Does anyone know how can I perform a simple collision check to push back camera so that it doesn't "go through" scene? Is it possible to make a camera respect the 3D objects "masses"? I'm trying to make a small simulator to fly around a building, and enter some rooms, but the camera will always go inside objects.
You can set 3 raycasters for each 3D directions. You append them and the camera to an empty object that you move (not the camera) so everything moves at once.
When your raycasters intersects something you make the difference between the intersection point coordinates and the empty object position. This gives you all the information you can need.
If you want to define objects parameters like masses, add them to object.userData and access them via the returned intersection array.
Related
I am trying to achieve movement of an object on walls, instead of only one plane. In this example, an object dragged on walls by using:
intersects = raycaster.intersectObjects([walls]);
object.position.copy(intersects[0].point);
However, with this method, the object jumps because the object's center moves to the mouse. There is a related question and helpful JSFiddle for dragging on one plane without jumpin Would you please help me to modify it for multiples planes (walls)? Thanks
After reading your comment, I think what you're looking for is you want the object to animate to the position. You can do this a few ways. The "threejs" way is to move it each frame (within the animate/update loop). You could do this with Vector3.lerp by storing intersects[0].point as your target location and lerping your object.position to it each frame. Another option is to use an animation library like animejs or gsap.
I need to get the camera up direction and i've tried many ways with no luck, i'm not an expert of quaternions so i'm doubting i did it right.
I've tried:
camera.up
camera.up.applyMatrix4(camera.matrixWorld);
new THREE.Vertex3(0,1,0).applyMatrix4(camera.matrixWorld);
camera.up.normalize().applyMatrix4(camera.matrixWorld);
after this i create two planes passing by two points of my interest, and add the plane helper to the scene and i can see they are very far from where i was expecting them. (i'm expecting two planes that looks like the top and bottom of the camera frustum).
P.s. the camera is a shadow camera of a directional light so an orthographic camera, and i manipulate the directional light position and target before doing this operation, but i've called updateMatrixWorld on the light, on it's target and the camera, on the camera i've called also updateProjectionMatrix... still no results
I've made a sandbox to see what i've tried till now, and better visualize what i want to achieve:
https://codesandbox.io/embed/throbbing-cache-j5yse
once i manage to get the green arrow to point to the top of the blue triangle of the camera helper i'm good to go
In the normal render flow, shadow camera matrices are updated as part of rendering the shadow map (WebGLShadowMap.render).
However, if you want the updated matrix values before the render, then you'll need to update them manually (you already understand this part).
The shadow camera is a property of (not a child of) the DirectionalLight. As such, it doesn't follow the same rules as other scene objects when it comes to updating its matrices (because it's not really a child of the scene). Instead, you need to call the shadow property's updateMatrices method (inherited from LightShadow.updateMatrices).
const dl = new THREE.DirectionalLight(0xffffff, 1)
dl.shadow.updateMatrices(dl) // <<------------------------ Updates the shadow camera
This updates the shadow camera with information from the DirectionalLight's own matrix, and its target's matrix, to properly orient the shadow camera.
Finally, it looks like you're trying to get the "world up" of the camera. Personally, I'd use the convenience function localToWorld:
let up = new THREE.Vector3(0, 1, 0)
dl.shadow.camera.localToWorld(up) // destructively converts "up" from local-to-camera into world coordinates
via trial and errors i've figured out that what gave me the correct result was:
calling
directionalLight.shadow.updateMatrices(...)
and then
new THREE.Vector3(0,1,0).applyQuaternion(directionalLight.shadow.camera.quaternion)
I have some project for child http://kinosura.kiev.ua/sova/ and i need to check faceIndex of all cubes in screen.
Now i use intersections array from mouse, but is working only when user pointer at the cube.
How to make ray or rays from camera to all object to check faceIndex ?
I try to make four rays to cubes but if i set cube.position as origin of like this:
raycaster.setFromCamera( cube1.positoin , camera )
I get empty array of intersections.
I also try to set static 2d vector as origin (get coordinate from mouse) but i have relative renderer size and this coordinate all time change... its not work(
Thanks for answer anyway.
I suggest that you try another approach It appears that your cubes do not cover one another, relative to the camera view. So use the surface normals, and compare them to the view direction to determine if they are facing the camera or facing away from the camera by a simple one-per-polygon dot product.
When you are creating your geometry, before adding it a THREE.Mesh call .generateFaceNormals() on it.
Instead of ray casting, iterate through all faces, grab the surface normal of the face, transform relative to the view (inverse transpose of the object's matrix), then dot(). might sound complicated, at first, but it's actually just a couple of steps and much faster than doing a lot of raycasts (which will probably include this anyway!)
I'm quite new to three.js and lacking some basic understanding of the coordinate systems obviously.
I have an Object3D "group" that has some children (planes). I use "group" to rotate the group of planes, which works fine. Now camera can move and parent object can rotate. One can click on the planes to select them. What I want now is to let the selected plane fly into the camera.
If I just move the plane to the camera position it flys in any direction but mostly not to the camera. Certainly because "group" seems to be the "world" for the child objects. If I move a plane along the z-axis the plane move along the z-axis of the parent.
I don't understand which coordinates I need to take (or transform) to move the plane bound to "group" in front of the camera.
Basically I demoed with three.js what famo.us did, just spent some two hours on it or so. I faked the wanted effect with an additional plane that is not grouped and which I can just move to camera without transformations. The demo is available here:
http://hwg.rattat.net/famo.html.
Would be nice if somebody could tell me how to get this working. I could still live with the fake, when I would be able to place the additional plane exactly over the selected plane.
Thanks in advance,
Christian
The question of converting local coordinates to world coordinates has been addressed at THREE.js: Calculate world space position of a point on an object . There might also be helping information at how to: get the global/world position of a child object .
I have a surface to which a set of 3d objects is drawn. The task is to determine an object by the given coordinates on the surface.
For example: some objects are drawn on the desktop application, I need to determine on which object user clicked.
Could you please advise, how such task is usually resolved? Am I need to create remember a top-most object for each pixel? I don't think it is the best approach.
Any thoughts are welcome!
Thanks!
The name for this task is picking (which ought to help you Google for more help on it). There are two main approaches:
Ray-casting: find the line that starts at the camera position and passes through the surface point you are interested in. (The line "under the mouse", or "under your finger" for a touch screen.) Depending on which 3D system you are using, there may be an API call to generate this line: for example Camera.ViewportPointToRay in Unity3D, or you may have to generate it yourself by inverting the camera transform. Find all the points of intersection between this line and the objects in your scene. Which of these points is closest to the near plane of the camera? You can use space partitioning to speed this up.
Rendering: do an extra render pass, in which instead of writing textures to the frame buffer, you record which objects were drawn. You don't do the render pass for the whole screen, you just do it for the area (e.g. the pixel) you are interested in. (This is GL_SELECT mode in OpenGL: see the Picking Tutorial for details.)
If you've described the surface somehow in 3D space, then the ray, defined by your point of observation and a 3D point that is a solution for where you clicked, should intersect one or more objects in your world, if indeed you clicked on one of them.
Given the equations for the surfaces of the objects, you can determine where this ray intersects the objects, if at all, since you also know the equation for the ray in the same coordinate system.
The object that has the closest intersection point to your point of observation (assuming you're looking at the objects from above) is the winner.