alphaToCoverage not showing alpha

[lambocorp]

When I attempt to use alphaToCoverage on a material, the pixels with alpha become all white.

https://codesandbox.io/p/sandbox/quirky-kalam-fnwnfw

Notably, renderer.antialias is false. Postprocessing docs say to initialize renderer this way.
And then use MSAA by EffectComposer.multisampling.
Threejs docs say that alphaToCoverage only works in MSAA enabled scenarios, so it should work here right? Even though their doc says to use antialias: true.

I expected the pixels to have transparency.

• Three: [e.g. 0.171.0]
• Post Processing: [6.36.6]

alphaToCoverage: Can only be used with MSAA-enabled contexts (meaning when the renderer was created with antialias parameter set to true).

[vanruesc]

This issue is unrelated to postprocessing. The white outlines around transparent edges appear when transparent is set to false. setting it to true fixes it. I'm not sure why this happens, but it also occurs without postprocessing.

A few notes regarding the example setup:

• You're only using a single RenderPass
  • The EffectComposer automatically sets renderToScreen back to true when the pass is added because EffectComposer.autoRenderToScreen is true. However, setting that to false wouldn't help either, because then you'd get no ouput on the canvas.
  • Instead, you should use a final EffectPass or CopyPass to render the internal result to the canvas.
• Using renderer.render() is exactly the same as using a single RenderPass that renders directly to screen.
  • Antialiasing doesn't work in this case because you're not rendering to a texture but to the canvas which has antialias set to false.

Here's a fixed demo: https://stackblitz.com/edit/postprocessing-v6-befqytyk?file=src%2FApp.js

[lambocorp]

The link added does not work.

[vanruesc]

You're probably running into a browser configuration issue 🤔 https://developer.stackblitz.com/platform/webcontainers/browser-config

#works-on-my-machine

[lambocorp]

Perhaps you are running into a browser configuration issue? I sent to a friend and they experienced the same result I did. That said, I appreciate you sharing this template and checking in on the issue, I will try and use the template in the future if I have other issues.

…

On Thu, Feb 6, 2025 at 7:11 AM Raoul v. R. ***@***.***> wrote: You're probably running into a browser configuration issue 🤔 https://developer.stackblitz.com/platform/webcontainers/browser-config #works-on-my-machine Screenshot_20250206_130738.jpg (view on web) <https://github.com/user-attachments/assets/2b67526b-2dbc-4dcc-937e-be8f40f2ed58> — Reply to this email directly, view it on GitHub <#680 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AYUYCAR5Z6C4TELW3JEVDZT2ONGNRAVCNFSM6AAAAABWQSOKO2VHI2DSMVQWIX3LMV43OSLTON2WKQ3PNVWWK3TUHMZDMMZZGY2TEMJQGM> . You are receiving this because you authored the thread.Message ID: ***@***.***>