Pixel Movement

by Forum_account
Pixel Movement
A pixel movement library for isometric and top-down maps.

bump() issue

ID:313602
 
Feb 17 2012, 12:05 pm
Keywords: bump
I'm trying to make bouncy walls using bump(). However, a problem occurs when you bump into two walls at the same time (by bumping into the met corners of two): your velocity is flipped twice.

I can think of a couple ways to solve this, but none are particularly simple, i.e. they would probably create new bugs.
Feb 17 2012, 1:37 pm
The library didn't always behave this way. When it started to detect both bumps I remember thinking about making the library only call bump once. I decided against it because it'd ignore some bumps - if you create a wall that causes damage when you bump into it, certain situations wouldn't register.

I ultimately left it in there. For this effect you can do something like this:

mob
    bump(atom/a, d)
        if(d == SOUTH && vel_y < 0)
            vel_y *= -1


That way if you bump two walls, only the first time is vel_y < 0 so it only flips your velocity once.

The alternative is to change the library. The only thing I can think of is to have bump() and bumped() events - the library would call mob.bump(SOUTH) when you bump something in that direction and the default behavior would call atom.bumped(mob, SOUTH) for all the objects you bumped into.
Feb 23 2012, 5:41 pm
Just for future reference, the solution I went with is the first. The alternative seems like a lot more unnecessary work put into the core.