Nvidia defaults to wrapped shifts, but this is undefined behaviour on
OpenGL's spec. Explicitly mask/clamp according to what the guest shader
requires.
Implement VOTE using Nvidia's intrinsics. Documentation about these can
be found here
https://developer.nvidia.com/reading-between-threads-shader-intrinsics
Instead of using portable ARB instructions I opted to use Nvidia
intrinsics because these are the closest we have to how Tegra X1
hardware renders.
To stub VOTE on non-Nvidia drivers (including nouveau) this commit
simulates a GPU with a warp size of one, returning what is meaningful
for the instruction being emulated:
* anyThreadNV(value) -> value
* allThreadsNV(value) -> value
* allThreadsEqualNV(value) -> true
ballotARB, also known as "uint64_t(activeThreadsNV())", emits
VOTE.ANY Rd, PT, PT;
on nouveau's compiler. This doesn't match exactly to Nvidia's code
VOTE.ALL Rd, PT, PT;
Which is emulated with activeThreadsNV() by this commit. In theory this
shouldn't really matter since .ANY, .ALL and .EQ affect the predicates
(set to PT on those cases) and not the registers.
This is the default behavior of the copy constructor, so it doesn't need
to be specified.
While we're at it we can make the other non-default constructor
explicit.
Prevents a truncation warning from occurring with MSVC. Also the
internal data structures already treat it as a size_t, so this is just a
discrepancy in the interface.
These are std::shared_ptr instances underneath the hood, which means
copying them isn't as cheap as a regular pointer. Particularly so on
weakly-ordered systems.
This avoids atomic reference count increments and decrements where they
aren't necessary for the core set of operations.
While changing this code, simplify tracking code to allow returning
the base address node, this way callers don't have to manually rebuild
it on each invocation.
This commit implements gl_ViewportIndex and gl_Layer in vertex and
geometry shaders. In the case it's used in a vertex shader, it requires
ARB_shader_viewport_layer_array. This extension is available on AMD and
Nvidia devices (mesa and proprietary drivers), but not available on
Intel on any platform. At the moment of writing this description I don't
know if this is a hardware limitation or a driver limitation.
In the case that ARB_shader_viewport_layer_array is not available,
writes to these registers on a vertex shader are ignored, with the
appropriate logging.
ReinUsesLisp