iTowns renderer, since others might want to use it as well, like @Desplandis for his EDL (points cloud rendering).

gchoqueux · 2026-02-02T14:55:25Z

packages/Main/src/Converter/Feature2Mesh.js

        mesh.material.color = new THREE.Color(0xffffff);
    }
+
+    mesh.castShadow = true;


mesh.castShadow = true; is hard coded value
We prefer global property : TiledGeometryLayer.castShadow to handle castShadow tile meshes

gchoqueux · 2026-02-02T15:23:55Z

packages/Main/src/Core/Prefab/Globe/SkyManager.ts

            // disable fog only during render
            // to let its parameters be modified elsewhere
            if (this.enabled) { this.scene.fog = null; }
-            this.update(camera);
+            this.update();
        };
        scene.onAfterRender = () => {
            if (this.enabled) { this.scene.fog = this.fog; }


Practice using updates and rendering in iTowns to take advantage of other features (user events, visibility, frozen

extends SkyManager, from LayerGeometry to use LayerGeometry.updateinstead ofscene.onBeforeRender`,

use LayerGeometry.visible instead of enable/disable

use LayerGeometry.object3d.onAfterRender instead of scene.onAfterRender

add this.sky, this.sunLight, this.sunLight.target, this.skyLight in LayerGeometry.object3d and Layer.visible = false, this will avoid additions and deletions in scene.

As it is preferable to avoid this.composer.addPass and removePass and use pass.enabled.

gchoqueux · 2026-02-02T15:30:47Z

packages/Main/src/Core/Prefab/Globe/SkyManager.ts


-    update(camera: THREE.Camera) {
+    update() {
+        const camera = this.view.camera3D as THREE.PerspectiveCamera | THREE.OrthographicCamera;


if you use LayerGeometry.update(context, layer, node) the context have the view and the current camera.

gchoqueux · 2026-02-02T15:44:50Z

packages/Main/src/Core/TileMesh.ts

+        this.receiveShadow = true;
+


same comment, could use global property ?

gchoqueux · 2026-02-02T15:46:14Z

packages/Main/src/Layer/OGC3DTilesLayer.js

+        model.castShadow = true;
+        model.receiveShadow = true;


could use global property, from 3d tile layer ?

jailln · 2026-02-04T09:17:23Z

Nice feature @Neptilo , great visual improvement 🤩
I made some tests and 3D tiles display seemed quite slower so I ran a quick performance test and found out that we spend a lot of time picking:

Do you think we could remove replace the picking by something less costly?

Neptilo · 2026-02-04T15:41:56Z

I made some tests and 3D tiles display seemed quite slower so I ran a quick performance test and found out that we spend a lot of time picking
Do you think we could remove replace the picking by something less costly?

My computer is too good to notice any performance issue! ^^" At least I can see it in the profiler.
I found a way to fix this.

Neptilo · 2026-02-04T15:56:07Z

@gchoqueux I suggest we discuss the architecture decisions of SkyManager separately since they are not directly related to shadow integration and deal with code that was there prior to this PR

jailln · 2026-02-05T15:34:56Z

I made some tests and 3D tiles display seemed quite slower so I ran a quick performance test and found out that we spend a lot of time picking
Do you think we could remove replace the picking by something less costly?

My computer is too good to notice any performance issue! ^^" At least I can see it in the profiler. I found a way to fix this.

Thanks, the perfs are way better !

gchoqueux · 2026-02-09T14:11:41Z

@gchoqueux I suggest we discuss the architecture decisions of SkyManager separately since they are not directly related to shadow integration and deal with code that was there prior to this PR

There are issues in the SkyManager class, on the master branch, and I don’t think it’s a good idea to postpone fixing them, because:

These existing issues are creating additional problems in this PR Shadows #2691, which means more work for both development and review.
If the original issues are fixed later, it will require more work on SkyManager, shadows, and another review on these two areas.

