[osg-users] Value of a variable in shaders?

[Robert Osfield]

Hi Marlin,

On Fri, 28 Sep 2018 at 07:40, Robert Osfield <robert.osfield at gmail.com> wrote:
> To pass data into shaders you have use a combination of uniforms (osg::Unfiorm), textures (osg::Textre*) and vertex attributes.  With recent 3.4.x onwards you also have the option of passing in constants via #prama(tic) shader composition system that passes #define values into the compilation of shaders.

Seems I mis-read your question :-)

Testing internal values in shader is an easy thing to do, what I end
up doing is build up shaders bit by bit making sure each bit works on
it's own before I assemble it into a more complex shader.  When I want
to test values I usually just set the fragment colour value, though
often this will have a processed version of the value to make it
visible.  You can use #ifdef's in shaders to toggle the debug code
paths and even toggle these paths on/off via the
osg::StateSet::setDefine("ENABLE_DEBUG");

Robert.