Solid Particle System rollover on particle event

[OXY11]

there's a way to intercept the rollover on a single particle, in addition to the click?

[jerome]

what do you mean by "rollover" on a single particle ?

[OXY11]

on a Solid Particle System each particle is Pickable, and it is possible to trigger a function when mouse click on them.

I need to trigger a function when the mouse rolls over a particle.

Is it possible?

[jerome]

http://doc.babylonjs.com/tutorials/Picking_Collisions

Well, I'm not the specialist in pickability and rays. But the SPS is a simple mesh, so dectecting when the mouse pointer rolls over it is the same process than with any other mesh (just can't retrieve the right PG, @Wingnut might have this in his endless indexed archive somewhere  )

I guess the right way is to emit a ray, what actually the function pick() does, permanently and not only on the mouse click event. Not sure it's performance friendly though.

So in brief, this would be the same code than for the click event, but not registered to any event and called each frame :

var pickResult = scene.pick(x, y);

if (pickResult.hit)  ...

 

[OXY11]

OK thank you very much
But this way I can not know what hit particle, but only if I hit the SPS.
Or am I wrong?
I would need to read the IDX of the affected particle.

[jerome]

yep you can : http://doc.babylonjs.com/overviews/Solid_Particle_System#pickable-particles

set the SPS as pickable (isPickable: true) and an array called sps.pickedParticles is then populated for you : each key is the mesh faceId, each array element is an object {idx: particleID, faceId: faceIDInTheParticle} 

 

here is a slightly modified example with a rollover : http://www.babylonjs-playground.com/#2FPT1A#68

[OXY11]

WOW!!!

thanks a lot!!

[RyanONeill1970]

This works really well and it doesn't suffer from CPU or GPU performance as @jerome thought it might.

If I was really wary of performance issues (mobile for example) then maybe mouse / touch events could be captured which would flag that the ray should be checked again.

For example, surrounding the scene.pick with the following;

     SPS.setParticles();

     pl.position = camera.position;

     if ( mouseUpdated )

     {

           mouseUpdated = false;

           var pickResult = scene.pick(scene.pointerX, scene.pointerY);

           if (pickResult.hit) {

               rollover(pickResult);

           }

      }

 

[RyanONeill1970]

Actually, I'm wrong, it seems to hit the GPU quite hard so I'll try this with the mouse monitoring flag approach.