Backends can normally handle shader inputs solely by looking at
load_input intrinsics, and ignore the nir_variables in nir->inputs.
One exception is fragment shader inputs. load_input doesn't capture
the necessary interpolation information - flat, smooth, noperspective
mode, and centroid, sample, or pixel for the location. This means
that backends have to interpolate based on the nir_variables, then
associate those with the load_input intrinsics (say, by storing a
map of which variables are at which locations).
With GL_ARB_enhanced_layouts, we're going to have multiple varyings
packed into a single vec4 location. The intrinsics make this easy:
simply load N components from location <loc, component>. However,
working with variables and correlating the two is very awkward; we'd
much rather have intrinsics capture all the necessary information.
Fragment shader input interpolation typically works by producing a
set of barycentric coordinates, then using those to do a linear
interpolation between the values at the triangle's corners.
We represent this by introducing five new load_barycentric_* intrinsics:
- load_barycentric_pixel (ordinary variable)
- load_barycentric_centroid (centroid qualified variable)
- load_barycentric_sample (sample qualified variable)
- load_barycentric_at_sample (ARB_gpu_shader5's interpolateAtSample())
- load_barycentric_at_offset (ARB_gpu_shader5's interpolateAtOffset())
Each of these take the interpolation mode (smooth or noperspective only)
as a const_index, and produce a vec2. The last two also take a sample
or offset source.
We then introduce a new load_interpolated_input intrinsic, which
is like a normal load_input intrinsic, but with an additional
barycentric coordinate source.
The intention is that flat inputs will still use regular load_input
intrinsics. This makes them distinguishable from normal inputs that
need fancy interpolation, while also providing all the necessary data.
This nicely unifies regular inputs and interpolateAt functions.
Qualifiers and variables become irrelevant; there are just
load_barycentric intrinsics that determine the interpolation.
v2: Document the interp_mode const_index value, define a new
BARYCENTRIC() helper rather than using SYSTEM_VALUE() for
some of them (requested by Jason Ekstrand).
Signed-off-by: Kenneth Graunke <kenneth@whitecape.org>
Reviewed-by: Chris Forbes <chrisforbes@google.com>
Reviewed-by: Jason Ekstrand <jason@jlekstrand.net>
This is similar to nir_channel except that it lets you grab more than one
channel by providing a mask.
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
There's no reason for having a macro *and* a python generator. We can
easily just do the whole thing in python. This has the advantage that we
are no longer definining ALU# macros which conflict with the ones in
brw_fs_builder.h.
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
It's what all the call-sites once, so gets rid of a bunch of inlined
glsl_get_base_type() at the call-sites.
Signed-off-by: Rob Clark <robclark@freedesktop.org>
Reviewed-by: Jason Ekstrand <jason@jlekstrand.net>
As they are not standard C++ and are not supported by MSVC C++ compiler.
Just have nir_imm_double match nir_imm_float above.
Reviewed-by: Connor Abbott <cwabbott0@gmail.com>
Reviewed-by: Sinclair Yeh <syeh@vmware.com>
v2:
- Group num_components and bit_size together (Jason)
Signed-off-by: Samuel Iglesias Gonsálvez <siglesias@igalia.com>
Reviewed-by: Jason Ekstrand <jason@jlekstrand.net>
No need for it not to be const, and lets caller declare it const if
desired.
Signed-off-by: Rob Clark <robclark@freedesktop.org>
Reviewed-by: Eric Anholt <eric@anholt.net>
v2:
- Make the users to give the right bit_sizes as arguments (Jason).
Signed-off-by: Samuel Iglesias Gonsálvez <siglesias@igalia.com>
Reviewed-by: Jason Ekstrand <jason@jlekstrand.net>
v2: Squash multiple commits addressing the new parameter in different
files so we don't break the build (Iago)
v3: Fix tgsi (Samuel)
v4: Fix nir_clone.c (Samuel)
v5: Fix vc4 and freedreno (Iago)
v6 (Sam)
- Fix build errors in nir_lower_indirect_derefs
- Use helper to get type size from nir_alu_type.
Signed-off-by: Iago Toral Quiroga <itoral@igalia.com>
Signed-off-by: Samuel Iglesias Gonsalvez <siglesias@igalia.com>
Tested-by: Rob Clark <robdclark@gmail.com>
Reviewed-by: Jason Ekstrand <jason@jlekstrand.net>
Reviewed-by: Samuel Iglesias Gonsálvez <siglesias@igalia.com>
Reviewed-by: Iago Toral Quiroga <itoral@igalia.com>
