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esengine/source/src/Physics/Verlet/SpatialHash.ts
2020-08-25 14:21:37 +08:00

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module es {
export class SpatialHash {
public gridBounds: Rectangle = new Rectangle();
public _raycastParser: RaycastResultParser;
/**
* 散列中每个单元格的大小
*/
public _cellSize: number;
/**
* 1除以单元格大小。缓存结果因为它被大量使用。
*/
public _inverseCellSize: number;
/**
* 缓存的循环用于重叠检查
*/
public _overlapTestCircle: Circle = new Circle(0);
/**
* 保存所有数据的字典
*/
public _cellDict: NumberDictionary = new NumberDictionary();
/**
* 用于返回冲突信息的共享HashSet
*/
public _tempHashSet: Collider[] = [];
constructor(cellSize: number = 100) {
this._cellSize = cellSize;
this._inverseCellSize = 1 / this._cellSize;
this._raycastParser = new RaycastResultParser();
}
/**
* 将对象添加到SpatialHash
* @param collider
*/
public register(collider: Collider) {
let bounds = collider.bounds;
collider.registeredPhysicsBounds = bounds;
let p1 = this.cellCoords(bounds.x, bounds.y);
let p2 = this.cellCoords(bounds.right, bounds.bottom);
// 更新边界以跟踪网格大小
if (!this.gridBounds.contains(p1.x, p1.y)) {
this.gridBounds = RectangleExt.union(this.gridBounds, p1);
}
if (!this.gridBounds.contains(p2.x, p2.y)) {
this.gridBounds = RectangleExt.union(this.gridBounds, p2);
}
for (let x = p1.x; x <= p2.x; x++) {
for (let y = p1.y; y <= p2.y; y++) {
// 如果没有单元格,我们需要创建它
let c: Collider[] = this.cellAtPosition(x, y, true);
if (!c.firstOrDefault(c => c.hashCode == collider.hashCode))
c.push(collider);
}
}
}
/**
* 从SpatialHash中删除对象
* @param collider
*/
public remove(collider: Collider) {
let bounds = collider.registeredPhysicsBounds;
let p1 = this.cellCoords(bounds.x, bounds.y);
let p2 = this.cellCoords(bounds.right, bounds.bottom);
for (let x = p1.x; x <= p2.x; x++) {
for (let y = p1.y; y <= p2.y; y++) {
// 单元格应该始终存在,因为这个碰撞器应该在所有查询的单元格中
let cell = this.cellAtPosition(x, y);
if (!cell)
console.log(`从不存在碰撞器的单元格中移除碰撞器: [${collider}]`);
else
cell.remove(collider);
}
}
}
/**
* 使用蛮力方法从SpatialHash中删除对象
* @param obj
*/
public removeWithBruteForce(obj: Collider) {
this._cellDict.remove(obj);
}
public clear() {
this._cellDict.clear();
}
/**
* debug绘制空间散列的内容
* @param secondsToDisplay
* @param textScale
*/
public debugDraw(secondsToDisplay: number, textScale: number = 1) {
for (let x = this.gridBounds.x; x <= this.gridBounds.right; x++) {
for (let y = this.gridBounds.y; y <= this.gridBounds.bottom; y++) {
let cell = this.cellAtPosition(x, y);
if (cell && cell.length > 0)
this.debugDrawCellDetails(x, y, cell.length, secondsToDisplay, textScale);
}
}
}
/**
* 返回边框与单元格相交的所有对象
* @param bounds
* @param excludeCollider
* @param layerMask
*/
public aabbBroadphase(bounds: Rectangle, excludeCollider: Collider, layerMask: number): Collider[] {
this._tempHashSet.length = 0;
let p1 = this.cellCoords(bounds.x, bounds.y);
let p2 = this.cellCoords(bounds.right, bounds.bottom);
for (let x = p1.x; x <= p2.x; x++) {
for (let y = p1.y; y <= p2.y; y++) {
let cell = this.cellAtPosition(x, y);
if (!cell)
continue;
// 当cell不为空。循环并取回所有碰撞器
for (let i = 0; i < cell.length; i++) {
let collider = cell[i];
// 如果它是自身或者如果它不匹配我们的层掩码 跳过这个碰撞器
if (collider == excludeCollider || !Flags.isFlagSet(layerMask, collider.physicsLayer))
continue;
if (bounds.intersects(collider.bounds)) {
if (!this._tempHashSet.firstOrDefault(c => c.hashCode == collider.hashCode))
this._tempHashSet.push(collider);
}
}
}
}
return this._tempHashSet;
}
/**
* 通过空间散列强制执行一行并用该行命中的任何碰撞器填充hits数组。
