Implements a very basic GLSL deinterlace that simply halves the vertical
resolution and then interpolates between the fields. This can be toggled
on or off.
The reasons for being so basic is:
- Speed, very quick code running in OpenGL
- It would seem the highest quality deinterlacers are temporally based
which doesn't make much sense for the viewer, particularly since we can't
double the frame rate since our timecode is fixed to the frames.
Higher quality interlacing/deinterlacing will be present in the actual
renderer.
Viewer init was kind of too late since in many cases the sequence
would start caching and crash the app before the user could even read
the message. Moving to the startup makes it clearer from the beginning.
The nodes now have more control over how their accelerated shaders/sample
functions are run, as well as how items are popped off the value tables.
This allows for various optimizations that we didn't have access to before.
Improves minor issues with frame queue implemented in earlier commit. Also links
ViewerWindow with the queue and a separate timer to make it much smoother.
Rather than have to decode EXRs and display them in the span of one frame,
decode into memory ahead of time so that they're ready for upload. Has the
potential to speed up playback by about 5-6x.