当 div 的宽度减小时，用 raycaster 检测不完全准确，three.js(v72)

Question

这是我计算交集的代码：

var wallWidth = 1200;
var wallHeight = 500;
var containerWidth=1200,containerHeight=700; //div 
//camera
camera = new THREE.PerspectiveCamera(60, containerWidth/containerHeight, 1, 10000);
camera.position.set(0, -wallHeight / 2 + 10, wallWidth);

这是我的函数，它在鼠标移动时与对象相交

function onDocumentMouseMove(event) {

        mouse.x = ( event.clientX / containerWidth ) * 2 - 1;
        mouse.y = -( event.clientY / containerHeight ) * 2 + 1;

        var deltaX = event.clientX - mouseX;
        var deltaY = event.clientY - mouseY;

        raycaster.setFromCamera(mouse, camera);
        var intersects = raycaster.intersectObjects(interactiveObj, true);

        if (intersects.length > 0) {
            //interaction with object
        }

        render();
    }

它工作正常，即当 div 的宽度为 100% 时，我在 intersects 对象中获取值，但是当我将 div 大小减小到 80% 时，对象拾取不正确，即当鼠标离对象很远时拾取对象。

Answer 1

使用下面的代码来改变你的鼠标矢量

Document MouseMove 函数（事件）{

    mouse.x = ( (event.clientX -renderer.domElement.offsetLeft) / renderer.domElement.width ) * 2 - 1;
    mouse.y = -( (event.clientY - renderer.domElement.offsetTop) / renderer.domElement.height ) * 2 + 1;

    var deltaX = event.clientX - mouseX;
    var deltaY = event.clientY - mouseY;

    raycaster.setFromCamera(mouse, camera);
    var intersects = raycaster.intersectObjects(interactiveObj, true);

}

Answer 2

Instead of using event.clientX - renderer.domElement.offsetLeft you can just use event.offsetX

我遇到了同样的问题，Brakebein 的回答最适合我的需要。

Answer 3

下面这种获取鼠标相对位置的方式貌似比较准确

var rect = renderer.domElement.getBoundingClientRect();
mouse.x = ( ( event.clientX - rect.left ) / rect.width ) * 2 - 1;
mouse.y = - ( ( event.clientY - rect.top ) / rect.height ) * 2 + 1;

Answer 4

在使用 React 搜索此变体很长时间后，帮助我提高了 raycaster 精度（也许它对某人有帮助）：

class Scene extends React.Component {

 componentDidMount() {
  const width = 400;
  const height = 400;

  const scene = new THREE.Scene();
  const camera = new THREE.PerspectiveCamera(95, width / height, 1, 1000);
  const renderer = new THREE.WebGLRenderer({ antialias: true });
  var controls = new OrbitControls(camera);



  const geometry = new THREE.SphereGeometry(2, 100, 100);

  .....

  const material = new THREE.MeshBasicMaterial({
    color: "#00bfff",
    map: canvasTexture
});
  const sphere = new THREE.Mesh(geometry, material);

  camera.position.z = 3;
  scene.add(sphere);
  renderer.setClearColor("#FFF");
  renderer.setSize(width, height);

  this.scene = scene;
  this.camera = camera;
  this.renderer = renderer;
  this.material = material;
  this.sphere = sphere;
  this.geometry = geometry;
  this.mouse = new THREE.Vector2();
  this.raycaster = new THREE.Raycaster();
 }

 ...

 clickHandler = event => {

  const mainEl = document.getElementById("mainBlock");
  const rect = mainEl.getBoundingClientRect();

  this.mouse.x = (event.clientX - rect.left) / mainEl.clientWidth * 2 - 1;
  this.mouse.y = -((event.clientY - rect.top) / mainEl.clientHeight) * 2 + 1; 

  this.raycaster.setFromCamera(this.mouse, this.camera);
  const intersects = this.raycaster.intersectObject(this.sphere);


  if (intersects.length !== 0) {
    ...
  }
};

render() {
  <div
    id="mainBlock"
    style={{ width: "400px", height: "400px" }}
    ref={mount => {
      this.mount = mount;
    }}
    onClick={this.clickHandler}
  >
     ...
  </div>
}

}

当 div 的宽度减小时，用 raycaster 检测不完全准确，three.js(v72)

Detection with raycaster not completely accurate when the width of div is reduced, three.js(v72)

three.js

raycasting