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50 Tips for Working with Unity (Best Practices)纯干货

About these tips

These tips are not all applicable to every project.

Process

1. Avoid branching assets. There should always only ever be one version of any asset. If you absolutelyhave to branch a prefab, scene, or mesh, follow a process that makes it very clear which is the rightversion. The “wrong” branch should have a funky name, for example, use a double underscore prefix:__MainScene_Backup. Branching prefabs requires a specific process to make it safe (see under the section Prefabs).

2. Each team member should have a second copy of the project checked out for testing if you are using version control. After changes, this second copy, the clean copy, should be updated and tested. No-one should make any changes to their clean copies. This is especially useful to catch missing assets.

3. Consider using external level tools for level editing. Unity is not the perfect level editor. For example, we have used TuDee to build levels for a 3D tile-based game, where we could benefit from the tile-friendly tools (snapping to grid, and multiple-of-90-degrees rotation, 2D view, quick tile selection). Instantiating prefabs from an XML file is straightforward. See Guerrilla Tool Development for more ideas.

4. Consider saving levels in XML instead of in scenes. This is a wonderful technique:

You can still use Unity as a level editor (although you need not). You will need to write some code to serialize and deserialize your data, and load a level both in the editor and at runtime, and save levels from the editor. You may also need to mimic Unity’s ID system for maintaining references between objects.

5. Consider writing generic custom inspector code. To write custom inspectors is fairly straightforward, but Unity’s system has many drawbacks:

You can address these issues by essentially re-implementing the inspector system. Using a few tricks of reflection, this is not as hard as it seems, details are provided at the end of the article.

Scene Organisation

6. Use named empty game objects as scene folders. Carefully organise your scenes to make it easy to find objects.

7. Put maintenance prefabs and folders (empty game objects) at 0 0 0. If a transform is not specifically used to position an object, it should be at the origin. That way, there is less danger of running into problems with local and world space, and code is generally simpler.

8. Minimise using offsets for GUI components. Offsets should always be used to layout components in their parent component only; they should not rely on the positioning of their grandparents. Offsets should not cancel each other out to display correctly. It is basically to prevent this kind of thing:

Parent container arbitrarily placed at (100, -50). Child, meant to be positioned at (10, 10), then placed at (90, 60) [relative to parent].

This error is common when the container is invisible, or does not have a visual representation at all.

9. Put your world floor at y = 0. This makes it easier to put objects on the floor, and treat the world as a 2D space (when appropriate) for game logic, AI, and physics.

10. Make the game runnable from every scene. This drastically reduces testing time. To make all scenes runnable you need to do two things:

First, provide a way to mock up any data that is required from previously loaded scenes if it is not available.

Second, spawn objects that must persist between scene loads with the following idiom:

myObject = FindMyObjectInScene();
 
if (myObjet == null)
{
   myObject = SpawnMyObject();
}

Art

11. Put character and standing object pivots at the base, not in the centre. This makes it easy to put characters and objects on the floor precisely. It also makes it easier to work with 3D as if it is 2D for game logic, AI, and even physics when appropriate.

12. Make all meshes face in the same direction (positive or negative z axis). This applies to meshes such as characters and other objects that have a concept of facing direction. Many algorithms are simplified if everything have the same facing direction.

13. Get the scale right from the beginning. Make art so that they can all be imported at a scale factor of 1, and that their transforms can be scaled 1, 1, 1. Use a reference object (a Unity cube) to make scale comparisons easy. Choose a world to Unity units ratio suitable for your game, and stick to it.

14. Make a two-poly plane to use for GUI components and manually created particles. Make the plane face the positive z-axis for easy billboarding and easy GUI building.

15. Make and use test art

Prefabs

16. Use prefabs for everything. The only game objects in your scene that should not be prefabs should be folders. Even unique objects that are used only once should be prefabs. This makes it easier to make changes that don’t require the scene to change. (An additional benefit is that it makes building sprite atlases reliable when using EZGUI).

