[osg-users] how to get the handle of opengl texture that corresponds to a OSG::Texture

[Qingjie Zhang]

Hi Robert,

I fount it! I'm so sorry for my carelessness.
Thank you soooo much!!

Qingjie.


robertosfield wrote:
> Hi Qingjie,
> 
> 
> This is no longer about the OSG, it's about C++.  Your mistake is straight forward C++ issue of not matching the base classes parameters when overidding a method:  The Camera::DrawCallback base class is:
> 
> 
>         /** Draw callback for custom operations.*/
>         struct OSG_EXPORT DrawCallback : virtual public Object
>         {
>             DrawCallback() {}
> 
>             DrawCallback(const DrawCallback&,const CopyOp&) {}
> 
>             META_Object(osg, DrawCallback);
> 
>             /** Functor method called by rendering thread. Users will typically override this method to carry tasks such as screen capture.*/
>             virtual void operator () (osg::RenderInfo& renderInfo) const;
> 
>             /** Functor method, provided for backwards compatibility, called by operator() (osg::RenderInfo& renderInfo) method.*/
>             virtual void operator () (const osg::Camera& /*camera*/) const {}
>         };
> 
> 
> Please look carefully at your own code to see your mistake.
> 
> 
> Robert.
> 
> 
> 
> 
> 
> 
> On 10 September 2015 at 04:42, Qingjie Zhang < ()> wrote:
> 
> > Hi Robert,
> > To get the handle of opengl texture, I attached a DrawCallback to the main camera, doing like these codes:
> > struct MyCameraPostDrawCallback : public osg::Camera::DrawCallback
> > {
> >         virtual void operator()(const osg::RenderInfo &renderInfo)
> >         {
> >                 int contextID = renderInfo.getContextID();
> >                 GLuint frontTexHandle = m_frontTex->getTextureObject(contextID)->id();
> >                 GLuint backTexHandle = m_backTex->getTextureObject(contextID)->id();
> >         }
> > };
> > camera->setPostDrawCallback(new MyCameraPostDrawCallback);
> > 
> > But the function operator() int the callback does not run, I tried setPostDrawCallback() and setFinalDrawCallback(), they were the same.
> > I was thinking that the DrawCallback would run every frame...
> > Can you tell me when the callback runs?
> > And, to get the handle,  is it right to attach DrawCallback to camera? If not, can you tell me the detailed method to get the handle?
> > 
> > Thank you,
> > 
> > Qingjie.
> > 
> > 
> > robertosfield wrote:
> > 
> > > Hi Qingjie,
> > > On 9 September 2015 at 09:27, Qingjie Zhang < ()> wrote:
> > > 
> > > 
> > > > Do you mean the DrawCallback in the Camera class, which contains
> > > > virtual void operator () (osg::RenderInfo& renderInfo) ? And here I can use the RenderInfo right?
> > > > 
> > > > 
> > > 
> > > 
> > > Yes.  You can attach draw callbacks to Drawables, StateAtttribute and Camera's.
> > > 
> > > 
> > >  
> > > 
> > > 
> > > > 
> > > > As I know, the following code can get a contextID:
> > > > camera->getGraphicsContext()->getState()->getContextID();
> > > > Is this contextID same as the upper one?
> > > > 
> > > > 
> > > 
> > > 
> > > If you only need the contexID then getting it from the graphics context is perfectly fine.  What route to take depends on when you need to do your queries.
> > > 
> > > 
> > > I would add that the TextureObject for each context is only created by the draw thread for each context, so the TextureObject won't exist right away when you create your osg::Texture and assign them to the scene graph.
> > > 
> > > 
> > > 
> > > Robert.
> > > 
> > >  
> > > 
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> > 
> > 
> > 
> > 
> > 
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> > 
> > 
> > 
> 
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