Three.js Example 注解 —— canvas_geometry_shapes.html
2023-09-11 14:22:55 时间
本文搬自我的Github，https://github.com/555chy/three.js-example-comment，有兴趣的可以一起来完善，这个为Three.js的Example进行注解，方便初学者阅读
three.js 官网 Example 地址：https://threejs.org/examples/
<!DOCTYPE html>
<html lang="en">
<head>
<title>three.js canvas - geometry - shapes</title>
<meta charset="utf-8">
<!--
如果没有设置viewport的width的话，网页很可能会超出手机屏幕宽度，具体多宽，要看浏览器定义的默认宽度是多少
user-scalable=no，规定了用户不能缩放网页，但有些浏览器对该项支持不是很好，故需要设置minimum-scale和maximum-scale相同来限制用户缩放
-->
<meta name="viewport" content="width=device-width, user-scalable=no, minimum-scale=1.0, maximum-scale=1.0">
<style>
body {
font-family: Monospace;
background-color: #f0f0f0;
margin: 0px;
overflow: hidden;
}
#info {
position: absolute;
top: 0px;
width: 100%;
padding: 5px;
text-align:center;
}
</style>
</head>
<body>
<canvas id="debug" style="position:absolute; left:100px"></canvas>
<div id="info"><a href="http://threejs.org" target="_blank">three.js</a> - shape geometry</div>
<script src="../build/three.js"></script>
<!--
想要使用CanvasRenderer，必须添加如下两个js文件
Projector.js顾名思义上将3d图像投影到Canvas("2d")上，如果没有该文件会报如下错误
THREE.Projector has been moved to /examples/js/renderers/Projector.js. three.js:42883:3
TypeError: THREE.RenderableVertex is not a constructor
-->
<script src="js/renderers/Projector.js"></script>
<script src="js/renderers/CanvasRenderer.js"></script>
<!--
统计插件(FPS，渲染时间，chrome内存使用率)，min表示js代码经过压缩
-->
<script src="js/libs/stats.min.js"></script>
<script>
var container, stats;
var camera, scene, renderer;
var group, text, plane;
var targetRotation = 0;
var targetRotationOnMouseDown = 0;
var mouseX = 0;
var mouseXOnMouseDown = 0;
var windowHalfX = window.innerWidth / 2;
var windowHalfY = window.innerHeight / 2;
init();
animate();
function init() {
container = document.createElement( 'div' );
document.body.appendChild( container );
/*
透视相机
PerspectiveCamera(fov, aspect, near, far)
fov(视场)：从相机位置能够看到的部分场景。推荐默认值45
aspect(长宽比)：渲染结果输出区域的横向长度和纵向长度的比值。推荐默认值window.innerWidth/window.innerHeight
near(近面)：定义从距离相机多近的地方开始渲染场景。推荐默认值0.1
far(远面)：定义相机可以从它所处的位置看多远。默认值1000
*/
camera = new THREE.PerspectiveCamera( 50, window.innerWidth / window.innerHeight, 1, 1000 );
//定义相机的位置，有如下两种方式。如果不设置的话，相机位置为默认的Vector3{x:0,y:0,z:0}
camera.position.set( 0, 150, 500 );
camera.position.y = 150;
camera.position.z = 500;
scene = new THREE.Scene();
/*
Group对象，实质就是一个Object3D对象，打包后对象可以一起操作。
打包过后，对象就有里层对象和外层对象，如上面例子中group是里层对象，line1和line2是外层对象。
里层对象相对外层对象作相对运动，即里层对象所有运动都是相对于外层对象而言的。
*/
group = new THREE.Group();
group.position.y = 50;
scene.add( group );
function addShape( shape, color, x, y, z, rx, ry, rz, s ) {
// flat shape
var geometry = new THREE.ShapeGeometry( shape );
/*
MeshBasicMaterial：与光照无关，仅根据材质的颜色或贴图来渲染物体
color：材质的颜色
map：材质的贴图
wireframe: 显示三角形线框还是显示面
side：可选的值有THREE.FrontSide(仅渲染正面)、THREE.BackSide(仅渲染背面)、THREE.DoubleSide(双面渲染)
