GLAD 1 creates unusable loaders for EGL, while the newly released GLAD 2
does not, so for consistency I thought that it would be a good idea to
uniform things beforehand. While it had some API changes some renames
were all that was needed and everything works like before, at least on
the Wayland branch.
I've kept the structure identical, although this new generator has quite
a few hefty features, such as a single header mode.
I've also added GLAD to `thirdparty/README.md`, but I haven't specified
that in the commit title because it's a very small "fix".
Somehow I missed the failing CI report from trailing whitespace.
Fixed a couple typos found by codespell while at it, and misc
trailing semicolons in one of the files.
- Removed empty paragraphs in XML.
- Consistently use bold style for "Example:", on a new line.
- Fix usage of `[code]` when hyperlinks could be used (`[member]`, `[constant]`).
- Fix invalid usage of backticks for inline code in BBCode.
- Fix some American/British English spelling inconsistencies.
- Other minor fixes spotted along the way, including typo fixes with codespell.
- Don't specify `@GlobalScope` for `enum` and `constant`.
Fix that Windows receive WINDOW_EVENT_MOUSE_EXIT on startup.
When moving the mouse cursor from one window to a different one, make sure that the first window receives the WINDOW_EVENT_MOUSE_EXIT event before the second window receives the WINDOW_EVENT_MOUSE_ENTER event.
Send Mouse-Move events also for Windows, that are currently not focused.
For determining the currently hovered window, consider not just the currently focused window, but also other windows.
Send mouse move events to focused window instead of hovered window.
Replace all TODO uses of `#warning` by proper TODO comments, and will open
matching bug reports to keep track of them.
We don't have a great track record fixing TODOs, but I'd wager we're even
worse for fixing these "TODO #warning" so we should prohibit this usage.
- `LIBC_FILEIO_ENABLED` wasn't defined anywhere, even in _other platforms_.
- `NO_NETWORK` is also never defined. It probably isn't enough anyway to
disable network APIs in the current codebase.
- `UNIX_SOCKET_UNAVAILABLE` is never defined in this code but used by some
other platforms, clarify that.
- `NO_STATVFS` can be removed as Android supports it since API level 19,
which is our current min SDK level. It's also only used for
`DirAccessUnix::get_space_left()` which is anyway overridden by
`DirAccessJAndroid::get_space_left()` so it shouldn't make a difference.
* Fixed documentation for `DirAccess.get_space_left()`.
- `NO_FCNTL` is likely also a remnant of early Android days, in current NDK
r23 it seems to be available. Also cleaned up unused `fcntl.h` includes.
- `NO_ALLOCA` is never defined, and we use alloca in many places now.
Implements https://github.com/godotengine/godot-proposals/issues/3371.
New `target` presets
====================
The `tools` option is removed and `target` changes to use three new presets,
which match the builds users are familiar with. These targets control the
default optimization level and enable editor-specific and debugging code:
- `editor`: Replaces `tools=yes target=release_debug`.
* Defines: `TOOLS_ENABLED`, `DEBUG_ENABLED`, `-O2`/`/O2`
- `template_debug`: Replaces `tools=no target=release_debug`.
* Defines: `DEBUG_ENABLED`, `-O2`/`/O2`
- `template_release`: Replaces `tools=no target=release`.
* Defines: `-O3`/`/O2`
New `dev_build` option
======================
The previous `target=debug` is now replaced by a separate `dev_build=yes`
option, which can be used in combination with either of the three targets,
and changes the following:
- `dev_build`: Defines `DEV_ENABLED`, disables optimization (`-O0`/`/0d`),
enables generating debug symbols, does not define `NDEBUG` so `assert()`
works in thirdparty libraries, adds a `.dev` suffix to the binary name.
Note: Unlike previously, `dev_build` defaults to off so that users who
compile Godot from source get an optimized and small build by default.
Engine contributors should now set `dev_build=yes` in their build scripts or
IDE configuration manually.
Changed binary names
====================
The name of generated binaries and object files are changed too, to follow
this format:
`godot.<platform>.<target>[.dev][.double].<arch>[.<extra_suffix>][.<ext>]`
For example:
- `godot.linuxbsd.editor.dev.arm64`
- `godot.windows.template_release.double.x86_64.mono.exe`
Be sure to update your links/scripts/IDE config accordingly.
