Three.CurvePath和自定义标记
我正在使用Three.JS创建游戏，我已经建模并成功导入了在Sketchup中创建的城市。我现在需要动态添加一些“跟我来”箭头（根据下面样机中的黄色箭头）。我相信我可能需要使用Three.CurvePath来实现这一点，但我不确定这是否是最好的方法 - 我是否需要手动建模路径并计算每个箭头对象的切线，以便它们自然地指向角落（如每个左转在模型中？）
希望这是有道理的！
1 个答案:
答案 0 :(得分：8)
我可能有一个解决方案。 有一段时间没有使用过three.js所以不确定这是否是最优雅的解决方案。 我从Shapes Example开始，因为它显示：
- 如何在程序上构建路径（使用也处理曲线的命令）
- 如何从这样的路径中提取分数
- 生成路径
- 遍历路径和插值（位置和旋转）
所以我把问题分成了：
生成路径 我重复使用圆角矩形定义，它看起来类似于截图的一部分。
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, 200, 200, 20 );
您的路径可能不是圆角矩形，但可用的曲线函数类型（quadraticCurveTo，bezierCurveTo，splineThru）非常有用。
想到的另一个想法是使用Ruby脚本将Sketchup中的路径坐标导出到three.js。要么从头开始编写，要么使用现有脚本。这是one 很容易在谷歌上找到。
遍历路径
幸运的是，three.js已经通过Path的getPoint(t)实现了这一点，其中t是一个从0.0到1.0的数字，表示路径上的遍历。所以获得位置是微不足道的，因为在路径上获得下一个插值位置。然后，只需使用Math.atan2()来获得轮换：
t = (t + s)%1.0;//increment t while maintaining it between 0.0 and 1.0
var p = path.getPoint(t);//point at t
var pn = path.getPoint((t+s)%1.0);//point at next t iteration
if(p != null && pn != null){
//move to current position
arrow.position.x = p.x;
arrow.position.y = p.y;
//get orientation based on next position
arrow.rotation.z = Math.atan2(pn.y-p.y,pn.x-p.x);
}
总之，下面是一个基本的例子（使用立方体而不是箭头形状）来说明基于形状示例生成和遍历three.js中的路径：
<!DOCTYPE html>
<html lang="en">
<head>
<title>path interpolation</title>
<meta charset="utf-8">
<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;
}
</style>
</head>
<body>
<canvas id="debug" style="position:absolute; left:100px"></canvas>
<script src="../build/three.min.js"></script>
<script src="js/libs/stats.min.js"></script>
<script>
var container, stats;
var camera, scene, renderer;
var 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();
var t = 0.0;//traversal on path
var s = 0.001;//speed of traversal
var arrow;//mesh to move/rotate on path
var path;//Path object to traverse
function init() {
container = document.createElement( 'div' );
document.body.appendChild( container );
camera = new THREE.PerspectiveCamera( 50, window.innerWidth / window.innerHeight, 1, 1000 );
camera.position.set( 0, 150, 500 );
scene = new THREE.Scene();
parent = new THREE.Object3D();
parent.position.y = 50;
scene.add( parent );
arrow = new THREE.Mesh( new THREE.CubeGeometry(20,10,10),new THREE.MeshBasicMaterial({color: 0x009900}));
parent.add(arrow);
//this is helpful as a visual aid but not crucial
function addShape( shape, extrudeSettings, color, x, y, z, rx, ry, rz, s ) {
var points = shape.createPointsGeometry();
var spacedPoints = shape.createSpacedPointsGeometry( 50 );
// transparent line from equidistance sampled points
var line = new THREE.Line( spacedPoints, new THREE.LineBasicMaterial( { color: color, opacity: 0.2 } ) );
line.rotation.set( rx, ry, rz );
parent.add( line );
// equidistance sampled points
var pgeo = spacedPoints.clone();
var particles2 = new THREE.ParticleSystem( pgeo, new THREE.ParticleBasicMaterial( { color: color, size: 2, opacity: 0.5 } ) );
particles2.rotation.set( rx, ry, rz );
parent.add( particles2 );
}
// Rounded rectangle
//generating the path and populating it is crucial tough
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, 200, 200, 20 );
path = roundedRectShape;
var extrudeSettings = { amount: 20 }; // bevelSegments: 2, steps: 2 , bevelSegments: 5, bevelSize: 8, bevelThickness:5
extrudeSettings.bevelEnabled = true;
extrudeSettings.bevelSegments = 2;
extrudeSettings.steps = 2;
addShape( roundedRectShape, extrudeSettings, 0x000000, -150, 150, 0, 0, 0, 0, 1 );
renderer = new THREE.WebGLRenderer( { antialias: true } );
