Are there examples I can borrow from regarding rotating a camera around its own X, Y and Z axes? I learned yesterday that I can use the translate(X|Y|Z) methods to move a camera along its own axes. Are there equivalents for rotation as well?
In the development version ( three.js r58dev ), a new function has been added for rotating an object on it's own axis:
Object3D.rotateOnAxis( axis, angle );
axis must be a unit-length Vector3, and angle is in radians.
three.js r58dev
Related
I have rotated a group called pivot following this example:
https://jsfiddle.net/of1vfhzz/1/
And applying the function rotateAroundObjectAxis(object, axis, radians) from this thread:
Rotation around an axis three.js
the function is showed belove
function rotateAroundObjectAxis(object, axis, radians) {
rotObjectMatrix = new THREE.Matrix4();
rotObjectMatrix.makeRotationAxis(axis.normalize(), radians);
object.matrix.multiply(rotObjectMatrix);
object.rotation.setFromRotationMatrix(object.matrix);
}`
The meshes inside pivot, rotate in the right way but also the axis orientation change and since I want move these object along the z axis, how can I do? There is a way to set up, after a rotation ,the z axis as before, without changing the rotation of this group of objects?
Some project background:
I have a Sprite particle field that is randomly generated. The camera is located at position 0, 0, 0. The particle field is all around the camera. I'm using Raycaster to be able to select the particle that is clicked on and change it's color. Once clicked I would like the camera to focus on this particle. I'm also attempting to use Tween to glide the particle into view.
I've attempted several different methods and none of them work. They are described here:
A traditional lookAt method that used Raycaster to pick up the intersect point from clicking.
var raycaster = new THREE.Raycaster();
raycaster.setFromCamera(mouse, this.camera);
var intersects = raycaster.intersectObjects( this.starfield.children );
this.camera.lookAt(intersects[0].object.position)
A distanceTo method where the distance between the camera and the intersect coordinates is used to move the camera. This only moves the camera along the z plane. It wont actually change its POV.
var cameraPosition = new THREE.Vector3(this.camera.position.x, this.camera.position.y, this.camera.position.z);
var intersectPosition = new THREE.Vector3(intersects[0].object.position.x, intersects[0].object.position.y , intersects[0].object.position.z );
var zoomPos = intersectPosition.distanceTo( cameraPosition );
const newCameraPosition = cameraPosition.addVectors(this.camera.position, vector.setLength(zoomPos));
I calculated the angle of rotation for each X, Y, and Z axis via tan and cos equations. I then attempted to rotate the camera by those degrees. I even tried converting them to radians to see if that would make a difference with the rotation method. It didnt :(
I don't know what else to do. At this stage I'm completely open to a different approach as long as I get this camera working. I'm very stuck,
any help would be greatly appreciated!
Instead of using
intersects[0].object.position
try using
intersects[0].point
.point is the world space position of the hit.
.objectis the object the triangle belongs to. .object.position is just the origin of that object, in this case the particle system. The particle positions themselves are relative to this origin.
I have mapped an equirectangular image onto a sphere using three.js, placed the camera in the middle of the sphere, and am using the OrbitControls to handle things like zooming & rotation.
This all works fantastically until I want to programmatically adjust what the camera is looking at (I tween camera.target) which ends up changing, I believe, the position of the camera. The issue here is that afterwards when you rotate, you rotate out of the sphere. What would be the proper way to achieve this only by adjusting camera.rotation and camera.zoom. I'm okay with stripping down the OrbitControls but don't fully understand how the rotation should work and am also open to other optins.
If you are using OrbitControls in the center of a panorama, you should leave controls.target at the origin, and set the camera position close to the origin:
camera.position.set( 0, 0, 1 );
By setting
controls.enablePan = false;
controls.enableZoom = false;
the camera will always remain a distance of 1 from the origin, i.e., on the unit sphere.
Then, to look at ( x, y, z ), you programmatically set the camera's position like so:
camera.position.set( x, y, z, ).normalize().negate();
That way, when the camera looks at the target (the origin), it will automatically be looking at ( x, y, z ), too.
three.js r.85
I have a scene in Three.js (r67) with a camera that is controlled by OrbitControls.
If I now select an arbitrary point (Vector3) in the scene, what would be the best way to bring this point (programmatically) to the nearest camera position just by rotating the camera?
Example Scenario
In the below picture the left side is the starting point. The camera rotates around the green sphere (like OrbitControls) where the center of the camera is the center of the sphere. I now like to automatically rotate the camera around the sphere (doing the minimum amount of moves) so that the red box is nearest to the camera (like on the right side).
Independntly to the method of selecting the point in the scene, there's several understanding to what you mean by "bringing camera just by rotating".