More flexible `optimize` and `debug_symbols` options
====================================================
The optimization level and whether to generate debug symbols can be further
specified with the `optimize` and `debug_symbols` options. So the default
values listed above for the various `target` and `dev_build` combinations
are indicative and can be replaced when compiling, e.g.:
`scons p=linuxbsd target=template_debug dev_build=yes optimize=debug`
will make a "debug" export template with dev-only code enabled, `-Og`
optimization level for GCC/Clang, and debug symbols. Perfect for debugging
complex crashes at runtime in an exported project.
- `_DEBUG` is MSVC specific so it didn't make much sense to define for
Android and iOS builds.
- iOS was the only platform to define `DEBUG`. We don't use it anywhere
outside thirdparty code, which we usually don't intend to debug, so it
seems better to be consistent with other platforms.
- Consistently define `NDEBUG` to disable assert behavior in both `release`
and `release_debug` targets. This used to be set for `release` for all
platforms, and `release_debug` for Android and iOS only.
- Due to the above, I removed the only use we made of `assert()` in Godot
code, which was only implemented for Unix anyway, should have been
`DEV_ENABLED`, and is in PoolAllocator which we don't actually use.
- The denoise and recast modules keep defining `NDEBUG` even for the `debug`
target as we don't want OIDN and Embree asserting all over the place.
Instead of updating all viewports, then blitting all viewports
to the backbuffer, then swapping all buffers, we run through
all viewports and render, blit, and swap backbuffer before
going to the next viewport.
Adds support for LTO on macOS and Android. We don't have much experience
with LTO on these platforms so for now we keep it disabled by default
even when `production=yes` is set.
Similarly for iOS where we ship object files for the user to link in
Xcode so LTO makes builds extremely slow to link.
`production=yes` defaults to full LTO.
ThinLTO is much faster for LLVM-based compilers but seems to produce
bigger binaries (at least for the Web platform).
This lets the engine and projects use the same color codes
in the terminal on all platforms. This includes support for
`print_rich()` (GDScript) and `print_line_rich()` (C++).
Previously it was used only on debug builds, but recent
additions to variant_call.cpp have made that unit too
large even in release_debug.
It was originally set to debug only because using it
breaks mingw, so this only reinstates it for MSVC where
it shouldn't have any drawbacks (famous last words).
Test-Information:
Builds for me with
scons -j 40 platform=windows target=release_debug
and my game then runs from it.
Implement built-in classes Vector4, Vector4i and Projection.
* Two versions of Vector4 (float and integer).
* A Projection class, which is a 4x4 matrix specialized in projection types.
These types have been requested for a long time, but given they were very corner case they were not added before.
Because in Godot 4, reimplementing parts of the rendering engine is now possible, access to these types (heavily used by the rendering code) becomes a necessity.
**Q**: Why Projection and not Matrix4?
**A**: Godot does not use Matrix2, Matrix3, Matrix4x3, etc. naming convention because, within the engine, these types always have a *purpose*. As such, Godot names them: Transform2D, Transform3D or Basis. In this case, this 4x4 matrix is _always_ used as a _Projection_, hence the naming.
* Map is unnecessary and inefficient in almost every case.
* Replaced by the new HashMap.
* Renamed Map to RBMap and Set to RBSet for cases that still make sense
(order matters) but use is discouraged.
There were very few cases where replacing by HashMap was undesired because
keeping the key order was intended.
I tried to keep those (as RBMap) as much as possible, but might have missed
some. Review appreciated!
popup no longer tries to close itself a second time
popup no longer closes after having been reopened
fixed bug in RenameDialog not calling base (by inspection)
fixes#59181fixes#60921
reverts #59287
fixed and simplified gl_manager_windows
swap buffers now called for all windows
fixed missing pixel format setting in additional windows
this makes them work in OpenGL contexts
changed verbose error printing to write once
this error message happens very frequently while opengl3 is not finished
removed dead code no longer needed after changes
fixed comments that were misinformation
window messages during window creation now handled
these were previously discarded
messages now tunnel the required context
changed failure to create opengl3 window on windows to be more fatal
marked a problem with pen code
conditional compilation of vulkan and opengl3 on windows fixed
windows debug builds now show messages on debug console also
rendering driver selection box now shows only compiled drivers
marked some problematic code
thanks to akien-mga for patiently rewriting my style mistakes
Adds the is_process_running function to the native OS class and exposes it to script.
This is implemented on Windows and Unix platforms. A stub is provided for other platforms that do not support this function.
Documentation is updated to reflect new API function.
These typedefs don't save much typing compared to the full `Ref<Resource>`
and `Ref<RefCounted>`, yet they sometimes introduce confusion among
new contributors.