overdraw:过渡描绘。如果用THREE.CanvasRenderer对象，有缝隙时需设置该值。例如当前如果使用0.5以下的值，三角形的分界线就很明显。但是使用WebGLRenderer则不会有分割线
*/
var material = new THREE.MeshBasicMaterial( { color: color, overdraw: 0.5 } );
//双面渲染，否则只会渲染单面
//material.side = THREE.doubleSide;
var mesh = new THREE.Mesh( geometry, material );
mesh.position.set( x, y, z );
//这里的旋转是绕着原点旋转
mesh.rotation.set( rx, ry, rz );
//这里的放大是将原坐标乘以一定的比例
mesh.scale.set( s, s, s );
group.add( mesh );
// line
var geometry = shape.createPointsGeometry();
//封口
geometry.vertices.push( geometry.vertices[ 0 ].clone() );
geometry.colors = [];
//var base = 0xff0000 / geometry.vertices.length;
for(var i=0; i<geometry.vertices.length; i++) {
//geometry.colors[i] = new THREE.Color(parseInt(base * i));
geometry.colors[i] = new THREE.Color(0xffffff);
geometry.colors[i].setHSL(i / geometry.vertices.length, 0.5, 0.5);
}
//WebGLRenderer不支持linewidth，只有CanvasRenderer才支持该属性
var material = new THREE.LineBasicMaterial( { linewidth: 10, color: 0x333333, transparent: true, vertexColors: THREE.VertexColors } );
var line = new THREE.Line( geometry, material );
line.position.set( x, y, z );
line.rotation.set( rx, ry, rz );
line.scale.set( s, s, s );
group.add( line );
//three.js:41585 THREE.ParticleBasicMaterial has been renamed to THREE.PointsMaterial.
//var material = new THREE.PointsMaterial( { size: 10, color: 0xff0000, program: programFill } );
/*
THREE.ParticleSystem has been renamed to THREE.Points.
此外，该对象只能在WebGLRenderer中显示
*/
//var points = new THREE.Points(pointsGeometry, material);
var doublePI = Math.PI * 2;
var programFill = function ( context ) {
context.beginPath();
context.arc( 0, 0, 5, 0, doublePI, true );
context.fill();
};
//WebGLRenderer不支持Sprite，只有CanvasRenderer才支持
//添加辅助点
function addAuxiliarySprite(vector, x, y, z, rz, s) {
//three.js:41564 THREE.Particle has been renamed to THREE.Sprite.
var sprite = new THREE.Sprite(new THREE.SpriteCanvasMaterial( { color: 0xff0000, program: programFill }));
var pos = vector.clone().rotateAround(new THREE.Vector2(0, 0), rz);
sprite.position.set(pos.x, pos.y, 0);
sprite.position.multiplyScalar(s);
sprite.position.add(new THREE.Vector3(x, y, z));
group.add(sprite);
}
for(var i=0; i<shape.curves.length; i++) {
var curve = shape.curves[i];
if(curve instanceof THREE.LineCurve) {
//2, function LineCurve( v1, v2 )
addAuxiliarySprite(curve.v1, x, y, z, rz, s);
addAuxiliarySprite(curve.v2, x, y, z, rz, s);
} else if(curve instanceof THREE.QuadraticBezierCurve) {
//3, function QuadraticBezierCurve( v0, v1, v2 )
addAuxiliarySprite(curve.v0, x, y, z, rz, s);
addAuxiliarySprite(curve.v1, x, y, z, rz, s);
addAuxiliarySprite(curve.v2, x, y, z, rz, s);
} else if(curve instanceof THREE.CubicBezierCurve) {
//4, function CubicBezierCurve( v0, v1, v2, v3 )
addAuxiliarySprite(curve.v0, x, y, z, rz, s);
addAuxiliarySprite(curve.v1, x, y, z, rz, s);
