IPhone Optimization Tips

Revision as of 17:31, 8 November 2010

• Ragdolls make the game significantly slower. Give the player the option to use ragdolls or not.
• Skinned Mesh Renderer:
  • Set Quality to 1 Bone
  • Uncheck Skin Normals
• Set iPhone Script Call Optimization to “Fast but no Exceptions”. Naturally, set it to “Slow and Safe” during debug.
• Don’t play new compressed music at the middle of the game, it freezes the game for a short duration. Play it at scene initialization instead.
• Remove most (or all) lights from your scene. Use baked lighting instead.
• In Project Settings > Time: Set Maximum Allowed Timestep to 0.1 bringing the game’s framerate to at least a guaranteed 10 fps minimum, assuming your bottleneck is coming from the physics. Use the profiler to find out where your bottleneck is.
• Keep drawcalls under 20 if at all possible

Scripting tips:

• Avoid SendMessage() calls, create a script/class variable to hold a reference to the specific scripts you want to call, and use a standard method call. Method calls are ~100x faster than SendMessage()!
• Avoid Find or GetComponent type calls during normal runtime if at all possible, use script variables to hold references.
• initialize script variables in Awake()

For example in Javascript:

var myScriptRef : MyScriptName;
var anotherScriptRef : AnotherScriptName;
var playerGO : GameObject;

function Awake() {
   myScriptRef = FindObjectOfType(MyScriptName);// returns the first active instance of MyScriptName script in the scene/level
   if(myScriptRef == null) 
	Debug.Log("ScriptName::Awake() myScriptRef - MyScriptName is not found!  Key function NOT possible!");

   var gameObjectFind : GameObject = GameObject.Find("MyGameObject");
   if(gameObjectFind == null) 
	Debug.Log("ScriptName::Awake() gameObjectFind - MyGameObject is not found!  Key function NOT possible!");	
   else {
	anotherScriptRef =  gameObjectFind.GetComponent(AnotherScriptName);
   }

   playerGO = GameObject.FindWithTag("Player"); // finds my player object using the GameObject.tag field
   if(playerGO == null) 
	Debug.Log("ScriptName::Awake() playerGO - Player is not found!  Key function NOT possible!");
}

• Limit FixedUpdate function complexity, perform most of your game processing in Update or LateUpdate
• process player input (touches, accelometer, etc...) in Update
• use timed and framerate function calling to reduce heavy processing every frame. For example, instead of processing an entire array of gameObjects every frame, create a coroutine, and call it on a frame schedule.
• Ensure complex coroutines aren't called multiple times in a single frame

In Javascript:

var fixedFrameProcessingRate : int = 10; // we'll use every 10 frames private var currentFrame : int = 0; private var frameImCurrentlyProcessing : int = 0;

function Update() {

  // let's call DoComplexProcessing based on the setting fixedFrameProcessingRate 
  if(Time.frameCount >= currentFrame) {
     DoComplexProcessing();
     currentFrame = Time.frameCount + fixedFrameProcessingRate;
  } 

  // this method will only execute once during a given frame
  DoMeOnlyOncePerFrame();

}

function DoComplexProcessing() {

 // do something complex here

}

function DoMeOnlyOncePerFrame() {

 if(frameImCurrentlyProcessing == Time.frameCount)      
   return;
 else {
    frameImCurrentlyProcessing = Time.frameCount;
    // do something complex here
 }

}