This makes the node system somewhat more high-level with the intent of making
working with them far more flexible and stable. By making the architecture more
abstracted, it becomes far less rigid which should allow us to do even more
with it and make it much less crash prone.
Yep, this is another one of my "famous" sweeping rewrites. Expect things to break.
Goals for this are:
- Greatly simplify node connections (particularly with arrays) so the code requires less maintenance/is more stable
- Redesign node structure to address issues where UI would stall for lengthy periods of time
- Less reliance on shared ptrs/greater reliance on QObject system for inheritance/memory management
- General code cleanup and improvements
Rather than plugging a matrix into the video input node, the matrix is now
multiplied by the video input using a math node. This is probably more
sensible from a user perspective.
This also means the renderer is tolerant of texture sizes that are not equal
to the sequence size, however most nodes will downsample the texture to the
sequence size (and if not, it will be downsampled once it is cached). Textures
will still *always* be in reference space and the sequence's format. This seems
like the best compromise between backend and frontend congruity.
Transitions are nodes but have a few parameters that are programmatic and always
required. This lets people write external code for transitions as well.
It seems unwise to let NodeInputs take more than one value, but at times
it makes sense to create a list or array of inputs. This class will create
sub-parameters as an easy way to provide variable inputs while also enforcing
one connection per input parameter.
This is also the primary motivation for the previous commit (disambiguating
when a NodeParam's parent is a Node vs some other type).