Babylon.js OnIntersectionEnterTrigger not triggering with camera - javascript

I'm using Babylon.js 2.4.0.
I have a mesh (in the shape of a couch) loaded from a .obj file, and a camera set up like this:
let camera = new BABYLON.FreeCamera('camera1', new BABYLON.Vector3(0, 2, 0), scene);
camera.checkCollisions = true;
camera.applyGravity = true;
camera.ellipsoid = new BABYLON.Vector3(1, 1, 1);
camera.attachControl(canvas, false);
camera.speed = 0.5;
camera.actionManager = new BABYLON.ActionManager(scene);
I want to set up an event so that when I walk through the couch, "intersection" is logged to the console:
let action = new BABYLON.ExecuteCodeAction(
{ trigger: BABYLON.ActionManager.OnIntersectionEnterTrigger, parameter: { mesh: couchMesh }},
(evt) => {
console.log("intersection");
}
);
this.camera.actionManager.registerAction(action);
When I walk through the mesh, nothing is logged to the console.
I've created an example on the Babylon.js Playground using an example that they provide to check that it wasn't a problem with my mesh or camera set up, and it doesn't appear to be (the playground doesn't work either).

A camera in Babylon.js has no action manager, so even if you set one it won't really work.
To get this to work using action managers, you could define an invisible box around the camera, with a predefined size and attach the action manager to the mesh created. then set the mesh's parent to be the camera, and you are done. Here is your playground with those changes - http://www.babylonjs-playground.com/#KNXZF#3
Another solution is to use the internal collision system of babylon js, and set the camera's onCollide function to actually do something :) Here is en example - http://www.babylonjs-playground.com/#KNXZF#4
Notice that in the second playground, the camera won't go throug the box, as the collision system prevents it from doing so. I am not sure about your usecase, so it is hard to say which one of the two will work better.
If you need a "gate" system (knowing when a player moved through a gate, for example), use the 1st method. The 2nd is much cleaner, but has its downsides.

Related

Three.JS instance can't be re-created

I'm trying to destroy (or destruct or dispose) an 'instance' of Three.JS using this:
Full example: https://jsfiddle.net/v7oLzs4m/58/
function kill() {
const rendererDomWas = renderer.domElement;
renderer.dispose();
controls.dispose();
renderer = scene = camera = controls = null;
document.body.removeChild( rendererDomWas );
shouldRender = false;
}
function animate() {
if(!shouldRender) {return} // no more requesting animation frames if 'shouldRender' is false
frameID = window.requestAnimationFrame( animate );
renderer.render( scene, camera );
}
(i.e. disposing, setting references to null, and stopping the draw loop from touching renderer while shouldRender is false)
It appears to work at first (The renderer content stops showing) but when I re-create the instance, it never comes back.
It's as if something is still... holding onto the GLContext which prevents it from being invoked again.
Why can't I re-create a new instance of Three.JS?
I'm not sure why this works (since I was already doing this in my Fiddle...)
But it turns out the secret ingredient (for me) to letting Three.JS get GC'd/disposed is this:
window.cancelAnimationFrame(frameID);
I suppose that this stops the render function from being stored in the hardware-level draw loop, which holds references to GLContext (and the chain)
The GC can't ever happen unless the 'loop is broken'
(Correct me if I'm wrong please)

In A-Frame: How do I get the VR camera

In this example:
https://glitch.com/~query-aframe-cameras
I have registered a component which launches a projectile in the direction the user is looking (with a little boost for elevation)
Spacebar or Screen Tap to launch - be sure to be looking above the horizon!
It fails in mobile vr (stereo camera) mode:
Projectiles continue to fire, but from the default orientation of the mono, not the stereo camera
I'm using:
var cam = document.querySelector('a-scene').camera.el.object3D;
var camVec = new THREE.Vector3();
var camDir = cam.getWorldDirection(camVec);
to get the camera information and spit the projectiles back
QUERY:
HOW DO I GET THE STEREO CAMERA INFORMATION
The problem will be due to this bug in THREE.js.
https://github.com/mrdoob/three.js/issues/18448
Following the documented workaround, the code here works with correct direction tracking on my Quest 2.
https://cuddly-endurable-soap.glitch.me
(there's a couple of other changes in here: to test this on my VR headset I also had to upgrade to A-Frame 1.1.0, and make the code fire the balls on a timer, since I don't have any keys to press when using it! Neither of these was enough to fix the problem, though).
This code will set up CamDir as you need it.
var camQ = new THREE.Quaternion();
cam.updateMatrixWorld();
camQ.setFromRotationMatrix(cam.matrixWorld);
var camDir = new THREE.Vector3(0, 0, 1);
camDir.applyQuaternion(camQ);
The following code also works (and is more efficient), but is less easy to understand.
var camDir = new THREE.Vector3();
var e = cam.matrixWorld.elements;
camDir.set(e[ 8 ], e[ 9 ], e[ 10 ]).normalize();
I picked it up from here:
https://lace-fern-ghost.glitch.me/
Which I found a link to from here:
https://github.com/aframevr/aframe/issues/4412
(but I can't find any reference to explain why these components matrixWorld.elements are the right ones to use here to get the direction).

