Re: [GD-General] Zen of Model Rendering

[Thatcher U. <tu...@tu...>]

On Jan 18, 2003 at 08:07 +1100, Chris Brodie wrote:

> For a surface to be rendered you of course need a separate
> DrawArrays call (or something similar in D3D). I knew this so I used
> separate index lists. Now I render the triangles and it all works
> well, however performance bites and I have a thought. I have a
> single Vertex array. If I had an object of 10k polys using 10
> textures I now presented the vertex array to the API 10 times. This
> has got to be bad, since on average 90% of those verts won't even be
> needed. I guess I've found my performance problem.
> 
> So I decompose the giant vertex array in to mini vertex arrays per
> surface and remap the indices back in to the new array. This works,
> but I'm left feeling all those duplicate verts in each array (along
> seams for example) are evil.
> 
> Have I don't the right thing? Is this 'the' way to do it?

Yes, this is the normal way.  The duplicated edge verts are usually
much less evil than the alternatives.

-- 
Thatcher Ulrich
http://tulrich.com