A-Frame Trigger javascript function on collide with camera

Question

I am trying to trigger my score function whenever the camera collide or touch an object like:

<a-entity id="rock" static-body obj-model="obj:models/rock_mesh.obj;mtl:images/rock_mesh.mtl" rotation="0 90 0" position="7.30242379045994 0.3 0">
     </a-entity>

I equip my a score text on my camera:

 <a-text id="score" value="0" position="-0.2 -0.5 -1" color="red" width="5" anchor="left"></a-text>

And trying to trigger a function like this:

let score = 0;
score = score + 1
$("#score").setAttribute('text','value','Score '+score)

This is just a draft up code, I am still new to javascript

How can i do this? Incrementing the score on the screen whenever my camera touches this "rock" object?

How can i detect the collision or touch with the object and my camera?

Thanks in advance.

Answer 1

The simplest way to detect collisions would be detecting if the THREE bounding boxes are overlapping

You can use Ngo Kevins aabb-collider which emits hitstart upon collision. Remember though, the camera does not have it's own geometry:

<a-camera foo geometry="primitive: box" aabb-collider="objects: a-box"></a-camera>
<a-box scale="2 2 2" class="box" color="blue" position="0 1.6 -5" ></a-box>

with foo being a simple event listener for hitstart.

AFRAME.registerComponent("foo", {
  init: function() {
     this.el.addEventListener("hitstart", (e)=>{
         // Collision ! increment the score
     })
  }
})

Fiddle here.

If possible, I wouldn't detect collisions with your model, but create some collision boxes.

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It's also worth mentioning, if You'd want to use a physics engine in your project, Don McCurdys Physics System also enables collision detection. Instead of hitstart, You'd need to listen for collision.