Mapping dots to facets or particles to vertices

[JohnK]

In this thread @jps0611 posted

Quote

I want to do a particle system and have it form the outline of the surface of a mesh. Any playgrounds out there that illustrate this?

rather than further hijacking the thread I'll post some thoughts here.

First thought was of 2D particles but to cheat a bit and just put the same image on each triangular facet. To do this make the uvs for each triangular facet the same and map an equilateral section from an image containing a dot https://www.babylonjs-playground.com/#708IX4

Then extend this using an image with many dots https://www.babylonjs-playground.com/#708IX4#2

But this does not really answer the question, so onto putting solid particles at each vertex. Since for example a box is flat shaded it has repeated vertices and does not have many vertices so first you need to minimize the vertices to remove repeats and increase the number first.

https://www.babylonjs-playground.com/#708IX4#3

And here's on distributing solid particles over The Cat. As the Cat has over 77000 vertices one particle per vertex locks up your computer, the PG is 1 vertex in 20. As the facets are not distributed uniformly neither are the particles. https://www.babylonjs-playground.com/#BAW2GG

An now back to dot texture https://www.babylonjs-playground.com/#708IX4#4

 

[MarianG]

Awseome 

[Guest]

Excellent!!

[Wingnut]

Nice!  FUN!!! 

But, we all know what REALLY needs to happen, right?  Yep... smart particles, coded in SIMD style, with each particle having its own webWorker task.  The particles need to "think" like Starlings.   (Boy, is Wingnut talking some crap here, eh?) 

https://www.google.com/search?q=starling+swarms&source=lnms&tbm=vid&sa=X&ved=0ahUKEwi-htbN-4raAhVI9mMKHS2mB8AQ_AUIDCgD&biw=1216&bih=625

Murmurations.  First time I have ever seen that term.  hmm.

http://www.iamnop.com/particles/   Let's just go reverse-engineer that pig.  All the source code is there. 

At above URL, right-click-dragging on the sphere shape... is just SO SO cool.  The shapes are so "springy" and the particles so "over-shooty".  *sigh*  And the plane shape?  I want a trampoline made of THAT material.   And beds/mattresses... man, COMFY!  Super-rubber. 

It's probably all done in post-production.... errr... I mean post-processing.  heh.  Friggin' GPU geniuses.  (drool)

Sorry if I doused your enthusiasm fire, John.  But if we're going after "Nop", we're going to need the big guns.  heh.

[iiceman]

Remember the fun we had with particles back then: 

Maybe you could use the 2D particles and control them to cover the model using the vertext data... I mean we had a cool möbius strip (http://www.babylonjs-playground.com/#2KOEWJ#9) back then so placing them statically on some fixed positions should also be possible, right?

[Wingnut]

Heya Iceman!  Good to see ya! 

Yep, every day... we are making "the good ol' days". 

"statically on some fixed positions"?  Are you watching the same "Particle Dream" demo as I am?

I don't see anything static or fixed.  Not only are the particles loosely-but-tightly adhering-to the surfaces of morphing mesh (wolf, bear, horse, etc), but each particle is also staying evenly spaced FROM it's fellow particle.  Yet, it can be influenced by right or left clicks, which create drag-able 3D-ish gravity wells/bubbles, which are distance-from-center force-varied.

Essentially, 3D fluid dynamics.  Gruesome.

I don't mean to belittle any demos or discourage hopes, but... evenly distributing particles across a non-morphing surface... is only the start (if a Particle Dream-like action is sought).  The particles in Particle Dream actually FLY to the surface (with over-shoot and recovery), and not to a fixed point.  Instead, they float, "attracted-to" the surface/gravity-well/gravity-bubble, yet repelling and attracting toward/from each surrounding particle... in order to accomplish the even distribution.  And then... each particle never stops moving a tiny amount (physics).

Mega-gruesome.  Particle impostors.

I'm a party(-cle) pooper, aren't I?  Sorry.  If the goal is to match or spank Particle Dreams, then we can't just "phone this in".  We might need MANY bottles of Jack Daniels... for this baby. 

But, at least you have multiple people sitting around your campfire, JPS, John, Ice.  You should have seen my physics joint and ipod controller campfires. You ain't NEVER seen campfires THAT lonely and cold.  This campfire already has TRIPLE the interest/attendance. 

With hugs...
Enthusiasm-killer Wingnut