Older OpenGL defines two equations for converting from signed-normalized
to floating point data. These are:
f = (2c + 1)/(2^b - 1) (equation 2.2)
f = max{c/2^(b-1) - 1), -1.0} (equation 2.3)
Both OpenGL 4.2+ and OpenGL ES 3.0+ mandate that equation 2.3 is to be
used in all scenarios, and remove equation 2.2. DirectX uses equation
2.3 as well. Intel hardware only supports equation 2.3, so Gen7.5+
systems that use the vertex fetcher hardware to do the conversions
always get formula 2.3.
This can make a big difference for 10-10-10-2 formats - the 2-bit value
can represent 0 with equation 2.3, and cannot with equation 2.2.
Ivybridge and older were using equation 2.2 for OpenGL, and 2.3 for ES.
Now that Ivybridge supports OpenGL 4.2, this is wrong - we need to use
the new rules, at least in core profile. That would leave Gen4-6 doing
something different than all other hardware, which seems...lame.
With context version promotion, applications that requested a pre-4.2
context may get promoted to 4.2, and thus get the new rules. Zero cases
have been reported of this being a problem. However, we've received a
report that following the old rules breaks expectations. SuperTuxKart
apparently renders the cars red when following equation 2.2, and works
correctly when following equation 2.3:
https://github.com/supertuxkart/stk-code/issues/2885#issuecomment-353858405
So, this patch deletes the legacy equation 2.2 support entirely, making
all hardware and APIs consistently use the new equation 2.3 rules.
If we ever find an application that truly requires the old formula, then
we'd likely want that application to work on modern hardware, too. We'd
likely restore this support as a driconf option. Until then, drop it.
This commit will regress Piglit's draw-vertices-2101010 test on
pre-Haswell without the corresponding Piglit patch to accept either
formula (commit 35daaa1695ea01eb85bc02f9be9b6ebd1a7113a1):
draw-vertices-2101010: Accept either SNORM conversion formula.
Reviewed-by: Jason Ekstrand <jason@jlekstrand.net>
Reviewed-by: Ian Romanick <ian.d.romanick@intel.com>
Reviewed-by: Chris Forbes <chrisforbes@google.com>
We're going to want subgroup ID for SPIR-V subgroups eventually anyway.
We really only want to push one and calculate the other from it. It
makes a bit more sense to push the subgroup ID because it's simpler to
calculate and because it's a real API thing. The only advantage to
pushing the base thread ID is to avoid a single SHL in the shader.
Reviewed-by: Iago Toral Quiroga <itoral@igalia.com>
Previously, brw_nir_lower_intrinsics added the param and then emitted a
load_uniform intrinsic to load it directly. This commit switches things
over to use a specific NIR intrinsic for the thread id. The one thing I
don't like about this approach is that we have to copy thread_local_id
over to the new visitor in import_uniforms.
Reviewed-by: Iago Toral Quiroga <itoral@igalia.com>
Now that we're always growing the param array as-needed, we can
allocate the param array in common code and stop repeating the
allocation everywere. In order to keep things sane, we ralloc the
[pull_]param array off of the compile context and then steal it back
to a NULL context later. This doesn't get us all the way to where
prog_data::[pull_]param is purely an out parameter of the back-end
compiler but it gets us a lot closer.
Reviewed-by: Jordan Justen <jordan.l.justen@intel.com>
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
It's already only ever called from brw_compile_cs and only handles
compute intrinsics. Let's just make it CS-specific. We can always
make it handle other stages again later if we want.
Reviewed-by: Jordan Justen <jordan.l.justen@intel.com>
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
This adds a NIR pass that decides which portions of UBOS we should
upload as push constants, rather than pull constants.
v2: Switch to uint16_t for the UBO block number, because we may
have a lot of them in Vulkan (suggested by Jason). Add more
comments about bitfield trickery (requested by Matt).
v3: Skip vec4 stages for now...I haven't finished wiring up support
in the vec4 backend, and so pushing the data but not using it
will just be wasteful.
Reviewed-by: Matt Turner <mattst88@gmail.com>
We're already doing this in the FS back-end. This just does the same
thing in the vec4 back-end.
Reviewed-by: Alejandro Piñeiro <apinheiro@igalia.com>
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
The NIR pass already handles remapping system values to attributes for
us so we delete the system value code as part of the conversion.
We also change nir_lower_vs_inputs to take an explicit inputs_read
bitmask and pass in the inputs_read from prog_data instead from pulling
it out of NIR. This is because the version in prog_data may get
EDGEFLAG added to it on some old platforms.
Reviewed-by: Alejandro Piñeiro <apinheiro@igalia.com>
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
Mostly a dummy git mv with a couple of noticable parts:
- With the earlier header cleanups, nothing in src/intel depends
files from src/mesa/drivers/dri/i965/
- Both Autoconf and Android builds are addressed. Thanks to Mauro and
Tapani for the fixups in the latter
- brw_util.[ch] is not really compiler specific, so it's moved to i965.
v2:
- move brw_eu_defines.h instead of brw_defines.h
- remove no-longer applicable includes
- add missing vulkan/ prefix in the Android build (thanks Tapani)
v3:
- don't list brw_defines.h in src/intel/Makefile.sources (Jason)
- rebase on top of the oa patches
[Emil Velikov: commit message, various small fixes througout]
Signed-off-by: Emil Velikov <emil.velikov@collabora.com>
Reviewed-by: Jason Ekstrand <jason@jlekstrand.net>
