steeplechase/unity/Assets/Scripts/Bird.cs

using System.Collections;
using System.Collections.Generic;
using UnityEngine;

public class Bird : MonoBehaviour
{
    const float horizontalSpeed = 100f;
    const float verticalSpeed = 5f;
    const float amplitude = 30f;

    private float startTime;
    float _startingY;
    [SerializeField] Sprite _blueBird;
    [SerializeField] Sprite _yellowBird;
    DragonMovement.AttackType _attackType;

    public DragonMovement.AttackType AttackType { get => _attackType; set => _attackType = value; }

    void Start()
    {
        startTime = Time.time;
        _startingY = transform.position.y;

        int type = Random.Range(0, 2);
        if (type == 0) {
            AttackType = DragonMovement.AttackType.CONE;
            GetComponent<SpriteRenderer>().sprite = _blueBird;
        }
        else
        {
            AttackType = DragonMovement.AttackType.FIREBALL;
            GetComponent<SpriteRenderer>().sprite = _yellowBird;
        }
    }

    void Update()
    {
        float y = _startingY + (amplitude * Mathf.Sin(verticalSpeed * (Time.time - startTime)));
        transform.position = new Vector3(transform.position.x - Time.deltaTime * horizontalSpeed, y, transform.position.z);

        if (transform.position.x < -100f)
        {
            GameObject.Destroy(this.gameObject);
        }
    }

    public void Eat()
    {
        GameObject.Destroy(this.gameObject);
    }
}