how are arrays stored in memory in the iOs Player

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I am developing an iOs project which needs to store a lot of optimised level data.

Because I am developing for iOS I want the smallest memory foot print possible.

The data is a large number (tens of thousands) of simple structures e,g,

'MyVector' is a class with 3 int members x,y, and z

MyVector3[] a10000Vectors = new MyVector3[10000];

Does anyone know how an array of this kind would be stored in memory?

Is there a single block of memory with 30000 closely packed ints or is it this plus another array of 10,000 pointers into 10,000 addresses in this block or is it a list of 10,000 pointers and 10,000 separately allocated tiny blocks of memory or something else?

Also does it make a difference if these are structs or classes? Do structs and classes have the same distinction in Unity that they do under .Net/Mono. Are structs values and classes reference values?

Is it smaller to have 3 separate arrays of int one for each components of the vectors?

Thanks in advance for any help.

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Answer by Eric5h5 · Apr 05, 2012 at 04:50 PM

Unity uses Mono, so anything that applies to Mono applies to Unity. A Vector3 is 3 floats, so one Vector3 uses 12 bytes. There are no ints involved (although ints and floats both use 4 bytes.) Making 3 arrays of floats vs. 1 array of Vector3 makes no difference as far as memory goes; you are using the same amount of data both ways.

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Jumblegreen · Apr 05, 2012 at 05:07 PM 0

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Thanks for this.

Am I right in assu$$anonymous$$g that if you use classes ins$$anonymous$$d of structs there would be 10,000 separately allocations on the heap plus one for the list/array of pointers to those allocations?

eAi · Apr 05, 2012 at 05:13 PM 0

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Correct. In the case you specify, there should be 360,000 bytes allocated (plus some overhead, of course).

how are arrays stored in memory in the iOs Player

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