Nvidia's OpenGL driver maps gl(Named)BufferSubData with some requirements
to a fast. This path has an extra memcpy but updates the buffer without
orphaning or waiting for previous calls. It can be seen as a better
model for "push constants" that can upload a whole UBO instead of 256
bytes.
This path has some requirements established here:
http://on-demand.gputechconf.com/gtc/2014/presentations/S4379-opengl-44-scene-rendering-techniques.pdf#page=24
Instead of using the stream buffer, this commits moves constant buffers
uploads to calls of glNamedBufferSubData and from my testing it brings a
performance improvement. This is disabled when the vendor is not Nvidia
since it brings performance regressions.
Originally on the last commit I thought TLD4 acted the same as TLD4S and
didn't have a mask. It actually does have a component mask. This commit
corrects that.
This commit fixes an issue where not all 4 results of tld4 were being
written, the color component was defaulted to red, among other things.
It also implements the bindless variant.
Bindless textures were using u64 to pack the buffer and offset from
where they come from. Drop this in favor of separated entries in the
struct.
Remove the usage of std::set in favor of std::list (it's not std::vector
to avoid reference invalidations) for samplers and images.
Greatly shrinks the amount of generated code for GetDecodeTable().
Collapses an assembly output of 9000+ lines down to ~3621 with Clang,
and 6513 down to ~2616 with GCC, given it's now allowed to construct all
the entries as a sequence of constant data.
Given the overall size of the maps are very small, we can use arrays of
pairs here instead of always heap allocating a new map every time the
functions are called. Given the small size of the maps, the difference
in container lookups are negligible, especially given the entries are
already sorted.
TLD4S always outputs 4 values, the previous code checked a component
mask and omitted those values that weren't part of it. This commit
corrects that and makes sure all 4 values are set.
Ignore global memory operations instead of invoking undefined behaviour
when constant buffer tracking fails and we are blasting through asserts,
ignore the operation.
In the case of LDG this means filling the destination registers with
zeroes; for STG this means ignore the instruction as a whole.
The default behaviour is still to abort execution on failure.