17. Use separate prefabs for specialisation; do not specialise instances. If you have two enemy types, and they only differ by their properties, make separate prefabs for the properties, and link them in. This makes it possible to

If you have too many enemy types, specialisation should still not be made in instances in the editor. One alternative is to do it procedurally, or using a central file / prefab for all enemies. A single drop down could be used to differentiate enemies, or an algorithm based on enemy position or player progress.

18. Link prefabs to prefabs; do not link instances to instances. Links to prefabs are maintained when dropping a prefab into a scene; links to instances are not. Linking to prefabs whenever possible reduces scene setup, and reduce the need to change scenes.

19. As far as possible, establish links between instances automatically. If you need to link instances, establish the links programmatically. For example, the player prefab can register itself with theGameManager when it starts, or the GameManager can find the Player prefab instance when it starts.

Don’t put meshes at the roots of prefabs if you want to add other scripts. When you make the prefab from a mesh, first parent the mesh to an empty game object, and make that the root. Put scripts on the root, not on the mesh node. That way it is much easier to replace the mesh with another mesh without loosing any values that you set up in the inspector.

Use linked prefabs as an alternative to nested prefabs. Unity does not support nested prefabs, and existing third-party solutions can be dangerous when working in a team because the relationship between nested prefabs is not obvious.

20. Use safe processes to branch prefabs. The explanation use the Player prefab as an example.

Make a risky change to the Player prefab is as follows:

  1. Duplicate the Player prefab.
  2. Rename the duplicate to __Player_Backup.
  3. Make changes to the Player prefab.
  4. If everything works, delete __Player_Backup.

Do not name the duplicate Player_New, and make changes to it!

Some situations are more complicated. For example, a certain change may involve two people, and following the above process may break the working scene for everyone until person two finished. If it is quick enough, still follow the process above. For changes that take longer, the following process can be followed:

  1. Person 1:
    1. Duplicate the Player prefab.
    2. Rename it to __Player_WithNewFeature or __Player_ForPerson2.
    3. Make changes on the duplicate, and commit / give to Person 2.
  2. Person 2:
    1. Make changes to new prefab.
    2. Duplicate Player prefab, and call it __Player_Backup.
    3. Drag an instance of __Player_WithNewFeature into the scene.
    4. Drag the instance onto the original Player prefab.
    5. If everything works, delete __Player_Backup and __Player_WithNewFeature.

Extensions and MonoBehaviourBase

21. Extend your own base mono behaviour, and derive all your components from it.

This allows you to implement some general functionality, such as type safe Invoke, and more complicated Invokes (such as random, etc.).

22. Define safe methods for Invoke, StartCoroutine and Instantiate.

Define a delegate Task, and use it to define methods that don’t rely on string names. For example:

public void Invoke(Task task, float time)
{
   Invoke(task.Method.Name, time);
}

23. Use extensions to work with components that share an interface. It is sometimes convenient to get components that implement a certain interface, or find objects with such components.

The implementations below uses typeof instead of the generic versions of these functions. The generic versions don’t work with interfaces, but typeof does. The methods below wraps this neatly in generic methods.

//Defined in the common base class for all mono behaviours
public I GetInterfaceComponent<I>() where I : class
{
   return GetComponent(typeof(I)) as I;
}
 
public static List<I> FindObjectsOfInterface<I>() where I : class
{
   MonoBehaviour[] monoBehaviours = FindObjectsOfType<MonoBehaviour>();
   List<I> list = new List<I>();
 
   foreach(MonoBehaviour behaviour in monoBehaviours)
   {
      I component = behaviour.GetComponent(typeof(I)) as I;
 
      if(component != null)
      {
         list.Add(component);
      }
   }
 
   return list;
}

24. Use extensions to make syntax more convenient. For example:

public static class CSTransform 
{
   public static void SetX(this Transform transform, float x)
   {
      Vector3 newPosition = 
         new Vector3(x, transform.position.y, transform.position.z);
 
      transform.position = newPosition;
   }
   ...
}

25. Use a defensive GetComponent alternative. Sometimes forcing component dependencies (throughRequiredComponent) can be a pain. For example, it makes it difficult to change components in the inspector (even if they have the same base type). As an alternative, the following extension of GameObjectcan be used when a component is required to print out an error message when it is not found.