addAuxiliarySprite(curve.v2, x, y, z, rz, s);
addAuxiliarySprite(curve.v3, x, y, z, rz, s);
} else if(curve instanceof THREE.SplineCurve) {
//1, function SplineCurve( points /* array of Vector2 */ )
for(var j=0;j<curve.points.length;j++) {
addAuxiliarySprite(curve.points[j], x, y, z, rz, s);
}
} else if(curve instanceof THREE.ArcCurve) {
//6, function ArcCurve( aX, aY, aRadius, aStartAngle, aEndAngle, aClockwise )
addAuxiliarySprite(new THREE.Vector2(curve.aX, curve.aY), x, y, z, rz, s);
} else if(curve instanceof THREE.EllipseCurve) {
//8, function EllipseCurve( aX, aY, xRadius, yRadius, aStartAngle, aEndAngle, aClockwise, aRotation )
addAuxiliarySprite(new THREE.Vector2(curve.aX, curve.aY), x, y, z, rz, s);
} else {
//输出"函数名"和"参数个数"
console.log(curve.constructor.name + "(" + curve.constructor.length + ")");
}
}
}
// California
var californiaPts = [];
californiaPts.push( new THREE.Vector2 ( 610, 320 ) );
californiaPts.push( new THREE.Vector2 ( 450, 300 ) );
californiaPts.push( new THREE.Vector2 ( 392, 392 ) );
californiaPts.push( new THREE.Vector2 ( 266, 438 ) );
californiaPts.push( new THREE.Vector2 ( 190, 570 ) );
californiaPts.push( new THREE.Vector2 ( 190, 600 ) );
californiaPts.push( new THREE.Vector2 ( 160, 620 ) );
californiaPts.push( new THREE.Vector2 ( 160, 650 ) );
californiaPts.push( new THREE.Vector2 ( 180, 640 ) );
californiaPts.push( new THREE.Vector2 ( 165, 680 ) );
californiaPts.push( new THREE.Vector2 ( 150, 670 ) );
californiaPts.push( new THREE.Vector2 ( 90, 737 ) );
californiaPts.push( new THREE.Vector2 ( 80, 795 ) );
californiaPts.push( new THREE.Vector2 ( 50, 835 ) );
californiaPts.push( new THREE.Vector2 ( 64, 870 ) );
californiaPts.push( new THREE.Vector2 ( 60, 945 ) );
californiaPts.push( new THREE.Vector2 ( 300, 945 ) );
californiaPts.push( new THREE.Vector2 ( 300, 743 ) );
californiaPts.push( new THREE.Vector2 ( 600, 473 ) );
californiaPts.push( new THREE.Vector2 ( 626, 425 ) );
californiaPts.push( new THREE.Vector2 ( 600, 370 ) );
californiaPts.push( new THREE.Vector2 ( 610, 320 ) );
//shape是二维几何体，和SVG中的path功能类似。数组参数相当于逐个lineTo
var californiaShape = new THREE.Shape( californiaPts );
// Triangle
var triangleShape = new THREE.Shape();
triangleShape.moveTo( 80, 20 );
triangleShape.lineTo( 40, 80 );
triangleShape.lineTo( 120, 80 );
triangleShape.lineTo( 80, 20 ); // close path
// Heart
var x = 0, y = 0;
var heartShape = new THREE.Shape(); // From http://blog.burlock.org/html5/130-paths
heartShape.moveTo( x + 25, y + 25 );
heartShape.bezierCurveTo( x + 25, y + 25, x + 20, y, x, y );
heartShape.bezierCurveTo( x - 30, y, x - 30, y + 35,x - 30,y + 35 );
heartShape.bezierCurveTo( x - 30, y + 55, x - 10, y + 77, x + 25, y + 95 );
heartShape.bezierCurveTo( x + 60, y + 77, x + 80, y + 55, x + 80, y + 35 );
heartShape.bezierCurveTo( x + 80, y + 35, x + 80, y, x + 50, y );
