鼠标/画布X，Y到Three.js世界X，Y，Z

时间：2012-10-24 18:12:54

标签： three.js point projection mouse-coordinates

我一直在寻找一个与我的用例相匹配的例子，却找不到一个。我正在尝试将屏幕鼠标坐标转换为考虑到相机的3D世界坐标。

解决方案我发现所有人都进行射线交叉以实现物体拾取。

我要做的是将Three.js对象的中心定位在鼠标当前“结束”的坐标上。

我的相机位于x：0，y：0，z：500（虽然它会在模拟过程中移动）并且我的所有物体都在z = 0时具有不同的x和y值，所以我需要知道世界X ，Y基于假设az = 0表示将跟随鼠标位置的对象。

此问题看似类似问题，但没有解决方案：Getting coordinates of the mouse in relation to 3D space in THREE.js

鉴于鼠标在屏幕上的位置是“top-left = 0,0 | bottom-right = window.innerWidth，window.innerHeight”，任何人都可以提供将Three.js对象移动到鼠标的解决方案沿z = 0？

的坐标

9 个答案:

答案 0 :(得分：106)

您不需要在场景中使用任何对象来执行此操作。

您已经知道相机的位置。

使用vector.unproject( camera )可以获得指向所需方向的光线。

您只需要从相机位置延伸该光线，直到光线尖端的z坐标为零。

你可以这样做：

var vec = new THREE.Vector3(); // create once and reuse
var pos = new THREE.Vector3(); // create once and reuse

vec.set(
    ( event.clientX / window.innerWidth ) * 2 - 1,
    - ( event.clientY / window.innerHeight ) * 2 + 1,
    0.5 );

vec.unproject( camera );

vec.sub( camera.position ).normalize();

var distance = - camera.position.z / vec.z;

pos.copy( camera.position ).add( vec.multiplyScalar( distance ) );

变量pos是3D空间中的点，“鼠标下方”和平面z=0中的位置。

编辑：如果您需要“鼠标下方”和平面z = targetZ中的点，请将距离计算替换为：

var distance = ( targetZ - camera.position.z ) / vec.z;

three.js r.98

答案 1 :(得分：5)

在r.58中，这段代码对我有用：

var planeZ = new THREE.Plane(new THREE.Vector3(0, 0, 1), 0);
var mv = new THREE.Vector3(
    (event.clientX / window.innerWidth) * 2 - 1,
    -(event.clientY / window.innerHeight) * 2 + 1,
    0.5 );
var raycaster = projector.pickingRay(mv, camera);
var pos = raycaster.ray.intersectPlane(planeZ);
console.log("x: " + pos.x + ", y: " + pos.y);

答案 2 :(得分：2)

获取3d对象的鼠标坐标使用projectVector：

var width = 640, height = 480;
var widthHalf = width / 2, heightHalf = height / 2;

var projector = new THREE.Projector();
var vector = projector.projectVector( object.matrixWorld.getPosition().clone(), camera );

vector.x = ( vector.x * widthHalf ) + widthHalf;
vector.y = - ( vector.y * heightHalf ) + heightHalf;

获取与特定鼠标坐标相关的three.js 3D坐标，使用相反的unprojectVector：

var elem = renderer.domElement, 
    boundingRect = elem.getBoundingClientRect(),
    x = (event.clientX - boundingRect.left) * (elem.width / boundingRect.width),
    y = (event.clientY - boundingRect.top) * (elem.height / boundingRect.height);

var vector = new THREE.Vector3( 
    ( x / WIDTH ) * 2 - 1, 
    - ( y / HEIGHT ) * 2 + 1, 
    0.5 
);

projector.unprojectVector( vector, camera );
var ray = new THREE.Ray( camera.position, vector.subSelf( camera.position ).normalize() );
var intersects = ray.intersectObjects( scene.children );

有一个很好的例子here。但是，要使用项目向量，必须有一个用户单击的对象。相交将是鼠标位置上所有对象的数组，无论其深度如何。

答案 3 :(得分：2)

以下是我根据WestLangley的回复编写的ES6课程，该课程适用于THREE.js r77。

请注意，它假定渲染视口占用整个浏览器视口。

RevertToSelf()

你可以使用这样的类：

class CProjectMousePosToXYPlaneHelper
{
    constructor()
    {
        this.m_vPos = new THREE.Vector3();
        this.m_vDir = new THREE.Vector3();
    }

    Compute( nMouseX, nMouseY, Camera, vOutPos )
    {
        let vPos = this.m_vPos;
        let vDir = this.m_vDir;

        vPos.set(
            -1.0 + 2.0 * nMouseX / window.innerWidth,
            -1.0 + 2.0 * nMouseY / window.innerHeight,
            0.5
        ).unproject( Camera );