public static T GetSafeComponent<T>(this GameObject obj) where T : MonoBehaviour
{
   T component = obj.GetComponent<T>();
 
   if(component == null)
   {
      Debug.LogError("Expected to find component of type " 
         + typeof(T) + " but found none", obj);
   }
 
   return component;
}

Idioms

26. Avoid using different idioms to do the same thing. In many cases there are more than one idiomatic way to do things. In such cases, choose one to use throughout the project. Here is why:

Examples of idiom groups:

Time

27. Maintain your own time class to make pausing easier. Wrap Time.DeltaTime andTime.TimeSinceLevelLoad to account for pausing and time scale. It requires discipline to use it, but will make things a lot easier, especially when running things of different clocks (such as interface animations and game animations).

Spawning Objects

28. Don’t let spawned objects clutter your hierarchy when the game runs. Set their parents to a scene object to make it easier to find stuff when the game is running. You could use a empty game object, or even a singleton with no behaviour to make it easier to access from code. Call this objectDynamicObjects.

Class Design

29. Use singletons for convenience. The following class will make any class that inherits from it a singleton automatically:

public class Singleton<T> : MonoBehaviour where T : MonoBehaviour
{
   protected static T instance;
 
   /**
      Returns the instance of this singleton.
   */
   public static T Instance
   {
      get
      {
         if(instance == null)
         {
            instance = (T) FindObjectOfType(typeof(T));
 
            if (instance == null)
            {
               Debug.LogError("An instance of " + typeof(T) + 
                  " is needed in the scene, but there is none.");
            }
         }
 
         return instance;
      }
   }
}

Singletons are useful for managers, such as ParticleManager or AudioManager or GUIManager.

30. For components, never make variables public that should not be tweaked in the inspector.Otherwise it will be tweaked by a designer, especially if it is not clear what it does. In some rare cases it is unavoidable. In that case use a two or even four underscores to prefix the variable name to scare away tweakers:

public float __aVariable;

31. Separate interface from game logic. This is essentially the MVC pattern.

Any input controller should only give commands to the appropriate components to let them know the controller has been invoked. For example in controller logic, the controller could decide which commands to give based on the player state. But this is bad (for example, it will lead to duplicate logic if more controllers are added). Instead, the Player object should be notified of the intent of moving forward, and then based on the current state (slowed or stunned, for example) set the speed and update the player facing direction. Controllers should only do things that relate to their own state (the controller does not change state if the player changes state; therefore, the controller should not know of the player state at all). Another example is the changing of weapons. The right way to do it is with a method on PlayerSwitchWeapon(Weapon newWeapon), which the GUI can call. The GUI should not manipulate transforms and parents and all that stuff.

Any interface component should only maintain data and do processing related to it’s own state. For example, do display a map, the GUI could compute what to display based on the player’s movements. However, this is game state data, and does not belong in the GUI. The GUI should merely display game state data, which should be maintained elsewhere. The map data should be maintained elsewhere (in theGameManager, for example).

Gameplay objects should know virtually nothing of the GUI. The one exception is the pause behaviour, which is may be controlled globally through Time.timeScale (which is not a good idea as well… see ). Gameplay objects should know if the game is paused. But that is all. Therefore, no links to GUI components from gameplay objects.

In general, if you delete all the GUI classes, the game should still compile.

You should also be able to re-implement the GUI and input without needing to write any new game logic.

