/** @jsxImportSource preact */ import { useEffect, useRef, useState, useCallback } from "preact/hooks"; import type { ComponentChildren, JSX } from "preact"; const canvasDimensionLimits = new WeakMap(); /** Keep the existing DPR budget, then account for browser pinch zoom. */ function getCanvasPixelRatio( element: HTMLElement, context?: WebGLRenderingContext | WebGL2RenderingContext, ): number { const scale = window.visualViewport?.scale || 1; const requested = Math.min(window.devicePixelRatio || 1, 2) * scale; const width = Math.max(element.clientWidth, 1); const height = Math.max(element.clientHeight, 1); let maxDimension = 8192; if (context) { let limit = canvasDimensionLimits.get(context); if (limit === undefined) { limit = Math.min( maxDimension, context.getParameter(context.MAX_TEXTURE_SIZE), context.getParameter(context.MAX_RENDERBUFFER_SIZE), ); canvasDimensionLimits.set(context, limit); } maxDimension = limit; } // Rendering the full element preserves its CSS position and native input // geometry while panning. Bound allocations when zooming large canvases. return Math.min( requested, maxDimension / Math.max(width, height), Math.sqrt(16_777_216 / (width * height)), ); } /** Pinch zoom changes visualViewport without resizing the element's CSS box. */ function createCanvasResizeObserver(onResize: () => void) { const viewport = window.visualViewport; let frame = 0; let disconnected = false; const schedule = () => { if (frame || disconnected) return; frame = requestAnimationFrame(() => { frame = 0; onResize(); }); }; const observer = new ResizeObserver(schedule); window.addEventListener("resize", schedule, { passive: true }); viewport?.addEventListener("resize", schedule, { passive: true }); return { observe(element: Element, options?: ResizeObserverOptions) { observer.observe(element, options); }, unobserve(element: Element) { observer.unobserve(element); }, disconnect() { disconnected = true; observer.disconnect(); cancelAnimationFrame(frame); window.removeEventListener("resize", schedule); viewport?.removeEventListener("resize", schedule); }, }; } type HtmlInCanvasContext = CanvasRenderingContext2D & { drawElementImage: (element: Element, x: number, y: number) => DOMMatrix | void; }; type HtmlInCanvasElement = HTMLCanvasElement & { updateElementGeometry?: ( element: Element, options: { canvasTransform: DOMMatrix }, ) => void; }; /** * Android can expose the API, but renderer crashes were reported on effect * pages (issue #50). A process crash cannot be caught in JavaScript. Keep * Android on the DOM/overlay fallback until native capture is validated there. * Neither Chrome's flag nor its default-on support (Chrome 157+) may bypass it. */ function isHtmlInCanvasBlocked(): boolean { if (typeof navigator === "undefined") return false; const platform = (navigator as Navigator & { userAgentData?: { platform?: string }; }).userAgentData?.platform; return platform === "Android" || /Android/i.test(navigator.userAgent); } /** Configure the capture subtree for both generations of the experimental API. */ function prepareHtmlInCanvas(source: HTMLCanvasElement, content: HTMLElement) { if ("content" in source) { source.setAttribute("content", "drawable"); content.setAttribute("drawable", ""); } else { source.setAttribute("layoutsubtree", ""); } } /** Capture pixels and keep the native DOM hit-test region aligned with them. */ function drawHtmlInCanvas( source: HTMLCanvasElement, context: CanvasRenderingContext2D, content: HTMLElement, ) { const transform = (context as HtmlInCanvasContext).drawElementImage(content, 0, 0); const canvas = source as HtmlInCanvasElement; // Chrome 154 decoupled geometry from drawing before enabling automatic 2D // synchronization. Older versions have no update method; newer versions // synchronize automatically and return void. Use the returned matrix as-is: // drawElementImage already accounts for the canvas's pixel density. if (transform && typeof canvas.updateElementGeometry === "function") { canvas.updateElementGeometry(content, { canvasTransform: transform }); } } import { effect, frame as gpuFrame, init, sampler, surface, target, type Effect, type Gpu, type Surface, type Target, type Texture, } from "vgpu"; export type ForceFieldShape = "hexagon" | "triangle" | "square"; export type ForceFieldGridReveal = "always" | "hover" | "click" | "both"; export interface ForceFieldOptions { /** Cell shape of the energy lattice. */ shape?: ForceFieldShape; /** Field color as [r, g, b] in 0-1 range. */ color?: [number, number, number]; /** Color of the dissolve edge glow as [r, g, b] in 0-1 range. */ edgeColor?: [number, number, number]; /** Overall field opacity (0 to 1). */ opacity?: number; /** Cells across the shorter screen axis (4 to 80). */ cellScale?: number; /** Thickness of the lattice lines (0.005 to 0.2). */ lineWidth?: number; /** Brightness of the lattice grid (0 to 1). */ gridOpacity?: number; /** How the lattice is revealed: always visible, near the cursor, by click ripples, or both. */ gridReveal?: ForceFieldGridReveal; /** Brightness of the revealed lattice in hover/click/both modes (0 to 3). */ gridRevealStrength?: number; /** Radius of the hover reveal in CSS pixels (60 to 800). */ gridRevealRadius?: number; /** Fade smoothness of the reveal edge (0.02 to 1). */ gridFade?: number; /** Random per-cell flash speed (0 to 4). */ flashSpeed?: number; /** Random per-cell flash brightness (0 to 1). */ flashIntensity?: number; /** Scale of the drifting energy noise (0.5 to 12). */ flowScale?: number; /** Drift speed of the energy noise (0 to 4). */ flowSpeed?: number; /** Brightness of the energy noise (0 to 4). */ flowIntensity?: number; /** Glow creeping in from the screen edges, the fresnel analog (0 to 4). */ edgeGlow?: number; /** How far the edge glow reaches into the screen (0.02 to 0.6). */ edgeFalloff?: number; /** Reveal progress. 1 is fully materialized, 0 is gone (noise dissolve). */ reveal?: number; /** Scale of the dissolve noise (0.5 to 12). */ dissolveScale?: number; /** Width of the burning dissolve edge (0.005 to 0.2). */ dissolveWidth?: number; /** Brightness of the dissolve edge (0 to 12). */ dissolveGlow?: number; /** Expansion speed of click ripples in screens per second (0.1 to 4). */ rippleSpeed?: number; /** Ring thickness of click ripples (0.01 to 0.4). */ rippleWidth?: number; /** How softly ripple rings feather into the page, 0 is tight, 1 is airy (0 to 1). */ rippleBlend?: number; /** Lifetime of one ripple in seconds (0.3 to 5). */ rippleDuration?: