Olive: [Feature Request] More keyframe interpolation options

[Brimson]

Blender's VSE is the only open-source NLE with keyframe interpolation outside of the usual _smooth_ and _linear_. However, Blender's VSE does not have hardware-accelerated GLSL effects 😉

Here's a screenshot of available keyframe interpolations in the Blender 2.8 beta:

openFrameworks has the ofxAnimatable C++ add-on dedicated to this

Natron also allows keyframe easing with their Shadertoy GLSL plugins. Not asking for a robust animation system, just more options for smoother transitions and effects.

[alcomposer]

There are two parts to this:

• Having either different easing modes or cubic-bezier interpolation controls

• Having a GUI to control the easing. Currently the editor panel incorporates a dope sheet style editor. To allow more control a graph editor would be ideal.

[itsmattkc]

My intention is to have cubic bezier interpolation, I was researching it for one of the effects and I think it'd be fairly easy to implement. The graph editor UI would probably take the longest.

But yes, this is absolutely on the radar, thanks for reminding me :)

[itsmattkc]

Added to master in 69a33c756cb5bdc5683dc899bb40137cff042e29