[PATCH] Improvements to obstructions

[Stan]

There are several improvements that could be made wrt obstructions:

1. Allow circular static obstructions:

Some buildings are circular, and it's weird that the ability to place them sometimes depends on the angle. If you check the stonehenge wonder f.e., the invisible corners are very big.

All wall towers should also have circular obstructions as the player can't determine the rotation of the first tower (but the rotation of the first tower is determined by the angle of the wall). So when starting a wall-piece in the direction you want, it can either obstruct the tower, or create a gap because the obstruction gets rotated.

Since the obstructions are always rasterized, it shouldn't be very calculation intensive to support circular static obstructions (just adding a check in the rasterization loop).

2. It should be possible to overlay different obstruction types on one template

Most buildings aren't made to serve as a wall. So passages should be guaranteed between them. This would be possible by overlaying two different obstructions:

• An obstruction that blocks pathfinding, so units don't walk through the building
• A bigger obstruction that blocks construction, so buildings can't be placed close enough, and units can always pass.

The gap between two buildings should be wide enough so units can actually cross in that gap.

Walls on the other hand are in a different situation, and should probably block more pathfinding than they block construction, so they can create a certain obstruction overlap, and block all units with certainty. This may be a bit more difficult to achieve.

Note that these double obstructions seem already possible, since it's done with the gate (a gate has 3 obstructions, of which the center one can be made passable but not be constructed on). So I guess it mainly misses a way to put this into the schema.

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Together, this should fix most issues with wall-placement, make building placement more relaxing, but also help fixing issues like #3517 (due to the guaranteed gap).

[elexis]

Reported commands.txt for a19.

[sanderd17]

I made this ticket a bit broader, as multiple improvements can be made.

[sanderd17]

Partial implementation of round obstructions. It works nicely for placing buildings, and works good with the long-range pathfinder, but supporting the vertex pathfinder is hard.

[sanderd17]

The clearance patch is ready for review (the other is just a WiP).

The clearance patch cleans up the "onlyCenterpoint" parameter used with the previous pathfinder, and allows obstructions to have a clearance defined. Setting the clearance for regular units to 4 makes sure there's always a gap that's big enough for units to pass through.

Walls on the other hand get a negative clearance, allowing them to overlap a bit. The overlap is only 1m, so trees and other resources don't get berried completely inside the wall (the minimum obstruction size is 1.5m, so there's always at least 0.5m of the tree sticking out to be gathered).

This patch changes the gameplay too, as due to the clearance, you need more space to build stuff. So perhaps as a compensation, some structures could get a bit smaller obstruction size.

[sanderd17]

Note from fatherbushido: corpses are broken, and some other templates in the other/ directory (XML validation errors).

[sanderd17]

Clearances made optional, as they're only useful on entities that are placed by the player (and thus shouldn't be defined on the other templates)

[sanderd17]

Fix bridge actors

[fatherbushido]

I tested the clearance patch. I ve got a really nice feeling (more realistic city building, better wall placement...).

[wraitii]

Just a small comment: when playing around with clearance, please please please test edge cases. The pathfinder demo map is pretty good for small corridors for example.

Please also check compatibility between the short-range and long-range pathfinder. I literally cannot count how many "unit is stuck" issues were caused by this.

Re-the circular static obstruction thing: I believe the main reason for their non-existence is the lack of support in the short-range pathfinder. AFAIK there are no easy solutions to this problem.

[sanderd17]

@wraitii, the clearance patch doesn't change anything to already placed buildings. It just guarantees there to be a certain clearance between a new foundation and already existing obstructions. Perhaps I should try to find a different name, as it indeed collides with the clearance of units :/ The clearance for units is needed clearance, the clearance for buildings is guaranteed clearance.

So as it only restricts building placement further (for regular buildings), there are no extra bugs that can happen with regular buildings.

But when calculating the guaranteed clearance, you do need to take the unit clearance into account so it's certain units can pass.

First, static obstructions are enlarged by the unit clearance (0.8), I think this happens on both sides, so buildings must be 1.6m apart to allow short-range pathfinder passability for units. Then the long-range pathfinder marks all tiles impassable that overlap the extended static obstruction with 1m² tiles, so with the diagonals of those tiles, you'd need to add 2*sqrt(2) to the minimum distance to guarantee passability for units.

So the required clearance for passability should be around 4.42. I first thought the clearance of 0.8 wasn't needed on both sides, so it would have been enough with 3.62 (or rounded up to 4).

I don't know if there are any mistakes in my calculations now, but at worst, it can cause bugs that were already possible.

[Itms]

Move tickets from the review queue to the rfc one.

[Itms]

I tested the patch, and as fatherbushido, I liked the feeling :)

One comment on the code: I would call TestStaticShape with w + 2*clearance instead of passing to the whole code a clearance with a double value, for semantics' sake.

[elexis]

Feature freeze in 2 days.

[wraitii]

Patch works, but: -I don't like that it has no connection to footprint. Things are already confusing enough. -I don't like the name, it's confusing with pathfinder clearance with which it has nothing to do. That at least should be changed before committing.

I rebased it in the meantime, removing review keyword for inactivity.

[elexis]

Backlogging due to lack of progress