实现原理是使用TWEEN.Tween实现动画效果
实现
汽车模型加载
使用Promise编写模型的异步加载方法
参数position是汽车初始位置，参数rotation是汽车初始朝向
Car.prototype.loadCar = function (position, rotation) {
let onProgress = function (xhr) {
};
return new Promise((resolve, reject) => {
if (!this.model) {
let loader = new THREE.GLTFLoader();
loader.load(this.url, gltf => {
const model = gltf.scene || gltf.scenes[0];
model.position.x = position.x;
model.position.y = position.y;
model.position.z = position.z;
model.scale.set(0.25, 0.25, 0.25);
model.rotation.set(rotation.x, rotation.y, rotation.z);
this.model = model;
this.scene.add(model);
resolve(model);
}, onProgress, xhr => {
console.error(xhr);
console.info('模型 ' + url + ' 加载失败');
reject(xhr);
});
} else {
resolve(this.model);
}
});
}
调用：
第1个参数是汽车初始位置，第2个参数表示汽车初始朝向：西
await car.loadCar(positions[0], car.WEST);
汽车行驶
参数start是行驶起点位置，参数end是行驶终点位置，参数speed是速度
this.model是汽车模型，onUpdate事件中，不断更新它的position
this.label是汽车车牌号标签，onUpdate事件中，不断更新它的position
Car.prototype.moveCar = function (start, end, speed) {
let distance = this.distance(start, end);
let time = distance / speed * 1000;
return new Promise((resolve, reject) => {
this.tween = new TWEEN.Tween({
x: start.x,
y: start.y,
z: start.z
}).to({
x: end.x,
y: end.y,
z: end.z
}, time).start().onUpdate(e => {
if (this.model) {
this.model.position.x = e.x;
this.model.position.y = e.y;
this.model.position.z = e.z;
}
if (this.label) {
this.label.position.x = e.x;
this.label.position.y = e.y + 1.2;
this.label.position.z = e.z;
}
}).onComplete(() => {
TWEEN.remove(this.tween);
resolve();
});
});
}
汽车转弯
参数start是动画开始时的汽车朝向，end是动画结束时的汽车朝向
Car.prototype.rotateCar = function (start, end) {
return new Promise((resolve, reject) => {
this.tween = new TWEEN.Tween({
x: start.x,
y: start.y,
z: start.z
}).to({
x: end.x,
y: end.y,
z: end.z
}, 300).start().onUpdate(e => {
if (this.model) {
this.model.rotation.set(e.x, e.y, e.z);
}
}).onComplete(() => {
TWEEN.remove(this.tween);
resolve();
});
});
}
汽车行驶多段路线
上述汽车行驶和汽车转弯方法都是异步方法，所以避免了回调地狱，不然下面的多段行驶及转弯就不好写了
Cars.prototype.carLine1 = function () {
if (!this.run) return;
let car = new Car(this.scene, this.renderer, './models/车红.glb');
this.cars.push(car);
let positions = [
{ x: -121, y: 1.5, z: -16 },
{ x: -130.5, y: 1.5, z: -16 },
{ x: -130.5, y: 1.5, z: 4 },
{ x: -82, y: 1.5, z: 4 },
{ x: -82, y: 1.5, z: 14.7 },
{ x: -18.8, y: 1.5, z: 14.7 },
{ x: -18.8, y: 1.5, z: 70 },
];
let speed = 5;
setTimeout(async () => {
await car.loadCar(
positions[0],
car.WEST);
car.showLabel(positions[0], "皖A67893");
await car.moveCar(
positions[0],
positions[1],
speed);
await car.rotateCar(
car.WEST,
car.SOUTH);
await car.moveCar(
positions[1],
positions[2],
speed);
await car.rotateCar(
car.SOUTH,
car.EAST);
await car.moveCar(
positions[2],
positions[3],
speed);
await car.rotateCar(
car.EAST,
car.SOUTH);
await car.moveCar(
positions[3],
positions[4],
speed);
await car.rotateCar(
car.SOUTH,
car.EAST);
await car.moveCar(
positions[4],
positions[5],
speed);
await car.rotateCar(
car.EAST,
car.SOUTH);
await car.moveCar(
positions[5],
positions[6],
speed);
car.unloadCar();
this.carLine1(2000);
}, 5000);
}
Cars.prototype.carLine2 = function () {
if (!this.run) return;
let car = new Car(this.scene, this.renderer, './models/车蓝.glb');
this.cars.push(car);
let positions = [
{ x: -5, y: 1.5, z: 70 },
{ x: -5, y: 1.5, z: 14.7 },
{ x: 70, y: 1.5, z: 14.7 }
];
let speed = 5;
setTimeout(async () => {
await car.loadCar(
positions[0],
car.NORTH);
car.showLabel(positions[0], "皖AD887U");
await car.moveCar(
positions[0],
positions[1],
speed);
await car.rotateCar(
car.NORTH,
car.EAST);
await car.moveCar(
positions[1],
positions[2],
