Visualiser Host Callbacks for Keypress Handling

[mondus]

It would be very useful to have host callback functions to handle user input. I.e. key presses (not so much mouse movement). In FLAME GPU 1 many simulations used custom key mappings to change the virtualisation. E.g. To display different data.

[Robadob]

We have quite a thorough UI systems within the visualiser already which allows environmental properties to be modified from the visualisation.

https://www.youtube.com/watch?v=9jPfBs81XmE

I'd need to see a good use-case to support this added complexity.

[mondus]

The main example would be using a keypress to change the visualisations bound variable or colour range. The FGPU1 version of the model visualisation linked above allowed this. I.e. Numerical values mapped through to displaying of the different collision/velocity maps.

[Robadob]

using a keypress to change the visualisations bound variable

That was what we agreed to replace with the UI elements for FLAMEGPU2.

or colour range

There's currently no means within FLAMEGPU to modify visualisation of agents "directly" from a visualisation, but agent colour can be tied to an agent variable which can be controlled from an environmental property.

Actually hiding agents/states might be a little harder.

[mondus]

Its not so much hiding agents or states but more about changing the display of agents from within the display loop. I.e. Changing from visualising agents temp to pressure is not just a case of modifying an environment variable or mapping the colour state to a particular variable. It would require a call to agent.setColor(...) from within the sim loop. Hence the need for a callback. I don't think it would work to have a separate thread poll for inputs as the Vis window has focus.

[Robadob]

No, you could add a colour variable to your agent, and change how it's set based on an environment property. Perhaps awkward, but far from impossible.

[mondus]

I'll try this later. Its a bit grim as the colour output mode would ideally be mutually exclusive so having multiple toggles (temp, distance, pressure etc) requires there to be a bias towards one colouring mode or blending of multiple colouring modes.

[Robadob]

I think you should be able to define a custom colour map, such that you can offset one of the values by 1000 or something to cover everything. Awkward, we could make a bespoke thing to do it slightly easier.

Similar to the viridis palette