Question onTriggerEnter2D is triggering even when box colliders don't touch

I have a simple bullet dodging game where triangle enemy objects fly across the screen from four directions.

But my enemies are sometimes taking a life from the player even when they were clearly dodged.

The thing that makes this hard for me to trouble shoot is that it's only a few of the enemies that do it.
And the ones that do it always seem to be from the same positions.

What might cause this and how can I fix it?

Thanks.

 

Short answer: just about anything. Welcome to software development!

Long answer: Time to start debugging! Here is how you can begin your exciting new debugging adventures:

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

Once you understand what the problem is, you may begin to reason about a solution to the problem.

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 names of the GameObjects or Components involved?
- 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.

Visit Google for how to see console output from builds. 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/

If you are working in VR, it might be useful to make your on onscreen log output, or integrate one from the asset store, so you can see what is happening as you operate your software.

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)" - Kurt Dekker (and many others)

Note: the

print()

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

If you do find something specific you don't understand, here is how to report your problem productively in the Unity3D forums:

http://plbm.com/?p=220

This is the bare minimum of information to report:

- what you want
- what you tried
- what you expected to happen
- what actually happened, log output, variable values, and especially any errors you see
- links to documentation you used to cross-check your work (CRITICAL!!!)

 

Thank you very much for all the info and suggestions!

I sprinkled my code with Debug.Log and found another couple bugs that were happening and was able to fix them.
Then after checking all my code, I determined it was not a code based problem.

Ultimately, I didn't realize I needed to select kinematic for my players rigidbody since I was controlling it via transform.
After changing that and the actual bugs, my little game is working as intended.

Also, I appreciate all the suggestions despite my lack of info.
This was my first post to a programming forum.
I'll try to describe my problem better next time.

 

Excellent!

That's the beauty of Unity: you get to modify all these NON-code things too... so it is important to keep those in mind as potential issues.

The more you use Unity, the more problems you encounter and solve, the more your brain will expand and grow so that thinking "oh yeah, let's look at the Rigidbody" becomes part of your flow.