speed);
car.unloadCar();
this.carLine2(3000);
}, 6000);
}
汽车行驶多段路线改进
上述汽车行驶多段路线的代码可以改进：
// 汽车朝向
let EAST = { x: 0, y: 1.5707963, z: 0 };
let SOUTH = { x: 0, y: 0, z: 0 };
let WEST = { x: 0, y: -1.5707963, z: 0 };
let NORTH = { x: 0, y: 3.1415926, z: 0 };
Cars.prototype.carLine1 = function () {
if (!this.run) return;
let car = new Car(this.scene, this.renderer, './models/车红.glb');
this.cars.push(car);
let positions = [
{ x: -121, y: 1.5, z: -16 },
{ x: -130.5, y: 1.5, z: -16 },
[WEST, SOUTH],
{ x: -130.5, y: 1.5, z: 4 },
[SOUTH, EAST],
{ x: -82, y: 1.5, z: 4 },
[EAST, SOUTH],
{ x: -82, y: 1.5, z: 14.7 },
[SOUTH, EAST],
{ x: -18.8, y: 1.5, z: 14.7 },
[EAST, SOUTH],
{ x: -18.8, y: 1.5, z: 70 },
];
let speed = 5;
setTimeout(async () => {
await car.loadCar(
positions[0],
WEST);
car.showLabel(positions[0], "皖A67893");
for (let i = 1; i < positions.length; i++) {
if (positions[i].length) {
await car.rotateCar(positions[i][0], positions[i][1]);
} else {
let start = positions[i - 1].length ? positions[i - 2] : positions[i - 1];
await car.moveCar(start, positions[i], speed);
}
}
car.unloadCar();
this.carLine1(2000);
}, 5000);
}
调用
let cars = new Cars(app.scene, app.renderer);
cars.carLine1();
cars.carLine2();
显示车牌号
Car.prototype.showLabel = function (position, text) {
let canvasDraw = new CanvasDraw();
let canvasTexture = canvasDraw.drawCarLabel(THREE, this.renderer, text, '#006688'); //标签
let spriteMaterial = new THREE.SpriteMaterial({
map: canvasTexture,
color: 0xffffff,
depthTest: false,
side: THREE.DoubleSide,
sizeAttenuation: false,
transparent: true,
opacity: 0.8
});
let sprite = new THREE.Sprite(spriteMaterial);
sprite.scale.set(0.2, 0.1, 0.2)
sprite.position.x = position.x;
sprite.position.y = position.y + 1.2;
sprite.position.z = position.z;
this.label = sprite;
this.scene.add(sprite);
return sprite;
}
完整代码
car.js
// 汽车
let Car = (function () {
function Car(scene, renderer, url) {
this.scene = scene;
this.renderer = renderer;
this.url = url;
this.clock = new THREE.Clock();
}
Car.prototype.loadCar = function (position, rotation) {
let onProgress = function (xhr) {
};
return new Promise((resolve, reject) => {
if (!this.model) {
let loader = new THREE.GLTFLoader();
loader.load(this.url, gltf => {
const model = gltf.scene || gltf.scenes[0];
model.position.x = position.x;
model.position.y = position.y;
model.position.z = position.z;
model.scale.set(0.25, 0.25, 0.25);
model.rotation.set(rotation.x, rotation.y, rotation.z);
this.model = model;
this.scene.add(model);
resolve(model);
}, onProgress, xhr => {
console.error(xhr);
console.info('模型 ' + url + ' 加载失败');
reject(xhr);
});
} else {
resolve(this.model);
}
});
}
Car.prototype.unloadCar = function () {
this.stopTween();
this.removeModel();
this.removeLabel();
}
Car.prototype.stopTween = function () {
if (this.tween) {
TWEEN.remove(this.tween);
} else {
setTimeout(() => {
this.stopTween();
}, 100);
}
}
Car.prototype.removeModel = function () {
if (this.model) {
this.scene.remove(this.model);
} else {
setTimeout(() => {
this.removeModel();
}, 100);
}
}
Car.prototype.removeLabel = function () {
if (this.label) {
this.scene.remove(this.label);
} else {
setTimeout(() => {
this.removeLabel();
}, 100);
}
}
Car.prototype.moveCar = function (start, end, speed) {
let distance = this.distance(start, end);
let time = distance / speed * 1000;
return new Promise((resolve, reject) => {
this.tween = new TWEEN.Tween({
x: start.x,
y: start.y,
z: start.z
}).to({
x: end.x,
y: end.y,
z: end.z
}, time).start().onUpdate(e => {
if (this.model) {
this.model.position.x = e.x;
this.model.position.y = e.y;