renderer.setSize( window.innerWidth, window.innerHeight );
container.appendChild( renderer.domElement );
stats = new Stats();
stats.domElement.style.position = 'absolute';
stats.domElement.style.top = '0px';
container.appendChild( stats.domElement );
document.addEventListener( 'mousedown', onDocumentMouseDown, false );
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;
camera.aspect = window.innerWidth / window.innerHeight;
camera.updateProjectionMatrix();
renderer.setSize( window.innerWidth, window.innerHeight );
}
//
function onDocumentMouseDown( event ) {
event.preventDefault();
document.addEventListener( 'mousemove', onDocumentMouseMove, false );
document.addEventListener( 'mouseup', onDocumentMouseUp, false );
document.addEventListener( 'mouseout', onDocumentMouseOut, false );
mouseXOnMouseDown = event.clientX - windowHalfX;
targetRotationOnMouseDown = targetRotation;
}
function onDocumentMouseMove( event ) {
mouseX = event.clientX - windowHalfX;
targetRotation = targetRotationOnMouseDown + ( mouseX - mouseXOnMouseDown ) * 0.02;
}
function onDocumentMouseUp( event ) {
document.removeEventListener( 'mousemove', onDocumentMouseMove, false );
document.removeEventListener( 'mouseup', onDocumentMouseUp, false );
document.removeEventListener( 'mouseout', onDocumentMouseOut, false );
}
function onDocumentMouseOut( event ) {
document.removeEventListener( 'mousemove', onDocumentMouseMove, false );
document.removeEventListener( 'mouseup', onDocumentMouseUp, false );
document.removeEventListener( 'mouseout', onDocumentMouseOut, false );
}
function onDocumentTouchStart( event ) {
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();
stats.update();
}
function render() {
t = (t + s)%1.0;//increment t while maintaining it between 0.0 and 1.0
var p = path.getPoint(t);//point at t
var pn = path.getPoint((t+s)%1.0);//point at next t iteration
if(p != null && pn != null){
//move to current position
arrow.position.x = p.x;
arrow.position.y = p.y;
//get orientation based on next position
arrow.rotation.z = Math.atan2(pn.y-p.y,pn.x-p.x);
}
parent.rotation.y += ( targetRotation - parent.rotation.y ) * 0.05;
renderer.render( scene, camera );
}
</script>
</body>
</html>
以为我会在此页面上直接添加一个可运行的代码段：
var container;
var camera, scene, renderer;
var 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();
var t = 0.0;//traversal on path
var s = 0.001;//speed of traversal
var arrows;//mesh to move/rotate on path
var path;//Path object to traverse
function init() {
container = document.createElement( 'div' );
document.body.appendChild( container );
camera = new THREE.PerspectiveCamera( 50, window.innerWidth / window.innerHeight, 1, 1000 );
camera.position.set( 0, 150, 500 );
scene = new THREE.Scene();
parent = new THREE.Object3D();
parent.position.y = 50;
scene.add( parent );
arrows = [];
for(var i = 0 ; i < 50; i++){
arrows[i] = new THREE.Mesh( new THREE.CubeGeometry(10,5,5),new THREE.MeshBasicMaterial({color: 0x009900}));
parent.add(arrows[i]);
}
//this is helpful as a visual aid but not crucial
function addShape( shape, extrudeSettings, color, x, y, z, rx, ry, rz, s ) {
var points = shape.createPointsGeometry();
var spacedPoints = shape.createSpacedPointsGeometry( 50 );
// transparent line from equidistance sampled points
var line = new THREE.Line( spacedPoints, new THREE.LineBasicMaterial( { color: color, opacity: 0.2 } ) );
line.rotation.set( rx, ry, rz );
parent.add( line );
// equidistance sampled points
var pgeo = spacedPoints.clone();
