My goal is to make an object controls like a spaceship, what I understand is that I need to use quaternions to achieve this goal. For start I'm trying to make my cube to start rotating to left as I press A key, this is the code for that:
if(controls.pressingA === true)
{
//var pLocal = new THREE.Vector3( 0, 0, -1 );
//var pWorld = pLocal.applyMatrix4( me.matrixWorld );
//var dir = pWorld.sub( me.position ).normalize();
var dir = me.getWorldDirection();
var quaternion = new THREE.Quaternion().setFromAxisAngle( dir, 0.05 );
me.rotation.setFromQuaternion( quaternion );
}
As I understand this code the the me.getWorldDirection() gets the axis that the object is facing, then I create quaternion on the axis that I got before and rotate given object by 0.05 degrees in rad, and finally with the last line of code I just apply to quaternion to my object. The problem I got is that it doesn't increase the rotation, it just sets my object to given rotation, how can I make it increase rotation instead of setting it?
Why don't you use one or combination of:
mesh.rotation.x += 0.05;
mesh.rotation.y += 0.05;
mesh.rotation.z += 0.05;
JSFiddle
If you are setting all of them, you can do this
mesh.rotation.set(9, 7, 3)
Related
When it comes to 3D animation, there are a lot of terms and concepts that I'm not familiar with (maybe a secondary question to append to this one: what are some good books to get familiar with the concepts?). I don't know what a "UV" is (in the context of 3D rendering) and I'm not familiar with what tools exist for mapping pixels on an image to points on a mesh.
I have the following image being produced by a 360-degree camera (it's actually the output of an HTML video element):
I want the center of this image to be the "top" of the sphere, and any radius of the circle in this image to be an arc along the sphere from top to bottom.
Here's my starting point (copying lines of code directly from the Three.JS documentation):
var video = document.getElementById( "texture-video" );
var scene = new THREE.Scene();
var camera = new THREE.PerspectiveCamera( 75, window.innerWidth / window.innerHeight, 0.1, 1000 );
var renderer = new THREE.WebGLRenderer();
renderer.setSize( window.innerWidth, window.innerHeight );
document.body.appendChild( renderer.domElement );
var texture = new THREE.VideoTexture( video );
texture.minFilter = THREE.LinearFilter;
texture.magFilter = THREE.LinearFilter;
texture.format = THREE.RGBFormat;
var material = new THREE.MeshBasicMaterial( { map: texture } );
var geometry = new THREE.SphereGeometry(0.5, 100, 100);
var mesh = new THREE.Mesh( geometry, material );
scene.add( mesh );
camera.position.z = 1
function animate()
{
mesh.rotation.y += 0.01;
requestAnimationFrame( animate );
renderer.render( scene, camera );
}
animate();
This produces the following:
There are a few problems:
The texture is rotated 90 degrees
The ground is distorted, although this may be fixed if the rotation is fixed?
Update: Upon further investigation of the sphere being produced, it's not actually rotated 90 degrees. Instead, the top of the image is the top of the sphere and the bottom of the image is the bottom of the sphere. This causes the left and right edges of the image to become the distorted "sideways ground" I saw
This is on the outside of the sphere. I want to project this to the inside of the sphere (and place the camera inside the sphere)
Currently if I place the camera inside the sphere I get solid black. I don't think it's a lighting issue because the Three.JS docs said that a MeshBasicMaterial didn't need lighting. I think the issue may be that the normals of all of the sphere faces point outward and I need to reverse them. I'm not sure how one would do this - but I'm pretty sure it's possible since I think this is how skyboxes work.
Doing some research I'm pretty sure I need to modify the "UV"s to fix this, I just don't know how or really what that even means...
Working Example
I forked #manthrax's CodeSandbox.io solution and updated it with my own:
https://codesandbox.io/s/4w1njkrv9
The Solution
So after spending a day researching UV mapping to understand what it meant and how it worked, I was able to sit down and scratch out some trig to map points on a sphere to points on my stereographic image. It basically came down to the following:
Use arccosine of the Y coordinate to determine the magnitude of a polar coordinate on the stereographic image
Use the arctangent of the X and Z coordinates to determine the angle of the polar coordinate on the stereographic image
Use x = Rcos(theta), y = Rsin(theta) to compute the rectangular coordinates on the stereographic image
If time permits I may draw a quick image in Illustrator or something to explain the math, but it's standard trigonometry
I went a step further after this, because the camera I was using only has a 240 degree vertical viewing angle - which caused the image to get slightly distorted (especially near the ground). By subtracting the vertical viewing angle from 360 and dividing by two, you get an angle from the vertical within which no mapping should occur. Because the sphere is oriented along the Y axis, this angle maps to a particular Y coordinate - above which there's data, and below which there isn't.