heartShape.bezierCurveTo( x + 35, y, x + 25, y + 25, x + 25, y + 25 );
// Square
var sqLength = 80;
var squareShape = new THREE.Shape();
squareShape.moveTo( 0,0 );
squareShape.lineTo( 0, sqLength );
squareShape.lineTo( sqLength, sqLength );
squareShape.lineTo( sqLength, 0 );
squareShape.lineTo( 0, 0 );
// Rectangle
var rectLength = 120, rectWidth = 40;
var rectShape = new THREE.Shape();
rectShape.moveTo( 0,0 );
rectShape.lineTo( 0, rectWidth );
rectShape.lineTo( rectLength, rectWidth );
rectShape.lineTo( rectLength, 0 );
rectShape.lineTo( 0, 0 );
// Rounded rectangle，lineTo负责直线部分，quadraticCurveTo负责圆角部分
var roundedRectShape = new THREE.Shape();
( function roundedRect( ctx, x, y, width, height, radius ){
ctx.moveTo( x, y + radius );
ctx.lineTo( x, y + height - radius );
ctx.quadraticCurveTo( x, y + height, x + radius, y + height );
ctx.lineTo( x + width - radius, y + height) ;
ctx.quadraticCurveTo( x + width, y + height, x + width, y + height - radius );
ctx.lineTo( x + width, y + radius );
ctx.quadraticCurveTo( x + width, y, x + width - radius, y );
ctx.lineTo( x + radius, y );
ctx.quadraticCurveTo( x, y, x, y + radius );
} )( roundedRectShape, 0, 0, 50, 50, 20 );
// Circle，需要的点是该圆的外切正方形
var circleRadius = 40;
var circleShape = new THREE.Shape();
circleShape.moveTo( 0, circleRadius );
circleShape.quadraticCurveTo( circleRadius, circleRadius, circleRadius, 0 );
circleShape.quadraticCurveTo( circleRadius, -circleRadius, 0, -circleRadius );
circleShape.quadraticCurveTo( -circleRadius, -circleRadius, -circleRadius, 0 );
circleShape.quadraticCurveTo( -circleRadius, circleRadius, 0, circleRadius );
// Fish
x = y = 0;
var fishShape = new THREE.Shape();
fishShape.moveTo(x,y);
fishShape.quadraticCurveTo(x + 50, y - 80, x + 90, y - 10);
fishShape.quadraticCurveTo(x + 100, y - 10, x + 115, y - 40);
fishShape.quadraticCurveTo(x + 115, y, x + 115, y + 40);
fishShape.quadraticCurveTo(x + 100, y + 10, x + 90, y + 10);
fishShape.quadraticCurveTo(x + 50, y + 80, x, y);
// Arc circle
var arcShape = new THREE.Shape();
arcShape.moveTo( 50, 10 );
//arc是相对当前位置，而absarc是绝对位置
arcShape.absarc( 10, 10, 40, 0, Math.PI*2, false );
//shape.holes，定义了一个路径数组，指在原来的形状上挖洞
var holePath = new THREE.Path();
holePath.moveTo( 20, 10 );
holePath.absarc( 10, 10, 10, 0, Math.PI*2, true );
//shape.curves和shape.holes都是array。curves存放的是Curve的子类，holes存放的是Path。
arcShape.holes.push( holePath );
// Smiley
var smileyShape = new THREE.Shape();
smileyShape.moveTo( 80, 40 );
smileyShape.absarc( 40, 40, 40, 0, Math.PI*2, false );
var smileyEye1Path = new THREE.Path();
smileyEye1Path.moveTo( 35, 20 );
// smileyEye1Path.absarc( 25, 20, 10, 0, Math.PI*2, true );
smileyEye1Path.absellipse( 25, 20, 10, 10, 0, Math.PI*2, true );
smileyShape.holes.push( smileyEye1Path );
var smileyEye2Path = new THREE.Path();
smileyEye2Path.moveTo( 65, 20 );
