Unlike the Key enum, which shows what a user would perceive as given key
in a particular layout, the scancode is a layout-independent identifier
for e.g. WASD movement in games.
Unfortunately the API availability is wildly different among the
toolkits -- SDL's is the most complete, GLFW is second, and then there's
Emscripten / HTML5 which provides just string identifiers. I tried to
add these for X11 as well, but quick googling led to a SO question where
it was left unanswered. Not worth my time.
There's the obvious advantage of them now being shorter to type, as one
no longer needs to prefix them with KeyEvent::. But the main reason I
did this was to allow various direct keyboard state queries to be
implemented, such as isKeyPressed(). With them being hidden in the event
class the only way would be to put the query directly there as well,
which isn't nice and is also not very discoverable.
A similar case was with mouse buttons, but that was already fixed with
the PointerEvent rework that happened in earlier commits. There the
additional complication was that MouseEvent::Button and
MouseMoveEvent::Button were incompatible enums. Application::Pointer
fixes that now as well.
This makes 2.0.6 as the oldest supported because in older versions it's
not possible to disable touch to mouse event translation, and it'd be
too annoying to have it special-cased there. The version bump should be
fine as Ubuntu 18.04 has 2.0.8.
All the new pointer events have float positions, this one was the odd one
out. And I didn't like the name anymore, so I took that as an opportunity
to change the position() data type without introducing a breaking change
for everyone.
Another considered change was adding Z offset to it, since HTML5 APIs
have that. However, all my googling led to just a single SO question from
2015, where someone said it's for trackballs that can navigate in 3D
space. I'm not sure if *scroll* is actually the best way to report those,
and since SDL3 didn't bother adding that and neither Android nor WINAPI
have anything like that, I'm not bothering either.
Unlike the previous commits, this is done for all apps at once, because
it's a comparatively simpler change. The only odd one out is
AbstractXApplication, where I introduced MouseScrollEvent just a few
commits back, so I simply renamed it without leaving a deprecated copy.
Then, ScreenedApplication needed some extra logic to handle the case of
apps not implementing any scroll event at all.
Pointer events are an unified abstraction over mouse, touch, pen and
potential other yet-to-be-invented pointer-like input methods. Their goal
is to expose all such input methods under a single interface so the
application side doesn't need to explicitly make sure that it's
touch-aware or pen-aware. This abstraction is already present in HTML5,
in Qt6 and in WINAPI as well, and is also what I adopted for the new UI
library because it *just makes sense*.
Unfortunately not even SDL3 took the opportunity to introduce that and
instead added a *third* separate event type for pen input in SDL3. At
first I thought that I wouldn't introduce any extra abstractions in the
Application classes (because that's what they are designed to be, as
lightweight as possible), but midway through introducing TouchEvent
classes and fighting SDL's touch->mouse and mouse->touch compatibility
translation (yes, it's both ways, depending on the platform) I realized
that a much simpler solution that doesn't require any event translation
or the users duplicating their event handling logic for several possible
input types is to introduce a single new event type that covers all.
Which is what this commit does -- it doesn't introduce anything
touch-related so far, just creates a new PointerEvent and
PointerMoveEvent class and corresponding virtual functions. Additionally,
I took this as an opportunity to make the position floating-point, since
that's what SDL3 does now as well, and GLFW did so since ever.
Plus, the Pointer and Pointers enums are directly on the Sdl2Application
class, to allow me to *finally* introduce pointer state queries. Which
weren't possible until now, because there were mutually incompatible
MouseEvent::Button and MouseMoveEvent::Button enums and putting them on
the base class would mean one would have to be translated and the other
not. With Pointer it's translated always, because there isn't any similar
enumeration in SDL that would cover mouse, touch and pen at the same
time.
The distance reported by it is useless for any practical purpose because
it doesn't report a ratio of the current and previous radius between all
points, but rather the distance. Which, well, have fun using for any sort
of zooming.
(And yeah, given that the MultiGestureEvent is gone in SDL3, I spent
quite some time looking at what it actually did in order to reimplement
that functionality on my end, and it felt *extremely weird* to me that it
always considered just that single point, never the others in order to
calculate any sort of radius. This is why, because it never considered
any sort of radius between the points, so the "Multi" in there is highly
questionable!)
So this test is just to make the uselessness easy to verify, nothing
more.
I wanted to add this for GlfwApplication, only to realize the timer there
is a double, in seconds, so accepting *integral* milliseconds there felt
very weird. Let's use the fancy new time types instead.
Also updated the docs to (hopefully) clarify that setSwapInterval() has
to be called in order for the interaction between the two to work
properly.
As usual, the old variant taking untyped milliseconds is a deprecated
alias to this one.
And for Sdl2Application print both the keycode and keysym, as the
current way with a keycode seems different from what both GLFW and HTML5
does. But the SDL2 scancode also doesn't feel right because compared to
GLFW and HTML5 it swaps Y and Z on my keyboard. SIGH.
In the Emscripten build, accepting events in EmscriptenApplication
prevents them from propagating further to the page, such as F1 that
would open a browser help page. That's not the case with SDL as SDL has
no concept of "accepting an event", so just document that in the test
code.
Which allows to get rid of a now-unneeded ArrayView include in the
header. Also, now that we're returning a StringView, it's useful to
have the view always null-terminated. In SDL2 and Emscripten it was
already like that, GLFW needed a minor change.
Right now only the command-line variant of it was checked. Since on
some platforms this requires the app to explicitly request a debug
context, the app needs to handle the case when it's passed via a
Configuration as well.
Disabling engine startup log or modifying enabled extensions /
workarounds from the application side was one of the common pain
points and this should *finally* solve the problem. This Configuration
is now inherited by the usual Platform::*Application::GLConfiguration /
Platform::Windowless*Application::Configuration classes people are used
to, so for the end user it's just as if these classes got a bunch new
options.
Having this, I also extended the ContextGLTest to verify that the
Configuration and command-line options do what's expected because that
hadn't automated tests until now. The test is mostly a copy of what I
did for Vulkan already, nothing special. Additionally all
Platform*ApplicationTest executables gained a new --quiet option to
verify that the GL::Context::Configuration subset gets correctly passed
from the Application code, because that's something we can't really
verify in an automated way.
Instead of first entering the main loop, processing events etc. This
also makes it finally possible to exit the application cleanly, with all
non-global destructors executed as well.
On Emscripten as well, however I'm keeping the Configuration::setTitle()
a no-op because the title is usually set by the HTML markup already and
so dynamic code implicitly changing it to something else doesn't make
much sense.
Vladimír Vondruš