Calculate this "minimum Y value"
For all points on the sphere:
If the point is above the minimum Y value, scale it linearly so that the first such value is counted as "0" and the top of the sphere is still counted as "1" for mapping purposes
If the point is below the minimum Y value, return nothing
Weird Caveats
For some reason the code I wrote flipped the image upside down. I don't know if I messed up on my trigonometry or if I messed up on my understanding of UV maps. Whatever the case, this was trivially fixed by flipping the sphere 180 degrees after mapping
As well, I don't know how to "return nothing" in the UV map, so instead I mapped all points below the minimum Y value to the corner of the image (which was black)
With a 240-degree viewing angle the space at the bottom of the sphere with no image data was sufficiently large (on my monitor) that I could see the black circle when looking directly ahead. I didn't like the visual appearance of this, so I plugged in 270 for the vertical FOV. this leads to minor distortion around the ground, but not as bad as when using 360.
The Code
Here's the code I wrote for updating the UV maps:
// Enter the vertical FOV for the camera here
var vFov = 270; // = 240;
var material = new THREE.MeshBasicMaterial( { map: texture, side: THREE.BackSide } );
var geometry = new THREE.SphereGeometry(0.5, 200, 200);
function updateUVs()
{
var maxY = Math.cos(Math.PI * (360 - vFov) / 180 / 2);
var faceVertexUvs = geometry.faceVertexUvs[0];
// The sphere consists of many FACES
for ( var i = 0; i < faceVertexUvs.length; i++ )
{
// For each face...
var uvs = faceVertexUvs[i];
var face = geometry.faces[i];
// A face is a triangle (three vertices)
for ( var j = 0; j < 3; j ++ )
{
// For each vertex...
// x, y, and z refer to the point on the sphere in 3d space where this vertex resides
var x = face.vertexNormals[j].x;
var y = face.vertexNormals[j].y;
var z = face.vertexNormals[j].z;
// Because our stereograph goes from 0 to 1 but our vertical field of view cuts off our Y early
var scaledY = (((y + 1) / (maxY + 1)) * 2) - 1;
// uvs[j].x, uvs[j].y refer to a point on the 2d texture
if (y < maxY)
{
var radius = Math.acos(1 - ((scaledY / 2) + 0.5)) / Math.PI;
var angle = Math.atan2(x, z);
uvs[j].x = (radius * Math.cos(angle)) + 0.5;
uvs[j].y = (radius * Math.sin(angle)) + 0.5;
} else {
uvs[j].x = 0;
uvs[j].y = 0;
}
}
}
// For whatever reason my UV mapping turned everything upside down
// Rather than fix my math, I just replaced "minY" with "maxY" and
// rotated the sphere 180 degrees
geometry.rotateZ(Math.PI);
geometry.uvsNeedUpdate = true;
}
updateUVs();
var mesh = new THREE.Mesh( geometry, material );
The Results
Now if you add this mesh to a scene everything looks perfect:
One Thing I Still Don't Understand
Right around the "hole" at the bottom of the sphere there's a multi-colored ring. It almost looks like a mirror of the sky. I don't know why this exists or how it got there. Could anyone shed light on this in the comments?
Here is as close as I could get it in about 10 minutes of fiddling with a polar unwrapping of the uv's.
You can modify the polarUnwrap function to try and get a better mapping....
https://codesandbox.io/s/8nx75lkn28
You can replace the TextureLoader().loadTexture() with
//assuming you have created a HTML video element with id="video"
var video = document.getElementById( 'video' );
var texture = new THREE.VideoTexture( video );
texture.minFilter = THREE.LinearFilter;
texture.magFilter = THREE.LinearFilter;
texture.format = THREE.RGBFormat;
to get your video fed in there...
More info here:
https://threejs.org/docs/#api/textures/VideoTexture
Also this may be useful to you:
https://community.theta360.guide/t/displaying-thetas-dual-fisheye-video-with-three-js/1160
I think, it's would be quite difficult to modify the UVs, so that the stereographic projected image will fit. The UVs of a sphere are set to fit textures with equirectangular projection.
To transform the image from stereographic to equirectangular, you might want to use Panorama tools like PTGui or Hugin. Or you can use Photoshop (apply Filter > Distort > Polar Coordinates > polar to rectangular).
