Harder, Better, Faster, Stronger · Harder, Better, Faster, Stronger Code Style and Architecture in Unity3D Richard Fine Sunday, 29 April 12. Introduction What is this talk all about?

Harder, Better, Faster, StrongerCode Style and Architecture in Unity3D

Richard Fine

Sunday, 29 April 12

Introduction

What is this talk all about?

1000 ways to SkinnedMeshRender a cat

It’s not what you do, it’s how you do it

(mostly)

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Architectural Foundations

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Pressing Concerns

Understandability

Flexibility

Extendability

Debuggability

Achievability

RunVeryFastability Performance

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Understandability

The Zen of Ronseal

Comments not needed

Short names do not run faster

AutoComplete

Be concise, not compact

Be consistent, not chaotic

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Flexibility and Extendability

You are frequently going to want to change your code a lot

Fearlessness through controlled coupling

Need To Know Basis

Think in sets

Be Liberal

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Performance

First make it work. Then make it fast.

But plan ahead for that...

Bad performance comes from restrictive architectures

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Technical Detailsthat I have known and loved

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InitialisationAwake, OnEnable, Start...?

Dependencies

Inter-object

Intra-object

Configuration

Edit and Continue

Frametime spikes

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InitialisationAwake

During scene load

During Instantiate()

Always after deserialization

No inter-object ordering with the same type

Not called on playmode recompileThus:

Good for self-init of public stateless things

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InitialisationOnEnable

Called immediately after Awake(), if created enabled

Called whenever set enabled, if not

Called after playmode recompile

Can’t guarantee other objects are Awake() yetThus:

Good for self-init of private and stateful things

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InitialisationStart

Before first Update

Not called if component is disabled

Not called on playmode recompile

Same frame as Instantiate(), but later on

Can be a coroutineThus:

Good for one-time-only public inter-object init

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InitialisationLazy Init

Initialise on first use

Caching properties:private MyComponent _theComponent;public MyComponent TheComponent{get {if (!_theComponent) _theComponent = GetComponent<MyComponent>();return _theComponent;

}}

Con: Unpredictable frametime spikes

Pro: Easy to change later onSunday, 29 April 12

InitialisationCustom Events

Do your own damn initialisation!

Extend Unity’s message list

Allows for more modular initialisation

Required for object pooling/recycling

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Messaging(Send|Broadcast)Message[Upwards]

Pros:Don’t need to know the receiver

Can be received by multiple components

Can start coroutines

Can be configured easily

ConsSlower than direct calls and delegates

Typo-prone

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MessagingEvent Objects

Wrap event data in a class (e.g. Collision)

Lets you pack more than one parameter

It’s a regular class, though:

It can have methods

It can have mutable state

This makes for some very nice patterns...

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MessagingExample: Bullet Damage System

RaycastAll and sort by distance

Pack shot information into a DamageEvent “evt”

SendMessage “TakeDamage” (evt) to each colliderSet evt.continue = false to stop the shot

Set evt.amount *= 0.5 to reduce damage

Set evt.type |= DamageTypes.Fire to ignite shot

Set evt.direction and re-raycast to ricochet

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MessagingExample: Save/Load system

Create a new List<SaveData> ‘saveDatas’

BroadcastMessage “Save” (saveDatas)

Receivers add their save data to the listOpportunity to ensure receiver is in a consistent state

Include some way to tell who’s data is who’s

Store list in memory for quicksave, write to disk for full

BroadcastMessage “Load” (saveDatas) to load

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ScriptableObjectNot just your regular Object

Custom asset types

Can’t be added to the scene

Don’t support components

No Start/Update, Coroutines, Invoke, messages, etc

Good for “data blobs,” tables, etc

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ScriptableObjectExample: Speech Table

Store speech for an NPC

Multiple variants of lines, to avoid repetition

Subtitles

Easy playback

Different speech for different NPCs, but same tech requirements

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ScriptableObjectExample: Speech Table

[Serializable] class SpeechTableEntry {

string Id;

AudioClip[] Clip;

string[] Subtitle;

}

class SpeechTable : ScriptableObject

{ SpeechTableEntry[] Entries; }

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ScriptableObjectExample: Speech Table

Creating a new speech table:table = ScriptableObject.CreateInstance<SpeechTable>();

AssetDatabase.CreateAsset(table, “Speech.asset”);

Edit in the inspector like anything elseWrite a custom inspector for great justice

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ScriptableObjectExample: Speech Table

Reference the table like any other object:SpeechTable MySpeechTable;

Use case: SpeechPlayer.PlayLine(“hurt”);

Find the entry with the given IDvar entry = MySpeechTable.Entries.First(e => e.Id == id);

Pick an AudioClip from the entry and play itAt random

Using an LRU

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ScriptableObjectversus Prefabs

“Can’t you do all this with prefabs?”Mostly, yes:

Can use a component on a prefab as a ‘data dump’

Add components to provide extra data in a pluggable fashion

But not quite:

Prefabs don’t work so well in the Object Browser, and can be inconvenient to edit

Separate files for separate data is friendlier to teams

May not want to let it be added to the scene

Violates the Ronseal principle

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I’ve probably run out of time by this point

So I’ll stop here.

Questions, Comments, Counterarguments?

Twitter: @Superpigemail: rfine@tbrf.netSunday, 29 April 12