smileyEye2Path.absarc( 55, 20, 10, 0, Math.PI*2, true );
smileyShape.holes.push( smileyEye2Path );
var smileyMouthPath = new THREE.Path();
// ugly box mouth
/*
smileyMouthPath.moveTo( 20, 40 );
smileyMouthPath.lineTo( 60, 40 );
smileyMouthPath.lineTo( 60, 60 );
smileyMouthPath.lineTo( 20, 60 );
smileyMouthPath.lineTo( 20, 40 );
*/
smileyMouthPath.moveTo( 20, 40 );
smileyMouthPath.quadraticCurveTo( 40, 60, 60, 40 );
smileyMouthPath.bezierCurveTo( 70, 45, 70, 50, 60, 60 );
smileyMouthPath.quadraticCurveTo( 40, 80, 20, 60 );
smileyMouthPath.quadraticCurveTo( 5, 50, 20, 40 );
smileyShape.holes.push( smileyMouthPath );
// Spline shape + path extrusion
var splinepts = [];
splinepts.push( new THREE.Vector2 ( 350, 100 ) );
splinepts.push( new THREE.Vector2 ( 400, 450 ) );
splinepts.push( new THREE.Vector2 ( -140, 350 ) );
splinepts.push( new THREE.Vector2 ( 0, 0 ) );
var splineShape = new THREE.Shape( );
splineShape.moveTo( 0, 0 );
//沿着提供的点集绘制一条光滑的曲线。
splineShape.splineThru( splinepts );
// addShape( shape, color, x, y, z, rx, ry, rz, s );
addShape( californiaShape, 0xffaa00, -300, -100, 0, 0, 0, 0, 0.25 );
addShape( triangleShape, 0xffee00, -180, 0, 0, 0, 0, 0, 1 );
addShape( roundedRectShape, 0x005500, -150, 150, 0, 0, 0, 0, 1 );
addShape( squareShape, 0x0055ff, 150, 100, 0, 0, 0, 0, 1 );
addShape( heartShape, 0xff1100, 60, 100, 0, 0, 0, Math.PI, 1 );
addShape( circleShape, 0x00ff11, 120, 250, 0, 0, 0, 0, 1 );
addShape( fishShape, 0x222222, -60, 200, 0, 0, 0, 0, 1 );
addShape( smileyShape, 0xee00ff, -200, 250, 0, 0, 0, Math.PI, 1 );
addShape( arcShape, 0xbb4422, 150, 0, 0, 0, 0, 0, 1 );
addShape( splineShape, 0x888888, -50, -100, 0, 0, 0, 0, 0.2 );
renderer = new THREE.CanvasRenderer();
//设置渲染器的"清除色"和"透明度"
renderer.setClearColor( 0xf0f0f0 );
//设置屏幕像素比，与Android上的DIP相仿，作用是在所有设备上的显示效果都相近
renderer.setPixelRatio( window.devicePixelRatio );
//设置待渲染场景的大小
renderer.setSize( window.innerWidth, window.innerHeight );
renderer.sortElements = false;
//将渲染器的DOM元素(即Canvas)添加到HTML中
container.appendChild( renderer.domElement );
//左上角的统计信息(FPS，渲染时间，chrome内存使用率)
stats = new Stats();
//这里注意，统计插件的dom元素是"dom"，而不是domElement
container.appendChild( stats.dom );
/*
element.addEventListener(event, function, useCapture)
useCapture，可选。true：事件句柄在捕获阶段执行；false：默认，事件句柄在冒泡阶段执行
*/
//mouse事件是针对PC浏览器的
document.addEventListener( 'mousedown', onDocumentMouseDown, false );
//touch事件是针对手持设备的
document.addEventListener( 'touchstart', onDocumentTouchStart, false );
document.addEventListener( 'touchmove', onDocumentTouchMove, false );
window.addEventListener( 'resize', onWindowResize, false );
}
function onWindowResize() {
windowHalfX = window.innerWidth / 2;
windowHalfY = window.innerHeight / 2;
//重新设置相机的宽高比。如果宽高比不对，那么正方形可能就不是正方形了
camera.aspect = window.innerWidth / window.innerHeight;
//更新透视相机的投影矩阵
camera.updateProjectionMatrix();
//更新待渲染场景的大小