Equirectangular projection of the image (with Photoshop), resized to 2:1 aspect ratio (not necessary for texture)
If you want the texture to be inside the sphere (or normals flipped), you are able to set the material to THREE.BackSide.
var material = new THREE.MeshBasicMaterial( { map: texture, side: THREE.BackSide } );
Maybe, you have to flip the texture horizontally then: How to flip a Three.js texture horizontally
Basically I want to set the rotation of an object along the world axis by an arbitrary angle. I'm currently using the rotateAroundWorldAxis function (found in another thread) to try to do that.
function render() {
// update mesh position
rotateAroundWorldAxis(mesh, new THREE.Vector3(1, 0, 0), angle);
renderer.render(scene, camera);
}
function rotateAroundWorldAxis(object, axis, radians) {
rotWorldMatrix = new THREE.Matrix4();
rotWorldMatrix.makeRotationAxis(axis.normalize(), radians);
rotWorldMatrix.multiply(object.matrix); // pre-multiply
object.matrix = rotWorldMatrix;
object.rotation.setFromRotationMatrix(object.matrix);
}
The problem is I only want to set the angle (as in rotation.x = angle), not increment it (as in rotation.x += angle). Does anybody know how to adapt the above function (rotateAroundWorldAxis) to allow me to set the angle instead of incrementing it?
jsfiddle here
remove the third line in that function
rotWorldMatrix.multiply(object.matrix); // pre-multiply
This is the line that "adds" the two rotations together.
I've looked at this question:
Mouse / Canvas X, Y to Three.js World X, Y, Z
and have implemented it in my code, the problem is that I can't seem to get it to work as others have stated.
I need to place an object in front of the camera via X and Y screen coords, not necessarily from the mouse.
This object will be at a specified distance in front of the camera, either from a pre-defined maximum distance or a calculated object distance.
Note: My Camera can be at any position in my scene and facing any direction
Here is my code:
this.reticlePos.x = 500;
this.reticlePos.y = 300;
this.reticlePos.z = 0.5;
this.projector.unprojectVector(this.reticlePos, this.camera);
//check for collisions, if collisions set distance to collision distance
var distance = this.RETICLE_RADIUS;
var direction = new THREE.Vector3( 0, 0, -1 );
direction.applyQuaternion( this.camera.quaternion );
this.rayCaster.set(this.camera.position, direction);
var collisionResults = this.rayCaster.intersectObjects(this.sceneController.obstacles);
if( collisionResults.length !== 0 ) {
// console.log('Ray collides with mesh. Distance :' + collisionResults[0].distance);
distance = collisionResults[0].distance - 20;
}
// set the reticle position
var dir = this.reticlePos.clone().sub( this.camera.position ).normalize();
var pos = this.camera.position.clone().add( dir.multiplyScalar( distance ) );
this.reticleMesh.position.copy( pos );
As you can see is is very similar to the linked question, yet I cannot see the object in front of my camera.
Any insight into this would be greatly appreciated.
I figured out the answer myself for anyone that checks this question later on.
To get my screen coordinates I needed to convert some input data from a gyroscope, and didn't realize that I still needed to do the following to my calculated screen coordinates:
this.reticlePos.x = ( this.reticlePos.x / window.innerWidth ) * 2 - 1;
this.reticlePos.y = - ( this.reticlePos.y / window.innerHeight ) * 2 + 1;
After doing this, everything works as expected.
I'm looking to understand quaternions for three.js, but for all the tutorials, I haven't been able to translate them into the application I need. This is the problem:
Given a sphere centered at (0,0,0), I want to angle an object on the sphere's surface, that acts as the focal point for the camera. This point is to be moved and rotated on the surface with keyboard input.
Setting the focal point into a chosen orbit is easy of course, but maintaining the right rotation perpendicular to the surface escapes me. I know quaternions are neccessary for smooth movement and arbitrary axis rotation, but I don't know where to start.
The second part then is rotating the camera offset with the focal point. The snippet I found for this does not have the desired effect anymore, as the cameraOffset does not inherit the rotation:
var cameraOffset = relativeCameraOffset.clone().applyMatrix4( focalPoint.matrixWorld );
camera.position.copy( focalPoint.position.clone().add(cameraOffset) );
camera.lookAt( focalPoint.position );
Update 1: Tried it with fixed camera on the pole and rotating the planet. But unless I'm missing something important, this fails as well, due to the directions getting skewed completely when going towards the equator. (Left becomes forward). Code in update is:
acceleration.set(0,0,0);
if (keyboard.pressed("w")) acceleration.x = 1 * accelerationSpeed;
if (keyboard.pressed("s")) acceleration.x = -1 * accelerationSpeed;
if (keyboard.pressed("a")) acceleration.z = 1 * accelerationSpeed;
if (keyboard.pressed("d")) acceleration.z = -1 * accelerationSpeed;
if (keyboard.pressed("q")) acceleration.y = 1 * accelerationSpeed;
if (keyboard.pressed("e")) acceleration.y = -1 * accelerationSpeed;
velocity.add(acceleration);
velocity.multiplyScalar(dropOff);
velocity.max(minV);
velocity.min(maxV);
planet.mesh.rotation.x += velocity.x;
planet.mesh.rotation.y += velocity.y;
planet.mesh.rotation.z += velocity.z;
So I'm still open for suggestions.