I suppose, You want to rotate the camera in the way, to make the selected point in the center of the screen.
This is simple:
camera.lookAt(your_point_in_scene);
You could do this more complicated. Firstly, find the current pointing vector. By default camera looks in direction Vector(0,0,1). When we rotate it in the same rotation as a camera, we will have camera direction:
var vec = new THREE.Vector3(0,0,1);
vec.applyQuaternion(camera.rotation._quaternion);
Now we must determine angle to rotate our camera, and axis, around which we would rotate.
Axis of rotation could be found as a cross product of camera direction and vector from camera to object. Angel could be extracted from dot product:
var object_dir = object_world_point.clone().sub(camera.position);
var axis = vec.clone().crossProduct(object_dir);
var angle = Math.acos( vec.clone().dot(object_dir) / vec.length() / object_dir.length());
Having angle and axis, we could rotate camera:
camera.rotateOnAxis(axis, angle);
Or, if you want to make it smooth:
// before animation started
var total_rotation = 0,
rotateon,
avel = 0.01; // 0.01 radian per second
if(total_rotation < angle){
rotateon = avel * time_delta;
camera.rotateOnAxis(axis, angle);
total_rotation += rotateon;
}
Well that's not hard Oo
You have a center/target point for the camera. You calculate the difference from the target position to the point position and normalize that vector to the length of the camera-centerpoint-distance (i.e. something like pointdistance.multiplyScalar(cameradistance.length() / pointdistance.length()) ).
And that's it. If I understood your question correctly. All you do is "extend" the point's positioni onto your "camera movement dome" and then you have the ideal new camera position. The camera's rotation is done automatic since you always target the center point.
Aaand if you want to smoothen the camera movement a bit you can just interpolate the angle (not the positions directly) with e.g. an exponential function, whatever you prefer.
Hi Dear please follow this
Independntly to the method of selecting the point in the scene, there's several understanding to what you mean by "bringing camera just by rotating".
I suppose, You want to rotate the camera in the way, to make the selected point in the center of the screen.
This is simple:
camera.lookAt(your_point_in_scene);
You could do this more complicated. Firstly, find the current pointing vector. By default camera looks in direction Vector(0,0,1). When we rotate it in the same rotation as a camera, we will have camera direction:
var vec = new THREE.Vector3(0,0,1);
vec.applyQuaternion(camera.rotation._quaternion);
Now we must determine angle to rotate our camera, and axis, around which we would rotate.
Axis of rotation could be found as a cross product of camera direction and vector from camera to object.
Angle could be extracted from dot product:
var object_dir = object_world_point.clone().sub(camera.position);
var axis = vec.clone().crossProduct(object_dir);
var angle = Math.acos( vec.clone().dot(object_dir) / vec.length() / object_dir.length());
I'm trying to have a plane face away from the camera with same orientation so it's aligned in the viewport.
I have a plane in front of the camera, perfectly aligned to the cameras viewport, and I want to flip it in front of the camera, along the objects Y axis, regardless of camera orientation.
The following will orient my plane to face at the camera and works for any orientation:
target.rotation.copy(camera.rotation);
The following will then flip the plane along the plane's Y axis:
target.rotation.y += Math.PI;
All good so far? Except when the camera rotation has a funky tilt to it, let's say it's looking up and to the left, tilted slightly to the right, the plane's flip is tilted, but not the same way as the camera, leaving me with a plane tilted either to the left or right...
I've tried several things such as:
target.rotation.z -= camera.rotation.z;
Nothing... Thanks for your help.
So the problem I was running into was when the camera was in negative z coordinates. This causes the flip on the Y axis to get messed up.
So basically you would do something like this:
var target = new THREE.Object3D();
//position
target.position.copy(s.camera.position);
target.position.add(THREE.Utils.cameraLookDir(s.camera).multiplyScalar(300));
//rotation
target.rotation.copy(s.camera.rotation);
target.rotation.y += PI;
target.rotation.z = -s.camera.rotation.z;
if (s.camera.position.z < 0) {
target.rotation.z = s.camera.rotation.z;
}
EDIT:
Add the following to appropriate spots in your program.
camera.rotation.eulerOrder = 'XZY';
target.rotation.eulerOrder = 'XZY';
Seems to solve previously encountered tilt issues! (see below)
RESOLVED:
Flipped planes tilted the wrong way in some instances, for example when in negative z coords and also the y rotation is not equal to 0, example: point in space hovering and looking at 0, 0, 0.
This is the solution I was looking for when I found this page (taken from this answer):
mesh.lookAt( camera.position );
The local z-axis of the mesh should then point toward the camera.