Spiral Animation Background

"use client"import { useEffect, useRef, useState } from 'react'import { gsap } from 'gsap'// 向量工具类class Vector2D {    constructor(public x: number, public y: number) {}    static random(min: number, max: number): number {        return min + Math.random() * (max - min)    }}class Vector3D {    constructor(public x: number, public y: number, public z: number) {}    static random(min: number, max: number): number {        return min + Math.random() * (max - min)    }}// 动画控制器class AnimationController {    private timeline: gsap.core.Timeline    private time = 0    private canvas: HTMLCanvasElement    private ctx: CanvasRenderingContext2D    private dpr: number    private size: number    private stars: Star[] = []    private readonly changeEventTime = 0.32    private readonly cameraZ = -400    private readonly cameraTravelDistance = 3400    private readonly startDotYOffset = 28    private readonly viewZoom = 100    private readonly numberOfStars = 5000    private readonly trailLength = 80    constructor(canvas: HTMLCanvasElement, ctx: CanvasRenderingContext2D, dpr: number, size: number) {        this.canvas = canvas        this.ctx = ctx        this.dpr = dpr        this.size = size        this.timeline = gsap.timeline({ repeat: -1 })        this.setupRandomGenerator()        this.createStars()        this.setupTimeline()    }    private setupRandomGenerator() {        const originalRandom = Math.random        const customRandom = () => {            let seed = 1234            return () => {                seed = (seed * 9301 + 49297) % 233280                return seed / 233280            }        }        Math.random = customRandom()        this.createStars()        Math.random = originalRandom    }    private createStars() {        for (let i = 0; i < this.numberOfStars; i++) {            this.stars.push(new Star(this.cameraZ, this.cameraTravelDistance))        }    }    private setupTimeline() {        this.timeline            .to(this, {                time: 1,                duration: 15,                repeat: -1,                ease: "none",                onUpdate: () => this.render()            })    }    public ease(p: number, g: number): number {        if (p < 0.5)             return 0.5 * Math.pow(2 * p, g)        else            return 1 - 0.5 * Math.pow(2 * (1 - p), g)    }    public easeOutElastic(x: number): number {        const c4 = (2 * Math.PI) / 4.5        if (x <= 0) return 0        if (x >= 1) return 1        return Math.pow(2, -8 * x) * Math.sin((x * 8 - 0.75) * c4) + 1    }    public map(value: number, start1: number, stop1: number, start2: number, stop2: number): number {        return start2 + (stop2 - start2) * ((value - start1) / (stop1 - start1))    }    public constrain(value: number, min: number, max: number): number {        return Math.min(Math.max(value, min), max)    }    public lerp(start: number, end: number, t: number): number {        return start * (1 - t) + end * t    }    public spiralPath(p: number): Vector2D {        p = this.constrain(1.2 * p, 0, 1)        p = this.ease(p, 1.8)        const numberOfSpiralTurns = 6        const theta = 2 * Math.PI * numberOfSpiralTurns * Math.sqrt(p)        const r = 170 * Math.sqrt(p)        return new Vector2D(            r * Math.cos(theta),            r * Math.sin(theta) + this.startDotYOffset        )    }    public rotate(v1: Vector2D, v2: Vector2D, p: number, orientation: boolean): Vector2D {        const middle = new Vector2D(            (v1.x + v2.x) / 2,            (v1.y + v2.y) / 2        )        const dx = v1.x - middle.x        const dy = v1.y - middle.y        const angle = Math.atan2(dy, dx)        const o = orientation ? -1 : 1        const r = Math.sqrt(dx * dx + dy * dy)        const bounce = Math.sin(p * Math.PI) * 0.05 * (1 - p)        return new Vector2D(            middle.x + r * (1 + bounce) * Math.cos(angle + o * Math.PI * this.easeOutElastic(p)),            middle.y + r * (1 + bounce) * Math.sin(angle + o * Math.PI * this.easeOutElastic(p))        )    }    public showProjectedDot(position: Vector3D, sizeFactor: number) {        const t2 = this.constrain(this.map(this.time, this.changeEventTime, 1, 0, 1), 0, 1)        const newCameraZ = this.cameraZ + this.ease(Math.pow(t2, 1.2), 1.8) * this.cameraTravelDistance        if (position.z > newCameraZ) {            const dotDepthFromCamera = position.z - newCameraZ            const x = this.viewZoom * position.x / dotDepthFromCamera            const y = this.viewZoom * position.y / dotDepthFromCamera            const sw = 400 * sizeFactor / dotDepthFromCamera            this.ctx.lineWidth = sw            this.ctx.beginPath()            this.ctx.arc(x, y, 0.5, 0, Math.PI * 2)            this.ctx.fill()        }    }    private drawStartDot() {        if (this.time > this.changeEventTime) {            const dy = this.cameraZ * this.startDotYOffset / this.viewZoom            const position = new Vector3D(0, dy, this.cameraTravelDistance)            this.showProjectedDot(position, 2.5)        }    }    public render() {        const ctx = this.ctx        if (!ctx) return        ctx.fillStyle = 'black'        ctx.fillRect(0, 0, this.size, this.size)        ctx.save()        ctx.translate(this.size / 2, this.size / 2)        const t1 = this.constrain(this.map(this.time, 0, this.changeEventTime + 0.25, 0, 1), 0, 1)        const t2 = this.constrain(this.map(this.time, this.changeEventTime, 1, 0, 1), 0, 1)        ctx.rotate(-Math.PI * this.ease(t2, 2.7))        this.drawTrail(t1)        ctx.fillStyle = 'white'        for (const star of this.stars) {            star.render(t1, this)        }        this.drawStartDot()        ctx.restore()    }    private drawTrail(t1: number) {        for (let i = 0; i < this.trailLength; i++) {            const f = this.map(i, 0, this.trailLength, 1.1, 0.1)            const sw = (1.3 * (1 - t1) + 3.0 * Math.sin(Math.PI * t1)) * f            this.ctx.fillStyle = 'white'            this.ctx.lineWidth = sw            const pathTime = t1 - 0.00015 * i            const position = this.spiralPath(pathTime)            const basePos = position            const offset = new Vector2D(position.x + 5, position.y + 5)            const rotated = this.rotate(                basePos,                 offset,                 Math.sin(this.time * Math.PI * 2) * 0.5 + 0.5,                 i % 2 === 0            )            this.ctx.beginPath()            this.ctx.arc(rotated.x, rotated.y, sw / 2, 0, Math.PI * 2)            this.ctx.fill()        }    }    public pause() {        this.timeline.pause()    }    public resume() {        this.timeline.play()    }    public destroy() {        this.timeline.kill()    }}// 星星类class Star {    private dx: number    private dy: number    private spiralLocation: number    private strokeWeightFactor: number    private z: number    private angle: number    private distance: number    private rotationDirection: number    private expansionRate: number    private finalScale: number    constructor(cameraZ: number, cameraTravelDistance: number) {        this.angle = Math.random() * Math.PI * 2        this.distance = 30 * Math.random() + 15        this.rotationDirection = Math.random() > 0.5 ? 1 : -1        this.expansionRate = 1.2 + Math.random() * 0.8        this.finalScale = 0.7 + Math.random() * 0.6        this.dx = this.distance * Math.cos(this.angle)        this.dy = this.distance * Math.sin(this.angle)        this.spiralLocation = (1 - Math.pow(1 - Math.random(), 3.0)) / 1.3        this.z = Vector2D.random(0.5 * cameraZ, cameraTravelDistance + cameraZ)        const lerp = (start: number, end: number, t: number) => start * (1 - t) + end * t        this.z = lerp(this.z, cameraTravelDistance / 2, 0.3 * this.spiralLocation)        this.strokeWeightFactor = Math.pow(Math.random(), 2.0)    }    render(p: number, controller: AnimationController) {        const spiralPos = controller.spiralPath(this.spiralLocation)        const q = p - this.spiralLocation        if (q > 0) {            const displacementProgress = controller.constrain(4 * q, 0, 1)            const linearEasing = displacementProgress;            const elasticEasing = controller.easeOutElastic(displacementProgress);            const powerEasing = Math.pow(displacementProgress, 2);            let easing;            if (displacementProgress < 0.3) {                easing = controller.lerp(linearEasing, powerEasing, displacementProgress / 0.3);            } else if (displacementProgress < 0.7) {                const t = (displacementProgress - 0.3) / 0.4;                easing = controller.lerp(powerEasing, elasticEasing, t);            } else {                easing = elasticEasing;            }            let screenX, screenY;            if (displacementProgress < 0.3) {                screenX = controller.lerp(spiralPos.x, spiralPos.x + this.dx * 0.3, easing / 0.3);                screenY = controller.lerp(spiralPos.y, spiralPos.y + this.dy * 0.3, easing / 0.3);            } else if (displacementProgress < 0.7) {                const midProgress = (displacementProgress - 0.3) / 0.4;                const curveStrength = Math.sin(midProgress * Math.PI) * this.rotationDirection * 1.5;                const baseX = spiralPos.x + this.dx * 0.3;                const baseY = spiralPos.y + this.dy * 0.3;                const targetX = spiralPos.x + this.dx * 0.7;                const targetY = spiralPos.y + this.dy * 0.7;                const perpX = -this.dy * 0.4 * curveStrength;                const perpY = this.dx * 0.4 * curveStrength;                screenX = controller.lerp(baseX, targetX, midProgress) + perpX * midProgress;                screenY = controller.lerp(baseY, targetY, midProgress) + perpY * midProgress;            } else {                const finalProgress = (displacementProgress - 0.7) / 0.3;                const baseX = spiralPos.x + this.dx * 0.7;                const baseY = spiralPos.y + this.dy * 0.7;                const targetDistance = this.distance * this.expansionRate * 1.5;                const spiralTurns = 1.2 * this.rotationDirection;                const spiralAngle = this.angle + spiralTurns * finalProgress * Math.PI;                const targetX = spiralPos.x + targetDistance * Math.cos(spiralAngle);                const targetY = spiralPos.y + targetDistance * Math.sin(spiralAngle);                screenX = controller.lerp(baseX, targetX, finalProgress);                screenY = controller.lerp(baseY, targetY, finalProgress);            }            const vx = (this.z - controller['cameraZ']) * screenX / controller['viewZoom'];            const vy = (this.z - controller['cameraZ']) * screenY / controller['viewZoom'];            const position = new Vector3D(vx, vy, this.z);            let sizeMultiplier = 1.0;            if (displacementProgress < 0.6) {                sizeMultiplier = 1.0 + displacementProgress * 0.2;            } else {                const t = (displacementProgress - 0.6) / 0.4;                sizeMultiplier = 1.2 * (1.0 - t) + this.finalScale * t;            }            const dotSize = 8.5 * this.strokeWeightFactor * sizeMultiplier;            controller.showProjectedDot(position, dotSize);        }    }}export function SpiralAnimation({ width = 400, height = 400, className = "" }: { width?: number, height?: number, className?: string }) {    const canvasRef = useRef<HTMLCanvasElement>(null)    const animationRef = useRef<AnimationController | null>(null)    const [dimensions, setDimensions] = useState<{ width: number, height: number } | null>(null)    useEffect(() => {        // Only run on client        setDimensions({ width, height })    }, [width, height])    useEffect(() => {        if (!dimensions) return;        const handleResize = () => {            setDimensions({ width, height })        }        window.addEventListener('resize', handleResize)        return () => window.removeEventListener('resize', handleResize)    }, [dimensions, width, height])    useEffect(() => {        if (!dimensions) return;        const canvas = canvasRef.current        if (!canvas) return        const ctx = canvas.getContext('2d')        if (!ctx) return        const dpr = window.devicePixelRatio || 1        const size = Math.max(dimensions.width, dimensions.height)        canvas.width = size * dpr        canvas.height = size * dpr        canvas.style.width = `${dimensions.width}px`        canvas.style.height = `${dimensions.height}px`        ctx.scale(dpr, dpr)        animationRef.current = new AnimationController(canvas, ctx, dpr, size)        return () => {            if (animationRef.current) {                animationRef.current.destroy()                animationRef.current = null            }        }    }, [dimensions])    return (        <div className={`relative ${className}`} style={{ width, height }}>            <canvas                ref={canvasRef}                className="absolute inset-0 w-full h-full"            />        </div>    )}