Control Rendering Simulations

[thalerjonathan]

A simulation which has rendering output (e.g. Sugarscape) should be controllable so the modeller can explore better what is going on.

• The simulation should start in paused mode.
• Space allows to toggle between running/pause modes.
• in pause-mode one can use the left/right arrow keys to move backward and forward (up to the currently simulated step) in time by 1 time-unit (depending on the time-delta). When pressing the shift key in .addition, one jumps 10 time-units (depending on the selected time-delta).
• in pause-mode one can use the up/down arrow keys to jump to the beginning / current time-step of the simulation.
• when in pause-mode and having moved back in time, when resuming, the rendering picks up again from the most recent time-step.

[thalerjonathan]

The main loop is controlled by Gloss. Using dunai it is easy to evealuate the top-level MSF with the next step, we need then a function which removes the monadic layer(s) of the current step. The output is then rendered/appended to the outputs list and stored together with the continuation in a IORef to be available in the next-step callback.