246 lines
10 KiB
TypeScript
246 lines
10 KiB
TypeScript
module es {
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/**
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* 请注意，这不是一个完整的、多迭代的物理系统！它可以用于简单的、街机风格的物理。
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* 这可以用于简单的，街机风格的物理学
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*/
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export class ArcadeRigidbody extends Component implements IUpdatable {
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/** 这个刚体的质量。质量为0，则是一个不可移动的物体 */
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public get mass(){
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return this._mass;
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}
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public set mass(value: number){
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this.setMass(value);
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}
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/**
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* 0-1范围，其中0为无反弹，1为完全反射。
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*/
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public get elasticity() {
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return this._elasticity;
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}
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public set elasticiy(value: number){
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this.setElasticity(value);
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}
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/**
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* 0 - 1范围。0表示没有摩擦力，1表示物体会停止在原地
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*/
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public get friction(){
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return this._friction;
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}
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public set friction(value: number){
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this.setFriction(value);
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}
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/**
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* 0-9的范围。当发生碰撞时，沿碰撞面做直线运动时，如果其平方幅度小于glue摩擦力，则将碰撞设置为上限
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*/
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public get glue() {
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return this._glue;
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}
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public set glue(value: number){
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this.setGlue(value);
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}
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/**
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* 如果为真，则每一帧都会考虑到Physics.gravity
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*/
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public shouldUseGravity: boolean = true;
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/**
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* 该刚体的速度
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*/
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public velocity: Vector2 = new Vector2();
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/**
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* 质量为0的刚体被认为是不可移动的。改变速度和碰撞对它们没有影响
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*/
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public get isImmovable(){
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return this._mass < 0.0001;
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}
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public _mass = 10;
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public _elasticity = 0.5;
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public _friction = 0.5;
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public _glue = 0.01;
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public _inverseMass: number = 0;
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public _collider: Collider;
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constructor(){
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super();
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this._inverseMass = 1 / this._mass;
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}
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/**
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* 这个刚体的质量。质量为0，则是一个不可移动的物体
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* @param mass
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*/
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public setMass(mass: number): ArcadeRigidbody {
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this._mass = MathHelper.clamp(mass, 0, Number.MAX_VALUE);
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if (this._mass > 0.0001)
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this._inverseMass = 1 / this._mass;
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else
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this._inverseMass = 0;
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return this;
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}
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/**
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* 0-1范围，其中0为无反弹，1为完全反射。
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* @param value
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*/
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public setElasticity(value: number): ArcadeRigidbody {
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this._elasticity = MathHelper.clamp01(value);
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return this;
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}
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/**
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* 0 - 1范围。0表示没有摩擦力，1表示物体会停止在原地
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* @param value
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*/
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public setFriction(value: number): ArcadeRigidbody {
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this._friction = MathHelper.clamp01(value);
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return this;
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}
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/**
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* 0-9的范围。当发生碰撞时，沿碰撞面做直线运动时，如果其平方幅度小于glue摩擦力，则将碰撞设置为上限
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* @param value
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*/
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public setGlue(value: number): ArcadeRigidbody {
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this._glue = MathHelper.clamp(value, 0, 10);
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return this;
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}
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/**
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* 用刚体的质量给刚体加上一个瞬间的力脉冲。力是一个加速度，单位是每秒像素每秒。将力乘以100000，使数值使用更合理
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* @param force
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*/
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public addImpulse(force: Vector2) {
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if (!this.isImmovable) {
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this.velocity = Vector2.add(this.velocity, Vector2.multiply(force, new Vector2(100000))
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.multiply(new Vector2(this._inverseMass * Time.deltaTime)));
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}
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}
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public onAddedToEntity(){
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this._collider = this.entity.getComponent<es.Collider>(es.Collider);
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if (this._collider == null) {
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console.warn("ArcadeRigidbody 没有 Collider。ArcadeRigidbody需要一个Collider!");
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}
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}
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public update(){
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if (this.isImmovable || this._collider == null) {
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this.velocity = Vector2.zero;
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return;
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}
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if (this.shouldUseGravity)
