Add animationLoop.redraw() method.

[donmccurdy]

Background

When using LumaGL (via DeckGL) in applications, it can be useful to synchronously cause LumaGL to draw outside of its normal animation loop. For example, Google Maps API has its own animation loop – which cannot be manually controlled – and when a DeckGL layer is used on top of the Maps API basemap, we would like to ensure that the DeckGL layer's rendering is synchronized with the basemap's. Because the map may have multiple layers or none at all, depending on application state, it seems preferable for Maps API to manage the animation loop, rather than DeckGL.

Per earlier discussion (visgl/deck.gl#2179 (comment)) I propose adding an animationLoop.redraw() method to support this.

One alternative would be to create an API through which DeckGL can be used without an animation loop entirely, manually calling some .draw() method as needed. That seems like a more invasive change, and introduces complexity when the layer itself contains time-based animation.

To Do List

• Add label and assign to milestone
• Coding
• Doc update
• Whats new update
• Test

[donmccurdy]

Addressed by #896, thank you! :)