Add a second texture layer to geometry

Questions
1

I’m trying to do a classic lightmapping, i log a geometry attributes and see the 3 buffers: positions, normals, uv:

Object { position: {…}, normal: {…}, uv: {…} }
normal: Object { itemSize: 3, count: 24, normalized: false, … }
position: Object { itemSize: 3, count: 24, normalized: false, … }
uv: Object { itemSize: 2, count: 24, normalized: false, … }

My question is, how to add a second UV coordinates layer to display the lightmap ?

2

I believe the second set of UV attribute need to be named uv2

uv2: Object { itemSize: 2, count: 24, normalized: false, … }
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3

Here’s what i read in the documentation of materials:

image
image957×167 6.04 KB

I’m looking for an example of this “second set of uv coordinates”.

4

How do i create this new attribute ?

5

If the first uv attribute is already set, you can clone it.

const uvAttr = geometry.getAttribute("uv");
geometry.setAttribute("uv2", uvAttr.clone());
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6

Thank you, i’m gonna try that.

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