Three三维世界初体验

Posted on | In

教程：
WebGL中文网教程
three文档
碰撞检测
原理：
以物体的中心为起点，向各个顶点（vertices）发出射线，如果射线与其它的物体相交，则检查最近的一个交点与射线起点间的距离，如果这个距离比射线起点至物体顶点间的距离要小，则说明发生了碰撞。但是，当物体的中心在另一个物体内部时，是不能够检测到碰撞的。而且当两个物体能够互相穿过，且有较大部分重合时，检测效果也不理想。

代码示例
碰撞实例

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// 初始化Three
var renderer;
function initThree() {
    renderer = new THREE.WebGLRenderer();

    renderer.setSize(window.innerWidth, window.innerHeight);

    width = document.getElementById('canvas-frame').clientWidth;
    height = document.getElementById('canvas-frame').clientHeight;
    renderer = new THREE.WebGLRenderer({
        antialias : true
    });
    renderer.setSize(width, height);
    document.getElementById('canvas-frame').appendChild(renderer.domElement);
    renderer.setClearColor(0xffffff, 1.0);
}

// 初始化Camera
var camera;
function initCamera() {
    // 设置透视相机
    camera = new THREE.PerspectiveCamera(45, width / height, 1, 10000);
    // 设置相机位置
    camera.position.x = 200;
    camera.position.y = 500;
    camera.position.z = 800;
    // 设置相机哪里为上
    // camera.up.x = 0;
    // camera.up.y = 0;
    // camera.up.z = 1;
    // 设置相机看向哪
    camera.lookAt(new THREE.Vector3(0, 0, 0));
}

// 初始化场景
var scene;
function initScene() {
    scene = new THREE.Scene();
}

// 初始化灯光
var light;
function initLight() {
    light = new THREE.DirectionalLight(0xFF0000,1);
    light.position.set(100,100,1);
    scene.add(light);
}

// 初始化里面的元素
var cube;
var mesh;
function initObject() {
    for(var k =0;k<2;k++){
        // 一个几何体
        var geometry = new THREE.BoxGeometry( 100,100,100);
        // 不同面设置不同颜色
        for ( var i = 0; i < geometry.faces.length; i += 2 ) {

            var hex = Math.random() * 0xffffff;
            geometry.faces[ i ].color.setHex( hex );
            geometry.faces[ i + 1 ].color.setHex( hex );

        }
        // 设置纹理
        // var material = new THREE.MeshBasicMaterial( { vertexColors: THREE.FaceColors} );
        var material = new THREE.MeshLambertMaterial( { color: Math.random() * 0xffffff } )
        // 把几何体跟纹理混合起来
        mesh = new THREE.Mesh( geometry,material);
        // 元素的位置
        mesh.position.set(0,k*50,k * 400);
        // 把元素加到场景里
        scene.add(mesh);
    }
}

// 渲染
var stats;
function render()
{
    // renderer.clear();
    // mesh.position.x =mesh.position.x +1;
    renderer.render(scene, camera);
    requestAnimationFrame(render);
    stats.update();
    // TWEEN.update();
}

// 性能检测
function initStats(){
    stats = new Stats();
    stats.setMode(1); // 0: fps, 1: ms
// 将stats的界面对应左上角
    stats.domElement.style.position = 'absolute';
    stats.domElement.style.left = '0px';
    stats.domElement.style.top = '0px';
    document.body.appendChild( stats.domElement );
    setInterval( function () {
        stats.begin();
        // 你的每一帧的代码
        stats.end();
    }, 1000 / 60 );
}

// 初始化网格
function initGrid(){
    // 网格的边长是1000，每个小网格的边长是50
    var helper = new THREE.GridHelper( 1000, 50,0x0000ff, 0x808080 );
    var helper2 = new THREE.GridHelper( 1000, 50,0x0000ff, 0x808080 );
    helper2.rotation.x = Math.PI/2;
    scene.add( helper );
    scene.add(helper2);
}

