CesiumGS/cesium

Make bloom post process check for selected feature

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#7,984 opened on Jul 8, 2019

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category - post-processinggood first issuetype - enhancement

Description

Right now you can apply certain post process effects to just one feature. The bloom shader doesn't do any check to allow you to apply it to just to the selected feature as you would expect.

This is potentially pretty easy, you just need to take the check from another post process like the black and white one: https://github.com/AnalyticalGraphicsInc/cesium/blob/master/Source/Shaders/PostProcessStages/BlackAndWhite.glsl

and apply it in the bloom shader: https://github.com/AnalyticalGraphicsInc/cesium/blob/master/Source/Shaders/PostProcessStages/BloomComposite.glsl

The forum thread here has an example you could use for testing. Note that you'd need to test the selected feature on a model, since entities aren't yet supported there (see https://github.com/AnalyticalGraphicsInc/cesium/issues/6705).

Contributor guide

Tech stack
javascript
Domain
frontend
Issue type
feature
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
2
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
1-3 hours
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
stale
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
clear
Prerequisites
Cesium post processingGLSL shader basics
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
80
Research direction
Look at the BlackAndWhite.glsl shader to extract the selected feature check code, then integrate it into BloomComposite.glsl. Test using a model (not entity) as described in the forum thread. Ensure the bloom effect only applies to the selected feature.