问题
I'm trying my hands on three.js
I am moving the camera using a tween, and it works quite good. At the end of the animation, however, the camera jumps back to its initial position.
I found out that the mousemove event was causing that behavior. How can i fix this problem and keep both the tween movement and the mouse move?
I have constructed my three.js based on this example;
Mousemove declared inside render function
function render() {
camera.position.x += ( mouseX - camera.position.x ) * 0.04;
camera.position.y += ( - mouseY - camera.position.y ) * 0.04;
camera.lookAt( scene.position );
TWEEN.update();
renderer.render( scene, camera );
}
Tween movement
function setupTween (position, target, duration) {
TWEEN.removeAll();
new TWEEN.Tween (position)
.to (target, duration)
.easing (TWEEN.Easing.Quadratic.InOut)
.onUpdate (
function() {
// copy incoming position into camera position
camera.position.copy (position);
})
.start();
};
tween function source
UPDATE
Complete working code:
<script>
var container,
i,
camera,
scene,
renderer,
particles,
geometry,
materials = [],
color,
sprite,
size,
mouseX = 0,
mouseY = 0,
isTweening,
windowHalfX = window.innerWidth / 2,
windowHalfY = window.innerHeight / 2;
// +++++ three.js +++++
// +++++ +++++ +++++ +++++ +++++
function init() {
container = document.createElement( 'div' );
document.body.appendChild( container );
camera = new THREE.PerspectiveCamera(45, window.innerWidth / window.innerHeight, 0.5, 2000 );
camera.position.set (0,0,1900);
scene = new THREE.Scene();
scene.fog = new THREE.FogExp2( 0x000000, 0.0005 );
geometry = new THREE.Geometry();
var textureLoader = new THREE.TextureLoader();
for ( i = 0; i < 1000; i ++ ) {
var vertex = new THREE.Vector3();
vertex.x = Math.random() * 2000 - 1000;
vertex.y = Math.random() * 2000 - 1000;
vertex.z = Math.random() * 2000 - 1000;
geometry.vertices.push( vertex );
}
sprite = textureLoader.load( "circle.png" );
color = [0.90, 0.05, 0.8];
size = 8.5;
materials = new THREE.PointsMaterial( { size: size, map: sprite, blending: THREE.AdditiveBlending, depthTest: false, transparent : false } );
materials.color.setHSL( color[0], color[1], color[2] );
particles = new THREE.Points( geometry, materials );
scene.add( particles );
renderer = new THREE.WebGLRenderer({ antialias: true, alpha: true });
renderer.setPixelRatio( window.devicePixelRatio );
renderer.setSize( window.innerWidth, window.innerHeight );
container.appendChild( renderer.domElement );
document.addEventListener( 'mousemove', onDocumentMouseMove, false );
}
function onWindowResize() {
windowHalfX = window.innerWidth / 2;
windowHalfY = window.innerHeight / 2;
camera.aspect = window.innerWidth / window.innerHeight;
camera.updateProjectionMatrix();
renderer.setSize( window.innerWidth, window.innerHeight );
}
function onDocumentMouseMove( event ) {
mouseX = event.clientX - windowHalfX;
mouseY = event.clientY - windowHalfY;
}
function animate() {
requestAnimationFrame( animate );
render();
}
function startTween() {
isTweening = false;
var target = new THREE.Vector3(getRandomNumber(), getRandomNumber(), getRandomNumber());
new TWEEN.Tween (camera.position.clone())
.to (target, 1000)
.easing (TWEEN.Easing.Quadratic.InOut)
.onUpdate( function() {
camera.position.copy(this);
})
.onStart ( function() {
isTweening = true;
})
.onComplete ( function() {
isTweening = false;
})
.start();
}
function getRandomNumber() {
// get a number between -1000 and -500 and 500 and 1000
return ( Math.random() * 500 + 500 ) * ( Math.random() < 0.5 ? -1 : 1 );
}
function render() {
if(!isTweening && (mouseX || mouseY)) {
// more a generic approach, not just transforming x and y (maybe it needs to be improved a bit)
var upVector = camera.up.clone().transformDirection(camera.matrix);
var forwardVector = new THREE.Vector3().subVectors(scene.position, camera.position).normalize();
var rightVector = new THREE.Vector3().crossVectors(forwardVector, upVector);
camera.translateOnAxis(rightVector, mouseX);
camera.translateOnAxis(upVector, -mouseY);
mouseX = mouseY = 0;
}
camera.lookAt( scene.position );
TWEEN.update();
renderer.render( scene, camera );
}
init();
animate();
setTimeout(function(){
startTween();
},2500);
</script>
回答1:
I think, you should only update the position by the mousemove event, when it's not tweening. So you need to check if its currently tweening or not.
var isTweening = false;
new TWEEN.Tween (camera.position)
.to (target, duration)
.easing (TWEEN.Easing.Quadratic.InOut)
.onStart ( function() {
isTweening = true;
})
.onComplete ( function() {
isTweening = false;
})
.start();
// in your render loop
function render() {
if (!isTweening) {
camera.position.x += ( mouseX - camera.position.x ) * 0.04;
camera.position.y += ( - mouseY - camera.position.y ) * 0.04;
}
camera.lookAt( scene.position );
TWEEN.update();
renderer.render( scene, camera );
}
You don't need to set an onUpdate function and copy the new position to camera.position. You can just pass over camera.position to the tween and it will work.
EDIT:
I didn't see the link to example. Now, I know which kind of navigation is used (which is actually used in a lot of three.js examples). It's not the mousemove event that is causing your problem, it's this kind of calculating the new camera position (camera.position.x += ( mouseX - camera.position.x ) * 0.04;). So, I changed the code of the example a bit, especially the navigation. Here are the important parts:
document.addEventListener( 'mousemove', onDocumentMouseMove, false );
function onDocumentMouseMove( event ) {
mouseX = (event.movementX * 0.5) || event.mozMovementX || event.webkitMovementX || 0;
mouseY = (event.movementY * 0.5) || event.mozMovementY || event.webkitMovementY || 0;
}
function render() {
if(!isTweening && (mouseX || mouseY)) {
// more a generic approach, not just transforming x and y (maybe it needs to be improved a bit)
var upVector = camera.up.clone().transformDirection(camera.matrix);
var forwardVector = new THREE.Vector3().subVectors(scene.position, camera.position).normalize();
var rightVector = new THREE.Vector3().crossVectors(forwardVector, upVector);
camera.translateOnAxis(rightVector, mouseX);
camera.translateOnAxis(upVector, -mouseY);
mouseX = mouseY = 0;
}
camera.lookAt( scene.position );
TWEEN.update();
}
function startTween() {
isTweening = false;
var target = new THREE.Vector3(getRandomNumber(), getRandomNumber(), getRandomNumber());
new TWEEN.Tween (camera.position.clone())
.to (target, 1000)
.easing (TWEEN.Easing.Quadratic.InOut)
.onUpdate( function() {
camera.position.copy(this);
})
.onStart ( function() {
isTweening = true;
})
.onComplete ( function() {
isTweening = false;
})
.start();
}
function getRandomNumber() {
// get a number between -1000 and -500 and 500 and 1000
return ( Math.random() * 500 + 500 ) * ( Math.random() < 0.5 ? -1 : 1 );
}
And you are right about TWEEN.onUpdate: you need to copy the new values to camera.position. My earlier approach do also work, but then all of the functionality of THREE.Vector3 gets lost. I didn't realize that until now.
来源：https://stackoverflow.com/questions/36679873/three-js-tween-camera-and-mousemove-event