The Minecraft boat-drop mystery

Huge thanks to Natalie for sending it to me!

CORRECTIONS
- None yet, let me know if you spot anything!

Filming by Matt Parker
Editing by Gus Melton
Minecraft footage by Oliver Dunk
Written and performed by Matt Parker
Produced by Nicole Jacobus
Music by Howard Carter
Design by Simon Wright and Adam Robinson

MATT PARKER: Stand-up Mathematician

[akaHarvesteR]

As a game dev, this is the level of bug-reporting quality we only dare hope for in our wildest fever dreams.

[nathanjames.]

Floating point numbers causes boats to break. Makes sense, since boats need to float correctly.

[Chase]

Another fun fact: If a boat falls from 44970 blocks high, it will not break despite it being in the sequence calculated. This is because after falling for that long, the tiny difference between and 0.04 compounds enough to offset the boat by more than the 0.001 block margin to have the ON_LAND status.

This also means that boats are safe to fall from any height of 43543 or higher until you get all the way up to 1794944 blocks, at which point the boat is offset by the 0.04 blocks needed to wrap back around into the range where it can take damage, after falling for nearly 8 minutes.

[LeDoctorBones]

The status of neither being in the air nor on the ground is what we in more basic speech call "Swimming".

[Mogswamp]

Him: Warning math people they don't need to know anything about Minecraft to enjoy the video

Me: A Minecraft person, worried that I need to know anything about math to enjoy the video

[logan]

imagine being the mojang dev that receives the bug report containing a full stand-up maths video

[tissuepaper]

9:42 The reason we need to check that fall damage was actually caused by falling is that Ender Pearls deal fall damage to the user when used.

[dkfrumwithin]

Last time I saw a gaming breakdown this specific it involved parallel universes.

[existenceispain_geekthesiren]

1:17 i am delighted at the knowledge that the on-line encyclopedia of integer sequences exists

[johnchessant]

12:54 "famously, multiples of 5 are at least 5 apart"

[barryberg]

Climbing on a ladder doesnt count as in the air, while also not being on the ground

[emoharalampiev]

An interesting thing is that the boat breaks into sticks and planks. And here's the thing, once upon a time boats were really fragile, they would break from crashing too hard, and they of course also break when you hit them, and in both of those instances they used to break into blocks and planks. Then in an update a long time ago they made it so that they don't break as easily (can't break by crashing) and if you break them by hitting them they drop themselves (or in other words a boat item).

But with that bug they still drop the old drops.

[jackdog]

I love how we’re all just accepting that the situations where falling from a great height whilst sitting in a boat kills you are the bugs and the ones where you survive with no repercussions are the game working as intended.

[geoffp]

Programming tip of the day: floating-point values that get repeatedly added should, whenever possible, be chosen to be exactly-representable numbers. Instead of 0.04, the acceleration should have been chosen to be 0.0390625 ( = 1/32 + 1/128 ); then the problem would not have arisen.

(In memory of the late Garry Tee, who taught me this many years ago. Rest in Peace.)

This bug was just marked as fixed! \o/

[hugoiwata]

I like that, as soon as he told the numbers where that happened, my first instinct was to pause the video and put the sequence on OEIS. Next scene is he putting the sequence on OEIS and finding nothing.

[Kaiasky]

Oh this is SO funny to see a video about this. Fun fact--since most players have no clue about this and use driving boats off ledges as a safe way to get down cliffs, you can often trick people into exploding if you measure out a drop that's exactly the right height.

It gets a bit into the weeds, but the historical reason for the "don't calculate fall damage if you're falling" stuff is that boats used to break if you rammed them into land. That got removed, but the fix was kinda a hack and accidentally left this method in.

[maticjurac]

Finally, a video that combines three of my favorite things. Mathematics, floating point number tomfoolery and Minecraft.

[GrandMagusDK]

As a programmer, floating point imprecision has been cause for may hours of desperate debugging.

[Laesee_bee]

Never in my life did I think Camman18 would end up in a stand up maths video. We truly live in one of the times.