141 lines
3.6 KiB
TypeScript
141 lines
3.6 KiB
TypeScript
import { Vector } from "../Common/vector";
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// 包围盒类型
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export type BoundingRect = {
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x: number;
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y: number;
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width: number;
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height: number;
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};
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// 包围盒操作
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export const Bound = {
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/**
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* 从点集生成包围盒
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* @param points
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*/
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fromPoints(points: Array<[number, number]>): BoundingRect {
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let maxX = -Infinity,
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minX = Infinity,
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maxY = -Infinity,
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minY = Infinity;
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points.map(item => {
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if(item[0] > maxX) maxX = item[0];
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if(item[0] < minX) minX = item[0];
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if(item[1] > maxY) maxY = item[1];
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if(item[1] < minY) minY = item[1];
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});
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return {
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x: minX,
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y: minY,
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width: maxX - minX,
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height: maxY - minY
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};
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},
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/**
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* 由包围盒转化为四个顶点（顺时针）
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* @param bound
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*/
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toPoints(bound: BoundingRect): Array<[number, number]> {
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return [
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[bound.x, bound.y],
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[bound.x + bound.width, bound.y],
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[bound.x + bound.width, bound.y + bound.height],
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[bound.x, bound.y + bound.height]
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];
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},
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/**
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* 求包围盒并集
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* @param arg
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*/
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union(...arg: BoundingRect[]): BoundingRect {
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return arg.length > 1?
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arg.reduce((total, cur) => {
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let minX = total.x < cur.x? total.x: cur.x,
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maxX = total.x + total.width < cur.x + cur.width? cur.x + cur.width: total.x + total.width,
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minY = total.y < cur.y? total.y: cur.y,
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maxY = total.y + total.height < cur.y + cur.height? cur.y + cur.height: total.y + total.height;
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return {
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x: minX,
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y: minY,
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width: maxX - minX,
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height: maxY - minY
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};
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}): arg[0];
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},
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/**
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* 包围盒求交集
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* @param b1
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* @param b2
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*/
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intersect(b1: BoundingRect, b2: BoundingRect): BoundingRect {
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let x, y,
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maxX, maxY,
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overlapsX,
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overlapsY;
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if(b1.x < b2.x + b2.width && b1.x + b1.width > b2.x) {
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x = b1.x < b2.x? b2.x: b1.x;
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maxX = b1.x + b1.width < b2.x + b2.width? b1.x + b1.width: b2.x + b2.width;
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overlapsX = maxX - x;
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}
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if(b1.y < b2.y + b2.height && b1.y + b1.height > b2.y) {
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y = b1.y < b2.y? b2.y: b1.y;
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maxY = b1.y + b1.height < b2.y + b2.height? b1.y + b1.height: b2.y + b2.height;
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overlapsY = maxY - y;
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}
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if(!overlapsX || !overlapsY) return null;
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return {
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x,
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y,
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width: overlapsX,
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height: overlapsY
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};
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},
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/**
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* 求包围盒旋转后新形成的包围盒
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* @param bound
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* @param rot
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*/
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rotation(bound: BoundingRect, rot: number): BoundingRect {
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let cx = bound.x + bound.width / 2,
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cy = bound.y + bound.height / 2;
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return Bound.fromPoints(Bound.toPoints(bound).map(item => Vector.rotation(rot, item, [cx, cy])));
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},
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/**
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* 判断两个包围盒是否相交
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* @param b1
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* @param b2
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*/
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isOverlap(b1: BoundingRect, b2: BoundingRect): boolean {
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let maxX1 = b1.x + b1.width,
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maxY1 = b1.y + b1.height,
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maxX2 = b2.x + b2.width,
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maxY2 = b2.y + b2.height;
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if (b1.x < maxX2 && b2.x < maxX1 && b1.y < maxY2 && b2.y < maxY1) {
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return true;
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}
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return false;
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}
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};
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