ReflectorNode: Add getDepthNode().

[Mugen87]

Related issue: -

Description

A common use case with mirrors is to create faded reflections via some sort of distance attenuation, see https://discourse.threejs.org/t/creating-a-fading-reflection/3831.

This PR introduces a new constructor parameter depth. When set to true, the depth information of the reflection pass is saved into a depth texture.

It's then possible to query a depth texture node via getDepthNode(). Since ReflectorNode supports multiple virtual cameras, it's required to pass the current camera used for rendering to select the correct depth node.

@sunag Do you think this API goes in the right direction?

[github-actions]

📦 Bundle size

Full ESM build, minified and gzipped.

	Before	After	Diff
WebGL	689.92 170.93	689.92 170.93	+0 B +0 B
WebGPU	814.17 219.22	814.71 219.35	+537 B +132 B
WebGPU Nodes	813.68 219.06	814.22 219.22	+537 B +163 B

🌳 Bundle size after tree-shaking

Minimal build including a renderer, camera, empty scene, and dependencies.

	Before	After	Diff
WebGL	462.94 111.81	462.94 111.81	+0 B +0 B
WebGPU	537.52 145.03	537.56 145.04	+37 B +3 B
WebGPU Nodes	493.64 134.76	493.67 134.77	+37 B +7 B

[sunag]

Coincidentally I was thinking of something like this, but without the reflector. I made a change so that we don't need the camera as a parameter.

[mrdoob]

@Mugen87 Should a example use this? May go unnoticed otherwise.

[Mugen87]

Definitely. Just wanted to go ahead and add getDepthNode() for devs who want a replacement for ReflectorForSSRPass. This module is like reflector but with distance attenuation support. When developers can at least request the depth from ReflectorNode, they can built a custom solution until we provide a bit more API. Maybe adding getLinearDepthNode() would also be a good idea since otherwise the camera handling on app level is a bit tricky (you would need the internal virtual camera for this).

I'm still unsure about the API and the kind of internal solution. E.g. ReflectorNode could have a fade and maxDistance property but this is maybe too specific.

[sunag]

wip tiled lighting.