Lock is leaking when placed at sea level.

[Rito13]

Lock is leaking when placed at sea level adjacent to tiles that are not sea.

Expected result

Similar to one found on higher levels.

Actual result

Limitations

Works as expected when adjacent tile is sea.

It might be an OTTD bug that those tiles are not sea but are at sea level.

[zephyris]

Currently an intentional tradeoff between looking nice in the (by far) most common case, and glitches when next to sea level canals.

Might be possible to fix, not sure. Canal features can access tile height information, so the lock graphics can switch based on assuming water at sea level. They can't access information about the neighbouring tile, so can't directly ask if they neighbour water. There is a variable for which canal walls would be drawn, though I don't know if this is correctly available for lock tiles (see https://newgrf-specs.tt-wiki.net/wiki/NML:Canals). I don't think I've ever seen NML code which attempts this...

The case of a sea level canal tile next to a lock tile suggests some complexity.

[Rito13]

I don't know if this is correctly available for lock tiles (see https://newgrf-specs.tt-wiki.net/wiki/NML:Canals). I don't think I've ever seen NML code which attempts this...

https://newgrf-specs.tt-wiki.net/wiki/VariationalAction2/Canals
The NFO docs suggests that it should also work for locks.

[zephyris]

I set up a test build using the following, which doesn't work:

// switch for canal banks (for better behaviour when neighbouring sea-level canals)
switch (FEAT_CANALS, SELF, switch_waterfeature_locks_banks, dike_map) {
	0: waterfeature_locks_sealevel;
	waterfeature_locks_general;
}

// switch for elevation
switch (FEAT_CANALS, SELF, switch_waterfeature_locks_elevation, tile_height) {
	0: switch_waterfeature_locks_banks;
	waterfeature_locks_general;
}

// switch for tile type
switch (FEAT_CANALS, SELF, switch_waterfeature_locks_arctic_snowline, terrain_type) {
	TILETYPE_SNOW: waterfeature_locks_arctic_snow;
	switch_waterfeature_locks_elevation;
}

// switch for climate
switch (FEAT_CANALS, SELF, switch_waterfeature_locks_climate, climate) {
	CLIMATE_ARCTIC: switch_waterfeature_locks_arctic_snowline;
	switch_waterfeature_locks_elevation;
}

item(FEAT_CANALS, waterfeature_locks, WF_LOCKS) {
	graphics {
		default: switch_waterfeature_locks_climate;
	}
}

NML mistake? Or OpenTTD not supporting it?

[Rito13]

It does not work because dike_map is a bitset and value 0 would indicate that lock tile is surrounded by 8 other tiles with water. If you check only the 4 bits that indicate water on the side (not diagonal) it detects the ground tiles, but not canals.

// switch for canal banks (for better behaviour when neighbouring sea-level canals)
switch (FEAT_CANALS, SELF, switch_waterfeature_locks_banks, 
	getbits(dike_map,0,1) || getbits(dike_map,1,1) || getbits(dike_map,2,1) || getbits(dike_map,3,1)
) {
	1: waterfeature_locks_general;
	waterfeature_locks_sealevel;
}

Sorry for the graphics, I faild to make OGFX2 my self.

edit: The following does the same job.

// switch for canal banks (for better behaviour when neighbouring sea-level canals)
switch (FEAT_CANALS, SELF, switch_waterfeature_locks_banks, getbits(dike_map,0,4)) {
	0: waterfeature_locks_sealevel;
	waterfeature_locks_general;
}

[LordAro]

perhaps there's also an issue of the water on the middle tile of the docks too? river tile underneath seems to be leaking through there too

[zephyris]

Thanks @Rito13, I thought it was me being dumb!

The middle tile is a separate issue: #140 (which I'm very frustrated by, there must be a mask or ground tile which is a couple of pixels off, but I can't work it out).