AFrame updating material.offset for each object

I made an AFrame component for creating hotspot, and I want to change material.offset.y of a hotspot when I hover it with cursor. So I first tried using AFrame animaiton attribute, but visibly, we can’t access to this property with animation.

So I added a eventListener to the hotspot JS object and changing the getObject3D(‘mesh’).material.map.offset.y, but it update all hotspots texture when I hover one, and don’t know why… I checked if this was pointing on a specific hotspot, and it is ! So I don’t understand why all textures are updating…

Here is the code:

<a-scene light="defaultLightsEnabled: false">
            <a-assets>
                <!-- Loading Scenes -->
                <img src="./assets/scene/scene.jpg"             id="scene_spherical" />

                <!-- Loading Icons -->
                <img src="./assets/icons/close.png"             id="icon_close" />
                <img src="./assets/icons/hotspot_sprite.png"    id="icon_hotspot" />
                <img src="./assets/icons/powered.png"           id="icon_powered" />
                <img src="./assets/icons/store.png"             id="icon_store" />

                <!-- Loading Mixins -->
                <a-mixin id="mixin_hotspot"
                         geometry="primitive: circle; radius: 0.25"
                         material="shader: flat; src: #icon_hotspot; transparent: true; repeat: 1 0.5; offset: 0 0.5;"
                ></a-mixin>
            </a-assets>

            <a-hotspot position="-6.33 0.30 -1.46" product="terrazzo_kaza_d" class="" id="hotspot_terrazzo_kaza_d"></a-hotspot>
            <a-hotspot position="5.43 -0.03 -6.21" product="meuble_tv" class="" id="hotspot_meuble_tv"></a-hotspot>
            <a-hotspot position="3.34 -0.81 -7.77" product="tapis_lake" class="" id="hotspot_tapis_lake"></a-hotspot>
            <a-hotspot position="5.30 1.22 -0.81" product="isole_escalier" class="" id="hotspot_isole_escalier"></a-hotspot>
            <a-hotspot position="-3.74 1.10 7.27" product="papier_peint" class="" id="hotspot_papier_peint"></a-hotspot>
            <a-hotspot position="3.09 -0.69 7.35" product="shooting_sol" class="" id="hotspot_shooting_sol"></a-hotspot>
            <a-hotspot position="-6.98 1.86 0.60" product="isole_cuisine" class="" id="hotspot_isole_cuisine"></a-hotspot>
            <a-hotspot position="-0.38 -0.32 5.98" product="isole_table_rectangulaire" class="" id="hotspot_isole_table_rectangulaire"></a-hotspot>
            <a-hotspot position="2.66 1.76 -8.15" product="isole_voilage" class="" id="hotspot_isole_voilage"></a-hotspot>
            <a-hotspot position="-1.13 -0.34 -7.41" product="isole_canape2" class="" id="hotspot_isole_canape2"></a-hotspot>

            <a-sky src="#scene_spherical"></a-sky>
            <a-camera wasd-controls="enabled: false;" cursor="rayOrigin: mouse"></a-camera>
        </a-scene>

import loadProduct from '../libs/shop'

AFRAME.registerPrimitive('a-hotspot', {
    defaultComponents: {
        'hotspot-popup': {}
    },

    mappings: {
        product: 'hotspot-popup.product',
    }
})

AFRAME.registerComponent('hotspot-popup', {
    schema: {
        // variables
        product: {type: 'string'}
    },

    init: function() {
        this.el.setAttribute('mixin', 'mixin_hotspot')

        this.setHover()
        this.setClick()
    },

    setHover() {

        this.el.addEventListener('mouseenter', () => {
            let material = this.el.getObject3D('mesh').material
            if (material.map) {
                material.map.offset.y = 0
                material.map.offset.x = 0
            }
        })
        this.el.addEventListener('mouseleave', () => {
            let material = this.el.getObject3D('mesh').material
            if (material.map) {
                material.map.offset.y = 0.5
                material.map.offset.x = 0
            }
        })
    },

    tick: function () {
        let cursorRotation = document.querySelector('a-camera').getAttribute('rotation')
        this.el.setAttribute('rotation', cursorRotation)
    },

    setClick: function () {
        this.el.addEventListener('click', () => {
            console.log('load', this.data.product)
            loadProduct(this.data.product)
        });
    }
})

So if anyone know how to prevent this behaviour, don’t hesitate to comment this post please.

Thanks, Navalex

Answer

The reason why all images are given the same offset is because a-frame re-uses textures for performance reasons.

With a setup like this:

<a-box material="src: #image"></a-box>
<a-sphere material="src: #image"></a-sphere >

If you log both element.getObject3D("mesh").material.map.uuid – they will be the same (fiddle). Updating one affects the other.

---

If you give them an initial offset in the material (but a different one for each object):

<a-box material="src: #image; offset: 0 0.5"></a-box>
<a-sphere material="src: #image"></a-sphere >

a-frame will create another instance of THREE.Texture() them (fiddle).

---

Otherwise, you could create a component which replaces the texture with a copy:

this.el.addEventListener("materialtextureloaded", e => {
  // grab the object
  let obj = this.el.getObject3D("mesh")
  // grab the texture
  let map = obj.material.map
  // create a new one
  const texture = new THREE.TextureLoader().load(map.image.src);
  // without wrapping, it will just "stretch" instead of "repeating"
  texture.wrapS = texture.wrapT = THREE.RepeatWrapping;
  // assign the new texture
  obj.material.map = texture;
  // update the material
  obj.material.needsUpdate = true
})

Which brings us to something like this (including animation, wrapping etc)