[osg-users] issue about getting the material properties from the current state in rendering info

[Farshid Lashkari]

Hi Gianluca,

Have you tried using "getLastAppliedAttribute" on the osg::State object?

const osg::Material* mat = dynamic_cast<const
osg::Material*>(state.getLastAppliedAttribute(osg::StateAttribute::MATERIAL));
if(mat)
{
    // do something with material
}

I've used this method to access attributes from the current state and it
has worked for me.

Cheers,
Farshid

On Tue, Jun 23, 2015 at 9:49 AM, Gianluca Natale <natale at europe.altair.com>
wrote:

>  Thanks Sebastian,
>
> I’m simply trying to get the alpha value of the diffuse component of the
> material properties, because I have to pass it to an underlying
>
> graphic library that I use for rendering that custom drawable.
>
>
>
> BTW, I further investigated.
>
> In the following function:
>
>
>
> State::captureCurrentState(StateSet& stateset)
>
>
>
> The _attributeMap actually contains as MATERIAL attribute exactly the
> pointer to the osg::Material property that I created.
>
> But in the attribute stack it appears as the ‘last_applied_attribute’, and
> ‘changed’ is set to true.
>
> For all other attributes the pointers stored in ‘last_applied_attribute’
> are correct as well, but ‘changed’ is set to false.
>
> Also, in that AttributeStack the member attributeVec contains just one
> element, that is not the correct one (it points to a different
> osg::Material).
>
> While for all the other attributes, which have ‘changed’ set to false,
> last_applied_attribute coincides with the first element in attributeVec.
>
>
>
> I don’t know anything of that code, but I don’t understand why
> osg::Material appears to be changed while other attributes not.
>
> Or should I use a different API to get the current osg::Material?
>
>
>
> Thanks,
>
> Gianluca Natale
>
>
>
>
>
> *From:* osg-users [mailto:osg-users-bounces at lists.openscenegraph.org] *On
> Behalf Of *Sebastian Messerschmidt
> *Sent:* martedì 23 giugno 2015 18:15
> *To:* OpenSceneGraph Users; Osg Users
> *Subject:* Re: [osg-users] issue about getting the material properties
> from the current state in rendering info
>
>
>
>
>
> Am 23.06.2015 18:05, schrieb Gianluca Natale:
>
> Hi all,
>
> I’m using OSG 3.0.1.
>
> I have an issue when I try to retrieve the material properties from the
> rendering info, in my custom drawable.
>
>
>
> To be clearer:
>
> I have a custom drawable, for which I implemented a
>
>
>
> myDrawable::drawImplementation(osg::RenderInfo& osgRenderInfo).
>
>
>
> When I try to get the material properties inside that function, by
> following code:
>
>
>
> osg::StateSet  drwbStateSet;
>
> osg::State *state = osgRenderInfo.getState();
>
> state->captureCurrentState(drwbStateSet);
>
>
>
> the returned material properties is invalid.
>
> Specifically, I put a breakpoint in following function:
>
>
>
> StateSet::setAttribute(StateAttribute *attribute,
> StateAttribute::OverrideValue value)
>
>
>
> that is called inside captureCurrentState.
>
> When the attribute is an osg::Material, the _ptr is different from the one
> allocated when the material has been set, in the state set associated to a
> parent node of that drawable.
>
> Furthermore, _userDataContainer is 0x0000000000000000, so no valid
> osg::Material is returned in the captured state set.
>
> User data defaults to nullptr. So if you're not setting it up that is
> expected.
> As you don't explain why you are trying to inspect state during draw it is
> hard to guess what you are after.
> I simply guess that your state is set up somewhere further up in the
> stategraph (i.e. in one of the parents) and that state is set up lazy.
> Maybe Robert can give some insights here.
>
>
>
>
>
> Any idea of the possible cause of the issue? Where did I go wrong?
>
> BTW, all other attributes (polygon offset, polygon mode, etc…) are
> returned correctly.
>
> Are you sure you are setting up an osg::Material state attribute somewhere?
>
>
>
> Thanks,
>
> Gianluca Natale
>
>
>
>
>
>
>
>
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