[Bf-committers] Expanding the number of layers in Blender

Martin Poirier theeth at yahoo.com
Tue Dec 18 20:58:35 CET 2007


--- Timothy Baldridge <tbaldridge at gmail.com> wrote:

> That's the nice thing about bit fields. You can have
> object on
> multiple layers. I'd recomend doing a bit field
> array, where each byte
> the array represents 8 layers. But still you will
> have to iterate over
> the entire array to see if the object should be
> drawn, where as now
> it's as simple as:
> 
> if (objectmask & viewmask) {
>      draw_object();
> }
> 
> You will have to do this with a bitfield array:
> 
> for (x = 0; x < bfsize; x++){
>      if (objbf[x] & viewmask[x]) {
>           draw_object();
>           break;
>      }
> }

If bfsize is constant, compilers will most likely
unroll that into nice fast code which would be faster
than using liked list to represent belonging to a
layer.

Martin


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