For integer attributes, that is. This never worked and the MeshGLTest
even had an explicit test case for this, but it took me until now to
realize that this would be best caught at compile time. So now it is.
But since this functionality dates back to 2010, just removing the
values would likely break a lot of code (well, broken code, but still),
so the disallowed values are now deprecated, giving a compile time
warning when used, and are removed only on non-deprecated builds.
They're not parsed since 6b22a11170
(2020), so there's no point in keeping those workarounds. They're only
kept in utility application sources as they're parsed for pages, and in
tweakable implementations where it's easier to just copypaste the whole
ifdef expression from the header every time instead of modifying it to
not include DOXYGEN_GENERATING_OUTPUT.
Compared to Corrade, the improvement in compile time is about a minute
cumulative across all cores, or about 8 seconds on an 8-core system (~2
minutes before, ~1:52 after). Not bad at all. And this is with a
deprecated build, the non-deprecated build is 1:48 -> 1:41.
Originally, years ago, it was supplying the same input value on all
targets, and just special-cased the output on ES2 to account for the
lower bit depth. But then SwiftShader arrived, which doesn't actually
care that there's a RGBA4 framebuffer, and performs all calculations at
the full precision. Which, well, makes sense from a perf PoV, kind of, so
I adapted also the input to be quantized to 4 bits instead of 8.
BUT THEN, some Mesa update happened, or maybe it was like this always and
I just didn't realize because I was on NV cards for so long, and that
input which made SwiftShader produced the expected result, was *further
quantized*, deviating further from what was expected.
So I now ditched all that and I'm just comparing with a
sufficiently large delta. If some implementation returns exactly what was
expected for an 8-bit framebuffer even thought the framebuffer is 4-bit,
I don't care.
Partially needed to avoid build breakages because Corrade itself
switched as well, partially because a cleanup is always good. Done
except for (STL-heavy) code that's deprecated or SceneGraph-related APIs
that are still quite full of STL as well.
So far this was only possible by creating a temporary MeshView, while
everything else (index/vertex count, base vertex, base instance, ...)
was changeable directly on the Mesh.
Same as in the previous commit, most cases are inputs so a StringStl.h
compatibility include will do, the only breaking change is
GL::Shader::sources() which now returns a StringIterable instead of a
std::vector<std::string> (ew).
Awesome about this whole thing is that The Shader API now allows
creating a shader from sources coming either from string view literals
or Utility::Resource completely without having to allocate any strings
internally, because all those can be just non-owning references wrapped
with String::nullTerminatedGlobalView(). The only parts which aren't
references are the #line markers, but (especially on 64bit) those can
easily fit into the 22-byte (or 10-byte on 32bit) SSO storage.
Also, various Shader constructors and assignment operators had to be
deinlined in order to avoid having to include the String header, which
would be needed for Array destruction during a move.
Co-authored-by: Hugo Amiard <hugo.amiard@wonderlandengine.com>
Of course I used the wrong `CORRADE_FAIL_IF(false, ...)` in a few
places. Yet another confirmation it was too hard to use and a dedicated
macro is needed.
Consistently with checkLink(), this avoids having to explicitly include
both Iterable and Reference in shader code. Alsod allowing people to
have direct arrays of shaders, runtime-sized lists of shaders etc.
A compat include is provided on a deprecated build to avoid breaking
existing code.
There's no reason for those to exist anymore -- origiinally they were
added in a hopeful attempt to make use of parallel shader compilation,
but in practice that meant compiling at most two or three shaders at
once and still stalling until that was done, so not that great at all.
The new APIs provide much better opportunities for parallelism.
Fun fact:
CORRADE_INTERNAL_ASSERT_OUTPUT(vert.compile() && frag.compile());
is actually one character shorter than
CORRADE_INTERNAL_ASSERT_OUTPUT(GL::Shader::compile({vert, frag}));
so not even typing convenience would be a reason to keep these.
