[Bug][Player] 1 Pixel Below Ceiling - Builder Can't Be Assigned, The Rest Work

[kaywhyn]

See attached video. Something I discovered while investigating some ceiling shenanigans: If a lemming is one pixel below the deadly ceiling, you cannot assign the builder skill. All other skills can be assigned. This makes me wonder if the builder was made a special case for this situation, but this seems completely unintentional/a bug and very odd if all other skills can be assigned except for the builder when near the ceiling.

This came about, as I was investigating a jumper behavior with the ceiling that I found odd. I also show this near the end of the video. At the time I assign a jumper, there is a brief moment where the lemming is outside the playing field completely for a single frame but he still survives. I do find this odd, but I think as was explained to me by Icho, he hasn't completely left the level, as I think what determines that he survives is some of him is still inside the grey border. At the same time, the jumper skill shadow is completely at or below the grey border, meaning it doesn't lie about whether the lemming survives or not due to the deadly ceiling. I think if I zoom in so the border isn't there then it should be very clear that he's still inside the level.

edit: Ah, no he still disappears completely for a single frame even if the grey border isn't showing.

[namida]

Builder issue fixed in commit ecb4648. This was a matter of a specific check that prevented assigning the builder at that position, rather than an unintended result from other behaviors. I don't recall for sure why this check was as it was (Lemmix has a different behavior here that prevents builder assignments in the top few pixels, not just the absolute top one, so this would definitely have been a NeoLemmix-specific thing) - it may possibly have been to avoid builders pushing themselves out the top of the level back when the sides were solid? Regardless, this made it very easy to fix too.

[namida]

Regarding the Jumper - I did some testing and confirmed the Jumper behaves as it should. There is one frame at the peak of a jump where, from the right position, the lemming graphic is entirely outside the visible area, but if you check the lemming's actual pin position (for example via clear physics mode) the lemming is still inside the play area. A similar case can occur with gliders in updrafts too.