Windows export process:
Limit size of executable with embedded PCK to 4 GB.
Use "rcedit" before embedding PCK.
Capture and process "rcedit" errors.
Windows, Linux:
Add support for PCK loading from executable "pck" section.
The multithreaded importer often causes system-wide hangs when importing more than 20 files at a time.
Running the editor at normal priority allows other applications on the system to be responsive during long imports.
This method can be used to get the CPU model name.
It can be used in conjunction with
`RenderingServer.get_video_adapter_name()` and
`RenderingServer.get_video_adapter_vendor()` for annotating benchmarks
and automatic graphics quality configuration.
Implemented via `BCryptGenRandom` on Windows.
Implemented via `getentropy` syscall when available.
Implemented via `/dev/urandom` device as a fallback.
The `/dev/urandom` fallback can be disabled via the `NO_URANDOM` build
flag.
Note: The HTML5 version relies on emscripten file system urandom
device which itself uses the Crypto API when available or the plain
old not crypto-safe `Math.random()` otherwise.
Restore get_entropy.
Modify the create_sub_window method to set an icon for all sub windows, setting the icon to the same icon as the main window.
Co-Authored-By: Rémi Verschelde <rverschelde@gmail.com>
Replace WM_MOVE and WM_SIZE message handling with WM_POSCHANGED instead.
This is for multiple reasons:
1) Microsoft suggest using WM_POSCHANGED is more efficient
2) RectChanged callback is only called once for most window operations
3) Simplifies message handling code
[macOS] Fix transient windows not working in the full-screen mode.
[macOS] Fix moving transient windows to the other screen than parent window.
[macOS] Fix popup menu switch on hover.
[macOS] Use content origin rect for windows position (to ensure `DS.mouse_get_position` is equal to `DS.window_get_position` + mouse position from the input events).
[macOS] Fix incorrect input coordinates, when external display with different scaling in connected/disconnected.
[macOS/Windows] Fix moving fullscreen windows between the screens.
Add auto refocusing of the parent window, when the focused transient window is closed.
Remove redundant `DS.mouse_get_absolute_position` function (returns mouse position in the screen coordinates, same as `DS.mouse_get_position`).
Always build with the GUI subsystem.
Redirect stdout and stderr output to the parent process console.
Use CreateProcessW for blocking `execute` calls with piped stdout and stderr (prevent console windows for popping up when used with the GUI subsystem build, and have more consistent behavior with `create_process`).
Add `open_console` argument to the `execute` and `create_process` to open a new console window.
Remove `interface/editor/hide_console_window` editor setting.
Remove `Toggle System Console` menu option.
Remove `set_console_visible` and `is_console_visible` functions.
Building `target=release` and `target=release_debug` builds with MinGW-GCC
errors when linking with LTO.
Since it's only needed for `target=debug` builds anyway (bigger objects), which
we don't build with LTO, this works around the issue.
Equivalent `-Wa,-mbig-obj` for GCC/Clang.
This started being needed to compile harfbuzz in `target=debug` with MinGW/GCC,
but there doesn't seem to be any drawback to enabling `/bigobj` (aside from
losing support for pre-VS 2005 linkers, which we don't support).
- Rename OpenGL to GLES3 in the source code per community feedback.
- The renderer is still exposed as "OpenGL 3" to the user.
- Hide renderer selection dropdown until OpenGL support is more mature.
- The renderer can still be changed in the Project Settings or using
the `--rendering-driver opengl` command line argument.
- Remove commented out exporter code.
- Remove some OpenGL/DisplayServer-related debugging prints.
First implementation with Linux display manager.
- Add single-threaded mode for EditorResourcePreview (needed for OpenGL).
Co-authored-by: clayjohn <claynjohn@gmail.com>
Co-authored-by: Fabio Alessandrelli <fabio.alessandrelli@gmail.com>
Sets `AlignOperands` to `DontAlign`.
`clang-format` developers seem to mostly care about space-based indentation and
every other version of clang-format breaks the bad mismatch of tabs and spaces
that it seems to use for operand alignment. So it's better without, so that it
respects our two-tabs `ContinuationIndentWidth`.
This will allow adding developer checks which will be fully compiled out in
user builds, unlike `DEBUG_ENABLED` which is included in debug tempates and
the editor builds.
This define is not used yet, but we'll soon add code that uses it, and change
some existing `DEBUG_ENABLED` checks to be performed only in dev builds.
