Because otherwise the users likely have to do something similar on their
end to perform a texture upload etc., which means they'll either take
the easy path and upload everything including the unused area, or they
introduce various bugs in the process, leading to random artifacts,
especially when it comes to padding.
Which is exactly what I think is causing random test failures in the Ui
library text rendering, because the glyph cache filling process in
plugins is calculating the rectangle too tight, without considering
padding. Gonna fix that now.
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.
Along with the bits in Text library this is one of the last things that
still assume OpenGL present by default.
As usual, the old name and header is now a deprecated typedef.
This name isn't known to it at the time it parses the header (because no
such header gets included for it), which in turn causes Doxygen 1.12 to
generate a dummy ::Platform namespace. Which then gets a priority over
Magnum::Platform when linked to, and because it's dummy, it's reported
as an error because it's not allowed to link to undocumented stuff.
The test passes now. This made the benchmark run significantly faster.
~200 µs instead of 670. Are clears really taking up more time than all
those texture fetches? Strange.
Just cannot use gl_FragCoord in here. That's it, that's the fix. What's
however COMPLETELY unexpected is that this simple change made the
process significantly faster on my Intel GPU, from ~815 µs to 670! I
can't even pretend I understand what's going on here, but maybe doing
less math in the fragment shader when calculating the texture
coordinates (and thus possibly the driver having a better idea how to
prefetch or schedule?) is what made this faster? Or maybe it's due to
one uniform input less, and two interpolated values instead of four on
the way from the vertex shader?
The original implementation wrongly assumed that the input and output
pixel centers align, which would only be a case if the ratio of the
input and output sizes would be odd. Which it in practice isn't, usually
it's a 1024x1024 texture scaled down to 128x128 or something like that.
The flipped test cases added in the previous commit now pass.
According to the benchmark, the new code is very slightly slower (~815
µs vs ~805 before). The new code isn't really more complex than the old
one, it just does slightly different work -- there are new corner case
in the initial logic for marking the pixel inside or outside, on the
other hand some corner cases that had to be handled in the previous case
are no longer a thing.
If it's not, it's a programmer error (i.e., don't use Luminance or
packed formats, won't work), and since there's no way for the API to
report a failure in a programmatic way, this was causing hard-to-track
errors.
And the thing that changed for SwiftShader 4.1 was added EXT_texture_rg
support, which made the test work. So no, this was not a SwiftShader bug
at all.
Use a different overload to not have to create a temp framebuffer every
time, move also the error checking outside the loop and increase the
iteration count to actually have a result that isn't wildly different
every time.
No reason not to, even though the move is destructive. Also unblocks
Text::DistanceFieldGlyphCache which wasn't movable due to this and one
other problem.
It's too annoying otherwise, especially if padding is involved. Turns
out that if padding is zero, these don't really contribute to the layout
in any way.
While it's needed to call basically any useful function in there, its
definition isn't needed to create an instance of the AtlasLandfill
class, and that's what mainly matters.
The overhead of maintaining two classes with only very slight
differences in the API and the internals being basically identical is
not worth it. Too much potential for inconsistencies and doc errors.
Additionally, when I attempted to use it for the reworked Text glyph
cache, I realized I'd need to wrap them both under a common interface,
allowing easy use for both 2D and 2D array textures. And then it's
easier to just have the Atlas class done that way directly instead of
papering over that in a downstream API.
Instead of piling up a mountain if the other end is a ditch. Results in
better packing in most cases, but in one doesn't, so also adding an
option to disable this.
The docs image is now slightly more leveled, one pixel lower.
Vladimír Vondruš