Footage is a special case where the node parameters can reference objects that
exist outside of the graph. Therefore specific code is needed to
serialize/deserialize.
The import function was written early on in the rewrite as a multithreaded
background task that was considered somewhat flawed. While it worked for the
most part, there were possibilities of race conditions that could have
potentially been fatal, particularly since media could theoretically be
deleted while the import/probe tasks were running in the background.
With the save/load functions coming in, it became even more complicated as
projects may include metadata about the footage that can't be implemented
easily when the footage is imported/probed in the background. Making importing
a modal task fixes all of these issues, it's still done in a background thread
to not hang the GUI thread, but the GUI thread can be briefly "paused" in a
user friendly way so that all these functions can be safer.
Since rationals aren't a known Qt format, the QVariant container can't
automatically convert them to and from strings (for XML serialization). We have
to hijack these functions and do the conversion manually for those types.
Also moved the block name type to a node input, which means it's serialized
and copied by default (I'm not sure why it wasn't already like this).
Since we load in a separate thread, when the QObject based objects are
instantiated, they're created with affinity to that separate thread. Now we
specifically ensure they are moved to the main thread after their creation.
This functions more or less identically to using a media out value, but the
desired speed is preserved through block length changes, even if the block's
length is reduced to zero (i.e. no rounding errors).
This adds the ability to keyframe more than one value per input (e.g. a vec2,
vec3, etc.) so that you can animate, for example, an X axis separately from a
Y axis.
To allow keyframing of each axis of a vector 2/3/4, without simply separating
the inputs for each axis, the NodeInputs need to support more than one keyframe
track with the ability to merge them into a single value when necessary.
Widget now supports creating keyframe and standard values, supports dragging
from sliders (not creating an undo command for each drag), and everything is
undoable.
Previously the non-keyframed value was stored as a static keyframe but this
introduced issues when an input was in a state of keyframes being enabled but
0 keyframes existing. Having a standard value makes much more sense.
While the keyframes themselves are relatively simple, their usage is quite
complex and using QObjects as their base will help a ton of UI and backend
functionality.
Since all NodeInputs will generally only need their data type and default
value set once, we place it all into the constructor for cleaner and easier
to manage code.
To aid generating a cache ID, each viewer node needs a UUID. Previous iterations
tried to hash a name and time, but a UUID is a much more efficient way to do
this.
itsmattkc