when i use asset the script works, but when i use the script on prefab the script seems to not work because they keep moving to middle of screen instead of following the target.
It doesn’t show any errors in the Console, or in the script.
As you can see in the image the crabs are not following the target (Guy in red shirt), but staying in the middle. middle is not their spawn, it’s in the left lower corner, they keep going to middle(I have no idea how to add video, if i knew i would add)
Here is the code:
public class CrabFollow : MonoBehaviour
{
public GameObject target; //target i want prefab to follow
public float speed; //how fast the prefab moves
private void Update()
{
transform.position = Vector2.MoveTowards(transform.position, target.transform.position, speed * Time.deltaTime);
}
}
Break it up, practice social distancing in your code, one thing per line please.
“Programming is hard enough without making it harder for ourselves.” - angrypenguin on Unity3D forums
“Combining a bunch of stuff into one line always feels satisfying, but it’s always a PITA to debug.” - StarManta on the Unity3D forums
Once you have made your code usable and readable it is…
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 for iOS: How To - Capturing Device Logs on iOS or this answer for Android: How To - Capturing Device Logs on Android
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.
If your problem is with OnCollision-type functions, print the name of what is passed in!
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:
“When in doubt, print it out!™” - Kurt Dekker (and many others)
Note: the print() function is an alias for Debug.Log() provided by the MonoBehaviour class.
If these are both prefabs it seems pretty likely that your crab is referencing not the player from the actual game but a prefab in your project folder, which naturally does not actually move.
You need to have your spawner give the crab a reference to the actual in-game player object.
Yes exactly, so the crab cannot possibly reference the target without it being assigned at runtime, since prefabs cannot reference objects in the scene. Read my comment again. The spawner script needs to pass the reference to the newly spawned crab.
