One obvious use case is rendering a text that's just a bunch of \n
characters. With the current code, it would result in a completely empty
rectangle no matter how many newlines there would be, which isn't right
because -- even if nothing is actually visible -- it would break
anything that relies on the bounding rectangle for alignment and
positioning of other content.
Another case is for example the Ui library, which -- once ported to
use the new Renderer instead of the lower-level APIs -- wants to use the
bounding rectangle for cursor and selection positioning. And if it would
be empty for empty text, it'd mean empty input boxes would have
invisible cursor. Not good.
The old Renderer implementation seems to have handled this correctly --
but in f3d6ab4916, when porting to the new
APIs, I discarded that from the test, thinking it was some unnecessary
behavior. It wasn't, it was just never tested directly so I forgot it
was needed.
The tests all pass exactly as they did before, apart from slightly
different assertion messages. I moved the guts from Renderer.cpp to
RendererGL.cpp as the code relies on both GL and STL, to not have it
spread over too many places.
Apart from the fact that it blew up when the text was indeed empty,
which is fixed now (ugh), it was kinda obvious with the current
implementation but won't be when the guts get replaced with something
reasonable. So ensure we don't break existing use cases.
This is a replacement for the existing AbstractRenderer and Renderer2D /
Renderer3D classes, with no STL or other shittiness like excessive
allocations, and with a much better feature set. Deprecation of the old
APIs is going to happen next.
Compared to the old implementation it doesn't make use of the
complicated buffer mapping because -- unlike in 2012 -- such behavior
was since deemed questionable as the driver (or whichever translation
layer like ANGLE or Zink or Apple's GL-over-Metal) may still make a copy
anyway and doing so prevents buffer orphaning. So it's right now just
plain setData() / setSubData() calls. *If* it becomes some sort of a
bottleneck (which I doubt), I may reconsider, or add something else like
double buffering.
Builds upon RendererCore and generates index and vertex data from the
glyph positions and IDs. Documentation again coming later once
everything is in, next is a RendererGL which populates a GL::Mesh with
these.
A higher-level stateful wrapper around the low-level utilities, capable
of rendering text formed from multiple lines and multiple fonts. Will be
used as a backend for a new Renderer / RendererGL implementation.
No usage docs yet, those will come once the other two classes are made
as well.
So far the Renderer doesn't work with that, and neither the builtin
Vector shaders are be able use it, but gotta start somewhere.
I wanted to have the texture contents tested on ES, but it turns out
that implementing DebugTools::textureSubImage() for arrays is blocked on
another feature I badly need to finish first. Sigh.
One was a Doxygen workaround that shouldn't be needed anymore and an
API reference missing from e1c9c4d007, the
other was an inconsistency in a test that was just weird but shouldn't
affect anything.
I'm going to make a new Renderer class that's unlike the old one, and
isn't templated anymore either, so gotta make room for it first. I assume
that all existing code used the Renderer2D / Renderer3D typedefs so this
should be pretty much painless.
Ultimately this class will be gone, with only (then deprecated)
AbstractRenderer left, and Renderer2D / Renderer3D being aliases to it
-- internally it doesn't actually do anything dfferent, even the
positions are two-component in both cases.
The naming was adopted from CSS direction-aware alignment and it took me
quite a while to realize it feels alien, since everything else is using
"begin" and "end", not "start" and "end". So I'm renaming for
consistency.
These enums were originally introduced about 8 months ago but I don't
think anyone is using these yet, since they're not really advertised
anywhere and the existing to-be-deprecated high-level text renderer API
is so shitty that I don't expect it to be used for BIDI text and such,
at all. Sorry if you do, heh.
Now it's less code, and it also no longer results in random edge
artifacts because the padding area wasn't correctly uploaded. I'm going
to do the same change in the FreeTypeFont and StbTrueTypeFont next.
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.
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.
Neither a driver bug nor something wrong with the code. It's just
that with a tight flush rectangle the target texture may have some random
garbage left around the edges, causing the comparison to fail, so it's
now explicitly cleared upfront.
Doesn't happen when running the offending test alone (because I suppose
the memory is coming fresh from the driver, being zeroed out for security
purposes), only when running after the others (where I suspect it's now
reusing previous partially-filled memory which it didn't before). Doesn't
happen on NVidia either.
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.
So the users don't accidentally create an instance with the processed
format / size being different only to get greeted by a nasty bounds or
format assertion inside flushImage() / doSetImage().
Now it's only allowed to be done by a subclass (such as
DistanceFieldGlyphCacheGL, or, ahem, MagnumFont), and doSetImage()
additionally has an assert to notify the implementer that a subclass
needs to provide its own override.
This also feels kind of messy, honestly. It's as if the
DistanceFieldGlyphCache should never have been a subclass, maybe?
Now, instead of accessing the texture directly, it uses the public
setProcessedImage() API. For which it needs to subclass the cache in
order to advertise ImageProcessing, which means the class can no longer
have the implementations private.
I don't really like this, ideally none of this would be needed and
MagnumFont would implement fillGlyphCache() instead. Not sure how to do
that yet tho as there's still the issue with DistanceFieldGlyphCacheGL
being RGBA, so this is a half-assed solution until a better one is
found... or the plugin gets ditched completely.
They don't have anything specific to DistanceFieldGlyphCacheGL and on
the other hand contain special-casing for Luminance vs Red on ES2 that's
specific to GlyphCacheGL internals.
Additionally, in DistanceFieldGlyphCacheGL the code could assume that
the pixel format is either R8 with EXT_texture_rg present or RGBA8
without, here it has to check for EXT_texture_rg presence as
GlyphCacheGL can use R8 even without EXT_texture_rg.
Like with TextureTools::DistanceField, to make room for non-GL
implementations. Old names are deprecated aliases, same for headers. The
only remaining bit in the Text library is the Renderer class, but for
that one I first need to invent a non-shitty API so I can just deprecate
the old thing as a whole and create something reasonable from scratch in
RendererGL.
Vladimír Vondruš