Stencil buffer issues

Graphics and GPU Programming Programming

Started by 3TATUK2 October 22, 2013 07:22 PM

2 comments, last by TheChubu 10 years, 5 months ago

3TATUK2

715

Author

October 22, 2013 07:22 PM

so i "sort of" figured out my issue with the stencil... http://i.imgur.com/v4abqYA.png

the yellow is the stencil rendering of a sphere, so only the pixels it hit are processed by fragment shader

The problem is where rendering multiple spheres close to eachother... the stencil setup is slightly incorrect and part of it gets

Any idea what i might need?

This is the current setup:


        glDepthFunc( GL_LESS );
        glStencilMask( 0xFF );

        glCullFace( GL_FRONT );
        glStencilFunc( GL_ALWAYS, 1, 0xFF );
        glStencilOp( GL_KEEP, GL_REPLACE, GL_KEEP );
        
        renderSpheres();

        glCullFace( GL_BACK );
        glStencilFunc( GL_EQUAL, 1, 0xFF );
        glStencilOp( GL_KEEP, GL_ZERO, GL_REPLACE );

        renderSpheres();

3TATUK2

715

Author

October 22, 2013 08:59 PM

I fixed it by doing it like this:


        glDepthFunc( GL_LESS );
        glStencilMask( 0xFF );

        glCullFace( GL_FRONT );
        glStencilFunc( GL_ALWAYS, 1, 0xFF );
        glStencilOp( GL_KEEP, GL_REPLACE, GL_KEEP );
        
        renderSpheres();

        glCullFace( GL_BACK );
        glStencilFunc( GL_EQUAL, 1, 0xFF );
        glStencilOp( GL_KEEP, GL_KEEP, GL_INCR );

        renderSpheres();

And then before the third pass which renders the color onto the stencil: glStencilFunc( GL_EQUAL, 2, 0xFF );

But, does anyone know how to do this with one pass using glStencelOpSeparate()? I'm having some trouble with figuring that out

3TATUK2

715

Author

October 23, 2013 12:25 AM

Got it


glDisable( GL_CULL_FACE );
glStencilOpSeparate( GL_BACK, GL_ZERO, GL_INCR, GL_ZERO );
glStencilOpSeparate( GL_FRONT, GL_ZERO, GL_ZERO, GL_INCR );
render();
glEnable( GL_CULL_FACE );