Finally found the solution from a mixture of matrices and quaternions:
//Setup
var ux = new THREE.Vector3(1,0,0);
var uy = new THREE.Vector3(0,1,0);
var uz = new THREE.Vector3(0,0,1);
var direction = ux.clone();
var m4 = new THREE.Matrix4();
var dq = new THREE.Quaternion(); //direction quad base
var dqq; //final direction quad
var dq2 = new THREE.Quaternion();
dq2.setFromAxisAngle(uz,Math.PI/2); //direction perpendicular rot
//Update
if (velocity.length() < 0.1) return;
if (velocity.x) { focalPoint.translateY( velocity.x ); }
if (velocity.y) { focalPoint.translateX( velocity.y ); }
//create new direction from focalPoint quat, but perpendicular
dqq = dq.clone().multiply(focalPoint.quaternion).multiply(dq2);
velocity.multiplyScalar(dropOff);
//forward direction vector
direction = ux.clone().applyQuaternion(dqq).normalize();
//use Matrix4.lookAt to align focalPoint with the direction
m4.lookAt(focalPoint.position, planet.mesh.position, direction);
focalPoint.quaternion.setFromRotationMatrix(m4);
var cameraOffset = relativeCameraOffset.clone();
cameraOffset.z = cameraDistance;
cameraOffset.applyQuaternion(focalPoint.quaternion);
camera.position = focalPoint.position.clone().add(cameraOffset) ;
//use direction for camera rotation as well
camera.up = direction;
camera.lookAt( focalPoint.position );
This is the hard core of it. It pans (and with some extension rotates) around the planet without the poles being an issue.
I'm not sure to understand your problem.
But for help, I draw a boat on a sphere with the code below.
var geometry = new THREE.ShapeGeometry(shape);
var translation = new THREE.Matrix4().makeTranslation(boat.position.x, boat.position.y, boat.position.z);
var rotationZ = new THREE.Matrix4().makeRotationZ(-THREE.Math.degToRad(boat.cap));
var rotationX = new THREE.Matrix4().makeRotationX(-THREE.Math.degToRad(boat.latitude));
var rotationY = new THREE.Matrix4().makeRotationY(Math.PI / 2 + THREE.Math.degToRad(boat.longitude));
var roationXY = rotationY.multiply(rotationX);
geometry.applyMatrix(rotationZ);
geometry.applyMatrix(roationXY );
geometry.applyMatrix(translation);
First, I apply a rotation on Z to define boat cap
Then, I apply
rotation on Y,X to to set the boat perpendicular to the surface of
the sphere
Finally I apply a translation to put the boat on the
surafce of the sphere
The rotations order is important
I have a great problem about the rotation in three.js
I want to rotate my 3D cube in one of my game.
//init
geometry = new THREE.CubeGeometry grid, grid, grid
material = new THREE.MeshLambertMaterial {color:0xFFFFFF * Math.random(), shading:THREE.FlatShading, overdraw:true, transparent: true, opacity:0.8}
for i in [1...#shape.length]
othergeo = new THREE.Mesh new THREE.CubeGeometry(grid, grid, grid)
othergeo.position.x = grid * #shape[i][0]
othergeo.position.y = grid * #shape[i][1]
THREE.GeometryUtils.merge geometry, othergeo
#mesh = new THREE.Mesh geometry, material
//rotate
#mesh.rotation.y += y * Math.PI / 180
#mesh.rotation.x += x * Math.PI / 180
#mesh.rotation.z += z * Math.PI / 180
and (x, y, z) may be (1, 0, 0)
then the cube can rotate, but the problem is the cube rotate on its own axis,so after it has rotated, it can't rotate as expected.