// 初始化事件
var INTERSECTED;
function initEvent(){
    var objects=[];
    var raycaster = new THREE.Raycaster();
    var mouse = new THREE.Vector2();
    //监听全局点击事件,通过ray检测选中哪一个object
    document.addEventListener("mousedown", (event) => {
        console.log('mousedown');
        event.preventDefault();
        mouse.x = (event.clientX / this.renderer.domElement.clientWidth) * 2 - 1;
        mouse.y = - (event.clientY / this.renderer.domElement.clientHeight) * 2 + 1;

        raycaster.setFromCamera(mouse, this.camera);
        this.scene.children.forEach(child => {
            if (child instanceof THREE.Mesh) {//根据需求判断哪些加入objects,也可以在生成object的时候push进objects
                objects.push(child)
            }
        })
        var intersects = raycaster.intersectObjects(objects);


        if (intersects.length > 0) {
            if ( INTERSECTED ) INTERSECTED.material.emissive.setHex( INTERSECTED.currentHex );

            INTERSECTED = intersects[ 0 ].object;
            INTERSECTED.currentHex = INTERSECTED.material.emissive.getHex();
            INTERSECTED.material.emissive.setHex( 0x0000ff );
        }
        else {
            if ( INTERSECTED ) {
                INTERSECTED.material.emissive.setHex( INTERSECTED.currentHex );
                // 碰撞检测
                var originPoint = INTERSECTED.position.clone();
                var crash = false;
                for (var vertexIndex = 0; vertexIndex < INTERSECTED.geometry.vertices.length; vertexIndex++) {
                    // 顶点原始坐标
                    var localVertex = INTERSECTED.geometry.vertices[vertexIndex].clone();
                    // 顶点经过变换后的坐标
                    var globalVertex = localVertex.applyMatrix4(INTERSECTED.matrix);
                    // 获得由中心指向顶点的向量
                    var directionVector = globalVertex.sub(INTERSECTED.position);

                    // 将方向向量初始化
                    var ray = new THREE.Raycaster(originPoint, directionVector.clone().normalize());
                    // 检测射线与多个物体的相交情况

                    var collisionResults = ray.intersectObjects(objects);
                    // 如果返回结果不为空，且交点与射线起点的距离小于物体中心至顶点的距离，则发生了碰撞
                    if (collisionResults.length > 0 && collisionResults[0].distance < directionVector.length()) {
                        crash = true;

                    }
                }
                if(crash){
                    alert('crash');
                    INTERSECTED.position.set(0,0,400);
                }
            }
            INTERSECTED = null;

        }
    }, false);

    document.addEventListener("mousemove",(event) => {
        event.preventDefault();
        if(INTERSECTED){
            
            var mouse = new THREE.Vector2();
            console.log(( event.clientX / window.innerWidth ) * 2 - 1, - ( event.clientY / window.innerHeight ) * 2 + 1 );
            mouse.set( ( event.clientX / window.innerWidth ) * 2 - 1, - ( event.clientY / window.innerHeight ) * 2 + 1 );

            raycaster.setFromCamera( mouse, camera );
            var objects = [];
            scene.children.forEach(child => {
                if (child instanceof THREE.GridHelper) {
                    objects.push(child)
                }
            });

            var intersects = raycaster.intersectObjects( objects );

            if (intersects.length > 0) {
                var selected = intersects[ 0 ];
                // console.log(selected.point.x,selected.point.y,selected.point.z);
                INTERSECTED.position.copy(selected.point);
                INTERSECTED.position.divideScalar( 50 ).floor().multiplyScalar( 50 ).addScalar( 25 );
            }
        }
    },false);
}

