CesiumGS / CesiumGS/cesium

Order Independent Transparency incorrect additive blending

Open
#6,090 2 comments 0 reactions 0 assignees View on GitHub
category - graphics category - model/gltf type - bug
Dominant language
JavaScript
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Description

We use a tree model with alpha masked texture in gltf form that has a strange blending artifact when viewing many trees behind eachother and OIT enabled. The artifact is not present with OIT disabled, but then rendering is incorrect, as expected.

**OIT enabled**
![withoit](https://user-images.githubusercontent.com/881510/34604993-0b7f4e28-f20a-11e7-9c0b-3b29a64c767f.PNG)

**OIT disabled**
![nooit](https://user-images.githubusercontent.com/881510/34604983-04fd4230-f20a-11e7-92e8-fa7c0d1a339a.PNG)

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Research direction

The report concerns additive-blending artifacts in Order Independent Transparency when rendering many trees with alpha-masked glTF textures. No file, test, or entry point is named; first reproduce the scene with OIT enabled and disabled, then trace the OIT blending path. Done means the artifact is removed while transparent tree rendering remains correct.

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
25/100

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