Related to godotengine/godot-proposals#3371.
This is done by providing API access to app specific directories which don't have any limitations and allows us to bump the target sdk version to 30.
In addition, we're also bumping the min sdk version to 19 as version 18 is no longer supported by Google Play Services and only account of 0.3% of Android devices.
Input buffering is implicitly used by event accumulation, but this commit makes it more generic so it can be enabled for other uses.
For desktop OSs it's currently not feasible given main and UI threads are the same).
- API has been simplified: all events now go through `parse_input_event()`. Whether they are accumulated or not depends on the `use_accumulated_input` flag.
- Event accumulation is now thread-safe (it was not needed so far, but it prepares the ground for the following changes).
- Touch drag events now support accumulation.
- State the Godot version and full hash in the backtrace.
- Add decoration around the crash backtrace, both to make it stand out
from other messages and help the user figure out what they should copy.
The XDG Base Directory specification does not allow using relative paths
(which broke things in Godot anyway). If a relative path is detected,
it should be ignored.
We've been using standard C library functions `memcpy`/`memset` for these since
2016 with 67f65f6639.
There was still the possibility for third-party platform ports to override the
definitions with a custom header, but this doesn't seem useful anymore.
Exposes AddressSanitizer support in MSVC compiler. Can be installed via individual
components in the Visual Studio 2019 Installer.
Disabled by default. Compile the engine with `scons use_asan=yes`.
-Rendering server now uses a split RID allocate/initialize internally, this allows generating RIDs immediately but initialization to happen later on the proper thread (as rendering APIs generally requiere to call on the right thread).
-RenderingServerWrapMT is no more, multithreading is done in RenderingServerDefault.
-Some functions like texture or mesh creation, when renderer supports it, can register and return immediately (so no waiting for server API to flush, and saving staging and command buffer memory).
-3D physics server changed to be made multithread friendly.
-Added PhysicsServer3DWrapMT to use 3D physics server from multiple threads.
-Disablet Bullet (too much effort to make multithread friendly, this needs to be fixed eventually).
This is meant for users making custom builds to match the options used on
optimized, official builds.
This enables, on the platforms which support them:
- `use_static_cpp=yes` (portable binaries for Linux and Windows)
- `use_lto=yes` (link time optimizations - note: requires a lot of RAM!)
- `debug_symbols=no` (no debug symbols, smaller binaries)
Also abort when using MSVC with `production=yes`, as:
- It cannot optimize the GDScript VM like GCC or Clang do, leading to
significant performance drops.
- Its LTO support is unreliable, at least used to trigger crashes last
we tried it extensively.
All options can still be overridden if specified, and the `dev=yes` option
was changed to also support overrides.
- Based on C++11's `thread` and `thread_local`
- No more need to allocate-deallocate or check for null
- No pointer anymore, just a member variable
- Platform-specific implementations no longer needed (except for the few cases of non-portable functions)
- Simpler for `NO_THREADS`
- Thread ids are now the same across platforms (main is 1; others follow)
- Based on C++14's `shared_time_mutex`
- No more need to allocate-deallocate or check for null
- No pointer anymore, just a member variable
- Platform-specific implementations no longer needed
- Simpler for `NO_THREADS`
Happy new year to the wonderful Godot community!
2020 has been a tough year for most of us personally, but a good year for
Godot development nonetheless with a huge amount of work done towards Godot
4.0 and great improvements backported to the long-lived 3.2 branch.
We've had close to 400 contributors to engine code this year, authoring near
7,000 commit! (And that's only for the `master` branch and for the engine code,
there's a lot more when counting docs, demos and other first-party repos.)
Here's to a great year 2021 for all Godot users 🎆
Otherwise we can get situations where platform-specific opts with the same name
can override each other depending on the order at which platforms are parsed,
as was the case with `use_static_cpp` in Linux/Windows.
Fixes#44304.
This also has the added benefit that the `scons --help` output will now only
include the options which are relevant for the selected (or detected) platform.
The underscore prefix was used to avoid the conflict between the `RID` class
name and the matching enum value in `Variant::Type`.
This can be fixed differently by prefixing uses of the `RID` class in `Variant`
with the scope resolution operator, as done already for `AABB`.
`debug_symbols=yes` will now behave like `debug_symbols=full` did
before. The difference in compressed file sizes is not that large,
which means there isn't much point in having two different values.
This helps make the buildsystem easier to understand.
We want debug builds to have a console and easy stdout redirection by default.