32. Separate state and bookkeeping. Bookkeeping variables are used for speed or convenience, and can be recovered from the state. By separating these, you make it easier to

One way to do it is to define a SaveData class for each game logic class. The

[Serializable]
PlayerSaveData
{
   public float health; //public for serialisation, not exposed in inspector
} 
 
Player
{
   //... bookkeeping variables
 
   //Don’t expose state in inspector. State is not tweakable.
   private PlayerSaveData playerSaveData; 
}

33. Separate specialisation configuration.

Consider two enemies with identical meshes, but different tweakables (for instance different strengths and different speeds). There are different ways to separate data. The one here is what I prefer, especially when objects are spawned, or the game is saved. (Tweakables are not state data, but configuration data, so it need not be saved. When objects are loaded or spawned, the tweakables are automatically loaded in separately)

This method can become quite sophisticated (and sometimes, needlessly complicated, so beware!).

For example, to better make use of generic polymorphism, we may define our classes like this:

public class BaseTemplate
{
   ...
}
 
public class ActorTemplate : BaseTemplate
{
   ...
}
 
public class Entity<EntityTemplateType> where EntityTemplateType : BaseTemplate
{
   EntityTemplateType template;
   ...
}
 
public class Actor : Entity <ActorTemplate>
{
   ...
}

34. Don’t use strings for anything other than displayed text. In particular, do not use strings for identifying objects or prefabs etc. One unfortunate exception is animations, which generally are accessed with their string names.

35. Avoid using public index-coupled arrays. For instance, do not define an array of weapons, an array of bullets, and an array of particles , so that your code looks like this:

public void SelectWeapon(int index)
{ 
   currentWeaponIndex = index;
   Player.SwitchWeapon(weapons[currentWeapon]);
}
 
public void Shoot()
{
   Fire(bullets[currentWeapon]);
   FireParticles(particles[currentWeapon]);   
}

The problem for this is not so much in the code, but rather setting it up in the inspector without making mistakes.

Rather, define a class that encapsulates the three variables, and make an array of that:

[Serializable]
public class Weapon
{
   public GameObject prefab;
   public ParticleSystem particles;
   public Bullet bullet;
}

The code looks neater, but most importantly, it is harder to make mistakes in setting up the data in the inspector.

36. Avoid using arrays for structure other than sequences. For example, a player may have three types of attacks. Each uses the current weapon, but generates different bullets and different behaviour.

You may be tempted to dump the three bullets in an array, and then use this kind of logic:

public void FireAttack()
{
   /// behaviour
   Fire(bullets[0]);
}
 
public void IceAttack()
{
   /// behaviour
   Fire(bullets[1]);
}
 
public void WindAttack()
{
   /// behaviour
   Fire(bullets[2]);
}

Enums can make things look better in code…

public void WindAttack()
{
   /// behaviour
   Fire(bullets[WeaponType.Wind]);
}

…but not in the inspector.

It’s better to use separate variables so that the names help show which content to put in. Use a class to make it neat.

[Serializable]
public class Bullets
{
   public Bullet FireBullet;
   public Bullet IceBullet;
   public Bullet WindBullet;
}

This assumes there is no other Fire, Ice and Wind data.

37. Group data in serializable classes to make things neater in the inspector. Some entities may have dozens of tweakables. It can become a nightmare to find the right variable in the inspector. To make things easier, follow these steps:

This will group variables in collapsible units in the inspector, which is easier to manage.

[Serializable]
public class MovementProperties //Not a MonoBehaviour!
{
   public float movementSpeed;
   public float turnSpeed = 1; //default provided
}
 
public class HealthProperties //Not a MonoBehaviour!
{
   public float maxHealth;
   public float regenerationRate;
}
 
public class Player : MonoBehaviour
{
   public MovementProperties movementProeprties;
   public HealthPorperties healthProeprties;
}

Text

38. If you have a lot of story text, put it in a file. Don’t put it in fields for editing in the inspector. Make it easy to change without having to open the Unity editor, and especially without having to save the scene.

39. If you plan to localise, separate all your strings to one location. There are many ways to do this. One way is to define a Text class with a public string field for each string, with defaults set to English, for example. Other languages subclass this and re-initialize the fields with the language equivalents.

