Unity-Best-Practice

Some useful tips that I find useful while learning Unity.

Disclaimer: These tips are not absolute. Some of them might be actually bad in some situations, in light of the fact that I am still struggling to learn unity right now.

Scripting

1. use attribute to attach additional behavior to the methods and variables you create

public class SpinScript : MonoBehaviour 
{
    [Range(-100, 100)] public int speed = 0;

    void Update () 
    {
        transform.Rotate(new Vector3(0, speed * Time.deltaTime, 0));
    }
}

[ExecuteInEditMode]
public class ColorScript : MonoBehaviour 
{
    void Start()
    {
        renderer.sharedMaterial.color = Color.red;
    }
}

[HideInInspector] public bool inMainMenu;

Attribute Refernce

2. use properties instead of simple public variables in monobehaviour script

3. do not use only monobehaviour

4. use static, monobehavior, scriptableobject and singleton according to the situation

ScriptableObject:

using UnityEngine;

[CreateAssetMenu]
public class MyScriptableObject : ScriptableObject 
{
	public int SomeVariable;
  	
    void OnEnable() {
  	
	}
    void OnDisable() {
  	
	}
    void OnDestroy() {
  	
	}
}

ScriptableObject.CreateInstance<MyScriptableObject>();

Application:

data tables
...

5. keep in mind some general coding principles

SINGLE RESPONSIBILITY: A given class should be, ideally, responsible for just one task.
ABSTRACTION: see next rule
MODULARIZATION

6. use interface to abstract game object functionality

eg: IDamageable, IInventory

7. use coroutine instead of update to do simple routines

Also consider Invoke() and InvokeRepeating() .

Actually, consider using a tween library such as DOTween, iTween, etc.

8. use event to simplify dependency

think about events as a "broadcasting" system

9. stick to coding conventions

参考C# Style Guide

关于变量名大小写的问题，个人偏好public和property用小写Camelcase，private用下划线小写Camelcase，因为这样与 Unity本身的命名是一致的。

10. really know what Monobehaviour does

Monobehaviour Reference

use Awake() to set up references and Begin() to initialize
sometimes it's useful to implement some non-monobehaviour functions to be called by other scripts

11. robustness

if (hit.Rigidbody != null) {
  doSomthing();
}
else {
  Debug.Log("No Rigidbody attached to " + hit.name);
}

12. implement reset() for scripts that are reused extensively in your game

13. increase script reusability by separating data and logic

eg: Health.cs, Attack.cs

Data should only be assigned to public variables. Implementations should not contain any specific data.

14. use finite state machine to organize your game or a particular game object

A simple and nice implementation here: Unity3d-Finite-State-Machine

15. disable and enable components in a game object to achieve flexible behaviour

16. prefer event to SendMessage()

SendMessage(), BroadcastMessage() and SendMessageUpwards() use reflection and are therefore expensive. More importantly, they can result in ugly code and unexpectable errors.

17. use UnityEvent instead of plain C# event#

UnityEvent is similar to C# delegate and event, but is also compatible with UI system.

18. Prefer GameObject.FindWithTag() to GameObject.Find()

The latter use string matching and is therefore more expensive.

19. Think in terms of event-driven programming, don't just put everything in Update()

example:

public class EnemyObject : MonoBehaviour
{
//-------------------------------------------------------
//C# accessors for private variables
public int Health
{
  get{return _health;}
  set
  {
    //Clamp health between 0-100
    _health = Mathf.Clamp(value, 0, 100);
    //Check if dead
    if(_health <= 0)
    {
      OnDead();
      return;
    }
    //Check health and raise event if required
    if(_health <= 20)
    {
      OnHealthLow();
      return;
    }
  }
}
//-------------------------------------------------------
public int Ammo
{
  get{return _ammo;}
  set
  {
    //Clamp ammo between 0-50
    _ammo = Mathf.Clamp(value,0,50);
      //Check if ammo empty
    if(_ammo <= 0)
    {
      //Call expired event
      OnAmmoExpired();
      return;
    }
  }
}

20. Remove unused MonoBehaviour methods()

Empty monobehaviour methods will still be called if not removed.

21. Make every public fields properties and serialize private fields to make them editable in the inspector.

This is for the sake of encapsulation.

22. Use PlayerPref class to store game settings data to local directory

23. Use platform specific compilation to adapt to different platforms

	public void Quit()
    {
#if UNITY_EDITOR
        UnityEditor.EditorApplication.isPlaying = false;
#else
        Application.Quit();
#endif
    }

24. Make your script more usable

Tooltip, Space, TextArea, Header, ExecuteinEditMode, ContextMenu, ContextMenuItem, Range, Multiline Attribute

Edito

1. use icons to organize your scene

Animation

1. consider adjusting the curve in key frame animation

2. consider using IK(Inverse Kinematics) for Humanoid characters with a avatar

3. precompute hash values for animator parameters

because us string directly in Update() can be computationally expensive

using UnityEngine;
using System.Collections;

public class EthanScript : MonoBehaviour 
{
    Animator anim;
    int jumpHash = Animator.StringToHash("Jump");
    int runStateHash = Animator.StringToHash("Base Layer.Run");


    void Start ()
    {
        anim = GetComponent<Animator>();
    }


    void Update ()
    {
        float move = Input.GetAxis ("Vertical");
        anim.SetFloat("Speed", move);

        AnimatorStateInfo stateInfo = anim.GetCurrentAnimatorStateInfo(0);
        if(Input.GetKeyDown(KeyCode.Space) && stateInfo.nameHash == runStateHash)
        {
            anim.SetTrigger (jumpHash);
        }
    }
}

SunGuangdong/Unity-Best-Practice.md