Basically, the first step would be a waste of time, since we would end up reworking all the points mentioned in the second one anyway. It would be more logical and consistent to adapt the architecture right away.

…out it

…eorganize renderer.shadowMap setting

gchoqueux · 2026-02-18T15:40:19Z

The Shadows PR currently relies on the skyManager, which, in my opinion, shows some architectural and algorithmic weaknesses.

In addition, a performance issue has been reported in issue #2701. It's possible that this slowdown is related to an imperfect integration of the @takram packages, which would deserve clarification and stabilization before introducing an additional functional layer on top of it.

In this context, continuing to develop the Shadows feature without addressing these underlying points could make performance diagnostics more difficult and potentially lead us to rework this feature later.

I believe it would be preferable to first consolidate the foundation — particularly regarding the dependency integration and the performance issue — in order to ensure a more stable base moving forward.

Desplandis · 2026-02-19T19:13:17Z

@gchoqueux Both of you asked for my input on this PR, so here it is.

We discussed the other day with @Neptilo and I think we've reached a compromise that could satisfy both of you (didn't have time to discuss it with you yet). In my opinion, this PR could be implemented independently from the previous one. This would introduce a clearer separation of concerns (instead of the initially proposed monolithic approach) and allow this PR to be reviewed on its own.

We should address the sky manager in a dedicated issue (which I haven't open yet, lack of time!). The "layerisation" part seems relatively straightforward. However, the implementation of the "local" (or not?) post-processing passes requires further discussions before implementing any changes. I would gladly have your input in this subject.

Given that this new code implements the shadows independently of sky manager (minus some caveats, see below), I think it can be reviewed separately of the previous one.

Some ideas that I suggested when we discussed:

The sun position (required by both sky manager and sun light) should be derived from the date and stored in GlobeView
Have a backed SunDirectionalLight added as the default light of the globe scene (which owns a reference to the sun position)
Keep sky manager as it (the only change being the reference ownership of the sun position)

P.S.: The performance issue is also upstream, so we should open an issue !
See https://takram-design-engineering.github.io/three-geospatial/?path=/story/atmosphere-3d-tiles-renderer-integration--manhattan

Neptilo requested a review from Desplandis January 30, 2026 14:47

Neptilo added 3 commits January 30, 2026 15:52

feat: make tile meshes support and receive shadows

dcccced

feat: implement shadows from Sun light

556c3e7

feat: improve shadows and add date/time controls for sun position

d7515d2

Neptilo force-pushed the shadows branch from 712a0af to d7515d2 Compare January 30, 2026 14:52

fix: change access modifiers for some members of SkyManager to private

eef14cd

Neptilo commented Jan 30, 2026

View reviewed changes

Desplandis requested a review from gchoqueux January 30, 2026 15:31

gchoqueux reviewed Feb 2, 2026

View reviewed changes

perf: update shadow centering logic to avoid picking

1c72211

feat: define castShadow/receiveShadow as properties of the layers

d4f6ef6

Neptilo added 6 commits February 12, 2026 16:37

refactor: define TileLayerLike only once, fixing transpilation

c4b2e7f

feat: extract sunlight out of sky manager to allow using shadows with…

8a94b42

…out it

refactor: extract sunlight as a custom DirectionalLight class

1e1da1b

feat: add castShadow property to TileLayerLike interface to fix tests

f7559d6

chore: enable/disable effect pass instead of adding/removing them & r…

719cc80

…eorganize renderer.shadowMap setting

fix: check if this is defined in Feature2Mesh to fix tests

6ee277e

Neptilo requested a review from gchoqueux February 18, 2026 14:29

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Neptilo commented Jan 30, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

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jailln commented Feb 4, 2026

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Neptilo commented Feb 4, 2026

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Neptilo commented Feb 4, 2026

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jailln commented Feb 5, 2026

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gchoqueux commented Feb 9, 2026

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gchoqueux commented Feb 18, 2026

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Desplandis commented Feb 19, 2026

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