Determine if you are behind another player and they are facing away

Unity Engine
1

I wanted to determine if my transform is behind the other transform and both are facing the same direction.
(your typical RPG backstab skill check)

Is the code below close?

                    if (target == null)
                        return false;

                    Vector3 myDir = chr.transform.forward;
                    Vector3 yourDir = target.transform.forward;

                    myDir.y = 0;
                    yourDir.y = 0;
                  
                    var angle = Vector3.Angle(myDir, yourDir);
                    if (angle <= 45) // both looking the same direction
                        isPositionOK = true;
2

Does it work? Kinda looks like it might.

If not then start debugging.

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

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 put in Debug.Break() to pause the Editor when certain interesting pieces of code run, and then study the scene

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.

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://discussions.unity.com/t/839300/3

ALSO: just want to say I approve of your methodical breaking it out into temporary variables and doing it one step at a time because now it’s super-easy to debug!!