如何沿简单路径移动相机

Question

如何沿简单路径（由顶点/点数组创建）移动相机？我需要自动移动它，而不是像在第一人称射击游戏中那样通过键盘/鼠标事件？

寻找这个例子：http://threejs.org/examples/webgl_geometry_extrude_splines.html，它真的很好（而且很复杂），但作为一个刚开始学习 Three.js 的人，我需要一些简单的东西

Answer 1

所以，最好和最简单的解决方案（基于我的错误和研究——也许你可以找到更简单的解决方案）是使用 PathControls；你可以在这里找到图书馆：https://github.com/mrdoob/three.js/blob/master/examples/js/controls/PathControls.js

这个简单的解决方案基于这本书：Learning Three.js: "The JavaScript 3D Library for WebGL"；学三方面的东西很好，推荐大家读一读；首先我们将 PathControls.js 添加到我们的文档中：

<script src="js/PathControls.js"></script>

然后我们在 init() 函数之前添加一些变量：

var controls;
var clock = new THREE.Clock();
var pathControls;

现在我们需要在我们的 init() 函数上做一些工作，在创建场景、相机、灯光等之后：

controls = new function () {
this.numberOfPoints = 5;
this.segments = 64;
this.radius = 3;
this.radiusSegments = 5;
this.closed = false;
this.points = getPoints();

//you can take out this last one: it shows you the path on which the camera is moving
generatePoints(this.points, this.segments, this.radius, this.radiusSegments, this.closed);
}
pathControls = new THREE.PathControls(camera);

// configure the controller
pathControls.duration = 70

//speed, so you will not have the dash effect on a curve
pathControls.useConstantSpeed = true;
pathControls.lookSpeed = 0.1;
pathControls.lookVertical = true;
pathControls.lookHorizontal = true;
pathControls.verticalAngleMap = {srcRange: [ 0, 2 * Math.PI ], dstRange: [ 1.1, 3.8 ]};
pathControls.horizontalAngleMap = {srcRange: [ 0, 2 * Math.PI ], dstRange: [ 0.3, Math.PI - 0.3 ]};
pathControls.lon = 300;
pathControls.lat = 40;

// add the path
controls.points.forEach(function(e) {
  pathControls.waypoints.push([e.x, e.y, e.z]) });

// when done configuring init the control
pathControls.init();

// add the animationParent to the scene and start the animation
scene.add(pathControls.animationParent);
pathControls.animation.play(true, 0 );

最后，您需要在 animate() 函数中使用这 3 行代码，以便相机实际上会根据时间移动：

var delta = clock.getDelta();
THREE.AnimationHandler.update(delta);
pathControls.update(delta);

关于支持函数（我有这个只是一个 5 点的数组，但你可以使用更多更复杂的：这取决于你）：

function getPoints() {
    var points = [];
    points.push(new THREE.Vector3(0, 20, 0));
    points.push(new THREE.Vector3(100, 25, 0));
    points.push(new THREE.Vector3(100, 20, 100));
    points.push(new THREE.Vector3(0, 25, 100));
    points.push(new THREE.Vector3(0, 20, 0));
    return points;
}

这些是在您选择的路径上显示/绘制管子的功能，这样您就可以看到相机的实际移动情况（整个代码不需要）：

function generatePoints(points, segments, radius, radiusSegments, closed) {
  var tube = new THREE.TubeGeometry(new THREE.SplineCurve3(points), segments, radius, radiusSegments, false, closed);
  var tubeMesh = createMesh(tube);
  scene.add(tubeMesh);
}

function createMesh(geom) {
  mesh = THREE.SceneUtils.createMultiMaterialObject( geom, [
    new THREE.MeshLambertMaterial({color: 0x00ff00, transparent: true}),
    new THREE.MeshBasicMaterial({color: 0x000000, opacity: 0.3, wireframe: true, transparent: true})]);
 return mesh;
}

希望它对某人有用；对于整个代码，你可以在这里找到它：https://github.com/MarcinKwiatkowski1988/learningThreeJs/blob/master/movingCameraOnPath/myTry1_simply.html