Crouching system

using UnityEngine;

// a section of the script
public class MovementController : MonoBehaviour
{
    public float crouchHeight = 1.0f;

    private CharacterController characterController;
    private CollisionDetector crouchCollisionTop;
    private CollisionDetector crouchCollisionBottom;
    private bool crouching = false;
    private float heightDifference;
    private bool crouchedWhileAirborne = false;
    private bool couldNotStandUp = false;
    private float crouchCameraChange = 0;

    private void Start()
    {
        characterController = GetComponent<CharacterController>();
        crouchCollisionTop = GameObject.Find("collision_detector_top")
                             .GetComponent<CollisionDetector>();
        crouchCollisionBottom = GameObject.Find("collision_detector_bottom")
                             .GetComponent<CollisionDetector>();
        heightDifference = (characterController.height - crouchHeight);
    }

    private void Crouch()
    {
        crouching = true;

        // shrink the player capsule when crouching
        characterController.height = crouchHeight;

        if (characterController.isGrounded)
        {
            // because the player capsule is shrunk, move its center down by half the height
            // difference so that it's touching the floor
            characterController.center = new Vector3(0, -heightDifference / 2, 0);
        }
        else
        {
            // crouch in air by pulling legs up: move capsule's center up by half of
            // the height difference
            crouchedWhileAirborne = true;
            characterController.center = new Vector3(0, heightDifference / 2, 0);

            // since the capsule is now positioned higher, move the top collision
            // trigger up as well
            crouchCollisionTop.gameObject.transform.localPosition += new Vector3(0, heightDifference, 0);
        }
    }

    private void StandUp()
    {
        // remember that it wasn't possible to stand up so that it can be done later
        couldNotStandUp = crouchCollisionTop.IsColliding;
        if (couldNotStandUp) return;

        // because the crouch midair was different than on the ground, the stand up needs
        // to be adjusted accordingly
        if (crouchedWhileAirborne)
        {
            // move the top collision trigger back
            crouchCollisionTop.gameObject.transform.localPosition += new Vector3(0, -heightDifference, 0);

            if (!characterController.isGrounded)
            {
                // the player crouched in air, then stand uped before fully landing
                if (crouchCollisionBottom.IsColliding)
                {
                    // calculate remaining distance to the floor
                    float distanceToFloor = -(crouchCollisionBottom.CollidingObject.ClosestPointOnBounds(transform.position) - transform.position).y;
                    float change = heightDifference + controllerSkinWidth - distanceToFloor;

                    // move the whole player controller up
                    transform.Translate(Vector3.up * change);

                    // move the camera back to the position before the stand up
                    // so it can animate smoothly
                    crouchCameraChange = -change;
                }
            }
            else
            {
                // move player controller up to standing position then extend
                // legs back to the ground

                // since the capsule was moved up when crouching midair and will be reset
                // when ncrouching, move the whole player controller up to compensate
                transform.Translate(Vector3.up * heightDifference);

                // move the camera back to the position before the stand up so it can
                // animate smoothly
                crouchCameraChange = -heightDifference;
            }
            crouchedWhileAirborne = false;
        }

        // reset the capsule's center and height
        crouching = false;
        characterController.center = Vector3.zero;
        characterController.height = controllerHeight;
    }
}