        // Calculate a unit vector from the camera to the projected position
        vDir.copy( vPos ).sub( Camera.position ).normalize();

        // Project onto z=0
        let flDistance = -Camera.position.z / vDir.z;
        vOutPos.copy( Camera.position ).add( vDir.multiplyScalar( flDistance ) );
    }
}

vProjectedMousePos现在包含z = 0平面上的投影鼠标位置。

答案 4 :(得分：2)

使用orthographic camera

时，这对我有用 
let vector = new THREE.Vector3();
vector.set(
    (event.clientX / window.innerWidth) * 2 - 1,
    - (event.clientY / window.innerHeight) * 2 + 1,
    0
);
vector.unproject(camera);

WebGL three.js r.89

答案 5 :(得分：1)

ThreeJS正在慢慢地从投影仪上移开。（联合国）ProjectVector和带投影仪的解决方案.pickingRay（）不再工作，刚刚完成更新我自己的代码..所以最新的工作版本应该如下：

var rayVector = new THREE.Vector3(0, 0, 0.5);
var camera = new THREE.PerspectiveCamera(fov,this.offsetWidth/this.offsetHeight,0.1,farFrustum);
var raycaster = new THREE.Raycaster();
var scene = new THREE.Scene();

//...

function intersectObjects(x, y, planeOnly) {
  rayVector.set(((x/this.offsetWidth)*2-1), (1-(y/this.offsetHeight)*2), 1).unproject(camera);
  raycaster.set(camera.position, rayVector.sub(camera.position ).normalize());
  var intersects = raycaster.intersectObjects(scene.children);
  return intersects;
}

答案 6 :(得分：0)

这是我创建一个es6类的看法。使用Three.js r83。使用rayCaster的方法来自mrdoob：Three.js Projector and Ray objects 

    export default class RaycasterHelper
    {
      constructor (camera, scene) {
        this.camera = camera
        this.scene = scene
        this.rayCaster = new THREE.Raycaster()
        this.tapPos3D = new THREE.Vector3()
        this.getIntersectsFromTap = this.getIntersectsFromTap.bind(this)
      }
      // objects arg below needs to be an array of Three objects in the scene 
      getIntersectsFromTap (tapX, tapY, objects) {
        this.tapPos3D.set((tapX / window.innerWidth) * 2 - 1, -(tapY / 
        window.innerHeight) * 2 + 1, 0.5) // z = 0.5 important!
        this.tapPos3D.unproject(this.camera)
        this.rayCaster.set(this.camera.position, 
        this.tapPos3D.sub(this.camera.position).normalize())
        return this.rayCaster.intersectObjects(objects, false)
      }
    }

如果你想检查场景中的所有物体是否有命中，你会像这样使用它。我上面的递归标志是假的，因为对于我的用途，我不需要它。 

var helper = new RaycasterHelper(camera, scene)
var intersects = helper.getIntersectsFromTap(tapX, tapY, 
this.scene.children)
...

答案 7 :(得分：0)

虽然提供的答案在某些情况下很有用，但我几乎无法想象那些场景（可能是游戏或动画），因为它们根本不准确（猜测目标的NDC z？）。如果您知道目标z平面，则无法使用这些方法将屏幕坐标取消投影到世界坐标。但对于大多数情况，你应该知道这架飞机。

例如，如果您按中心（模型空间中的已知点）和半径绘制球体 - 您需要将半径作为未投影鼠标坐标的增量 - 但您不能！尽管尊重@WestLangley的方法并且targetZ不起作用，但它会给出不正确的结果（如果需要，我可以提供jsfiddle）。另一个例子 - 您需要通过鼠标双击设置轨道控制目标，但没有＆＃34;真实＆＃34;使用场景对象进行光线投射（当您无法选择时）。

我的解决方案是在z轴上创建目标点中的虚拟平面，然后使用此平面进行光线投射。目标点可以是当前轨道控制目标或需要在现有模型空间中逐步绘制的对象顶点等。这非常有效且很简单（打字稿中的示例）：

screenToWorld(v2D: THREE.Vector2, camera: THREE.PerspectiveCamera = null, target: THREE.Vector3 = null): THREE.Vector3 {
    const self = this;

    const vNdc = self.toNdc(v2D);
    return self.ndcToWorld(vNdc, camera, target);
}