// 动画组件
function initTween(){
    new TWEEN.Tween( mesh.position)
        .to( { x: -400,z:100,y:100 }, 3000 ).repeat( Infinity ).start();
}


function threeStart() {
    initThree();
    initCamera();
    initScene();
    initLight();
    initObject();
    initGrid();
    initStats();
    initEvent();
    // initTween();
    render();
}

threeStart();

拖拽优化：
使用three-drag-controller,替代mousemove时间监听

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import DragControls from 'three-dragcontrols';
import OrbitControls from 'three-orbitcontrols';
......
function initDragControls() {
    // 初始化拖拽控件
    var dragControls = new DragControls(meshList, camera, renderer.domElement);
    var controls = new OrbitControls(camera, renderer.domElement);
    
    // 鼠标略过事件
    dragControls.addEventListener('hoveron', function (event) {
       
    });
    // 开始拖拽
    dragControls.addEventListener('dragstart', function (event) {
        controls.enabled = false;
    });
    // 拖拽结束
    dragControls.addEventListener('dragend', function (event) {
        controls.enabled = true;
        // crashCheck();
    });
}

加入webpack管理，
优化后完整代码：
3d

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var THREE = require('three');
import DragControls from 'three-dragcontrols';
import OrbitControls from 'three-orbitcontrols';
import TransformControls from 'threejs-transformcontrols';

// 初始化Three
var renderer;
var width,height;
function initThree() {
    renderer = new THREE.WebGLRenderer();

    renderer.setSize(window.innerWidth, window.innerHeight);

    width = document.getElementById('canvas-frame').clientWidth;
    height = document.getElementById('canvas-frame').clientHeight;
    renderer = new THREE.WebGLRenderer({
        antialias : true
    });
    renderer.setSize(width, height);
    document.getElementById('canvas-frame').appendChild(renderer.domElement);
    renderer.setClearColor(0xffffff, 1.0);
}

// 初始化Camera
var camera;
function initCamera() {
    // 设置透视相机
    camera = new THREE.PerspectiveCamera(45, width / height, 1, 10000);
    // 设置相机位置
    camera.position.x = 800;
    camera.position.y = 0;
    camera.position.z = 1000;
    // 设置相机哪里为上
    // camera.up.x = 0;
    // camera.up.y = 0;
    // camera.up.z = 1;
    // 设置相机看向哪
    camera.lookAt(new THREE.Vector3(0, 0, 0));
}

// 初始化场景
var scene;
function initScene() {
    scene = new THREE.Scene();
}

// 初始化灯光
var light;
function initLight() {
    light = new THREE.DirectionalLight(0xFF0000,1);
    light.position.set(100,100,1);
    scene.add(light);
}

// 初始化里面的元素
var cube;
var bus;
var meshList = [];
function initObject() {
    for(var k =0;k<2;k++){
        // 一个几何体
        var geometry = new THREE.BoxGeometry( 100,50,150);
        // 不同面设置不同颜色
        for ( var i = 0; i < geometry.faces.length; i += 2 ) {

            var hex = Math.random() * 0xffffff;
            geometry.faces[ i ].color.setHex( hex );
            geometry.faces[ i + 1 ].color.setHex( hex );

        }
        // 设置纹理
        // var material = new THREE.MeshBasicMaterial( { vertexColors: THREE.FaceColors} );
        var material = new THREE.MeshLambertMaterial( { color: Math.random() * 0xffffff } )
        // 把几何体跟纹理混合起来
        var mesh = new THREE.Mesh( geometry,material);
        meshList.push(mesh);
        // 元素的位置
        mesh.position.set(0,k*50,k * 400);
        // 把元素加到场景里
        scene.add(mesh);
    }
    var busGeometry = new THREE.BoxGeometry( 500,500,500);
    var butMaterial = new THREE.MeshLambertMaterial( { color: Math.random() * 0xffffff, transparent: true, opacity: 0.5} );
    bus = new THREE.Mesh(busGeometry,butMaterial);
    bus.position.set(0,0,0);
    scene.add(bus);
    var edges = new THREE.EdgesHelper( bus, 0x1535f7 );//设置边框，可以旋转
    scene.add( edges );
}

