All D-Bus interfaces call the unique identifier that is returned by their
calls "cookie", so rename the 'id' field to 'cookie' to match that.

Closes obsproject/obs-studio#4263

There are too many issues with 20.04 to successfully build with
VirtualCam - the azure kernel is missing videodev headers. For now,
use 18.04 LTS directly for main CI builds.

Both 18.04 and 20.04 include clang-format-10 without issue.

Fixes a bug where the output resolution wouldn't change when using a
service that uses the "supported resolutions" limitation. When switching
to a non-editable combo box, the signal used to detect whether the combo
box has had its value changed wouldn't work anymore because it was the
signal explicitly used for editable combos. So, to fix, just reapply the
normal combo box signal to detect when the value has been changed.

Fixes obsproject/obs-studio#4124

Previously the save callback would be called when the replay buffer
hotkey was pressed and not when the saving of the replay was finished.
When the 'get_last_replay' procedure was called after the saved callback
function, it would return the incorrect path, as the path would still
be the previous path.

Just need to forward declare D3D12 type.

Attempt to schedule shared texture copies against the command queue that
the game's swap chain uses to try to reduce artifacts. The heuristics
for obtaining the queue are not perfect, so provide a toggle to use the
previous behavior.

DMA-BUF importing for EGL renderers

Expose the Wayland socket to the sandbox, and enable Wayland at build
time using the new ENABLE_WAYLAND define for CMake.

Implement device_texture_create_from_dmabuf for EGL/X11 and EGL/Wayland.
The code is shared between them, in a new gl-egl-common.c file.

This is currently limited to a few common RGB(A) formats for now, which
seems to cover most use cases.

Import the DMA-BUF importing extensions from GLAD.

DMA-BUF is a widespread Linux buffer sharing mechanism. It is what's
commonly used zero-copy screen sharing by Wayland compositors.

Add a new 'device_texture_create_from_dmabuf' vfunc to gs_exports,
and stub implementations to libobs-opengl. Add a new public method
gs_texture_create_from_dmabuf() that calls this vfunc.

Closes obsproject/obs-studio#4086

In #3988, @RytoEx mentioned that the recent Qt upgrade to 5.15.2
introduced a regression in which Qt begins returning DPI/scaling
aware resolutions for each screen. While this was fixed for
new profiles, this was not reflected in the choice for the
Canvas (Base) Resolution in the Settings screen yet.

This commits fixes this issue, and calculates the correct
physical screen size again, respecting per-screen DPI scaling.

The Chromium sandbox is conflicting with the Flatpak sandbox in a non-trivial,
non-workaroundable way. Until Chromium / CEF provides a way to unconditionally
disable the entire sandbox, let's not degrade the Flatpak experience.

EGL/Wayland (Wayland, pt 3)

This reverts commit 36ab7b97.

The fact that a transition is a composition of two scenes was not
factored into the merging of this PR. Thus, it would apply to the
underlying scenes when transitioning, making the effectiveness of this
feature cause inconsistent rendering of the underlying scenes when
transitions are activated versus when they're not.

This is a workaround for QWaylandWindow never becoming exposed, or
receiving the QEvent::Expose [1].

[1] https://bugreports.qt.io/browse/QTBUG-86176

This will be used by a new event filter, added only when running as a Wayland
client, to force creating the obs_display instance even when not exposed.

This is a dangerous operation on Wayland, and is crashing not only
OBS Studio but also the whole compositor. Let's disable it for now
when running as a native Wayland client.

Some compositors (GNOME Shell, Plasma) still allow setting this
option on the window menu.

The sizeChanged callback is connected to the screenChanged signal,
and evidently the naming doesn't match. Rename the callback to
match the signal name.

Right after showing the OBSQTDisplay widget, it may happen that a
wl_surface is not yet created and attached to the window. When this
happens, creating the OBS display results in a crash.

Make QTToGSWindow return a boolean, indicating success or failure, and
don't create the OBS display on failure.

When a window is made invisible, then visible again, the
obs_display is reused. Turns out, QT destroys the wl_surface
associated with the previewer on Wayland. However, the EGL
surface created on top of this wl_surface is not, and any
attempt to attach a new buffer to it will crash OBS.

Destroy the obs_display when becoming invisible, and when
running as a Wayland client. Also nullify the display
variable on destruction, to avoid subclasses double-freeing
the obs display.

On Wayland, we want to query the window's underlying
platform for the Wayland surface, instead of foolishly
retrieving the X11 display.

Pass QWindow instead of WId directly, and set the surface
as the platform data on Wayland systems.

Introduce a new Wayland/EGL renderer.

We need to ensure we're running all X11 code on the same display.

Introduce the OBS_NIX_PLATFORM_WAYLAND enum value, and try to detect
it when OBS Studio runs by looking into the platform name.

This adds a menu item in the transitions config menu to access
filters for stinger transitions.

decklink-ui: fix double free of settings

This leads to a crash when the output is stopped, either by clicking the
stop button or when exiting OBS studio.

This crash is:
- intermittent in release builds
- reliable for me in debug builds

It is held by an `OBSData`, which, if not null, will automatically
call `obs_data_release()` on scope exit.

obs-transitions: Track Matte support for Stinger Transitions

This adds the ability to use a secondary black-and-white video as a mask
between source A and B of the transition. The greyscale value of each
pixel is used as the "slider" value in a linear interpolation between the
corresponding pixels in source A and source B.
The track matte can either be in the same file as the stinger itself
(next to the stinger or under the stinger, doubling the width or height
of the stinger depending of the selected layout) or a in a separate
dedicated file.
The same file/separate file behavior is controlled by the
"Matte Layout" option in the stinger settings.