Followup: Predictive positioning (rendering)

[parasyte]

Follows: #99 and #718

We have a new "frame_prediction" example which shows a naïve implementation of frame prediction built in user-code. This ticket will move the predictive positioning code into melonJS proper.

Some items to consider. All of these are in relation to the time delta of any skipped update:

• me.Entity.draw should extrapolate the entity position
• me.AnimationSheet.draw should handle the animation updates (in place of update)
• me.TMXTileset.draw should handle the animation updates (in place of update)
• me.Tween.draw should handle the tween updates (in place of update) even though it will not draw anything

This short spec will probably be pretty unstable until some edge cases are resolved. The edges are:

• me.sys.updatesPerFrame === me.sys.fps:
  • update overruns allocated compute time
  • draw overruns allocated compute time
  • update and draw overrun allocated compute time together (but not alone)
• me.sys.updatesPerFrame < me.sys.fps:
  • update overruns allocated compute time
  • draw overruns allocated compute time
  • update and draw overrun allocated compute time together (but not alone)

Where "allocated compute time" is equivalent to 1000 / me.sys.fps