Lake in the crater bowl #166

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opened 2026-10-11 20:23:51 +01:00 by liamjd · 0 comments

liamjd commented

2026-10-11 20:23:51 +01:00

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Milestone 2, terrain goal: "Crater map could have a lake at the bottom" (the milestone says "canyon", but this is the crater preset).

Proposal

An optional lake_depth (or a fill fraction) on the crater preset: 0 = dry.
After the levels are sampled, flood the crater interior from its lowest tile up to a surface level below the rim's lowest point, so the lake can never spill over the rim. Mark the flooded tiles through #164's mask, with this lake's own surface level. That level differs from any sea level, which is why #164 recommends per-tile surface levels.
Restrict the flood fill to inside the rim (_radial() < rim_radius). Low ground outside the crater must not fill just because it is below the lake surface.

Acceptance criteria

With a lake configured, the crater's lowest interior tiles are water, and every water tile is inside the rim.
The surface is below the lowest rim tile, so no water is drawn above the land that should contain it.
A dry rim of shore around the lake stays walkable and reachable. #162's reachability holds.
#163's landing site is not in the lake.
Unit test over a fixed seed for the containment property; headed screenshot for the look.

Depends on

#164.

Milestone 2, terrain goal: "Crater map could have a lake at the bottom" (the milestone says "canyon", but this is the crater preset). ## Proposal - An optional `lake_depth` (or a fill fraction) on the crater preset: 0 = dry. - After the levels are sampled, flood the crater interior from its lowest tile up to a surface level below the rim's **lowest point**, so the lake can never spill over the rim. Mark the flooded tiles through #164's mask, with this lake's own surface level. That level differs from any sea level, which is why #164 recommends per-tile surface levels. - Restrict the flood fill to inside the rim (`_radial() < rim_radius`). Low ground outside the crater must not fill just because it is below the lake surface. ## Acceptance criteria - [ ] With a lake configured, the crater's lowest interior tiles are water, and every water tile is inside the rim. - [ ] The surface is below the lowest rim tile, so no water is drawn above the land that should contain it. - [ ] A dry rim of shore around the lake stays walkable and reachable. #162's reachability holds. - [ ] #163's landing site is not in the lake. - [ ] Unit test over a fixed seed for the containment property; headed screenshot for the look. ## Depends on #164.

liamjd added this to the Terrain Generation milestone

2026-10-11 20:23:51 +01:00

liamjd added the

enhancement

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2026-10-11 20:23:51 +01:00