I find the page How to rotate a Three.js Vector3 around an axis?, but it just let a Vector3 point rotate around the world axis?
and I have tried to use matrixRotationWorld as
#mesh.matrixRotationWorld.x += x * Math.PI / 180
#mesh.matrixRotationWorld.y += y * Math.PI / 180
#mesh.matrixRotationWorld.z += z * Math.PI / 180
but it doesn't work, I don't whether I used it in a wrong way or there are other ways..
so, how to let the 3D cube rotate around the world's axis???
Since release r59, three.js provides those three functions to rotate a object around object axis.
object.rotateX(angle);
object.rotateY(angle);
object.rotateZ(angle);
Here are the two functions I use. They are based on matrix rotations. and can rotate around arbitrary axes. To rotate using the world's axes you would want to use the second function rotateAroundWorldAxis().
// Rotate an object around an arbitrary axis in object space
var rotObjectMatrix;
function rotateAroundObjectAxis(object, axis, radians) {
rotObjectMatrix = new THREE.Matrix4();
rotObjectMatrix.makeRotationAxis(axis.normalize(), radians);
// old code for Three.JS pre r54:
// object.matrix.multiplySelf(rotObjectMatrix); // post-multiply
// new code for Three.JS r55+:
object.matrix.multiply(rotObjectMatrix);
// old code for Three.js pre r49:
// object.rotation.getRotationFromMatrix(object.matrix, object.scale);
// old code for Three.js r50-r58:
// object.rotation.setEulerFromRotationMatrix(object.matrix);
// new code for Three.js r59+:
object.rotation.setFromRotationMatrix(object.matrix);
}
var rotWorldMatrix;
// Rotate an object around an arbitrary axis in world space
function rotateAroundWorldAxis(object, axis, radians) {
rotWorldMatrix = new THREE.Matrix4();
rotWorldMatrix.makeRotationAxis(axis.normalize(), radians);
// old code for Three.JS pre r54:
// rotWorldMatrix.multiply(object.matrix);
// new code for Three.JS r55+:
rotWorldMatrix.multiply(object.matrix); // pre-multiply
object.matrix = rotWorldMatrix;
// old code for Three.js pre r49:
// object.rotation.getRotationFromMatrix(object.matrix, object.scale);
// old code for Three.js pre r59:
// object.rotation.setEulerFromRotationMatrix(object.matrix);
// code for r59+:
object.rotation.setFromRotationMatrix(object.matrix);
}
So you should call these functions within your anim function (requestAnimFrame callback), resulting in a rotation of 90 degrees on the x-axis:
var xAxis = new THREE.Vector3(1,0,0);
rotateAroundWorldAxis(mesh, xAxis, Math.PI / 180);
I needed the rotateAroundWorldAxis function but the above code doesn't work with the newest release (r52). It looks like getRotationFromMatrix() was replaced by setEulerFromRotationMatrix()
function rotateAroundWorldAxis( object, axis, radians ) {
var rotationMatrix = new THREE.Matrix4();
rotationMatrix.makeRotationAxis( axis.normalize(), radians );
rotationMatrix.multiplySelf( object.matrix ); // pre-multiply
object.matrix = rotationMatrix;
object.rotation.setEulerFromRotationMatrix( object.matrix );
}
with r55 you have to change
rotationMatrix.multiplySelf( object.matrix );
to
rotationMatrix.multiply( object.matrix );
In Three.js R59, object.rotation.setEulerFromRotationMatrix(object.matrix); has been changed to object.rotation.setFromRotationMatrix(object.matrix);
3js is changing so rapidly :D
Just in case...in r52 the method is called setEulerFromRotationMatrix instead of getRotationFromMatrix
Somewhere around r59 this gets easier (rotate around x):
bb.GraphicsEngine.prototype.calcRotation = function ( obj, rotationX)
{
var euler = new THREE.Euler( rotationX, 0, 0, 'XYZ' );
obj.position.applyEuler(euler);
}
In Three.js R66, this is what I use (CoffeeScript version):
THREE.Object3D.prototype.rotateAroundWorldAxis = (axis, radians) ->
rotWorldMatrix = new THREE.Matrix4()
rotWorldMatrix.makeRotationAxis axis.normalize(), radians
rotWorldMatrix.multiply this.matrix
this.matrix = rotWorldMatrix
this.rotation.setFromRotationMatrix this.matrix
I solved in this way:
I created the 'ObjectControls' module for ThreeJS that allows you to rotate a single OBJECT (or a Group), and not the SCENE.
Include the libary:
<script src="ObjectControls.js"></script>
Usage:
var controls = new ObjectControls(camera, renderer.domElement, yourMesh);
You can find here a live demo here: https://albertopiras.github.io/threeJS-object-controls/
Here is the repo: https://github.com/albertopiras/threeJS-object-controls.