I am trying to make use of Raycaster in a ThreeJS scene to create a sort of VR interaction.
Everything works fine in normal mode, but not when I enable stereo effect.
I am using the following snippet of code.
// "camera" is a ThreeJS camera, "objectContainer" contains objects (Object3D) that I want to interact with
var raycaster = new THREE.Raycaster(),
origin = new THREE.Vector2();
origin.x = 0; origin.y = 0;
raycaster.setFromCamera(origin, camera);
var intersects = raycaster.intersectObjects(objectContainer.children, true);
if (intersects.length > 0 && intersects[0].object.visible === true) {
// trigger some function myFunc()
}
So basically when I try the above snippet of code in normal mode, myFunc gets triggered whenever I am looking at any of the concerned 3d objects.
However as soon as I switch to stereo mode, it stops working; i.e., myFunc never gets triggered.
I tried updating the value of origin.x to -0.5. I did that because in VR mode, the screen gets split into two halves. However that didn't work either.
What should I do to make the raycaster intersect the 3D objects in VR mode (when stereo effect is turned on)?
Could you please provide a jsfiddle with the code?
Basically, if you are using stereo in your app, it means you are using 2 cameras, therefore you need to check your intersects on both cameras views, this could become an expensive process.
var cameras =
{ 'camera1': new THREE.PerspectiveCamera(50, window.innerWidth / window.innerHeight, 1, 10000),
'camera2': new THREE.PerspectiveCamera(50, window.innerWidth / window.innerHeight, 1, 10000)
};
for (var cam in cameras) {
raycaster.setFromCamera(origin, cameras[cam]);
//continue your logic
}
You could use a vector object that simulates the camera intersection to avoid checking twice, but this depends on what you are trying to achieve.
I encountered a similar problem, I eventually found the reason. Actually in StereoEffect THREE.js displays the meshes on the two eyes, but in reality is actually adds only one mesh to the scene, exactly in the middle of the line left-eye-mesh <-> right-eye-mesh, hidden to the viewer.
So when you use the raycaster, you need to use it on the real mesh on the middle, not the illusion displayed on each eye !
I detailled here how to do it
Three.js StereoEffect displays meshes across 2 eyes
Hopes it solves your problem !
You can use my StereoEffect.js file in your project for resolving problem. See example of using. See my Raycaster stereo pull request also.
Related
I'm looking into making kind of a portal effect using Three.js.
The main idea is to be able to see through multiple windows another Scene.
Exactly like in this example :
https://www.ronja-tutorials.com/post/022-stencil-buffers/ (See gif in article, too big to upload here)
I found an exact example of what i'm trying to do using three.js.
Here is the link :
https://sites.google.com/site/cgwith3js/home/masking-with-stencil
The fiddle was not working but I changed it to make it work :
http://jsfiddle.net/yzhreu6p/23/
scene = new THREE.Scene();
sceneStencil = new THREE.Scene();
...
scene.add(box); // red one
...
function animate() {
requestAnimationFrame(animate);
renderer.clear();
// animate the box
box.position.x = Math.cos(clock.getElapsedTime()) * 10;
var gl = renderer.getContext();
// enable stencil test
gl.enable(gl.STENCIL_TEST);
//renderer.state.setStencilTest( true );
// config the stencil buffer to collect data for testing
gl.stencilFunc(gl.ALWAYS, 1, 0xff);
gl.stencilOp(gl.REPLACE, gl.REPLACE, gl.REPLACE);
// render shape for stencil test
renderer.render(sceneStencil, camera);
// set stencil buffer for testing
gl.stencilFunc(gl.EQUAL, 1, 0xff);
gl.stencilOp(gl.KEEP, gl.KEEP, gl.KEEP);
// render actual scene
renderer.render(scene, camera);
// disable stencil test
gl.disable(gl.STENCIL_TEST);
}
Then I reuse the code in my project where I have kind of a town with buildings, and the hidden scene has a nyan cat textured box.
The problem I'm having is that the planes are disappearing when a building is behind and more serious problem, when there are buildings back the nyan cat texture, we see the texture in the building.
