Hi Paul,
We might be looking at two bugs here:
1) .osg isn't supporting shared primtive sets (what is the status
for the other
formats like .osgt?)
2) merge geometry is not handling cases where primitives are shared,
I'm not quite sure whether this is really a bug though, in some cases
merging only non shared primitive sets might be the thing to do, but in
other cases duplicating shared primtive sets and then merging might
be better. Perhaps an option for choosing would be appropriate, or
perhaps just leaving it to users to explictly duplicated shared elements
in the scene graph.
I think the first thing to tackle is item 1 as it's clearly a bug.
Robert.
On 4 November 2011 17:01, Paul Martz <[email protected]> wrote:
> Hi all -- I've attached a test file that demonstrates a mismatch in the
> behavior of the native OSG plugins and the osgUtil Optimizer. In a nutshell,
> when FLATTEN_STATIC_TRANSFORMS_DUPLICATING_SHARED_SUBGRAPHS copies a
> subgraph, it fails to set the DEEP_COPY_PRIMITIVES flag bit, resulting in
> PrimitiveSet instances being shared by the copied Geometry objects
> (Optimizer.cpp 4666). However, none of the native serializers (.osg, .ive,
> .osgt, or .osgb) support shared PrimitiveSets.
>
> You can reproduce the resulting inconsistency with the following steps:
> set OSG_NOTIFY_LEVEL=INFO
> set
> OSG_OPTIMIZER=FLATTEN_STATIC_TRANSFORMS_DUPLICATING_SHARED_SUBGRAPHS:MERGE_GEOMETRY
> osgconv test.osg result.osg
> This incorrectly fails to merge the Geometry objects because the shared
> PrimitiveSets created in the first pass prevent the merging of Geometry
> objects. (Output shows 4 Geometry objects, indicating a failure to merge.)
>
> In contrast:
> set OSG_OPTIMIZER=FLATTEN_STATIC_TRANSFORMS_DUPLICATING_SHARED_SUBGRAPHS
> osgconv test.osg intermed.osg
> set OSG_OPTIMIZER=MERGE_GEOMETRY
> osgconv intermed.osg result.osg
> This process correctly merges the Geometry objects, because going out to
> file eliminates the shared PrimitiveSets, allowing the MERGE_GEOMETRY to
> correctly perform its task. (Output shows 2 Geometry objects, indicating a
> successful merge.)
>
> Intuitively, both cases should behave the same, either they should both
> merge, or both fail to merge. My preference would be to deep copy the
> PrimitiveSets in the Optimizer so that both cases merge. Are there any
> reasons why I shouldn't proceed with such a fix?
>
> Thanks,
>
> --
> -Paul Martz Skew Matrix Software
> http://www.skew-matrix.com/
>
>
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>
>
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