mapbox / mapbox/mapbox-maps-ios

Support for Sea Level as Base Reference in 3D Extrusions

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Dominant language
Swift
Stars
601
Forks
196
PR merge metrics
No merged PRs in 30d

Description

New Feature

Hello,

Regardless of the options added to fillExtrusionBaseAlignment and fillExtrusionHeightAlignment (whether "flat" or "terrain"), the extrusion height always starts from the ground level, even when we set it to 0.

What we would like is the ability to force the extrusion to start from sea level, so that it visually penetrates the terrain in 3D mode—similar to how Google Earth does it, whether or not terrain (relief) mode is enabled.

Contributor guide

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First steps

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  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

Research direction

Start by tracing the fillExtrusionBaseAlignment and fillExtrusionHeightAlignment entry points in the 3D extrusion and terrain-rendering code. Compare behavior with terrain enabled and disabled, then determine how sea-level anchoring should be represented. Done means extrusions can start at sea level, including when their base is set to 0, and visually penetrate terrain as described.

Written by the indexing model from the issue text.

Assessment

Tech stack
ios, swift
Domain
computer-graphics, mobile
Issue type
Feature
Difficulty
5/5
Estimated time
Over a week
Activity status
Quiet
Clarity
Mostly clear
Newbie friendliness
45/100

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