Hello Robert,
I have already implemented the scenario that i am looking for in OpenGL by
setting the glUseProgram(0) to glUseProgram(whichShader).
And i wanted to implement the same scenario in OSG. None of the example that
accompany the repository have implemented
the scenario that i m looking for except a discussion in the mailing list.
One of it was forwarded to you in the previous mail since among many other
suggested methods yours one to be the better one considering the fact that
you described the cons of the others.
Regards
Sajjad
-- Forwarded message --
From: Robert Osfield
Date: Tue, Apr 28, 2009 at 10:34 AM
Subject: Re: [osg-users] Fwd: Fwd: shader implementation - newbie
To: OpenSceneGraph Users
Hi Sajjad,
This is almost certainly more complicated than you need. As I said I
not have to time to nurse maid you through learning about shaders.
The OSG has a number of places where it use shaders in its
implementation, and number of examples as well.
Robert.
On Tue, Apr 28, 2009 at 8:32 AM, ami guru wrote:
> Hello Robert,
>
> After going through the archives i have found that it has already
discussed
> the issue that is not present yet within the API.
>
> Something like SwitchStateSet.
>
> But you did have pave a way to get that done. I am not sure if anyone has
> done that and updated the repository.Your recommendation is as follows:
>
>
'
>
> Re: [osg-users] Rendering the scene multiple times with different shaders.
>
> Robert Osfield
> Thu, 22 May 2008 08:10:39 -0700
>
> Hi Stephane,
>
> On Thu, May 22, 2008 at 4:02 PM, Stephane Lamoliatte
> <[EMAIL PROTECTED]> wrote:
>> Robert, don't you think this feature could be done by some kind of custom
>> osgFX::Effect node ?
>
>
> You could probably write a custom node that overrides the cull
> callback and post processes/rebuild the StateGraph it's generated. I
> don't think this is an example of a osgFX::Effect though, such as
> class might belong in osgFX though.
>
>
> It might still be most efficient to tailor CullVisitor to do the
> remapping of the StateSet, such as by tweaking the pushStateSet
> method, that currently looks like:
>
> inline void pushStateSet(const osg::StateSet* ss)
>
> {
> _currentStateGraph = _currentStateGraph->find_or_insert(ss);
> if (_numberOfEncloseOverrideRenderBinDetails==0 &&
> ss->useRenderBinDetails() && !ss->getBinName().empty())
>
> {
> _currentRenderBin =
> _currentRenderBin->find_or_insert(ss->getBinNumber(),ss->getBinName());
> }
> if
> (ss->getRenderBinMode()==osg::StateSet::OVERRIDE_RENDERBIN_DETAILS)
>
> {
> ++_numberOfEncloseOverrideRenderBinDetails;
> }
> }
>
> One could possible add a check against an internal map of StateSet
> inside this function. The only draw back to adding this into
>
> CullVisitor is that it'd add an extra bool check to see if one needed
> to do the look up. i.e.
>
>
> inline void pushStateSet(const osg::StateSet* ss)
> {
> if (_doStateSetSubstituion)
>
> {
> StateSetMap::iterator itr =
> _statesetSubsitutionMap.find(ss);
> if (itr!= _statesetSubsitutionMap.end()) ss =
> itr->second.get();
> }
> _currentStateGraph = _currentStateGraph->find_or_insert(ss);
>
> if (_numberOfEncloseOverrideRenderBinDetails==0 &&
> ss->useRenderBinDetails() && !ss->getBinName().empty())
> {
> _currentRenderBin =
> _currentRenderBin->find_or_insert(ss->getBinNumber(),ss->getBinName());
>
> }
> if
> (ss->getRenderBinMode()==osg::StateSet::OVERRIDE_RENDERBIN_DETAILS)
> {
> ++_numberOfEncloseOverrideRenderBinDetails;
> }
> }
>
>
> The custom node would then populate the push and pop
> _statesetSubsitutionMap settings in its cull traversal.
>
> Feel free to experiment with such an implementation and it works out
> send it in to osg-submissions for consideration as
>
> part of the core OSG.
>
> Robert.
>
>
>
>
***''
>
> If i have understood that correctly you have suggested to to tailor the
> CullVisitor which means to make a subclass of CullVisitor like
> MyCullVisitor and override the functions that you have specified. Now i
want
> to get that implemented. And i need your suggestion on the items i have to
> cover more to understand and implement the scenario.
>
> First of all is there any example in OSG that implemented the CullVisitor
> concept. When i have have impelemented it how do i use that from the my
> createSceneGraph() function when i have the very same model that will be
> loaded with different shaders with user interaction.
>
>
> Regards
> Sajjad
>
> -
