playcanvas / playcanvas/engine

Incorrect Particle Rendering in Front of Transparent Canvas

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area: graphics
Dominant language
JavaScript
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Description

If you use a particle system with a transparent canvas, the particles render with some sort of additive or multiplicative action with the background color. This is particularly noticeable in AR applications (e.g. using 8th Wall).

Particles that appear in front of geometry are rendered as expected.

I have created an example project showing how they appear in front of black and white geometry compared to the transparent area. This is not an AR project, obviously, but the effect can still be seen.

https://playcanv.as/b/zxToKEDc/

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Research direction

Start by reproducing the issue in the linked example project, focusing on particle rendering over transparent canvas areas and comparing it with rendering in front of black and white geometry. Done means particles render correctly without the reported additive or multiplicative effect over transparency, including the AR-related case described.

Written by the indexing model from the issue text.

Assessment

Tech stack
javascript
Domain
computer-graphics
Issue type
Bug
Difficulty
4/5
Estimated time
3-5 days
Activity status
Stale
Clarity
Needs clarification
Newbie friendliness
35/100

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