Hi Gianluca, osg_ModelViewProjectionMatrix is the OSG's equivilant to gl_ModelViewProjectMatrix, and there is a mechanism in osg::State that can replace gl_ModelViewMatrixProjectMatrix usage in shaders with the osg_ equivalent at runtime. There isn't however a general customizable support for setting and substituting your own uniforms in this role.
In your own application I'd suggest when you set up your osg::Shader with the shader source you replace the MVP_matrix usage with gl_ or osg_ equivalent. Robert. On 2 September 2014 10:59, Gianluca Natale <[email protected]> wrote: > Hi all. > > First of all, sorry if mine is a silly question, I'm quite new to using > shaders in OSG. > > > > My scenario is this: > > I have a vertex shader that gets as uniform in-variable the model view > projection matrix, "MVP_matrix" is the name of that variable in my shader. > > The shader is written in GL4.3, so I cannot rely upon the deprecated > built-in variable gl_ModelViewProjection matrix. > > Now, I have to attach such shader in a program that is set in a state set > used to render my geometry (that state set is attached to the geode that > contains my drawable, where the geometry is defined). > > So, I would like that OSG automatically passes the model view projection > matrix to my shader during rendering traversal. > > I've seen in some OSG code that there is a predefined in-variable called > "osg_ModelViewProjectionMatrix" that I think is filled by OSG during > rendering traversal with the current model view projection matrix. Is that > correct? > > So, should I rely upon it in my shader, basically replacing my > "MVP_matrix" with "osg_ModelViewProjectionMatrix"? > > > > Further question: unfortunately the shader I have to use is shared among > other applications in my company, and not all of them use OSG for rendering > (some use pure OpenGL) L > > So it's likely that I cannot modify it (otherwise I should ask all > developers to change the name of the in-variable they pass directly to the > shader to "osg_ModelViewProjectionMatrix"). > > Hence the question: if I'm forced to use "MVP_matrix", is there a way I > can tell OSG to set automatically the value of > "osg_ModelViewProjectionMatrix" to "MVP_matrix" at run-time, i.e. during > rendering traversal? > > > > Thanks, > > Gianluca > > > > _______________________________________________ > osg-users mailing list > [email protected] > http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org > >
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