webVR resetPose replacement

I have a webVR project that used resetPose to reset the origin of the scene but apparently is now deprecated. I used it to reset the camera, so the user would look at the center of the scene again.
I assume this function isn't too hard to replicate: you either have to rotate the scene or the camera to the new origin. However I'm not that experienced with webVR or more importantly THREE.js.
I've tried to lookAt the center of the scene with the camera but I think the problem is that the webVR has control over it so I can't just move it.
Example initialisation of camera and scene
// Create a three.js camera.
camera = new THREE.PerspectiveCamera(75, window.innerWidth / window.innerHeight, 0.1, 10000);
camera.name = "Perspective Camera";
var group = new THREE.Group();
group.name = "Camera Group";
group.rotateY(Math.PI);
group.add(camera);
group.position.set(0, configuration.sphereRadius, 0);
group.permanent = true;
scene.add(group);
// Apply VR headset positional data to camera.
controls = new THREE.VRControls(camera);
According to this issue immersive-web/webxr droped support for resetPose method. They claim that devices have hardware button to force resetting pose or reset pose should be handled by application. Three.js don't have such method.
Here is simple but dirty way to reset pose (recenter, reset camera) by exiting VR and entering it again.
async function recenter() {
if (renderer.xr.isPresenting) {
let session = renderer.xr.getSession();
let buttonVR = document.getElementById("VRButton");
await session.end();
buttonVR.click();
}
}

How do you implement drag controls in the AutoDesk forge viewer?

I am trying to implement drag controls on this text geometry that I am creating in the viewer. I create the text like so:
createText(params) {
const textGeometry = new TextGeometry(params.text,
Object.assign({}, {
font: new Font(FontJson),
params
}));
const geometry = new THREE.BufferGeometry;
geometry.fromGeometry(textGeometry);
const material = this.createColorMaterial(
params.color);
const text = new THREE.Mesh(
geometry, material);
text.scale.set(params.scale, params.scale, params.scale);
text.position.set(
params.position.x,
params.position.y,
10);
this.intersectMeshes.push(text);
this.viewer.impl.scene.add(text);
this.viewer.impl.sceneUpdated(true);
return text;
}
This works great, the meshes get added to the viewer, I can see them. Fantastic! Thus far, it is good. Now, I want to be able to drag them around with my mouse after I have added them. I noticed that Three.js already has drag controls built in, so I just implemented them like so:
enableDragging(){
let controls = new THREE.DragControls( this.viewer, this.viewer.impl.camera.perspectiveCamera, this.viewer.impl.canvas );
controls.addEventListener( 'dragstart', dragStartCallback );
let startColor;
controls.addEventListener( 'dragend', dragendCallback );
function dragStartCallback(event) {
startColor = event.object.material.color.getHex();
event.object.material.color.setHex(0x000000);
}
function dragendCallback(event) {
event.object.material.color.setColor(startColor);
}
}
After a big of debugging, I have seen where the problem occurs. For some reason, when I click on one of the meshes, the raycaster doesn't find any intersections. I.E. the array I get back is empty. No matter where I click on these objects.
Is my implementation wrong, or did I provision these meshes wrong to make them draggable? I have gotten the drag controls to work outside of the viewer, just not within it.
This will not work, looking at the code of DragControls, the viewer implementation is too different in the way it implements the camera. You would need to either implement a custom version of DragControls or take a look at my transform tool and adapt it for custom meshes:
Moving visually your components in the viewer using the TransformTool

Physijs collision events

I have two boxes. One spawns on the ground and the other is dropped on top of it. Gravity is turned on. I am trying to get the collision event listener to fire on the bottom box which is resting on the ground. However, nothing is logged.
var c = new Physijs.BoxMesh( new THREE.CubeGeometry( 5, 5, 5 ), new THREE.MeshBasicMaterial({ color: 0x888888 }) );
c.__dirtyPosition = true;
c.position.set(10, 0,-5);
c.addEventListener('collision', function(object){
console.log("hello world"); // NOT FIRING
});
scene.add(c);
var p = c.clone();
p.__dirtyPosition = true;
p.position.y = 50;
scene.add(p);
I can't figure out what I'm doing wrong - could it be because of __dirtyPosition?
EDIT: I tested it without clone() and creating the second box anew, but it doesn't make a difference.
EDIT 2: It's worth mentioning that the simulation runs fine I just can't get the listener to work.
Relevant GitHub Issue
It looks like the clone method is part of THREEjs, not Physijs. So your code just clones the physical material, not the physical mesh. You're just going to have to create another BoxMesh using the same code you did for c.

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