var particles2 = new THREE.ParticleSystem( pgeo, new THREE.ParticleBasicMaterial( { color: color, size: 2, opacity: 0.5 } ) );
particles2.rotation.set( rx, ry, rz );
parent.add( particles2 );
}
// Rounded rectangle
//generating the path and populating it is crucial tough
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, 200, 200, 20 );
path = roundedRectShape;
var extrudeSettings = { amount: 20 }; // bevelSegments: 2, steps: 2 , bevelSegments: 5, bevelSize: 8, bevelThickness:5
extrudeSettings.bevelEnabled = true;
extrudeSettings.bevelSegments = 2;
extrudeSettings.steps = 2;
addShape( roundedRectShape, extrudeSettings, 0x000000, -150, 150, 0, 0, 0, 0, 1 );
renderer = new THREE.WebGLRenderer( { antialias: true } );
renderer.setSize( window.innerWidth, window.innerHeight );
container.appendChild( renderer.domElement );
document.addEventListener( 'mousedown', onDocumentMouseDown, false );
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;
camera.aspect = window.innerWidth / window.innerHeight;
camera.updateProjectionMatrix();
renderer.setSize( window.innerWidth, window.innerHeight );
}
//
function onDocumentMouseDown( event ) {
event.preventDefault();
document.addEventListener( 'mousemove', onDocumentMouseMove, false );
document.addEventListener( 'mouseup', onDocumentMouseUp, false );
document.addEventListener( 'mouseout', onDocumentMouseOut, false );
mouseXOnMouseDown = event.clientX - windowHalfX;
targetRotationOnMouseDown = targetRotation;
}
function onDocumentMouseMove( event ) {
mouseX = event.clientX - windowHalfX;
targetRotation = targetRotationOnMouseDown + ( mouseX - mouseXOnMouseDown ) * 0.02;
}
function onDocumentMouseUp( event ) {
document.removeEventListener( 'mousemove', onDocumentMouseMove, false );
document.removeEventListener( 'mouseup', onDocumentMouseUp, false );
document.removeEventListener( 'mouseout', onDocumentMouseOut, false );
}
function onDocumentMouseOut( event ) {
document.removeEventListener( 'mousemove', onDocumentMouseMove, false );
document.removeEventListener( 'mouseup', onDocumentMouseUp, false );
document.removeEventListener( 'mouseout', onDocumentMouseOut, false );
}
function onDocumentTouchStart( event ) {
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();
}
function render() {
t = (t + s)%1.0;//increment t while maintaining it between 0.0 and 1.0 - could map mouse x position/window width for fun :)
for(var i = 0 ; i < 50; i++){//for each box
var ti = ((i/50.0)+t)%1.0;//compute the traversval including each box's own offset on the path
var p = path.getPoint(ti);//point at t
var pn = path.getPoint((ti+s)%1.0);//point at next t iteration
if(p != null && pn != null){
//move to current position
arrows[i].position.x = p.x;
arrows[i].position.y = p.y;
//get orientation based on next position
arrows[i].rotation.z = Math.atan2(pn.y-p.y,pn.x-p.x);
}
}
parent.rotation.y += ( targetRotation - parent.rotation.y ) * 0.05;
renderer.render( scene, camera );
} body {
font-family: Monospace;
background-color: #f0f0f0;
margin: 0px;
overflow: hidden;
}<script src="https://cdnjs.cloudflare.com/ajax/libs/three.js/r71/three.min.js"></script>
相关问题
最新问题
- 我写了这段代码，但我无法理解我的错误
- 我无法从一个代码实例的列表中删除 None 值，但我可以在另一个实例中。为什么它适用于一个细分市场而不适用于另一个细分市场？
- 是否有可能使 loadstring 不可能等于打印？卢阿
- java中的random.expovariate()
- Appscript 通过会议在 Google 日历中发送电子邮件和创建活动
- 为什么我的 Onclick 箭头功能在 React 中不起作用？
- 在此代码中是否有使用“this”的替代方法？
- 在 SQL Server 和 PostgreSQL 上查询，我如何从第一个表获得第二个表的可视化
- 每千个数字得到
- 更新了城市边界 KML 文件的来源？