Help on making a shotgun spread pattern ?

[HyHy]

Hello I'm new to babylonjs and I've been trying to make a constant shotgun spread pattern in babylon.js for a couple of days.

For the moment my approach consists of having a couple of lines ready to be displayed in an array :

       let sgPellets = [
            BABYLON.Mesh.CreateLines("lines", [
                        shotgunPosition,
                        meshFound.pickedPoint
            ], this.Player.game.scene),
            BABYLON.Mesh.CreateLines("lines", [
                        shotgunPosition,
                        meshFound.pickedPoint
            ], this.Player.game.scene),
        ] 

where shotgunPosition is the absolute position of the shotgun mesh in the world and meshFound.pickedPoint is the position of where I'm aiming at (on a mesh).

So I can draw a line (the first of the array in this case) between the shotgun mesh and the mesh I click on.

Now for the second line, I want it to rotate a bit on the y axis from the first (which is exactly where I'm aiming at) so:

          for(let k=0; k<sgPellets.length; k++){
            sgPellets[k].setPivotPoint(shotgunPosition);
            sgPellets[k].isPickable = false;
            switch(k){
                case 1:
                    sgPellets[k].rotation.y += 0.1
                    break
            }
           }

It does work well when I look on the sides 

but not when I look up or down.

It is surely because you cant extand indifinitly on the axis. But then, what's the workaround ?

I think I'm missing something on the math side

Does anyone have any hints on how to make the angle constant between the two lines anywhere you look ? Thank you.?

[Wingnut]

Hello HyHy, and welcome to the BJS forum.  What an interesting project you have!  Cool!

I don't have any answers to your issues, but I want to show you a neat system that our friend @jerome built.  (at least I THINK he built it) 

https://www.babylonjs-playground.com/#CNMNR#1

It's called the Solid Particle System, or SPS.  It's useful-for-you features are:

  - SPS is a very performance-optimized system
  - Particles/Pellets have basic collision-detect
  - Pellets have auto-calculated gravitational force, or disable gravity
  - Pellets have adjustable frustum/spread
  - Pellets have adjustable muzzle velocity
  - SPS systems allow a manual emit-count... a "pulse" of particles, and then go-idle, as wanted  (a shot)
  - SPS pellets have easily-adjustable pellets-per-shot (pellet cluster-density)
  - SPS pellets can have multiple and odd shapes, in case you want to shoot rock-salt instead of BB's
  - Pellets can be deleted (recycled) upon collision
  - Pellets can fall to the ground or just disappear, at a certain distance, after they have missed the target/collision

In my opinion, the SPS system is PERFECT for your "upland game" game/sim.  I think you should give it some thought/consideration.

Stay tuned... others will comment soon, I think.  Meantime, SPS experimenters - let's create a basic SPS shotgun for/with HyHy... to see how well he/she likes it.

(okay, okay, I would like to see/play-with an SPS shotgun, too.  Sounds like fun!!!  Let's see, we have an "explode-the-mesh" thing laying around here, too, yes?)

[trevordev]

@HyHy Im not sure I understand what you want (A playground with the current behavior would be helpful) but for a shotgun spread I would try this https://playground.babylonjs.com/#TG814J here the spread is a set of rays pointing in the z direction, if wanting to show the spread in a certain orientation (eg. from camera) you can rotate the direction by the camera's rotationQuaternion.