Windows makes reading the stdout/stderr stream from gui applications too cumbersome
(and most users don't know about it, and just wonder why they don't see a thing).
On Windows, WINDOW_EVENT_FOCUS_IN was never sent by the display server
for popups, because WM_ACTIVATE events are received during the call to
_update_window_style, which happened before the callbacks were set.
This was causing some issues with the way Popup is now handling closing on
parent focus.
Now _update_window_style is only called during show_window, after Window
initialized callbacks.
This code currently isn't compiled (and cannot compile).
We plan to re-add OpenGL ES-based renderer(s) in Godot 4.0 alongside Vulkan
(probably ES 3.0, possibly also a low-end ES 2.0), but the code will be quite
different so it's not relevant to keep this old Godot 3.2 code.
The `drivers/gles2` code from the `3.2` branch can be used as a reference for
a potential new implementation.
Previously `joypad_count` was used as the index into the d_joypads array when initializing a new gamepad.
This caused the accidental override of an already connected device when a gamepad with a lower id was disconnected and connected again.
fixes#17566
It's too hard to get compatibility between GNU and BSD sed,
so let's just use perl oneliners.
And improve it to also remove trailing tabs, not just spaces.
Until https://github.com/psf/black/pull/1328 makes it in a stable release,
we have to use the latest from Git.
Apply new style fixes done by latest black.
Implements exit codes into the engine so tests can return their statuses.
Ideally we don't do this, and we use FIXUP logic to 'begin' and 'end' the engine execution for tests specifically.
Since realistically we're initialising the engine here we don't want to do that, since String should not require an engine startup to test a single header.
This lowers the complexity of running the unit tests and even for
physics should be possible to implement such a fix.
Its last use was removed in Godot 3.0, so it no longer makes sense to define.
Also removed `D3D_DEBUG_INFO` for Windows as it's likely a left over from a
long time ago pre-opensourcing when Godot had some form of Direct3D 9 support?
When creating a window, Godot would first register it to the WM(show it) and then set its flags.
This works fine on a floating WM, but on tiling WMs as soon as a window gets registered
the WM immediately acts on the window by scaling it up and treating it as a generic window,
being registered without any special flags.
This commit separates the showing of the window into another function and calls it after the most important flags are set,
making windows with special flags(eg. all popups) work again on tiling WMs.
Fixes#37930
Detecting the case where WM_SIZE is received during the window creation.
There's no need to call window_resize on the Vulkan context.
Also creating a WindowData entry early enough to avoid storing a
separate WindowData wrongly associated to INVALID_WINDOW_ID.
Fixes#39199
The previous code for OS_Windows::get_ticks_usec() multiplied the tick count by 1000000 before dividing by ticks_per_second. The ticks is counted in a 64 bit integer and is susceptible to overflow when a machine has been running for a long period of time (days) with a high frequency timer.
This PR separates the overall calculation into one for seconds and one for the remainder, removing the possibility of overflow due to the multiplier.
I couldn't find a tool that enforces it, so I went the manual route:
```
find -name "thirdparty" -prune \
-o -name "*.cpp" -o -name "*.h" -o -name "*.m" -o -name "*.mm" \
-o -name "*.glsl" > files
perl -0777 -pi -e 's/\n}\n([^#])/\n}\n\n\1/g' $(cat files)
misc/scripts/fix_style.sh -c
```
This adds a newline after all `}` on the first column, unless they
are followed by `#` (typically `#endif`). This leads to having lots
of places with two lines between function/class definitions, but
clang-format then fixes it as we enforce max one line of separation.
This doesn't fix potential occurrences of function definitions which
are indented (e.g. for a helper class defined in a .cpp), but it's
better than nothing. Also can't be made to run easily on CI/hooks so
we'll have to be careful with new code.
Part of #33027.
Which means that reduz' beloved style which we all became used to
will now be changed automatically to remove the first empty line.
This makes us lean closer to 1TBS (the one true brace style) instead
of hybridating it with some Allman-inspired spacing.
There's still the case of braces around single-statement blocks that
needs to be addressed (but clang-format can't help with that, but
clang-tidy may if we agree about it).
Part of #33027.
Using `clang-tidy`'s `modernize-use-default-member-init` check and
manual review of the changes, and some extra manual changes that
`clang-tidy` failed to do.
Also went manually through all of `core` to find occurrences that
`clang-tidy` couldn't handle, especially all initializations done
in a constructor without using initializer lists.
Part of #33027, also discussed in #29848.
