107 lines
3.2 KiB
TypeScript
107 lines
3.2 KiB
TypeScript
/**
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* 战场防御线：反弓曲线路径 + 锯齿齿形
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*/
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export type LngLat = [number, number]
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/** 二次贝塞尔 B(t) = (1-t)²P0 + 2(1-t)t P1 + t² P2 */
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function quadraticBezier(P0: LngLat, P1: LngLat, P2: LngLat, t: number): LngLat {
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const u = 1 - t
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return [
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u * u * P0[0] + 2 * u * t * P1[0] + t * t * P2[0],
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u * u * P0[1] + 2 * u * t * P1[1] + t * t * P2[1],
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]
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}
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/**
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* 生成反弓曲线路径：通过 path 各点，弧面向进攻方向（西侧）凸出
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* @param path 关键点 [[lng, lat], ...]（如大不里士→萨南达季→克尔曼沙赫）
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* @param bulgeWest 向西凸出量（经度，正值表示弧顶在西侧/面向进攻方）
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* @param samplesPerSegment 每段贝塞尔采样点数
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*/
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export function createCurvedDefensePath(
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path: LngLat[],
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bulgeWest: number = 0.35,
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samplesPerSegment: number = 24
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): LngLat[] {
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if (path.length < 2) return path
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const out: LngLat[] = []
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for (let i = 0; i < path.length - 1; i++) {
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const a = path[i]
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const b = path[i + 1]
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const midLng = (a[0] + b[0]) / 2
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const midLat = (a[1] + b[1]) / 2
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const control: LngLat = [midLng - bulgeWest, midLat]
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const startK = i === 0 ? 0 : 1
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for (let k = startK; k <= samplesPerSegment; k++) {
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out.push(quadraticBezier(a, control, b, k / samplesPerSegment))
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}
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}
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return out
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}
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/**
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* 沿路径线性插值增加点（直线段）
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*/
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export function interpolatePath(path: LngLat[], stepsPerSegment: number = 4): LngLat[] {
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if (path.length < 2) return path
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const out: LngLat[] = []
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for (let i = 0; i < path.length - 1; i++) {
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const a = path[i]
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const b = path[i + 1]
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const startK = i === 0 ? 0 : 1
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for (let k = startK; k <= stepsPerSegment; k++) {
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const t = k / stepsPerSegment
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out.push([a[0] + (b[0] - a[0]) * t, a[1] + (b[1] - a[1]) * t])
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}
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}
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return out
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}
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/**
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* 锯齿防御线：沿 path 每 toothWidth（比例）生成齿，齿高 toothHeight，朝向法向（敌方侧）
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* @param path 路径点 [[lng, lat], ...]（可先经 interpolatePath 插值）
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* @param toothWidth 齿宽（与段长同单位，经纬度）
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* @param toothHeight 齿高（法向伸出）
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*/
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export function createDefenseLine(
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path: number[][],
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toothWidth: number,
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toothHeight: number
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): number[][] {
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const coords: number[][] = []
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for (let i = 0; i < path.length - 1; i++) {
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const start = path[i] as [number, number]
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const end = path[i + 1] as [number, number]
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const dx = end[0] - start[0]
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const dy = end[1] - start[1]
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const L = Math.sqrt(dx * dx + dy * dy)
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if (L < 1e-9) continue
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const ux = dx / L
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const uy = dy / L
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const nx = -uy
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const ny = ux
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const numTeeth = Math.max(1, Math.floor(L / toothWidth))
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const actualWidth = L / numTeeth
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for (let j = 0; j < numTeeth; j++) {
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const t1 = j * actualWidth
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const t2 = t1 + actualWidth * 0.5
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const t3 = (j + 1) * actualWidth
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coords.push([start[0] + ux * t1, start[1] + uy * t1])
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coords.push([
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start[0] + ux * t2 + nx * toothHeight,
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start[1] + uy * t2 + ny * toothHeight,
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])
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coords.push([start[0] + ux * t3, start[1] + uy * t3])
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}
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}
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coords.push(path[path.length - 1] as [number, number])
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return coords
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}
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