this.model.position.z = e.z;
}
if (this.label) {
this.label.position.x = e.x;
this.label.position.y = e.y + 1.2;
this.label.position.z = e.z;
}
}).onComplete(() => {
TWEEN.remove(this.tween);
resolve();
});
});
}
Car.prototype.rotateCar = function (start, end) {
return new Promise((resolve, reject) => {
this.tween = new TWEEN.Tween({
x: start.x,
y: start.y,
z: start.z
}).to({
x: end.x,
y: end.y,
z: end.z
}, 300).start().onUpdate(e => {
if (this.model) {
this.model.rotation.set(e.x, e.y, e.z);
}
}).onComplete(() => {
TWEEN.remove(this.tween);
resolve();
});
});
}
Car.prototype.showLabel = function (position, text) {
let canvasDraw = new CanvasDraw();
let canvasTexture = canvasDraw.drawCarLabel(THREE, this.renderer, text, '#006688'); //标签
let spriteMaterial = new THREE.SpriteMaterial({
map: canvasTexture,
color: 0xffffff,
depthTest: false,
side: THREE.DoubleSide,
sizeAttenuation: false,
transparent: true,
opacity: 0.8
});
let sprite = new THREE.Sprite(spriteMaterial);
sprite.scale.set(0.2, 0.1, 0.2)
sprite.position.x = position.x;
sprite.position.y = position.y + 1.2;
sprite.position.z = position.z;
this.label = sprite;
this.scene.add(sprite);
return sprite;
}
Car.prototype.distance = function (p1, p2) {
return Math.sqrt(Math.pow(p1.x - p2.x, 2) + Math.pow(p1.y - p2.y, 2) + Math.pow(p1.z - p2.z, 2));
}
return Car;
})();
cars.js
// 多个车辆
let Cars = (function () {
// 汽车朝向
let EAST = { x: 0, y: 1.5707963, z: 0 };
let SOUTH = { x: 0, y: 0, z: 0 };
let WEST = { x: 0, y: -1.5707963, z: 0 };
let NORTH = { x: 0, y: 3.1415926, z: 0 };
function Cars(scene, renderer) {
this.scene = scene;
this.renderer = renderer;
this.cars = [];
this.run = true;
}
Cars.prototype.carLine1 = function () {
if (!this.run) return;
let car = new Car(this.scene, this.renderer, './models/车红.glb');
this.cars.push(car);
let positions = [
{ x: -121, y: 1.5, z: -16 },
{ x: -130.5, y: 1.5, z: -16 },
[WEST, SOUTH],
{ x: -130.5, y: 1.5, z: 4 },
[SOUTH, EAST],
{ x: -82, y: 1.5, z: 4 },
[EAST, SOUTH],
{ x: -82, y: 1.5, z: 14.7 },
[SOUTH, EAST],
{ x: -18.8, y: 1.5, z: 14.7 },
[EAST, SOUTH],
{ x: -18.8, y: 1.5, z: 70 },
];
let speed = 5;
setTimeout(async () => {
await car.loadCar(
positions[0],
WEST);
car.showLabel(positions[0], "皖A67893");
for (let i = 1; i < positions.length; i++) {
if (positions[i].length) {
await car.rotateCar(positions[i][0], positions[i][1]);
} else {
let start = positions[i - 1].length ? positions[i - 2] : positions[i - 1];
await car.moveCar(start, positions[i], speed);
}
}
car.unloadCar();
this.carLine1(2000);
}, 5000);
}
Cars.prototype.carLine2 = function () {
if (!this.run) return;
let car = new Car(this.scene, this.renderer, './models/车蓝.glb');
this.cars.push(car);
let positions = [
{ x: -5, y: 1.5, z: 70 },
{ x: -5, y: 1.5, z: 14.7 },
{ x: 70, y: 1.5, z: 14.7 }
];
let speed = 5;
setTimeout(async () => {
await car.loadCar(
positions[0],
NORTH);
car.showLabel(positions[0], "皖AD887U");
await car.moveCar(
positions[0],
positions[1],
speed);
await car.rotateCar(
NORTH,
EAST);
await car.moveCar(
positions[1],
positions[2],
speed);
car.unloadCar();
this.carLine2(3000);
}, 6000);
}
Cars.prototype.clear = function () {
this.run = false;
this.cars.forEach(car => {
car.unloadCar();
});
}
return Cars;
})();
调用
// 显示汽车
function showCars() {
cars = new Cars(app.scene, app.renderer);
cars.carLine1();
cars.carLine2();
}
// 清除汽车
function clearCars() {
cars.clear();
}
// 显示汽车
showCars();
总结
- 解耦：依赖的scene, renderer参数是通过构造函数传到Car和Cars对象中的
- 汽车行驶和转向等方法都是异步方法，可以避免回调地狱，这样汽车多段行驶的代码会写的比较清晰
- 在实现并完善功能的过程中不断重构：回调地狱的实现方式-->调用moveCar和rotateCar时直接传递坐标，很多坐标及转向数据和方法调用掺和在一起，看着眼花-->坐标和转向数据和方法调用逻辑分离，看着很清晰