More sophisticated techniques (appropriate when the body of text is large and / or the number of languages is high) will read in a spread sheet and provide logic for selecting the right string based on the chosen language.

Testing and Debugging

40. Implement a graphical logger to debug physics, animation, and AI. This can make debugging considerably faster. See here.

41. Implement a HTML logger. In some cases, logging can still be useful. Having logs that are easier to parse (are colour coded, has multiple views, records screenshots) can make log-debugging much more pleasant. See here.

42. Implement your own FPS counter. Yup. No one knows what Unity’s FPS counter really measures, but it is not frame rate. Implement your own so that the number can correspond with intuition and visual inspection.

43. Implement shortcuts for taking screen shots. Many bugs are visual, and are much easier to report when you can take a picture. The ideal system should maintain a counter in PlayerPrefs so that successive screenshots are not overwritten. The screenshots should be saved outside the project folder to avoid people from accidentally committing them to the repository.

44. Implement shortcuts for printing the player’s world position. This makes it easy to report the position of bugs that occur in specific places in the world, which in turns makes it easier to debug.

45. Implement debug options for making testing easier. Some examples:

46. For teams that are small enough, make a prefab for each team member with debug options.Put a user identifier in a file that is not committed, and is read when the game is run. This why:

47. Maintain a scene with all gameplay elements. For instance, a scene with all enemies, all objects you can interact with, etc. This makes it easy to test functionality without having to play too long.

48. Define constants for debug shortcut keys, and keep them in one place. Debug keys are not normally (or conveniently) processed in a single location like the rest of the game input. To avoid shortcut key collisions, define constants in a central place. An alternative is to process all keys in one place regardless of whether it is a debug function or not. (The downside is that this class may need extra references to objects just for this).

Documentation

49. Document your setup. Most documentation should be in the code, but certain things should be documented outside code. Making designers sift through code for setup is time-wasting. Documented setups improved efficiency (if the documents are current).

Document the following:

Naming Standard and Folder Structure

50. Follow a documented naming convention and folder structure. Consistent naming and folder structure makes it easier to find things, and to figure out what things are.

You will most probably want to create your own naming convention and folder structure. Here is one as an example.

Naming General Principles

  1. Call a thing what it is. A bird should be called Bird.
  2. Choose names that can be pronounced and remembered. If you make a Mayan game, do not name your level QuetzalcoatisReturn.
  3. Be consistent. When you choose a name, stick to it.
  4. Use Pascal case, like this: ComplicatedVerySpecificObject. Do not use spaces, underscores, or hyphens, with one exception (see Naming Different Aspects of the Same Thing).
  5. Do not use version numbers, or words to indicate their progress (WIP, final).
  6. Do not use abbreviations: DVamp@W should be DarkVampire@Walk.
  7. Use the terminology in the design document: if the document calls the die animation Die, then useDarkVampire@Die, not DarkVampire@Death.
  8. Keep the most specific descriptor on the left: DarkVampire, not VampireDark; PauseButton, notButtonPaused. It is, for instance, easier to find the pause button in the inspector if not all buttons start with the word Button. [Many people prefer it the other way around, because that makes grouping more obvious visually. Names are not for grouping though, folders are. Names are to distinguish objects of the same type so that they can be located reliably and fast.]
  9. Some names form a sequence. Use numbers in these names, for example, PathNode0, PathNode1. Always start with 0, not 1.
  10. Do not use numbers for things that don’t form a sequence. For example, Bird0, Bird1, Bird2 should be Flamingo, Eagle, Swallow.
  11. Prefix temporary objects with a double underscore __Player_Backup.

Naming Different Aspects of the Same Thing

Use underscores between the core name, and the thing that describes the “aspect”. For instance:

Do not use this convention just to distinguish between different types of items, for instance Rock_Small, Rock_Large should be SmallRock, LargeRock.

