Overdraw Time

Now there is a render mode for show how much of the scene is consuming overdraw time however there is no documentation on what overdraw time is. What is overdraw time?

 

I did a quick search on the internet from "overdraw time game engines" and from what i read, overdraw time is the time the engine takes to draw element that are not on the screen (this is what i kind of though it was). Is this what the overdraw render mode refers to?

 

There's a view mode in Unity that draws the overdraw regions in a different color - I forget here at work how to bring up that mode.

It was a cool orange color, 2d looking dispay - it made me want to use that render style in my game that's how cool it looks!

Basically Overdraw is what it sounds like - one (or more) objects that are drawn over or on top of another - in effect, wasted drawing time.

Ideally to save processing time you want to draw ONLY what is visible in the camera and nothing more.

This was one of the reasons why backface culling was introduced into 3D graphics; if the polygon is facing away from you, don't bother to draw it (and save time)...

If you have 2 objects both facing forward but one is in front of the other, unless you have some real fancy depth sorting or clipping function in place, both objects will still be drawn, even though all of one (or half etc.,) can be skipped.

The overdraw view in Unity lets you see the overdrawn areas in your scene providing you with information that you can use to perhaps reduce the amount of overdraw and improve your scene's performance.

-Will

 

So if the poly is facing away from you it will not be in the overdraw ?

In other words, if i have an object where 1 poly is facing towards you and the other 100.000 are facing away from you unity culls them automatically and everything is peachy ?

Does this also apply to the iphone ?