A* Pathfinding: Edit for 2D

December 19, 2019

A* Pathfinding

2D Conversion

ISSUES

Pathing In Circles Away from Target

They move in a large circle around the entire game area. They go in a half circle consistenly then stop in about the same place everytime (either directly above or below the middle of the play area).

Test 1: Tone Values Down

I tried toning all their numbers down since my game area is relatively small in case they were just constantly over shooting node targets, but this did not change the behavior.

I think the direction I am aiming and moving them must be incorrect with how I changed the Vector math from 3D to 2D.

DETERMINED ISSUE

They can only respond to the player’s X position. If the player moves, the properly oriented ones will move slightly to keep at the same X value, whereas those facing the other direction will travel in a large circle to reach the same X value (since I guess they cannot rotate very easily).

Test 2: Edit Rotation Calculation

I just needed to remove an extra (-90) that was being applied to the rotation vectors for aiming them at the target. This completely fixed the issue for their initial movement, but they only move in the x direction after that initial reaching of the target now.

DETERMINED ISSUE

The target position is not changing its Y value for some reason, only its X value.

Next Steps

Either their rotation is messed up (so moving right only moves them along x axis) or the overall translation is messed up and is only moving them left and right. It could be another z/y conversion error somewhere.

Test 3: Change NodeFromWorldPoint Method to Use worldPosition.y instead of z

It looks like PathFindingHeap was using AGrid NodeFromWorldPoint function to determine the proper node from world points, but this was using the z value of the Vector3 input as to determine the y coordinate in the overall grid. This is why it was constantly hovering at the same low Y value, because those were the nodes that correlated with a z input of 0.

SOLVED

These combined edits fixed the pathfinding logic completely. They now constantly followed the target position properly and it updated accordingly.