More dynamic brushes

[blairmacintyre]

Given that we can now load a scene into an aframe program, and we can actually use the same code to render in this aframe program as we do in apainter, we have the potential to create animated, dynamic "brushes" of the sort something like Tilt Brush can't do (via model export / import in other programs).

Simple things like particle systems (stars, fire, pixel-trails) that react to how the apainter model is moved and animated in the target program.

[dmarcos]

It's defintively possible with the current API. When defining a brush one also can declare a tick method and include any animation logic there.