On Mon, Sep 9, 2013 at 9:44 AM, Paul Berry <[email protected]> wrote: > On 5 September 2013 17:52, Matt Turner <[email protected]> wrote: >> >> On Wed, Aug 28, 2013 at 1:59 PM, Paul Berry <[email protected]> >> wrote: >> > +[vertex shader] >> > +#version 150 >> >> We don't need to specify the #version anymore, now that it's added by >> shader_runner, given the [require] section. > > > Argh, you're right. I keep forgetting about that. Fixed. > >> >> >> > + >> > +in vec4 vertex; >> > +out vec4 vertex_to_gs; >> > + >> > +void main() >> > +{ >> > + vertex_to_gs = vertex; >> > +} >> > + >> > +[geometry shader] >> > +#version 150 >> > + >> > +layout(triangles_adjacency) in; >> > +layout(triangle_strip, max_vertices = 3) out; >> > + >> > +in vec4 vertex_to_gs[6]; >> > + >> > +void main() >> > +{ >> > + for (int i = 0; i < 3; i++) { >> > + gl_Position = vertex_to_gs[2*i]; >> >> If I understand correctly, in the first geometry shader invocation >> this will emit vertices 1, 3, and 5 from your picture. Is that what >> you're referring to when you say "the first triangle is clockwise"? >> >> I wasn't clear whether you meant the triangle 1-2-3, or 1-3-5. From >> the comment and picture I'd have thought the first, and from the code >> I'd have thought the second. Both, as it turn out are clockwise. > > > Your understanding from the code is correct. Triangle 1-2-3's orientation > isn't really significant for this particular test, since it is an "adjacent > triangle". The vertices comprising the adjacent triangles are tested > adequately by triangle-strip-adj.shader_test. > > I've updated the comment to look like this: > > # Note that the only triangles drawn by this test are triangles 1-3-5, > # 5-3-7, 5-7-9, and 9-7-11. The other triangles shown in the diagram > # are "adjacent triangles". > # > # Note also that triangles 1-3-5, 5-3-7, 5-7-9, and 9-7-11 are all > # clockwise, so we expect gl_FrontFacing to be false. > > Is that clear enough, or should I explain in more detail?
Nope, that makes sense. Thanks Paul! _______________________________________________ Piglit mailing list [email protected] http://lists.freedesktop.org/mailman/listinfo/piglit
