Point opacity issue in MacOS Safari

Hi again,

I have a Points with the following material:

new ShaderMaterial({
  uniforms: {
    uTexture: {
      value: Textures.get('points')
    uOpacity: { value: 1 },
    uActivePoint: { value: -1 }
  blending: AdditiveBlending,
  depthWrite: false,
  transparent: true,
  vertexColors: true

and this in the vertex shader:

// hide point when it's selected or hovered
vOpacity = uOpacity * min(1.0, abs(uActivePoint - index));

vOpacity is then being used in the fragment shader to show/hide the point.

This works perfectly everywhere, except in MacOS Safari (currently on 17.4.1 (19618.
I don’t have access to a PC, so idk about browsers on Windows atm.

Let me illustrate with some screenshots, here’s a point by default:

Once it’s selected, I show the actual star at the same position, so it should be hidden.

Safari (you can see the rays from the point):

It’s not super annoying, but it would be nice to understand why it’s happening, so if anyone has an idea, don’t hold back :slight_smile: