Re: Memory management in games

[David Botton <david@botton.com>]

Please see these two articles in the advanced section of the AdaPower 
Source Code Treasury

Memory Management with Storage Pools (Anh Vo)
http://www.adapower.com/index.php?Command=Class&ClassID=Advanced&CID=222

Memory Management with Storage Pools - Update (Anh Vo)
http://www.adapower.com/index.php?Command=Class&ClassID=Advanced&CID=223

You probably should look through the advanced section in general for 
other good ideas and practices.

David botton


On 2004-11-27 14:48:48 -0500, "Luke A. Guest" 
<laguest@n_o_p_o_r_k_a_n_d_h_a_m.abyss2.demon.co.uk> said:

> Hi,
> 
> Further to my posts in the game dev thread, I've decided to go back on my
> original thoughts and do the game engine in Ada (I can always *cough* port
> *cough* gnat *cough* ;-D).
> 
> Now, one of my design requirements is that I *must* be able to see *all*
> memory allocations and track them, this is so I can build in debugging
> tools into my engine. I have just done this in C++ by overriding the
> global new/delete operators and using macros to redefine
> new/delete/mallo/free/calloc/etc. to point to my new memory management
> class. These macros also pass the filename and line number from where the
> memory was allocated. Also, this class keeps track of all allocations in a
> list template. I currently just dump out the contents of the list on exit.
> 
> So, I need to be able to do the same in Ada. Enter Storage Pools, ok, it's
> not difficult to write a pool class, I've just written a simple one. But,
> what a game engine requires is the ability to allocate a big block of
> memory and then allocate other blocks from this, so it's like a
> hierarchical pool system.
> 
> e.g. Under Linux, I might allocated a block of memory to use for the
> entire game (from a start up script), say 50Mb and this will be used for
> this session
> 
> e.g On a PS2 we have something more challenging, the underlying OS needs
> some memory to load the game ELF and have some memory to use for it's own
> data structures, so in the game I say, give me 25Mb for this session.
> 
> Then from this pool, other pools/objects are allocated. So, I need a way
> to override the default memory allocation method for everything, including
> library routines. Can this be done portably? I know I can specify the
> T'Storage_Pool for a type, will this work for libgnat.a types as well?
> 
> I've seen that GNAT provides the System.Memory package, this isn't
> standard, so should I just go out of my way and import the memory
> allocation functions I require (malloc on Linux, memalign on PS2, etc.)?
> 
> Also, what would be the best method of passing the function name where the
> allocation call is, through to the allocator, so that I can show where an
> allocation was made? I could use gnatprep I suppose, but obviously would
> prefer to be portable. FYI, there will be two builds as memory allocation
> tracking would not be in the final release mode build as it's extra
> overhead.
> 
> Thanks,
> Luke.