Dynamic water (plane) level

[sprunk]

Bill of materials to be done before starting this ticket:

• 1445

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It would be good if the water plane height could be adjusted dynamically. This is a pretty common request but has historically been considered difficult, both to implement in engine and to workaround game-side. Currently to raise the water level by X you have to adjust the entire terrain by -X instead, which comes with its own caveats.

A water plane level getter function exists but is not used comprehensively (see #1445). The core of this ticket is a request is to pair it up with a setter, initially just for the plane, and of course expose it to Lua.

[sprunk]

Down the line the "always flat plane" limitation would be good to remove as well. It is way out of the scope of this ticket but it is good to keep it in mind in case it crops up when designing the implementation. The two approaches would be

• water could have a simulated flow. malric from ZK made a tech demo once (ZK forum thread, youtube vid, even better YT vid) but I don't know if there is source anywhere. Also I think it's an impractical gimmick.
• water could be defined by a separate heightmap (allows having rivers flowing from the mountains etc). This seems both simpler and more practical, though deformation would be a question (what if you flatten the mountain?). Though then deformation is also a gimmick so games with mountain rivers would likely just disable deformation.