Hi,
these days I have been trying to fix a test that uses transform feedback
on the out varying of a tessellation shader. The relevant part on that
shader is like this:
layout (vertices=4) out;
out block { vec4 value; } user_out[];
The test tries to use block.value as the varying name when calling
glTransformFeedbackVaryings, in order to get the data of the 4 vertices.
The test fails because on link time, it doesn't find that varying name.
On mesa, when linked, mesa tfeedback_candidate_generator (at
src/compiler/glsl/link_varyings) adds to the hashmap of possible
varyings for transform feedback the following names: block[0].value,
block[1].value, block[2].value, block[3].value. If I change the test to
use those 4 varyings names, instead of try to get the array directly,
the test passes.
So now is the moment to justify who is wrong per-spec, if mesa or the
test. At this moment Im biased to conclude that the test is wrong. But
after reading transform feedback specs (ext, feedback2, feedback3, gl44)
and tessellation shader, I was not able to find anything.
Could someone (I bet that the best person is Timothy Arceri) guide me a
little to know in which part of the spec should I look for?
Thanks in advance.
BR
_______________________________________________
mesa-dev mailing list
mesa-dev@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/mesa-dev
