Problems moving PCs on a map with a small grid

[Steeleyes]

There appears to be a bug in the token movement on maps with a small grid (with locked tokens). We have been suffering from this during our play sessions for the last month or so. I turned off all add ons and still had a problem. I finally got time today to do a little experimentation and send a post. Lo-res maps are good when playing across a network.

When the grid is 9x9 or less movements do not complete. They often stop part way or refuse to move at all. A green select-able square is shown at the target position but the player icon ends up in the wrong place on GM and client maps. The issue doesn't appear to manifest on maps with grids or 10x10 or greater. I needed two machines to see the problem (the GM can't really see the issue on their own).

It feels like a rounding error bug in the path the token takes to the destination square. Even when it works the path is a little eccentric (and slow) going along a cardinal direction for a while before homing in on the correct square.

Bresenham described how to implement the algorithm without rounding errors in 1962 so no real excuse.

[Moon Wizard]

Thanks for reporting. Currently, we are full bore on FGU at this point, so this probably won't get looked at anytime soon.

As a workaround, if you can increase the resolution of the map by 2-3x, then your grid sizes should be >9 range which should correct the issue for now.

Regards,
JPG

[Steeleyes]

Yes thanks for the fast response. I'll grow the map. Hopefully that bit of code won't make it into FGU.

[Moon Wizard]

It's completely different in FGU, and uses floating point precision, instead of pixel precision. Plus, the image control has been re-implemented from scratch. So, new bugs only.

Cheers,
JPG

[Delthos]

I have experienced this as well in my last session, and a couple times before. I've seen it both on the GM and Player side. We were in the middle of a game so didn't have time to really troubleshoot it. I was able to correct it by removing the tokens that were displaced or not able to be moved and re-adding them to the map, at least for a little while. It eventually comes back at random. Looking back I had created a map with very small squares to handle a large area encounter. I'm guessing this was the same issue as I've only ever encountered it on maps with small grid size. Good to know how to avoid it in the future though.