Thanks Erkki,

I hope to be able to finish the re-coding of my mesh generator this weekend
and i report back.

Best reagrds,

Jan

Erkki.Sondergaard wrote:
>On Tue, 18 Feb 2003 05:58:01 EST, "idoit" <ido### [at] tiscalise> wrote:
>>Could someone with intimate knowledge of the PovRay mesh data structures
>>or other relevant experiences advise me if rendering speed could be
>>improved by laying out the vertex vectors by iterating over the Z-axis
>>values first and keeping the X-axis constan as far as possible.
>
>It's been some years since I messed with this lets see how much I
>remember. POV-Ray allocates storage for each object as it's parsed, in
>the order the objects are parsed. Then all objects are traversed to
>build the bounding tree. Once rendering the system has to page in as
>the objects are referenced, thus locality of reference has a lot to
>say in avoiding paging. If the bounding tree doesn't fit in real
>storage you're in for a really long trace.
>
>>I.E. in pseudo code change:
>>for (z = 0; z < z_max; z++) for (x = 0; x < x_max; x++)  { print (<x,y,z>)}
>>to
>>for (x = 0; x < x_max; z++) for (z = 0; z < z_max; z++)  { print (<x,y,z>,)}
>
>Should make quite a difference, but reflections and light rays will
>cause objects to be referenced 'outside' the area they occupy
>on-screen. With 'well-behaved' meshes you can have memory usage up to
>4-8 times real memory without much paging, once the bounding tree is
>built.
>
>/Erkki
>

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