block.getX() in onPlayerInteract() - Bug?

Hi,
I'm using x, y and z coordinates very often but today was the first time I used (compared) them from onPlayerInteract() and another method (onBlockRedstoneChange()). That didn't work, so I wrote some debugging lines into my plugin that showed that the x coordinate of booth methods for the same block are different! I verified in-game that the coordinate from onBlockRedstoneChange() is valid.

Can you confirm this bug?

BTW: Here is the output from the debugging where the first value is from onBlockRedstoneChange and the second from onPlayerInteract(). The first line compares the worlds, second x, third y, last z:

Code:

16.11 07:46:12 [Server]16.11 07:46:12 [Server] INFO world vs world
16.11 07:46:12 [Server] INFO -176 vs -177
16.11 07:46:12 [Server] INFO 69 vs 69
16.11 07:46:12 [Server] INFO 252 vs 252

 

-176 is X? o-o
No idea.

 

Well, that's just weird.

 

Yes, I already noticed that aswell. On the negative x-axis, the value seems to be off by one sometimes (I compared it using a minimap). I never had to compare values, so it wasn't a problem for me, but yeah, I did notice.

 

@EvilSeph, @lukegb, @Dinnerbone, @sk89q, sorry for tagging you here but as leaky is down I need to get sure you read this as I need the bug to get fixed.

 

I could understand if the Y was wrong... but the X? I could possibly look into it later. I have a ton of stuff I want to look into in bukkit. Could I have the code you're using for checking this as well?

 

@feildmaster: PMd you.

 

When you find problems with an off-by-one result in negative integers, the usual cause is inconsistent ways of rounding floating point numbers to make integers.

Math.floor(-176.4) gives -177.0
Math.round(-176.4) gives -176.0
(int)(-176.4) gives -176

Math.floor(-176.6) gives -177.0
Math.round(-176.6) gives -177.0
(int)(-176.6) gives -176

I believe all of the getBlockX() kinds of methods should be using Math.floor() but there may still be some cases where someone decides to do it a different way. Using Math.floor() gives a consistent block distance size regardless of sign. For example, a distance calculation should result in two meters between 1.2 and -0.8 and still 2.0 meters when using Math.floor(1.2) [1] and Math.floor(-0.8) [-1] for example.

EDIT by Moderator: merged posts, please use the edit button instead of double posting.