next »

[thecodethinker]

I'm trying to test out A* pathfinding and I set it up to use some vertices in a navmesh as nodes but, when my sprite moves around corners it's texture overlaps with the corner of the navmesh.

What's a good way for me to prevent this?

Thanks in advance!

[qMopey]

As in you don't want the sprite to be able to go over nodes for which it is too big? I'd add in an additional check within the A* algorithm that does a "userdata callback", or whatnot. A* calls this function and passes a reference to the userdata, in your case the sprite, asking if this move is valid. Then you can do whatever custom collision detection check you like to specify if this piece of the graph is traversable or not.

The callback thing might be overkill and perhaps you can just hard-code this check directly into your A* implementation -- whichever you choose is up to your and your project.

An example would be each node contains a float that represents maximum scale, and any sprite over this scale size cannot travel on that particular node.

[bateleur]

How easy this is to fix depends on whether you need to support multiple sizes of sprite and whether your map has places which are passable to some sizes but not others.

If you only have one size of sprite then your basic problem is that your navmesh is wrong in the sense that it doesn't reflect the places the character can actually go. The fixes qMopey suggests will work, or it might be easier to just fix the mesh, depending on how you generated it.

If you need multiple sizes then the problem is you need a different mesh for each. However, if there are no narrow passages (passable only to smaller sprites) you can hack around this requirement by generating the mesh for the largest size of sprite and then letting smaller sprites take shortcuts if they can "see" their destination node early.