* @param start
* @param end
* @param hits
* @param layerMask
*/
public linecast(start: Vector2, end: Vector2, hits: RaycastHit[], layerMask: number){
let ray = new Ray2D(start, end);
this._raycastParser.start(ray, hits, layerMask);
// 在与网格相同的空间中获取起始/结束位置
let currentCell = this.cellCoords(start.x, start.y);
let lastCell = this.cellCoords(end.x, end.y);
let stepX = Math.sign(ray.direction.x);
let stepY = Math.sign(ray.direction.y);
// 我们要确保,如果我们在同一行或同一行,我们不会步进不必要的方向
if (currentCell.x == lastCell.x) stepX = 0;
if (currentCell.y == lastCell.y) stepY = 0;
// 计算单元边界。当这一步是正的下一个单元格在这一步之后意味着我们加1。
// 如果为负,则单元格在此之前,这种情况下不添加边界
let xStep = stepX < 0 ? 0 : stepX;
let yStep = stepY < 0 ? 0 : stepY;
let nextBoundaryX = (currentCell.x + xStep) * this._cellSize;
let nextBoundaryY = (currentCell.y + yStep) * this._cellSize;
// 确定射线穿过第一个垂直体素边界时的t值。y/horizontal。
// 这两个值的最小值将表明我们可以沿着射线走多少而仍然保持在当前体素中对于接近vertical/horizontal的射线来说可能是无限的
let tMaxX = ray.direction.x != 0 ? (nextBoundaryX - ray.start.x) / ray.direction.x : Number.MAX_VALUE;
let tMaxY = ray.direction.y != 0 ? (nextBoundaryY - ray.start.y) / ray.direction.y : Number.MAX_VALUE;
let tDeltaX = ray.direction.x != 0 ? this._cellSize / (ray.direction.x * stepX) : Number.MAX_VALUE;
let tDeltaY = ray.direction.y != 0 ? this._cellSize / (ray.direction.y * stepY) : Number.MAX_VALUE;
// 开始遍历并返回交叉单元格。
let cell = this.cellAtPosition(currentCell.x, currentCell.y);
if (cell && this._raycastParser.checkRayIntersection(currentCell.x, currentCell.y, cell)){
this._raycastParser.reset();
return this._raycastParser.hitCounter;
}
while (currentCell.x != lastCell.x || currentCell.y != lastCell.y){
if (tMaxX < tMaxY){
currentCell.x = MathHelper.approach(currentCell.x, lastCell.x, Math.abs(stepX));
tMaxX += tDeltaX;
}else{
currentCell.y = MathHelper.approach(currentCell.y, lastCell.y, Math.abs(stepY));
tMaxY += tDeltaY;
}
cell = this.cellAtPosition(currentCell.x, currentCell.y);
if (cell && this._raycastParser.checkRayIntersection(currentCell.x, currentCell.y, cell)){
this._raycastParser.reset();
return this._raycastParser.hitCounter;
}
}
this._raycastParser.reset();
return this._raycastParser.hitCounter;
}
/**
* 获取位于指定圆内的所有碰撞器
* @param circleCenter
* @param radius
* @param results
* @param layerMask
*/
public overlapCircle(circleCenter: Vector2, radius: number, results: Collider[], layerMask): number {
let bounds = new Rectangle(circleCenter.x - radius, circleCenter.y - radius, radius * 2, radius * 2);
this._overlapTestCircle.radius = radius;
this._overlapTestCircle.position = circleCenter;
let resultCounter = 0;
let potentials = this.aabbBroadphase(bounds, null, layerMask);
for (let i = 0; i < potentials.length; i++) {
let collider = potentials[i];
if (collider instanceof BoxCollider) {
results[resultCounter] = collider;
resultCounter++;
} else if (collider instanceof CircleCollider) {
if (collider.shape.overlaps(this._overlapTestCircle)) {
results[resultCounter] = collider;
resultCounter++;
}
} else if (collider instanceof PolygonCollider) {
if (collider.shape.overlaps(this._overlapTestCircle)) {
results[resultCounter] = collider;
resultCounter++;
}
} else {
throw new Error("overlapCircle against this collider type is not implemented!");
}
// 如果我们所有的结果数据有了则返回
if (resultCounter == results.length)
return resultCounter;
}
return resultCounter;
}
/**
* 获取单元格的x,y值作为世界空间的x,y值
* @param x
* @param y
*/
private cellCoords(x: number, y: number): Vector2 {
