Bug Tile sprite changing by themselves

Hi,
I'm facing a annonying bug and I have no idea where it comes from...
I have prefabs for my rooms, containing a grid. When generating my map, I instantiate them accordingly to an algorithm that I made for generating map layouts.

When instantiating the rooms, the tilemap seems to be messed up for some reason. Some (most) tiles works fine, while some other have their sprite changed or even removed.

Examples:

Tile selected from the grid with the selection tool of the tile palette
We can see here that the sprite is None


The tile object, having the correct sprite


---


What is looks like in game


What it looks like in the prefab
​

If anyone has any idea what is going on, it would be greatly appreciated.

Cheers
Thomas

 

Make a copy of that prefab, turn every tile to some silly shape like a smiley face. Load that instead of the current prefab. What happens?

Then try replace the tile that is changing with a smiley face. What happens?

Make a script that can print the name of the tile at that square. Is it always tiles_53? While the game is running, go in and delete the whole tilemap, then drag the prefab in? Is it fixed?

This is basic rip-tear-shred style debugging, and coupled with below it can give you information about what is happening.

You must find a way to get the information you need in order to reason about what the problem is.

What is often happening in these cases is one of the following:

- the code you think is executing is not actually executing at all
- the code is executing far EARLIER or LATER than you think
- the code is executing far LESS OFTEN than you think
- the code is executing far MORE OFTEN than you think
- the code is executing on another GameObject than you think it is
- you're getting an error or warning and you haven't noticed it in the console window

To help gain more insight into your problem, I recommend liberally sprinkling

Debug.Log()

statements through your code to display information in realtime.

Doing this should help you answer these types of questions:

- is this code even running? which parts are running? how often does it run? what order does it run in?
- what are the values of the variables involved? Are they initialized? Are the values reasonable?
- are you meeting ALL the requirements to receive callbacks such as triggers / colliders (review the documentation)

Knowing this information will help you reason about the behavior you are seeing.

You can also supply a second argument to Debug.Log() and when you click the message, it will highlight the object in scene, such as

Debug.Log("Problem!",this);

If your problem would benefit from in-scene or in-game visualization, Debug.DrawRay() or Debug.DrawLine() can help you visualize things like rays (used in raycasting) or distances.

You can also call Debug.Break() to pause the Editor when certain interesting pieces of code run, and then study the scene manually, looking for all the parts, where they are, what scripts are on them, etc.

You can also call GameObject.CreatePrimitive() to emplace debug-marker-ish objects in the scene at runtime.

You could also just display various important quantities in UI Text elements to watch them change as you play the game.

If you are running a mobile device you can also view the console output. Google for how on your particular mobile target, such as this answer or iOS: https://forum.unity.com/threads/how-to-capturing-device-logs-on-ios.529920/ or this answer for Android: https://forum.unity.com/threads/how-to-capturing-device-logs-on-android.528680/

Another useful approach is to temporarily strip out everything besides what is necessary to prove your issue. This can simplify and isolate compounding effects of other items in your scene or prefab.

Here's an example of putting in a laser-focused Debug.Log() and how that can save you a TON of time wallowing around speculating what might be going wrong:

https://forum.unity.com/threads/coroutine-missing-hint-and-error.1103197/#post-7100494

When in doubt, print it out!(tm)

Note: the

print()

function is an alias for Debug.Log() provided by the MonoBehaviour class.

 

Notice also that I had a bug when the tile sprite are changing multiple times during the same session, as if they were animated (they were not).

While dragging my mouse over them (not clicking!), it... did some things?