53 Three.js using the.pointcloud to bulk manage particles

Keywords: github Attribute

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brief introduction

When we use a large number of particles, we will soon encounter performance problems, because each particle added is a model, because each particle object is managed by three.js, so three.js provides another way to deal with a large number of particles, that is to use the THREE.PointCloud. Through theree.pointcloud, three.js no longer needs to manage a large number of single theree.sprite objects, but only needs to manage the instance of theree.pointcloud.

Implementation case

        //Create a container for the THREE.PointCloud particles
        var geometry = new THREE.Geometry();
        //Create the THREE.PointCloud texture
        var material = new THREE.PointCloudMaterial({size:4, vertexColors:true, color:0xffffff});

        //Loop adds the color and position of particles to the mesh
        for (var x = -5; x <= 5; x++) {
            for (var y = -5; y <= 5; y++) {
                var particle = new THREE.Vector3(x * 10, y * 10, 0);
                geometry.vertices.push(particle);
                geometry.colors.push(new THREE.Color(+randomColor()));
            }
        }

        //Instantiate the.pointcloud
        var cloud = new THREE.PointCloud(geometry, material);
        scene.add(cloud);

In the above code, we specify a location and color for each particle added to the THREE.PointCloud, and finally generate colorful particles.

Case code

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <style type="text/css">
        html, body {
            margin: 0;
            height: 100%;
        }

        canvas {
            display: block;
        }

    </style>
</head>
<body onload="draw();">
</body>
<script src="https://johnson2heng.github.io/three.js-demo/lib/three.js"></script>
<script src="https://johnson2heng.github.io/three.js-demo/lib/js/controls/OrbitControls.js"></script>
<script src="https://johnson2heng.github.io/three.js-demo/lib/js/libs/stats.min.js"></script>
<script src="https://johnson2heng.github.io/three.js-demo/lib/js/libs/dat.gui.min.js"></script>
<script>
    var renderer;

    function initRender() {
        renderer = new THREE.WebGLRenderer({antialias: true});
        //Render. Setclearcolor (new three. Color (0xeeeeee, 1.0)); / / set the background color
        renderer.setSize(window.innerWidth, window.innerHeight);
        document.body.appendChild(renderer.domElement);
    }

    var camera;

    function initCamera() {
        camera = new THREE.PerspectiveCamera(45, window.innerWidth / window.innerHeight, 1, 10000);
        camera.position.set(0, 0, 200);
    }

    var scene;

    function initScene() {
        scene = new THREE.Scene();
    }

    var light;

    function initLight() {
        scene.add(new THREE.AmbientLight(0x404040));

        light = new THREE.DirectionalLight(0xffffff);
        light.position.set(1, 1, 1);
        scene.add(light);
    }

    function initModel() {

        //Shaft assist (length of each shaft)
        var object = new THREE.AxesHelper(500);
        scene.add(object);

        //Create a container for the THREE.PointCloud particles
        var geometry = new THREE.Geometry();
        //Create the THREE.PointCloud texture
        var material = new THREE.PointCloudMaterial({size:4, vertexColors:true, color:0xffffff});

        //Loop adds the color and position of particles to the mesh
        for (var x = -5; x <= 5; x++) {
            for (var y = -5; y <= 5; y++) {
                var particle = new THREE.Vector3(x * 10, y * 10, 0);
                geometry.vertices.push(particle);
                geometry.colors.push(new THREE.Color(+randomColor()));
            }
        }

        //Instantiate the.pointcloud
        var cloud = new THREE.PointCloud(geometry, material);
        scene.add(cloud);

    }

    //Randomly generate color
    function randomColor() {
        var arrHex = ["0","1", "2", "3", "4", "5", "6", "7", "8", "9", "a", "b", "c", "d","e","f"],
            strHex = "0x",
            index;
        for(var i = 0; i < 6; i++) {
            index = Math.round(Math.random() * 15);
            strHex += arrHex[index];
        }
        return strHex;
    }

    //Initialize performance plug-ins
    var stats;

    function initStats() {
        stats = new Stats();
        document.body.appendChild(stats.dom);
    }

    //User interaction plug in left mouse button press and hold rotation, right mouse button press and hold translation, scroll wheel zoom
    var controls;

    function initControls() {

        controls = new THREE.OrbitControls(camera, renderer.domElement);

        // If you use the animate method, delete this function
        //controls.addEventListener( 'change', render );
        // Whether there is inertia in the meaning of damping or rotation when the animation is recycled
        controls.enableDamping = true;
        //Dynamic damping coefficient is the mouse drag rotation sensitivity
        //controls.dampingFactor = 0.25;
        //Can I zoom
        controls.enableZoom = true;
        //Auto rotate or not
        controls.autoRotate = false;
        //Set the maximum distance between the camera and the origin
        controls.minDistance = 20;
        //Set the maximum distance between the camera and the origin
        controls.maxDistance = 10000;
        //Enable right drag
        controls.enablePan = true;
    }

    //Generate gui settings configuration item
    var gui;
    function initGui() {
        //Declare an object to save the relevant data of the requirement modification
        gui = {

        };
        var datGui = new dat.GUI();
        //Add the setting attribute to the GUI, gui.add (object, attribute, min, max)
    }

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

    //Function triggered by window change
    function onWindowResize() {
        camera.aspect = window.innerWidth / window.innerHeight;
        camera.updateProjectionMatrix();
        render();
        renderer.setSize(window.innerWidth, window.innerHeight);

    }

    function animate() {
        //Update controller
        controls.update();
        render();

        //Update performance plug-ins
        stats.update();
        requestAnimationFrame(animate);
    }

    function draw() {
        initRender();
        initScene();
        initCamera();
        initLight();
        initModel();
        initControls();
        initStats();
        initGui();

        animate();
        window.onresize = onWindowResize;
    }
</script>
</html>

Posted by JeditL on Sun, 03 May 2020 02:44:19 -0700