return new Vector2(Math.floor(x * this._inverseCellSize), Math.floor(y * this._inverseCellSize));
}
/**
* 获取世界空间x,y值的单元格。
* 如果单元格为空且createCellIfEmpty为true则会创建一个新的单元格
* @param x
* @param y
* @param createCellIfEmpty
*/
private cellAtPosition(x: number, y: number, createCellIfEmpty: boolean = false): Collider[] {
let cell: Collider[] = this._cellDict.tryGetValue(x, y);
if (!cell) {
if (createCellIfEmpty) {
cell = [];
this._cellDict.add(x, y, cell);
}
}
return cell;
}
private debugDrawCellDetails(x: number, y: number, cellCount: number, secondsToDisplay = 0.5, textScale = 1) {
}
}
/**
* 包装一个Unit32列表碰撞器字典
* 它的主要目的是将int、int x、y坐标散列到单个Uint32键中使用O(1)查找。
*/
export class NumberDictionary {
public _store: Map<string, Collider[]> = new Map<string, Collider[]>();
public add(x: number, y: number, list: Collider[]) {
this._store.set(this.getKey(x, y), list);
}
/**
* 使用蛮力方法从字典存储列表中移除碰撞器
* @param obj
*/
public remove(obj: Collider) {
this._store.forEach(list => {
if (list.contains(obj))
list.remove(obj);
})
}
public tryGetValue(x: number, y: number): Collider[] {
return this._store.get(this.getKey(x, y));
}
/**
* 清除字典数据
*/
public clear() {
this._store.clear();
}
/**
* 根据x和y值计算并返回散列键
* @param x
* @param y
*/
private getKey(x: number, y: number): string {
return Long.fromNumber(x).shiftLeft(32).or(Long.fromNumber(y, true)).toString();
}
}
export class RaycastResultParser {
public hitCounter: number;
public static compareRaycastHits = (a: RaycastHit, b: RaycastHit) => {
return a.distance - b.distance;
};
public _hits: RaycastHit[];
public _tempHit: RaycastHit = new RaycastHit();
public _checkedColliders: Collider[] = [];
public _cellHits: RaycastHit[] = [];
public _ray: Ray2D;
public _layerMask: number;
public start(ray: Ray2D, hits: RaycastHit[], layerMask: number) {
this._ray = ray;
this._hits = hits;
this._layerMask = layerMask;
this.hitCounter = 0;
}
/**
* 如果hits数组被填充返回true。单元格不能为空!
* @param cellX
* @param cellY
* @param cell
*/
public checkRayIntersection(cellX: number, cellY: number, cell: Collider[]): boolean {
let fraction: Ref<number> = new Ref(0);
for (let i = 0; i < cell.length; i++) {
let potential = cell[i];
// 管理我们已经处理过的碰撞器
if (this._checkedColliders.contains(potential))
continue;
this._checkedColliders.push(potential);
// 只有当我们被设置为这样做时才会点击触发器
if (potential.isTrigger && !Physics.raycastsHitTriggers)
continue;
// 确保碰撞器在图层蒙版上
if (!Flags.isFlagSet(this._layerMask, potential.physicsLayer))
continue;
// TODO: rayIntersects的性能够吗?需要测试它。Collisions.rectToLine可能更快
// TODO: 如果边界检查返回更多数据我们就不需要为BoxCollider检查做任何事情
// 在做形状测试之前先做一个边界检查
let colliderBounds = potential.bounds;
if (colliderBounds.rayIntersects(this._ray, fraction) && fraction.value <= 1){
if (potential.shape.collidesWithLine(this._ray.start, this._ray.end, this._tempHit)) {
// 检查一下我们应该排除这些射线射线cast是否在碰撞器中开始
if (!Physics.raycastsStartInColliders && potential.shape.containsPoint(this._ray.start))
continue;
// TODO: 确保碰撞点在当前单元格中,如果它没有保存它以供以后计算
this._tempHit.collider = potential;
this._cellHits.push(this._tempHit);
}
}
}
if (this._cellHits.length == 0)
return false;
// 所有处理单元完成。对结果进行排序并将命中结果打包到结果数组中
this._cellHits.sort(RaycastResultParser.compareRaycastHits);
for (let i = 0; i < this._cellHits.length; i ++){
this._hits[this.hitCounter] = this._cellHits[i];
// 增加命中计数器,如果它已经达到数组大小的限制,我们就完成了
this.hitCounter ++;
if (this.hitCounter == this._hits.length)
return true;
}
return false;
}
public reset(){
this._hits = null;
this._checkedColliders.length = 0;
this._cellHits.length = 0;
}
}
}