//get normalized device cartesian coordinates (NDC) with center (0, 0) and ranging from (-1, -1) to (1, 1)
toNdc(v: THREE.Vector2): THREE.Vector2 {
    const self = this;

    const canvasEl = self.renderers.WebGL.domElement;

    const bounds = canvasEl.getBoundingClientRect();        

    let x = v.x - bounds.left;      

    let y = v.y - bounds.top;       

    x = (x / bounds.width) * 2 - 1;     

    y = - (y / bounds.height) * 2 + 1;      

    return new THREE.Vector2(x, y);     
}

ndcToWorld(vNdc: THREE.Vector2, camera: THREE.PerspectiveCamera = null, target: THREE.Vector3 = null): THREE.Vector3 {
    const self = this;      

    if (!camera) {
        camera = self.camera;
    }

    if (!target) {
        target = self.getTarget();
    }

    const position = camera.position.clone();

    const origin = self.scene.position.clone();

    const v3D = target.clone();

    self.raycaster.setFromCamera(vNdc, camera);

    const normal = new THREE.Vector3(0, 0, 1);

    const distance = normal.dot(origin.sub(v3D));       

    const plane = new THREE.Plane(normal, distance);

    self.raycaster.ray.intersectPlane(plane, v3D);

    return v3D; 
}

答案 8 :(得分：0)

我的画布小于我的整个窗口，需要确定单击的世界坐标：

// get the position of a canvas event in world coords
function getWorldCoords(e) {
  // get x,y coords into canvas where click occurred
  var rect = canvas.getBoundingClientRect(),
      x = e.clientX - rect.left,
      y = e.clientY - rect.top;
  // convert x,y to clip space; coords from top left, clockwise:
  // (-1,1), (1,1), (-1,-1), (1, -1)
  var mouse = new THREE.Vector3();
  mouse.x = ( (x / canvas.clientWidth ) * 2) - 1;
  mouse.y = (-(y / canvas.clientHeight) * 2) + 1;
  mouse.z = 0.5; // set to z position of mesh objects
  // reverse projection from 3D to screen
  mouse.unproject(camera);
  // convert from point to a direction
  mouse.sub(camera.position).normalize();
  // scale the projected ray
  var distance = -camera.position.z / mouse.z,
      scaled = mouse.multiplyScalar(distance),
      coords = camera.position.clone().add(scaled);
  return coords;
}

var canvas = renderer.domElement;
canvas.addEventListener('click', getWorldCoords);

这是一个例子。在滑动前后单击甜甜圈的相同区域，您会发现坐标保持不变（请检查浏览器控制台）：

// three.js boilerplate
var container = document.querySelector('body'),
    w = container.clientWidth,
    h = container.clientHeight,
    scene = new THREE.Scene(),
    camera = new THREE.PerspectiveCamera(75, w/h, 0.001, 100),
    controls = new THREE.MapControls(camera, container),
    renderConfig = {antialias: true, alpha: true},
    renderer = new THREE.WebGLRenderer(renderConfig);
controls.panSpeed = 0.4;
camera.position.set(0, 0, -10);
renderer.setPixelRatio(window.devicePixelRatio);
renderer.setSize(w, h);
container.appendChild(renderer.domElement);

window.addEventListener('resize', function() {
  w = container.clientWidth;
  h = container.clientHeight;
  camera.aspect = w/h;
  camera.updateProjectionMatrix();
  renderer.setSize(w, h);
})

function render() {
  requestAnimationFrame(render);
  renderer.render(scene, camera);
  controls.update();
}

// draw some geometries
var geometry = new THREE.TorusGeometry( 10, 3, 16, 100, );
var material = new THREE.MeshNormalMaterial( { color: 0xffff00, } );
var torus = new THREE.Mesh( geometry, material, );
scene.add( torus );

// convert click coords to world space
// get the position of a canvas event in world coords
function getWorldCoords(e) {
  // get x,y coords into canvas where click occurred
  var rect = canvas.getBoundingClientRect(),
      x = e.clientX - rect.left,
      y = e.clientY - rect.top;
  // convert x,y to clip space; coords from top left, clockwise:
  // (-1,1), (1,1), (-1,-1), (1, -1)
  var mouse = new THREE.Vector3();
  mouse.x = ( (x / canvas.clientWidth ) * 2) - 1;
  mouse.y = (-(y / canvas.clientHeight) * 2) + 1;
  mouse.z = 0.0; // set to z position of mesh objects
  // reverse projection from 3D to screen
  mouse.unproject(camera);
  // convert from point to a direction
  mouse.sub(camera.position).normalize();
  // scale the projected ray
  var distance = -camera.position.z / mouse.z,
      scaled = mouse.multiplyScalar(distance),
      coords = camera.position.clone().add(scaled);
  console.log(mouse, coords.x, coords.y, coords.z);
}

var canvas = renderer.domElement;
canvas.addEventListener('click', getWorldCoords);

render();
html,
body {
  width: 100%;
  height: 100%;
  background: #000;
}
body {
  margin: 0;
  overflow: hidden;
}
canvas {
  width: 100%;
  height: 100%;
}
<script src='https://cdnjs.cloudflare.com/ajax/libs/three.js/97/three.min.js'></script>
<script src=' https://threejs.org/examples/js/controls/MapControls.js'></script>

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