OpenGL allows the TCS to be missing and supplies an implicit passthrough
shader, but OpenGL ES does not (see section 7.3 of the ES 3.2 spec,
cited above in the code).
One open question is how to handle this for ARB_ES3_2_compatibility.
This patch raises the link error for all ES shading language programs,
but it might make sense to base it on the API. The approach taken in
this patch is more restrictive, but should still allow any valid ES
programs to work in GL.
Signed-off-by: Kenneth Graunke <kenneth@whitecape.org>
Reviewed-by: Andres Gomez <agomez@igalia.com>
e6e8475b0f