All the tests were updated to explicitly check that non-null-terminated
strings get handled properly (the GL label APIs have an explicit size,
so it *should*, but just in case). Also, because various subclasses
override the setter to return correct type for method chaining and the
override has to be deinlined to avoid relying on a StringView include,
the tests are now explicitly done for each leaf class, instead of the
subclass
The <string> being removed from the base class for all GL objects may
affect downstream projects which relied on it being included. In case of
Magnum, the breakages were already fixed in the previous commit.
Compile time improvement for the MagnumGL library alone is 0.2 second or
4% (6.1 seconds before, 5.9 after). Not bad, given that there's three
more files to compile and strings are still heavily used in other GL
debug output APIs and all shader stuff. For a build of just the GL
library and all tests, it goes down from 28.9 seconds to 28.1. Most
tests also still rely quite heavily on std::stringstream for debug
output testing, so the numbers still could go further.
It was used just for certain corner cases that weren't covered by
{EXT,OES}_draw_elements_base_vertex already, but because of a wrongly
understood extension interaction the EXT/OES multidraw entrypoint (which
isn't implemented on ANGLE) was used from these as well.
And while trying to disable the two extensions for the MeshGLTest I
discovered the test half-expects the ANGLE variant to be implemented and
so I finished it for both the single-draw and multi-draw case.
The extension interaction that makes base-vertex multidraw calls broken
on ANGLE will be fixed in the following commit.
Yes, this is only ever provided by an ANGLE extension, and as you might
have guessed, The Great Google Overlords didn't bother caring to have
this supported outside of their browser.
Since the main point of the low-level API is to make use of the
EXT_multi_draw_arrays / ANGLE_multi_draw / WEBGL_multi_draw extensions
for a reduced driver overhead *and* the builtin gl_DrawID variable, it
just doesn't make sense to provide a fallback to draw() in a loop. When
the extensions are not available, the user has to do extra work in order
to supply proper UBO draw offset for each draw call, and thus the
fallback path has basically no practical use.
On the other hand, draw() taking the MeshView instances is kept as-is --
this one is rather old and so breaking compatibility would be an
unnecessary pain point. Plus, since it has to allocate the contiguous
arrays internally, it's not desirable for any fast-path rendering
anyway.
It doesn't allow anything except full RGBA and 32-bit types to be read
from the framebuffer. Chromium browsers weren't complaining but Firefox
did. I remember a similar restriction from GLES2 but all implementations
I tested with including ANGLE and SwiftShader allow that already, so
it's practically just a WebGL limitation.
This doesn't actually fix the WebGL-specific error (there it
additionally disallows mismatched signedness in a vertex attribute) but
is nevertheless good to have correct.
Because a MeshView might not be the best thing to have when you are
submitting a batch of thousand draws. It takes a strided array views to
allow for more flexibility, but can also detect if the input is already
contiguous and use it as-is.
UNFORTUNATELY the GL 1.0 legacy still continues to stink and so there
has to be a 64-bit-specific overload which is the *actual* variant that
doesn't allocate because glMultiDrawElements takes a `void**` for INDEX
OFFSETS and it's IN BYTES! Which foolish soul designed such a thing back
in the 1860s, I wonder. There's no reason to not have an index offset
in elements because all indices have to have the same type ANYWAY. And
yes, I wasted about three hours debugging driver crashes because I
THOUGHT this parameter takes offset in elements, not bytes.
Also note: on 32-bit platforms this depends on latest Corrade with the
CORRADE_TARGET_32BIT definition. Spent an embarrassing amount of time
wondering why all local builds but Emscripten work.
Or, the horror when I comment-out half of it and it still kinda passes.
The new code tests it more thoroughly, with actually checking that
different draw produce different results instead of one draw overwriting
the other.
Plus also verifying interaction with gl_VertexID and gl_DrawID to ensure
it really behaves correctly:
- gl_VertexID should get the same value regardless of whether we
perform a multi-draw or a one-by-one fallback, so this catches issues
where the mesh would get reconfigured in some nasty way, losing this
information
- gl_DrawID should get properly populated if and only if we use the
multi-draw code path, so this catches issues where the fallback would
get used instead of the actual multi-draw code path
Vladimír Vondruš