To better explain here is an image
I'm looking for a solution where the images are not visible inside the building, I found people that are talking about stencilMask but it's new for me.
Do I need to create another scene to make it work independently ?
If someone can help me, thank you for reading.
I'm rather new to threejs, so what I'm doing might not be the most efficient way.
I have an object in AR on a mobile device and I want to know if I intersect with it when touching on the screen.
I use the following code to generate the raycast, and it works initally.
const tempMatrix = new THREE.Matrix4();
tempMatrix.identity().extractRotation(this.controller.matrixWorld);
this.raycaster.ray.origin.setFromMatrixPosition(this.controller.matrixWorld);
this.raycaster.ray.direction.set(0, 0, -1).applyMatrix4(tempMatrix);
However, I have the ability to reposition the object (i.e. reset the position so the object is in front, relative to the current camera direction and position) by moving and rotating the whole scene.
After the repositioning, the raycasting is completely offset and is not casting rays anywhere near where I touch the screen.
Repositioning is done like this (while it works, if there's a better way, let me know!) :
public handleReposition(): void {
const xRotation = Math.abs(this.camera.rotation.x) > Math.PI / 2 ? -Math.PI : 0;
const yRotation = this.camera.rotation.y;
this.scene.rotation.set(xRotation, yRotation, xRotation);
this.scene.position.set(this.camera.position.x, this.camera.position.y, this.camera.position.z);
}
How can I achieve to raycast to the correct new location?
Thanks!
Assuming this.scene is actually the main threejs Scene, it's usually a bad idea to change its rotation or position, since it will affect everything inside the scene, including the controller. I'd suggest moving your object instead, or add your object(s) to a Group and move that.
I'm trying to make a cube mesh to be always positioned in front of the XR camera.
No matter how I move my phone camera, the cube should appear right in front of the camera showing only one side of the cube.
Firstly, I added a cube mesh to the scene in the beginning:
material = new THREE.MeshLambertMaterial({ color: 0x9797CE });
box = new THREE.Mesh(new THREE.CubeGeometry(1, 1, 1), material);
box.position.set(0, 0, -3);
scene.add(box);
And then tried to draw the box in front of the XR camera:
function animate() {
let xrCamera = renderer.xr.getCamera(camera);
box.position.set(xrCamera.position.x, xrCamera.position.y, xrCamera.position.z - 3);
box.rotation.set(xrCamera.rotation.x, xrCamera.rotation.y, xrCamera.rotation.z);
renderer.render(scene, camera);
}
When I run the code, the cube appears in front of my phone camera.
But when I rotate my phone, the cube rotates itself in the same position not following the camera.
I also tried xrCamera.add(box) but it doesn't seem to work.
How can I correctly make the cube always appear still in front of the XR camera?
It's important to know that currently (r115) the transformation properties position, rotation and scale as well as the local matrix of the XR camera are not updated.
So instead of adding the box to xrCamera, add it to camera. Besides, keep in mind that WebXRManager.getCamera() is intended for internal use only and no part of the public API.
I have been solving a similar problem. I needed to get a point in front of camera using aframe API. But the challege was when the experience were on VR mode(fullscreen) and playing on movile or headset. In this context the management of the current camera is absolutely controlled by WebXR. With WebXR THREE applies headset pose to the object3D internally.
You only can use the matrixWorld of the three camera to access the camera world reference data, other properties or methods are not correct. In the case of aframe you must access to the object3D of the aframe camera entity and manage its matrixWorld. It is the only method to get correct information of the position/rotation/scale of the camera that it is move by the sensors of a movile or of a AR/VR goggles when the play is on VR/AR mode.
I use to get the in front of Camera Position With WebXR Headset Pose:
const distanceFromCamera = 250; // the depth in the screen, what ever you need
const inFrontOfCameraPosition = new AFRAME.THREE.Vector3( 0, 0, -distanceFromCamera );
const threeSceneCamera = <THREE.PerspectiveCamera>AFRAME.scenes[0].camera;
inFrontOfCameraPosition.applyMatrix4( threeSceneCamera.matrixWorld );
return { x: inFrontOfCameraPosition.x, y: inFrontOfCameraPosition.y, z: inFrontOfCameraPosition.z };
I'm fairly new to three.js and trying to get a better understanding of ray casting. I have used it so far in a game to show when an object collides with another on the page which works perfectly. In the game I'm building this is to take health from the hero as it crashes into walls.
