Fix #10452: Limit river generation max_search_nodes #11544
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2TallTyler
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2TallTyler
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…initializing Add a constant with the default value of 10000 and have the pathfinding settings refer to it. Add a preventative method to AyStar when it's initializing, to limit the number of max_search_nodes if left unattended.
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2TallTyler
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Prevent long stalls during river generation by capping the maximum search nodes to be the same as that defined in NPF.
Motivation / Problem
See #10452 (comment)
Terraforming occurs during river generation which causes issues for the pathfinding. If the tile the pathfinder is working with is no longer flat, a long stall occurs due to the pathfinding doing an exhaustive search around that tile, trying to connect a river path to it and ultimately failing in the end, leaving a river disconnected somewhere along the way from the spring to the sea.
The stall can last up to 3-5 minutes until all paths are tried.
https://github.com/OpenTTD/OpenTTD/assets/43006711/cbb18259-51cc-4f18-9b4e-3248334f4f11
Description
This PR fixes the stall, by preventing the pathfinder from initializing max_search_nodes as 0 (= infinite). Since AyStar is used, I created a constant with the default value equal to that of both NPF and YAPF and have it referred.
Limitations
This does not fix the river becoming disconnected due to terraforming.
Checklist for review
Some things are not automated, and forgotten often. This list is a reminder for the reviewers.