title: Does OpenGL stencil test happen before or after fragment program runs?
body: <p>When I set <code>glStencilFunc( GL_NEVER, . . . )</code> effectively disabling all drawing, and then run my [shader-bound] program I get no performance increase over letting the fragment shader run. I thought the stencil test happened before the fragment program. Is that not the case, or at least not guaranteed? Replacing the fragment shader with one that simply writes a constant to gl_FragColor does result in a higher FPS.</p>