Finding the Path

Pathfinding! It's what makes units go around obstacles instead of through them, and it's something that is now in the game.

I used something called the A* algorithm to implement pathfinding. It's a bit complicated, but basically it calculates the shortest walkable route between two points. The algorithm itself is generic, of course, so I had to figure out how to implement it specifically in Unity. Unity does include a built-in navigation utility, but word on The Internet is that it doesn't always work very well. Plus building it myself gave me a much better understanding of how it works and how I can customize it to my needs.


The first step was to divide my map into a grid of walkable and unwalkable nodes:

The red squares represent unwalkable nodes and correspond to the position of obstacles in the scene:

When a unit receives a move order, it requests a path from the pathfinding script, which returns to it a list of waypoint nodes for the unit to follow:

Then the unit simply moves toward each waypoint until it has reached the destination node. It's a basic system, but it works.

There's plenty to be added to the pathfinding, of course - units will need to know how to move as a group, how to avoid running into each other, and how to avoid unfavorable terrain. Luckily the A* algorithm makes adding this type of functionality very easy.

What's the step? Well, in no particular order I want to add attack abilities, a pause menu and a main menu, and start integrating actual character models. Stay tuned!

Here's a free game about jet-packing around a cyber-punk city. It's a good example of a game with only one mechanic that works because that mechanic feels so good.