Sharing uniforms between different programs

Questions
,
1

I have many SkinnedMesh characters using a custom ShaderMaterial,
which interprets a particular quad as a camera-facing “label” naming each character.

A label amounts to rendering some words using some font, and they are collectively packed as a single texture which is passed to the shader.

If we spawn a new character and re-pack the labels, the new packing needn’t extend the old one. Then potentially we might need to update the label-uv-mapping for every character.

Is it possible to update a single uniform (e.g. a DataTexture) which is shared by all the programs?

Cheers for any help,
Rob

2

Yeah. You can do like:

let mySharedUniform={
    value: myDataTexture
}

material1.uniforms.dataTexture = mySharedUniform

material2.uniforms.dataTexture = mySharedUniform

you can also make it a getter:

let timeUniform={
    get value(){ return performance.now()/1000; }
}
shader1.uniforms.time = timeUniform

shader2.uniforms.time = timeUniform
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3

Thanks @manthrax.

If we change the uniform, will it be re-uploaded exactly once, or once for each material instance?

I’m talking about the DataTexture here, not your nice epoch-seconds example.

4

Once. The DataTexture itself stores contains its (single) gpu handle.

1 Like