renderer.setSize( window.innerWidth, window.innerHeight );
}
function onDocumentMouseDown( event ) {
//通知 Web 浏览器不要执行与事件关联的默认动作(如果存在这样的动作)
event.preventDefault();
//在mousedown的时候动态绑定事件
document.addEventListener( 'mousemove', onDocumentMouseMove, false );
document.addEventListener( 'mouseup', onDocumentMouseUp, false );
document.addEventListener( 'mouseout', onDocumentMouseOut, false );
mouseXOnMouseDown = event.clientX - windowHalfX;
targetRotationOnMouseDown = targetRotation;
}
function onDocumentMouseMove( event ) {
/*
html的坐标轴是以左上角为(0,0)，右下方向为正方向
event.clientX=event.pageX返回当事件被触发时鼠标指针向对于浏览器可见区域的X坐标
event.offsetX返回当前事件相对于事件源元素（srcElement）的X坐标
event.screenX鼠标相对于用户显示器屏幕左上角的X坐标
*/
mouseX = event.clientX - windowHalfX;
//每一次旋转都从mousedown的角度开始计算
targetRotation = targetRotationOnMouseDown + ( mouseX - mouseXOnMouseDown ) * 0.02;
}
function onDocumentMouseUp( event ) {
//在mouseUp的时候解绑定相应事件
document.removeEventListener( 'mousemove', onDocumentMouseMove, false );
document.removeEventListener( 'mouseup', onDocumentMouseUp, false );
document.removeEventListener( 'mouseout', onDocumentMouseOut, false );
}
function onDocumentMouseOut( event ) {
//鼠标移出该区域的时候解除相应的事件绑定
document.removeEventListener( 'mousemove', onDocumentMouseMove, false );
document.removeEventListener( 'mouseup', onDocumentMouseUp, false );
document.removeEventListener( 'mouseout', onDocumentMouseOut, false );
}
function onDocumentTouchStart( event ) {
/*
event.touches存放的是多指触碰时的位置数组
三个等号是恒等，比较数值的同时也比较类型。
这里限制只有单指触摸的时候才执行相应的方法
*/
if ( event.touches.length == 1 ) {
event.preventDefault();
mouseXOnMouseDown = event.touches[ 0 ].pageX - windowHalfX;
targetRotationOnMouseDown = targetRotation;
}
}
function onDocumentTouchMove( event ) {
if ( event.touches.length == 1 ) {
event.preventDefault();
mouseX = event.touches[ 0 ].pageX - windowHalfX;
targetRotation = targetRotationOnMouseDown + ( mouseX - mouseXOnMouseDown ) * 0.05;
}
}
function animate() {
requestAnimationFrame( animate );
render();
//这里可以在render前后使用stats.begin和stats.end，也可以在每次渲染的时候调用一次stats.update
stats.update();
}
function render() {
/*
将旋转的角度按右手螺旋定则更新到原旋转角上
rotation.y是绕Y轴旋转
rotation.y其实是关于mouseX一元一次线性函数
*/
group.rotation.y += ( targetRotation - group.rotation.y ) * 0.05;
renderer.render( scene, camera );
}
</script>
</body>
</html>
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- Three.js Example 注解 —— canvas_particles_random.html
- Three.js Example 注解 —— canvas_particles_floor.html
- Three.js Example 注解 —— canvas_lines_colors_2d.html
- Three.js Example 注解 —— canvas_lines.html
- Three.js Example 注解 —— canvas_interactive_particles.html
- Three.js Example 注解 —— canvas_interactive_cubes_tween.html
- Three.js Example 注解 —— canvas_geometry_panorama_fisheye.html
- Three.js Example 注解 —— canvas_geometry_panorama.html
- Three.js Example 注解 —— canvas_geometry_hierarchy.html