Question

I need to implement 2D collision detection by arc. I have player(black dot) and enemies(red dots). Player can attack in any direction and his hit area is 120 degrees(green lines show it) and certain radius(black curve).

How to achieve this detection?

I have done code where angle is calculated between player and enemy but i cant understand how to use player’s direction vector to check if it inside arc.

Answer 1

Calculate the angle to the enemy and the distance away they are. Use this to check if they are in range.

The problem is simple if the area where a square since you are using Cartesian coordinates so by converting to radial coordinates, this problem becomes simple too.

With new information

• Vector A is the player’s direction vector.
• Calculate a vector B from the enemy to the player.

Check the length of vector B isn’t too long.

Then angle between the vectors is given by: acos(|A.B| / |A||B|)

If the angle is less than 60 degrees (half the 120) then the enemy is in range.