// 渲染
var stats;
function render()
{
    // renderer.clear();
    // mesh.position.x =mesh.position.x +1;
    renderer.render(scene, camera);
    requestAnimationFrame(render);
    // stats.update();
    // TWEEN.update();
}

// 性能检测
function initStats(){
    stats = new Stats();
    stats.setMode(1); // 0: fps, 1: ms
// 将stats的界面对应左上角
    stats.domElement.style.position = 'absolute';
    stats.domElement.style.left = '0px';
    stats.domElement.style.top = '0px';
    document.body.appendChild( stats.domElement );
    setInterval( function () {
        stats.begin();
        // 你的每一帧的代码
        stats.end();
    }, 1000 / 60 );
}

// 初始化网格
function initGrid(){
    // 网格的边长是1000，每个小网格的边长是50

    var helper = new THREE.GridHelper( 1000, 50,0x0000ff, 0x808080 );
    var helper2 = new THREE.GridHelper( 1000, 50,0x0000ff, 0x808080 );
    helper2.rotation.x = Math.PI/2;
    scene.add( helper );
    // scene.add(helper2);
}

// 初始化事件
var INTERSECTED;
function initEvent(){
    var objects= meshList;
    var raycaster = new THREE.Raycaster();
    var mouse = new THREE.Vector2();
    //监听全局点击事件,通过ray检测选中哪一个object
    // document.addEventListener("mousedown", (event) => {
    //     console.log('mousedown');
    //     event.preventDefault();
    //     mouse.x = (event.clientX / this.renderer.domElement.clientWidth) * 2 - 1;
    //     mouse.y = - (event.clientY / this.renderer.domElement.clientHeight) * 2 + 1;
    //
    //     raycaster.setFromCamera(mouse, this.camera);
    //     // this.scene.children.forEach(child => {
    //     //     if (child instanceof THREE.Mesh) {//根据需求判断哪些加入objects,也可以在生成object的时候push进objects
    //     //         objects.push(child)
    //     //     }
    //     // })
    //     var intersects = raycaster.intersectObjects(objects);
    //
    //
    //     if (intersects.length > 0) {
    //         if ( INTERSECTED ) INTERSECTED.material.emissive.setHex( INTERSECTED.currentHex );
    //
    //         INTERSECTED = intersects[ 0 ].object;
    //         INTERSECTED.currentHex = INTERSECTED.material.emissive.getHex();
    //         INTERSECTED.material.emissive.setHex( 0x0000ff );
    //     }
    //     else {
    //         if ( INTERSECTED ) {
    //             INTERSECTED.material.emissive.setHex( INTERSECTED.currentHex );
    //             // 碰撞检测
    //             if(crashCheck(objects)){
    //                 alert('crash');
    //                 INTERSECTED.position.set(0,0,400);
    //             }
    //         }
    //         INTERSECTED = null;
    //
    //     }
    // }, false);

    // document.addEventListener("mousemove",(event) => {
    //     event.preventDefault();
    //     if(INTERSECTED){
    //
    //         var mouse = new THREE.Vector2();
    //         mouse.set( ( event.clientX / window.innerWidth ) * 2 - 1, - ( event.clientY / window.innerHeight ) * 2 + 1 );
    //         // console.log(mouse.x,mouse.y);
    //         var vector = new THREE.Vector3( mouse.x, mouse.y, 0.5 ).unproject( camera );
    //         var raycaster = new THREE.Raycaster(camera.position, vector.sub( camera.position ).normalize());
    //         var objects = [bus];
    //         // scene.children.forEach(child => {
    //         //     if (child instanceof THREE.GridHelper) {
    //         //         objects.push(child)
    //         //     }
    //         // });
    //
    //         var intersects = raycaster.intersectObjects( objects );
    //
    //
    //         if (intersects.length > 0) {
    //             var selected = intersects[ 0 ];
    //             console.log(selected.point.x,selected.point.y,selected.point.z,INTERSECTED.position.z);
    //             INTERSECTED.position.set(selected.point.x,selected.point.y,INTERSECTED.position.z);
    //             INTERSECTED.position.divideScalar( 50 ).floor().multiplyScalar( 50 ).addScalar( 25 );
    //
    //         }
    //     }
    // },false);

