As you may know, we already created a basic tile loader , player character and 3D buildings in the first two posts. Now we’ll try something a little more different, a dynamic tile loader. Admittedly I had no idea what to call it, “dynamic” might not be the best word here but couldn’t come up with anything better (and I’m open to suggestions). But it’s something that loads tiles dynamically…. well no. Whatever.
So what’s the problem we’re trying to solve here again? Well, Basic Loader gave us a central tile and n other tiles around it depending on the range parameter. But that’s a (quite small) finite set of tiles and you will eventually run off the map if you run in the same direction for a while.
We’ll take the most straight forward way to solve this; extend the world as player character gets close to any edge. There are lots and lots of different ways to really. I mean, how to detect player is getting close to an edge, how to load tiles or how many tiles to load etc. They’ll all have different properties and side effects but I think I’ve chosen one of the simplest ways and will try to explain it in detail now.
Wait actually before that, let’s have a look what we’re trying to achieve;
- Yea guess I’ll try to enumerate like this. Anyway we’ll start with just like basic loader actually, one central tile and n tiles around it. Let’s say n=1 for the simplicity now, which yields 9 tiles, right? Something like this; (8 is the center tile, 2,3,4,7,9,12,13,14 are direct neighbors or Range1 tiles)
- We’re safe as long as the player character stays inside tile 8. But as soon as it gets out of the central tile, we calculate a tile movement vector representing the players movement between tiles. i.e. for 8 -> 7, movement vector will be Vector2(-1,0). for 8 -> 4 it’ll be Vector2(1,-1). (see GetMovementVector method)
One little problem here is; y-axis of the Unity3d coordinate system (or let’s say the scene I’m using) and TMS tile system is opposite. In other words, (0,0) is bottom-left in Unity3D while it’s top-left in TMS system. (see GetMovementVector method)
- We’ll pull a little trick here.. but let’s do it like this, what happens if the player character moves in a direction for hours? It’s a big big world as the songs says eh? Position vectors (of player, tiles and buildings) will grow and grow which will cause lots of precision problems after a while (7 digit numbers).
So once player character leaves central tile, we’ll assign new tile as the central tile and move it back to (0,0) with everything around it. Doing this, everything will be kept around (0,0) all the time (see Centralize method) and with everything moved in one frame, you’ll nothing absolutely nothing at all on screen!
- So now we have everything in the (0,0) again. Now we can create new tiles using the very same function we used for basic loader. Remember we had 8 as central tile and loaded other around that? When the player moves to Tile 7, it becomes the new central tile and we’ll load neighboring tiles 1,6,11. Simple eh?
- One last thing, we don’t want to end up with hundreds of tiles on screen right? This is totally up to you actually but I’ll just assume that ,tiles further away more than d (from central tile in manhattan distance) are unnecessary, and simply destroy them (see UnloadTiles function).
I guess that’s all for now, had a lot more to talk about but it was a long day and I’m very very exhausted at the moment. I hope it’s still readable, I’m not even sure what I’m doing at this point.
I’ll try to post something like a todo list soon, consist of possible improvements on this. Will also post it on Github as soon as possible.
Hope you like this little dynamic tile loader thingy, let me know what you think!
PS: just one more “dynamic tile loader” so that my SEO helper will shut up about low density -_-
Edit: There is a bug with the tile colliders at the moment. It collides with the player character, preventing him to move. I’ll fix and reupload it asap but untill then, you can simply move tile collider (big cube in (0,0,0)) to another tile and change “Layer Collision Settings” to prevent it colliding with anything. I did it like that but turns out “Layer Collision Settings” or even layers aren’t included into unitypackages. I’ll (hopefully) fix it in a few hours.
02.08.2016 – v1.1: Download PokemonGO Clone Part 3: Dynamic Tile Loader
-Fixed central tile collider problem by replacing it with a Rect