There's a lot of places in the code that assume macOS is never GLES, and
with the increasingly rotten native GL support on Apple platforms people
are switching to ANGLE. So we should make sure this use case works.
Reason is that Assimp custom material attribute names are also prefixed
with $ and other weird characters, which could lead to them appearing
before $LayerName, causing a layer to falsely appear unnamed. A space,
instead, is before all printable characters so it's guaranteed to be
always first.
Some things you just don't realize at first. Fortunately the binary
layout isn't pinned yet for the serialization format so this change is
mostly fine.
Looking at the snippets, these seem to have been written back when there
was no builtin shaders yet, it seems, not to mention
MeshTools::compile(), Trade::MeshData or any of the other high-level
APIs. Rather overwhelming to just throw huge code snippets at the user,
explaining a workflow with a custom-made mesh that's going to be drawn
with a custom-made shader, which is like level 999 of using the GL
library.
It was rather discouraging to start "Basic usage" with a boring-ass long
snippet. On the other hand showing just compile() first would lead
people to think it's all some opaque magic, so trying to balance that a
bit.
Also why the hell was the compile() snippet showing the horrendous GL
way of specifying attribute formats? This is not great either but at
least not redundant.
For example if we're looking for a 2D image named "cubemap", the
importer will tell us there's 0 2D images, making a potential mistake
(2D vs 3D) more obvious.
These shouldn't be needed (the newer classes such as Half or
CubicHermite don't have them and work fine), moreover Clang 12 is now
emitting the following warning for them:
Definition of implicit copy assignment operator for 'Foo' is
deprecated because it has a user-declared copy constructor
[-Wdeprecated-copy]
For example when the profiled value is something really crazy, like a
negative value stored in an unsigned type. Before it tripped up on
another assert much later, this now makes the problem being caught much
earlier.
Because its usage is rather specific, there wasn't no
extension-dependent dispatch happening and thus the extension was never
marked as used. But that was confusing since it actually is, so add an
explicit branch just to list the extension.
Memory-maps the file and uses openMemory() instead of openFile(). For
efficient data formats (such as glTF) can avoid reading the whole blob
if only the metadata or a part of the file is needed (for example the
peak usage for --info-materials with the Buggy.glb example model went
from 8.5 MB to 991 kB, as it reads just the JSON at the start and never
even pages in the buffer blobs at the end).
This currently only works for standalone files, files that reference
external images etc. would need to have file callbacks implemented. And
it's Sunday and I'm lazy.
Using openMemory() instead of openData() allows the implementation to
assume the data will stay in scope for as long as needed, which can
prevent unnecessary copies in some plugin implementations.
It warranted a new flag, DataFlag::ExternallyOwned, to describe this
kind of memory. I couldn't reuse Owned as that's used for allocations
owned by the instance, which is too little for certain future use cases.
For example returning *Data instances referencing an Owned memory would
mean the user has to assume the memory is gone when the importer
instance is gone, and that's generally not true for memory passed to
openMemory().
Originally I thought I would do this later, but then realized the
existing plugin implementations would need to get all updated again to
be aware of the new flag, with some being forgotten, and it's just
easier to do the whole thing in a single step.
This makes it much less annoying to pass arbitrarily typed data, such as
std::uint8_t or char8_t and what not. It was already done like this for
the new shader converter plugins, where the input is often 32-bit ints
for SPIR-V.
OTOH the internal virtual API is kept with ArrayView<const char>, as
that makes it easier to operate on by the implementations.
Vladimír Vondruš