    var an = 1;
    document.getElementById('J_left').addEventListener('click',function(e){
        e.preventDefault();
        e.stopPropagation();
        var radius = 1000;
        an = an + 1;
        // console.log(an);
        camera.position.z = radius * Math.cos( (Math.PI / 180 ) * (an) );
        camera.position.x = radius * Math.sin( (Math.PI / 180 ) * (an) );
        camera.lookAt(new THREE.Vector3(0, 0, 0));
        // console.log('left,x='+camera.position.x+',z='+camera.position.z);
    });
    document.getElementById('J_right').addEventListener('click',function(e){
        e.preventDefault();
        e.stopPropagation();
        var radius = 1000;
        an = an - 1;
        // console.log(an);
        camera.position.z = radius * Math.cos( (Math.PI / 180 ) * (an) );
        camera.position.x = radius * Math.sin( (Math.PI / 180 ) * (an) );
        camera.lookAt(new THREE.Vector3(0, 0, 0));
        // console.log('left,x='+camera.position.x+',z='+camera.position.z);
    });
}

function crashCheck(objects){
    if(INTERSECTED){
        var originPoint = INTERSECTED.position.clone();
        var crash = false;
        for (var vertexIndex = 0; vertexIndex < INTERSECTED.geometry.vertices.length; vertexIndex++) {
            // 顶点原始坐标
            var localVertex = INTERSECTED.geometry.vertices[vertexIndex].clone();
            // 顶点经过变换后的坐标
            var globalVertex = localVertex.applyMatrix4(INTERSECTED.matrix);
            // 获得由中心指向顶点的向量
            var directionVector = globalVertex.sub(INTERSECTED.position);

            // 将方向向量初始化
            var ray = new THREE.Raycaster(originPoint, directionVector.clone().normalize());
            // 检测射线与多个物体的相交情况

            var collisionResults = ray.intersectObjects(objects);
            // 如果返回结果不为空，且交点与射线起点的距离小于物体中心至顶点的距离，则发生了碰撞
            if (collisionResults.length > 0 && collisionResults[0].distance < directionVector.length()) {
                crash = true;
            }
        }
        if(crash){
            return true;
        }
    }
    return false;
}

// 动画组建
function initTween(){
    new TWEEN.Tween( mesh.position)
        .to( { x: -400,z:100,y:100 }, 3000 ).repeat( Infinity ).start();
}

function initDragControls() {
    // 添加平移控件
    // var transformControls = new TransformControls(camera, renderer.domElement);
    // scene.add(transformControls);

    // 初始化拖拽控件
    var dragControls = new DragControls(meshList, camera, renderer.domElement);
    var controls = new OrbitControls(camera, renderer.domElement);
    
    // 鼠标略过事件
    dragControls.addEventListener('hoveron', function (event) {
        // 让变换控件对象和选中的对象绑定
        // transformControls.attach(event.object);
    });
    // 开始拖拽
    dragControls.addEventListener('dragstart', function (event) {
        controls.enabled = false;
    });
    // 拖拽结束
    dragControls.addEventListener('dragend', function (event) {
        controls.enabled = true;
        crashCheck();
    });
}


function threeStart() {
    initThree();
    initCamera();
    initScene();
    initLight();
    initObject();
    initGrid();
    initDragControls();
    // initStats();
    initEvent();
    // initTween();
    render();
}

threeStart();

后期打算添加物理引擎Physijs