[Bf-committers] BMesh operator questions

Campbell Barton ideasman42 at gmail.com
Sat Mar 17 06:10:29 CET 2012

On Sat, Mar 17, 2012 at 2:09 PM, Nicholas Bishop
<nicholasbishop at gmail.com> wrote:
> A couple of BMesh questions I could use some guidance on:
> 1. Is it safe to hang on to element pointers after running an
> operator? E.g. if I have a BMFace pointer, then run a BMesh operator
> that can add faces, but never delete them, is my BMFace pointer still
> guaranteed to be valid?

Yes the pointers remain valid, but worth noting - the way BLI_mempool
works it can add faces in free slots of existing chunks - so a face
may be added *before* existing faces.
The pointer will be valid but the index may change.

> 2. Can operator slots of type 'buffer' be filled without using oflags
> or hflags? Something akin to BMO_slot_map_insert() I guess, but for
> buffers. I ask because it seems like using flags will force a lot of
> operations to be linear (relative to the number of elements) where
> they might otherwise be constant. E.g. maybe I already have an array
> of the three edges I want to put in a buffer slot, but instead I have
> to set a flag for the three edges, then internally all edges' flags
> must be checked? Unless internally it is doing something to avoid
> checking all edges?

Its not done much (at all?) but think it would be fine to just add
elements with BMO_slot_map_insert() directly, probably some parts of
our code could be optimized by doing this.

The bmesh operator code is not totally optimal anyway - the way it
allocates flags and frees per call, and uses flags - seems like its
intended for convenience more then speed.

> Thanks,
> -Nicholas
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- Campbell

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