Look at Entity

The following tutorial provides a resource pack method to detect when the player is looking at an entity. The code below must be placed inside the entity that will be looked at by the player, and will provide a variable v.look_at_entity which returns true when the entity is being looked at.

variable ​

"pre_animation": [
  "v.look_at_entity = Math.abs(Math.abs(q.rotation_to_camera(1) - q.camera_rotation(1)) - 180) < (20 / q.distance_from_camera) && Math.abs(q.rotation_to_camera(0) + q.camera_rotation(0)) < (10 / q.distance_from_camera);"
],

"pre_animation": [
  "v.rotation_to_camera_0 = -Math.atan2(-q.distance_from_camera * Math.sin(q.rotation_to_camera(0)) - 1, q.distance_from_camera * Math.cos(q.rotation_to_camera(0)));",
  "v.look_at_entity = Math.abs(Math.abs(q.rotation_to_camera(1) - q.camera_rotation(1)) - 180) < (20 / q.distance_from_camera) && Math.abs(v.rotation_to_camera_0 + q.camera_rotation(0)) < (60 / q.distance_from_camera);"
],

Modifying ​

The provided code is very accurate for the standard Minecraft mob size of 1 block wide and 2 blocks tall, but for entities of different sizes the parameters should be changed. The - 1 controls the positional offset of the center of the mob (- is upward, + is downward), the 20 controls the horizontal angle sensitivity, and the 60 controls the vertical angle sensitivity.

Explanation ​

The variable detects when the player is looking at the entity by checking if the rotation angle required for the entity to look at the player is opposite the rotation angle required for the player to look at the entity. The horizontal and vertical angle sensitivity are modified by the distance of the entity from the camera to maintain accuracy.