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this.velocity = Vector2.add(this.velocity, Vector2.multiply(Physics.gravity, new Vector2(Time.deltaTime)));
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this.entity.transform.position = Vector2.add(this.entity.transform.position, Vector2.multiply(this.velocity, new Vector2(Time.deltaTime)));
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let collisionResult = new CollisionResult();
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// 捞取我们在新的位置上可能会碰撞到的任何东西
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let neighbors = Physics.boxcastBroadphaseExcludingSelfNonRect(this._collider, this._collider.collidesWithLayers.value);
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for (let neighbor of neighbors) {
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// 如果邻近的对撞机是同一个实体，则忽略它
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if (neighbor.entity.equals(this.entity)) {
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continue;
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}
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if (this._collider.collidesWithNonMotion(neighbor, collisionResult)) {
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// 如果附近有一个ArcadeRigidbody，我们就会处理完整的碰撞响应。如果没有，我们会根据附近是不可移动的来计算事情
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let neighborRigidbody = neighbor.entity.getComponent<ArcadeRigidbody>(ArcadeRigidbody);
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if (neighborRigidbody != null) {
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this.processOverlap(neighborRigidbody, collisionResult.minimumTranslationVector);
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this.processCollision(neighborRigidbody, collisionResult.minimumTranslationVector);
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} else {
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// 没有ArcadeRigidbody，所以我们假设它是不动的，只移动我们自己的
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this.entity.transform.position = Vector2.subtract(this.entity.transform.position, collisionResult.minimumTranslationVector);
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let relativeVelocity = this.velocity.clone();
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this.calculateResponseVelocity(relativeVelocity, collisionResult.minimumTranslationVector, relativeVelocity);
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this.velocity = Vector2.add(this.velocity, relativeVelocity);
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}
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}
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}
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}
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/**
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* 将两个重叠的刚体分开。也处理其中一个不可移动的情况
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* @param other
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* @param minimumTranslationVector
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*/
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public processOverlap(other: ArcadeRigidbody, minimumTranslationVector: Vector2) {
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if (this.isImmovable) {
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other.entity.transform.position = Vector2.add(other.entity.transform.position, minimumTranslationVector);
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}else if(other.isImmovable) {
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this.entity.transform.position = Vector2.subtract(this.entity.transform.position, minimumTranslationVector);
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} else {
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this.entity.transform.position = Vector2.subtract(this.entity.transform.position, Vector2.multiply(minimumTranslationVector, Vector2Ext.halfVector()));
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other.entity.transform.position = Vector2.add(other.entity.transform.position, Vector2.multiply(minimumTranslationVector, Vector2Ext.halfVector()));
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}
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}
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/**
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* 处理两个非重叠的刚体的碰撞。新的速度将根据情况分配给每个刚体
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* @param other
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* @param minimumTranslationVector
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*/
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public processCollision(other: ArcadeRigidbody, minimumTranslationVector: Vector2) {
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// 我们计算两个相撞物体的响应。
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// 计算的基础是沿碰撞表面法线反射的物体的相对速度。
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// 然后，响应的一部分会根据质量加到每个物体上
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let relativeVelocity = Vector2.subtract(this.velocity, other.velocity);
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this.calculateResponseVelocity(relativeVelocity, minimumTranslationVector, relativeVelocity);
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// 现在，我们使用质量来线性缩放两个刚体上的响应
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let totalinverseMass = this._inverseMass + other._inverseMass;
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let ourResponseFraction = this._inverseMass / totalinverseMass;
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let otherResponseFraction = other._inverseMass / totalinverseMass;
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this.velocity = Vector2.add(this.velocity, new Vector2(relativeVelocity.x * ourResponseFraction, relativeVelocity.y * ourResponseFraction));
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other.velocity = Vector2.subtract(other.velocity, new Vector2(relativeVelocity.x * otherResponseFraction, relativeVelocity.y * otherResponseFraction));
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}
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/**
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* 给定两个物体和MTV之间的相对速度，本方法修改相对速度，使其成为碰撞响应
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* @param relativeVelocity
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* @param minimumTranslationVector
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* @param responseVelocity
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*/
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public calculateResponseVelocity(relativeVelocity: Vector2, minimumTranslationVector: Vector2, responseVelocity: Vector2 = new Vector2()){
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// 首先，我们得到反方向的归一化MTV：表面法线
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let inverseMTV = Vector2.multiply(minimumTranslationVector, new Vector2(-1));
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let normal = Vector2.normalize(inverseMTV);
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// 速度是沿碰撞法线和碰撞平面分解的。
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// 弹性将影响沿法线的响应（法线速度分量），摩擦力将影响速度的切向分量（切向速度分量）
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let n = Vector2.dot(relativeVelocity, normal);
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let normalVelocityComponent = new Vector2(normal.x * n, normal.y * n);
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let tangentialVelocityComponent = Vector2.subtract(relativeVelocity, normalVelocityComponent);
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if (n > 0)
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normalVelocityComponent = Vector2.zero;
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// 如果切向分量的平方幅度小于glue，那么我们就把摩擦力提升到最大
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let coefficientOfFriction = this._friction;
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if (tangentialVelocityComponent.lengthSquared() < this._glue)
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coefficientOfFriction = 1.01;
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// 弹性影响速度的法向分量，摩擦力影响速度的切向分量
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let t = Vector2.multiply(new Vector2((1 + this._elasticity)), normalVelocityComponent)
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.multiply(new Vector2(-1))
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.subtract(Vector2.multiply(new Vector2(coefficientOfFriction), tangentialVelocityComponent));
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responseVelocity.x = t.x;
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relativeVelocity.y = t.y;
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}
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}
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} |