I am now trying to implement a target which when hovered over some objects it will auto shoot. However the target only registers a target hit once the object passes through the target mesh rather than when its ray is cast through it.
to further detail this, the ray is cast from the camera through the target, if the target is on a mesh (stored as an object array) then I want it to trigger a function.
within my update function I have this:
var ray = new THREE.Raycaster();
var crossHairClone = crossHair.position.clone();
var coards = {};
coards.x = crossHairClone.x
coards.y = crossHairClone.y
ray.setFromCamera(coards, camera);
var collisionResults = ray.intersectObjects( collidableMeshList );
if ( collisionResults.length > 0 ) {
console.log('Target Hit!', collisionResults)
}
The console log is only triggered when the collidableMeshList actually touches the target mesh rather than when it is aiming at it.
How do I extend the ray to pass through the target (which I thought it was already doing) so that if anything hits the ray then it triggers my console log.
Edit
I've added a URL to the game in progress. There are other wider issues with the game, my current focus is just the target ray casting.
Game Link
Many thanks to everyone who helped me along the way on this one but I finally solved it, only not through the means that I had expected to. Upon reading into the setFromCamera() function it looks like it is mainly used around mouse coards which in my instance was not what I wanted. I wanted a target on the page and the ray to pass through this. For some reason my Ray was shooting vertically up from the centre of the whole scene.
In the end I tried a different approach and set the Rays position and direction directly rather rely on setting it from the cameras position.
var vector = new THREE.Vector3(crossHair.position.x, crossHair.position.y, crossHair.position.z);
var targetRay = new THREE.Raycaster(camera.position, vector.sub(camera.position).normalize());
var enemyHit = targetRay.intersectObject( enemy );
if ( enemyHit.length > 0 ) {
console.log('Target Hit!', targetRay)
}
I'll leave this up for a while before accepting this answer in case anyone has a better approach than this or has any corrections over what I have said in regards to setFromCamera().
I'm currently working on my first three js project, and getting quite an education. But, I've hit a wall, and am seeking a generalized outline of what to do.
I have three images that I want to use as background images. I want them to crossfade at a specified interval... let's say every 5 seconds, the background crossfades to the next one. After the last background is displayed, crossfade into the first one, and so forth in a loop.
I've found a few examples where there's crossfading between two objects, like this fiddle, but that seems to depend on having two cameras. I've taken other examples I've found as far as I could, nothing worthy of posting.
I don't understand enough about three, which is why I'm seeking help. If someone could help me define my approach, that would be fantastic. Should I be altering the opacity of my meshes? Doing something with shaders? Something else?
Here, at least, is how I'm adding one background:
camera = new THREE.PerspectiveCamera( 75, SCREEN_WIDTH / SCREEN_HEIGHT, 1, 10000 );
camera.position.z = 450;
scene = new THREE.Scene();
// Load the background texture
var summerTexture = THREE.ImageUtils.loadTexture( 'tree-animation/images/summer.png' );
summerMesh = new THREE.Mesh(
new THREE.PlaneGeometry(2, 2, 0),
new THREE.MeshBasicMaterial({
map: summerTexture,
}));
summerMesh.material.depthTest = false;
summerMesh.material.depthWrite = false;
backgroundCamera = new THREE.Camera();
summerScene = new THREE.Scene();
summerScene.add(backgroundCamera);
summerScene.add(summerMesh);
Any direction would be most appreciated!
This can be achieved by writing a custom shader and using the mix() or smooth-step() function between the images and add a clock to your render loop to update the shader uniforms to manipulate the transition in your shader over time.
Here is an example of a static blend of textures but can easily intergrated into your own project:
http://stemkoski.github.io/Three.js/Shader-Heightmap-Textures.html
check the frag shader