Structure

The organisation of your scenes, project folder, and script folder should follow a similar pattern.

Folder Structure

Materials
GUI
Effects
Meshes
   Actors
      DarkVampire
      LightVampire
      ...
   Structures
      Buildings
      ...
   Props
      Plants
      ...
   ...
Plugins
Prefabs
   Actors
   Items
   ...
Resources
   Actors
   Items
   ...
Scenes
   GUI
   Levels
   TestScenes
Scripts
Textures
GUI
Effects
...

Scene Structure

Cameras
Dynamic Objects
Gameplay
   Actors
   Items
   ...
GUI
   HUD
   PauseMenu
   ...
Management
Lights
World
   Ground
   Props
   Structure
   ...

Scripts Folder Structure

ThirdParty
   ...
MyGenericScripts
   Debug
   Extensions
   Framework
   Graphics
   IO
   Math
   ...
MyGameScripts
   Debug
   Gameplay
      Actors
      Items
      ...
   Framework
   Graphics
   GUI
   ...

How to Re-implement Inspector Drawing

1. Define a base class for all your editors

BaseEditor<T> : Editor 
where T : MonoBehaviour
{
   override public void OnInspectorGUI()
   {
      T data = (T) target;
 
      GUIContent label = new GUIContent();
      label.text = "Properties"; //
 
      DrawDefaultInspectors(label, data);
 
      if(GUI.changed)
      {         
         EditorUtility.SetDirty(target);
      }
   }
}

2. Use reflection and recursion to do draw components

public static void DrawDefaultInspectors<T>(GUIContent label, T target)
   where T : new()
{
   EditorGUILayout.Separator();
   Type type = typeof(T);      
   FieldInfo[] fields = type.GetFields();
   EditorGUI.indentLevel++;
 
   foreach(FieldInfo field in fields)
   {
      if(field.IsPublic)
      {
         if(field.FieldType == typeof(int))
         {
            field.SetValue(target, EditorGUILayout.IntField(
            MakeLabel(field), (int) field.GetValue(target)));
         }   
         else if(field.FieldType == typeof(float))
         {
            field.SetValue(target, EditorGUILayout.FloatField(
            MakeLabel(field), (float) field.GetValue(target)));
         }
 
         ///etc. for other primitive types
 
         else if(field.FieldType.IsClass)
         {
            Type[] parmTypes = new Type[]{ field.FieldType};
 
            string methodName = "DrawDefaultInspectors";
 
            MethodInfo drawMethod = 
               typeof(CSEditorGUILayout).GetMethod(methodName);
 
            if(drawMethod == null)
            {
               Debug.LogError("No method found: " + methodName);
            }
 
            bool foldOut = true;
 
            drawMethod.MakeGenericMethod(parmTypes).Invoke(null, 
               new object[]
               {
                  MakeLabel(field),
                  field.GetValue(target)
               });
         }      
         else
         {
            Debug.LogError(
               "DrawDefaultInspectors does not support fields of type " +
               field.FieldType);
         }
      }         
   }
 
   EditorGUI.indentLevel--;
}

The above method uses the following helper:

private static GUIContent MakeLabel(FieldInfo field)
{
   GUIContent guiContent = new GUIContent();      
   guiContent.text = field.Name.SplitCamelCase();      
   object[] descriptions = 
      field.GetCustomAttributes(typeof(DescriptionAttribute), true);
 
   if(descriptions.Length > 0)
   {
      //just use the first one.
      guiContent.tooltip = 
         (descriptions[0] as DescriptionAttribute).Description;
   }
 
   return guiContent;
}

Note that it uses an annotation in your class code to generate a tooltip in the inspector.

3. Define new Custom Editors

Unfortunately, you will still need to define a class for each MonoBehaviour. Fortunately, these definitions can be empty; all the actual work is done by the base class.

[CustomEditor(typeof(MyClass))]
public class MyClassEditor : BaseEditor<MyClass>
{}

In theory this step can be automated, but I have not tried it.

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