Enforcing the use of brackets even on single line statements would be
preferred, but `clang-format` doesn't have this functionality yet.
It changed name as part of the DisplayServer and input refactoring
in #37317, with the rationale that input no longer goes through the
main loop, so the previous Input singleton now only does filtering.
But the gains in consistency are quite limited in the renaming, and
it breaks compatibility for all scripts and tutorials that access
the Input singleton via the scripting language. A temporary option
was suggested to keep the scripting singleton named `Input` even if
its type is `InputFilter`, but that adds inconsistency and breaks C#.
Fixesgodotengine/godot-proposals#639.
Fixes#37319.
Fixes#37690.
Configured for a max line length of 120 characters.
psf/black is very opinionated and purposely doesn't leave much room for
configuration. The output is mostly OK so that should be fine for us,
but some things worth noting:
- Manually wrapped strings will be reflowed, so by using a line length
of 120 for the sake of preserving readability for our long command
calls, it also means that some manually wrapped strings are back on
the same line and should be manually merged again.
- Code generators using string concatenation extensively look awful,
since black puts each operand on a single line. We need to refactor
these generators to use more pythonic string formatting, for which
many options are available (`%`, `format` or f-strings).
- CI checks and a pre-commit hook will be added to ensure that future
buildsystem changes are well-formatted.
For us, it practically only changes the fact that `A<A<int>>` is now
used instead of the C++03 compatible `A<A<int> >`.
Note: clang-format 10+ changed the `Standard` arguments to fully
specified `c++11`, `c++14`, etc. versions, but we can't use `c++17`
now if we want to preserve compatibility with clang-format 8 and 9.
`Cpp11` is still supported as deprecated alias for `Latest`.
EngineDebugger is the new interface to access the debugger.
It tries to be as agnostic as possible on the data that various
subsystems can expose.
It allows 2 types of interactions:
- Profilers:
A subsystem can register a profiler, assigning it a unique name.
That name can be used to activate the profiler or add data to it.
The registered profiler can be composed of up to 3 functions:
- Toggle: called when the profiler is activated/deactivated.
- Add: called whenever data is added to the debugger
(via `EngineDebugger::profiler_add_frame_data`)
- Tick: called every frame (during idle), receives frame times.
- Captures: (Only relevant in remote debugger for now)
A subsystem can register a capture, assigning it a unique name.
When receiving a message, the remote debugger will check if it starts
with `[prefix]:` and call the associated capture with name `prefix`.
Port MultiplayerAPI, Servers, Scripts, Visual, Performance to the new
profiler system.
Port SceneDebugger and RemoteDebugger to the new capture system.
The LocalDebugger also uses the new profiler system for scripts
profiling.
- Removed platform-specific implementations.
- Now all semaphores are in-object, unless they need to be conditionally created.
- Similarly to `Mutex`, provided a dummy implementation for when `NO_THREADS` is defined.
- Similarly to `Mutex`, methods are made `const` for easy use in such contexts.
- Language bindings updated: `wait()` and `post()` are now `void`.
- Language bindings updated: `try_wait()` added.
Bonus:
- Rewritten the `#ifdef` in `mutex.h` to meet the code style.
Main:
- It's now implemented thanks to `<mutex>`. No more platform-specific implementations.
- `BinaryMutex` (non-recursive) is added, as an alternative for special cases.
- Doesn't need allocation/deallocation anymore. It can live in the stack and be part of other classes.
- Because of that, it's methods are now `const` and the inner mutex is `mutable` so it can be easily used in `const` contexts.
- A no-op implementation is provided if `NO_THREADS` is defined. No more need to add `#ifdef NO_THREADS` just for this.
- `MutexLock` now takes a reference. At this point the cases of null `Mutex`es are rare. If you ever need that, just don't use `MutexLock`.
- Thread-safe utilities are therefore simpler now.
Misc.:
- `ScopedMutexLock` is dropped and replaced by `MutexLock`, because they were pretty much the same.
- Every case of lock, do-something, unlock is replaced by `MutexLock` (complex cases where it's not straightfoward are kept as as explicit lock and unlock).
- `ShaderRD` contained an `std::mutex`, which has been replaced by `Mutex`.
This attribute is now part of the standard we target so we no longer
need compiler-specific hacks.
Also enables -Wimplicit-fallthrough for Clang now that we can properly
support it. It's already on by default for GCC's -Wextra.
Fixes new warnings raised by Clang's -Wimplicit-fallthrough.