i965: Work around incorrect usage of glDrawRangeElements in UE4
Unreal Engine 4 has a bug in usage of glDrawRangeElements,
causing it to be called with a number of vertices in place
of "end" parameter (which specifies the maximum array index
contained in indices).
Since there is unknown amount of games affected and we
could not identify that a game is built with UE4 - we are
forced to make a blanket workaround, disregarding max_index
in range calculations. Fortunately all such calls look like:
glDrawRangeElements(GL_TRIANGLES, 0, 3, 3, ...);
So we are able to narrow down this workaround.
This was uncovered after
b684030c3a656ffdbc93581856034e0982db46fd
broke a bunch of UE4 games.
Cc: 20.1 <mesa-stable@lists.freedesktop.org>
Closes: https://gitlab.freedesktop.org/mesa/mesa/-/issues/2917
Signed-off-by: Danylo Piliaiev <danylo.piliaiev@globallogic.com>
Reviewed-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/5203>