RE: [Algorithms] Scalability costs

[Tom F. <to...@mu...>]

> From: Jamie Fowlston [mailto:j.f...@re...]

[snip]

> Not regardless of hardware. For us, drawing several instances 
> of the same model
> saves us DMA bandwidth. CLOD trashes the ability to do that. 

VIPM won't. Since you use the same vertex data for all levels of detail,
multiple instances are very cheap. All you change is a bunch of indices. On
two of the future consoles I know well enough(*) to comment on, this will be
nice and fast. You'll need to DMA across the new indices, but that's tiny
amounts of memory. You may even be able to do the VIPM expands/collapses on
the ... you know ... thing that does the transforms - the expand/collapse
routine is absurdly simple. Which will make multiple instances awesomely
cheap!

Oh dear - I'm off again about VIPM. Sorry list :-)

> Polygons are very
> cheap to draw, so we might as well draw them.... Unless 
> anyone else knows
> better? :)
> 
> Maybe when we've had more experience of the machine we'll 
> change our minds. :)
> 
> Jamie

Tom Forsyth - Muckyfoot bloke.
Whizzing and pasting and pooting through the day.


(*) The one I don't know about, I knew exactly one hard fact about it - its
name. And then they changed it, and I can't remember what to. So I now know
precisely zero about it :-)