number; /** Brightness of ripples and impact flashes (0 to 8). */ rippleIntensity?: number; /** Max radius a ripple can reach, in screens (0.1 to 2). */ rippleMaxRadius?: number; /** Radius of the cell flash burst around an impact (0 to 0.5). */ impactRadius?: number; /** How much ripples push the page outward and warp the lattice (0 to 60). */ refraction?: number; /** Chromatic aberration inside refracted rings (0 to 8). */ aberration?: number; /** Living heat-haze shimmer that warps the page beneath the field (0 to 2). */ haze?: number; /** Lattice reacts to the page: cells over bright content glow brighter (0 to 1). */ pageReact?: number; /** Tints the page toward the field color, like looking through the shield (0 to 1). */ tint?: number; /** Glow following the cursor (0 to 3). */ hoverGlow?: number; /** Radius of the cursor glow in CSS pixels (40 to 600). */ hoverRadius?: number; /** Cells light up when the cursor crosses them (0 to 2). */ hoverCharge?: number; /** Fade the field out around the cursor instead of intensifying it. */ hideOnHover?: boolean; /** How much the page dims beneath the field (0 to 1). */ dim?: number; /** Bloom amount applied to bright field energy (0 to 3). */ bloom?: number; /** Bloom brightness cutoff (0 to 1). */ bloomThreshold?: number; /** Animated film grain over the field (0 to 1). */ grain?: number; /** Spawn ripples on click (default true). */ clickRipples?: boolean; /** Called with the impact position in CSS pixels after each click. */ onHit?: (x: number, y: number) => void; } export interface ForceFieldElements { /** Canvas with layoutsubtree that hosts the HTML content. */ source: HTMLCanvasElement; /** The element inside the source canvas that gets captured. */ content: HTMLElement; /** Canvas the WebGPU effect renders to. */ output: HTMLCanvasElement; } export interface ForceFieldInstance { /** Update effect options live. */ setOptions: (options: ForceFieldOptions) => void; /** Spawn a ripple at CSS pixel coordinates relative to the output canvas. */ impact: (x: number, y: number) => void; /** Re-read canvas size. Call when the element is resized. */ resize: () => void; /** Stop the loop and release all GPU resources. */ destroy: () => void; } const MAX_HITS = 10; const MIPS = 4; const DEFAULTS: Required> & { onHit: ((x: number, y: number) => void) | null; } = { shape: "hexagon", color: [0.15, 0.68, 1], edgeColor: [0.5, 0.8, 1], opacity: 0.9, cellScale: 16, lineWidth: 0.03, gridOpacity: 0.15, gridReveal: "click", gridRevealStrength: 1.5, gridRevealRadius: 250, gridFade: 0.35, flashSpeed: 0.6, flashIntensity: 0.1, flowScale: 3, flowSpeed: 0.5, flowIntensity: 0, edgeGlow: 0.2, edgeFalloff: 0.18, reveal: 1, dissolveScale: 3.5, dissolveWidth: 0.05, dissolveGlow: 6, rippleSpeed: 0.5, rippleWidth: 0.045, rippleBlend: 1, rippleDuration: 1.6, rippleIntensity: 0.1, rippleMaxRadius: 0.85, impactRadius: 0.16, refraction: 30, aberration: 2.5, haze: 0.5, pageReact: 0, tint: 0.1, hoverGlow: 0.25, hoverRadius: 350, hoverCharge: 1.6, hideOnHover: false, dim: 0, bloom: 1, bloomThreshold: 0.3, grain: 0.2, clickRipples: true, onHit: null, }; interface RectCache { readonly current: DOMRect; destroy: () => void; } function createRectCache(element: Element): RectCache { let current = element.getBoundingClientRect(); const refresh = () => { current = element.getBoundingClientRect(); }; const observer = new ResizeObserver(refresh); observer.observe(element); window.addEventListener("resize", refresh, { passive: true }); window.addEventListener("scroll", refresh, { capture: true, passive: true }); return { get current() { return current; }, destroy() { observer.disconnect(); window.removeEventListener("resize", refresh); window.removeEventListener("scroll", refresh, true); }, }; } type PaintableCanvas = HTMLCanvasElement & { onpaint?: (() => void) | null; requestPaint?: () => void; }; type ElementImageContext = CanvasRenderingContext2D & { drawElementImage?: (element: Element, x: number, y: number) => void; }; const FIELD_SHADER = /* wgsl */ ` struct FieldParams { hits: array, resolution: vec2f, color: vec3f, edgeColor: vec3f, mouse: vec2f, time: f32, shape: f32, opacity: f32, cellScale: f32, lineWidth: f32, gridOpacity: f32, gridRevealMode: f32, gridRevealStrength: f32, gridRevealRadius: f32, gridFade: f32, flashSpeed: f32, flashIntensity: f32, flowScale: f32, flowSpeed: f32, flowIntensity: f32, edgeGlow: f32, edgeFalloff: f32, reveal: f32, dissolveScale: f32, dissolveWidth: f32, dissolveGlow: f32, rippleSpeed: f32, rippleWidth: f32, rippleDuration: f32, rippleIntensity: f32, rippleMaxRadius: f32, impactRadius: f32, rippleBlend: f32, refraction: f32, aberration: f32, hoverGlow: f32, hoverRadius: f32, hoverCharge: f32, hideOnHover: f32, scroll: f32, haze: f32, pageReact: f32, tint: f32, dim: f32, hasContent: f32, pageLum: f32, } struct FieldOut { @location(0) color: vec4f, @location(1) emission: vec4f, } @group(0) @binding(0) var params: FieldParams; @group(0) @binding(1) var uContent: texture_2d; @group(0) @binding(2) var uSampler: sampler; fn mod289v3(x: vec3f) -> vec3f { return x - floor(x * (1.0 / 289.0)) * 289.0; } fn mod289v4(x: vec4f) -> vec4f { return x - floor(x * (1.0 / 289.0)) * 289.0; } fn permute(x: vec4f) -> vec4f { return mod289v4(((x * 34.0) + 1.0) * x); } fn taylorInvSqrt(r: vec4f) -> vec4f { return 1.79284291400159 - 0.85373472095314 * r; } fn snoise(v: vec3f) -> f32 { let C = vec2f(1.0 / 6.0, 1.0 / 3.0); let D = vec4f(0.0, 0.5, 1.0, 2.0); var i = floor(v + dot(v, C.yyy)); let x0 = v - i + dot(i, C.xxx); let g = step(x0.yzx, x0.xyz); let l = 1.0 - g; let i1 = min(g.xyz, l.zxy); let i2 = max(g.xyz, l.zxy); let x1 = x0 - i1 + C.xxx; let x2 = x0 - i2 + C.yyy; let x3 = x0 - D.yyy; i = mod289v3(i); let p = permute(permute(permute( i.z + vec4f(0.0, i1.z, i2.z, 1.0)) + i.y + vec4f(0.0, i1.y, i2.y, 1.0)) + i.x + vec4f(0.0, i1.x, i2.x, 1.0)); let n_ = 0.142857142857; let ns = n_ * D.wyz - D.xzx; let j = p - 49.0 * floor(p * ns.z * ns.z); let x_ = floor(j * ns.z); let y_ = floor(j - 7.0 * x_); let x = x_ * ns.x + ns.yyyy; let y = y_ * ns.x + ns.yyyy; let h = 1.0 - abs(x) - abs(y); let b0 = vec4f(x.xy, y.xy); let b1 = vec4f(x.zw, y.zw); let s0 = floor(b0) * 2.0 + 1.0; let s1 = floor(b1) * 2.0 + 1.0; let sh = -step(h, vec4f(0.0)); let a0 = b0.xzyw + s0.xzyw * sh.xxyy; let a1 = b1.xzyw + s1.xzyw * sh.zzww; var p0 = vec3f(a0.xy, h.x); var p1 = vec3f(a0.zw, h.y); var p2 = vec3f(a1.xy, h.z); var p3 = vec3f(a1.zw, h.w); let norm = taylorInvSqrt(vec4f(dot(p0, p0), dot(p1, p1), dot(p2, p2), dot(p3, p3))); p0 *= norm.x; p1 *= norm.y; p2 *= norm.z; p3 *= norm.w; var m = max(0.6 - vec4f(dot(x0, x0), dot(x1, x1), dot(x2, x2), dot(x3, x3)), vec4f(0.0)); m = m * m; return 42.0 * dot(m * m, vec4f(dot(p0, x0), dot(p1, x1), dot(p2, x2), dot(p3, x3))); } fn hash21(pIn: vec2f) -> f32 { var p = fract(pIn * vec2f(234.34, 435.345)); p += dot(p, p + 34.23); return fract(p.x * p.y); } fn hexCell(p: vec2f) -> vec4f { let s = vec2f(1.0, 1.7320508); let hC = floor(vec4f(p, p - vec2f(0.5, 1.0)) / s.xyxy) + 0.5; let h = vec4f(p - hC.xy * s, p - (hC.zw + 0.5) * s); let first = dot(h.xy, h.xy) < dot(h.zw, h.zw); let local = select(h.zw, h.xy, first); let id = select(hC.zw + 0.5, hC.xy, first); let cell = abs(local); let d = max(dot(cell, s * 0.5), cell.x); return vec4f(d, 0.5, id); } fn triCell(p: vec2f) -> vec4f { let l = vec2f(p.x - p.y * 0.57735027, p.y * 1.15470054); let id = floor(l); let f = l - id; let upper = step(1.0, f.x + f.y); var w = vec2f(f.x + f.y * 0.5, f.y * 0.8660254); w = mix(w, vec2f(1.5, 0.8660254) - w, upper); let d = min( w.y, min( dot(w, vec2f(0.8660254, -0.5)), dot(w - vec2f(1.0, 0.0), vec2f(-0.8660254, -0.5)) ) ); return vec4f(0.2886751 - d, 0.2886751, id * 2.0 + vec2f(upper, 0.0)); } fn squareCell(p: vec2f) -> vec4f { let id = floor(p); let f = fract(p) - 0.5; let a = abs(f); let d = max(a.x, a.y); return vec4f(d, 0.5, id); } fn cellInfo(p: vec2f) -> vec4f { if (params.shape < 0.5) { return hexCell(p); } if (params.shape < 1.5) { return triCell(p); } return squareCell(p); } fn cellFlash(id: vec2f) -> f32 { let rnd = hash21(id); let phase = rnd * 6.2831; let speed = 0.5 + rnd * 1.5; return smoothstep(0.6, 1.0, sin(params.time * params.flashSpeed * speed + phase)) * params.flashIntensity; } @fragment fn fs_main(@location(0) inUv: vec2f) -> FieldOut { let screenUv = vec2f(inUv.x, 1.0 - inUv.y); let frag = screenUv * params.resolution; let minAxis = min(params.resolution.x, params.resolution.y); let pageFrag = vec2f(frag.x, frag.y - params.scroll); let st = pageFrag / minAxis; var revealMask = 1.0; var dissolveEdge = 0.0; if (params.reveal < 0.999) { let dissolve = snoise(vec3f(st * params.dissolveScale, 3.7)) * 0.5 + 0.5; let revealGate = params.reveal * (1.0 + params.dissolveWidth * 2.0) - params.dissolveWidth; revealMask = smoothstep(revealGate - params.dissolveWidth, revealGate, 1.0 - dissolve); revealMask = 1.0 - revealMask; let edgeLow = smoothstep(revealGate - params.dissolveWidth, revealGate - params.dissolveWidth * 0.2, 1.0 - dissolve); let edgeHigh = smoothstep(revealGate - params.dissolveWidth * 0.15, revealGate, 1.0 - dissolve); dissolveEdge = edgeLow * (1.0 - edgeHigh) * step(0.001, params.reveal); } var ringContrib = 0.0; var impactBoost = 0.0; var pushVec = vec2f(0.0); let sigma = params.rippleWidth * mix(0.6, 2.6, params.rippleBlend); for (var i = 0u; i < 10u; i++) { let hit = params.hits[i]; let elapsed = params.time - hit.z; let isActive = step(0.0, hit.z) * step(0.0, elapsed) * step(elapsed, params.rippleDuration); if (isActive < 0.5) { continue; } let toHit = (pageFrag - hit.xy) / minAxis; let dist = length(toHit); let ringR = min(elapsed * params.rippleSpeed, params.rippleMaxRadius); let noiseD = snoise(vec3f(st * 5.0, elapsed * 2.0 + f32(i))) * 0.03 * (1.0 - params.rippleBlend * 0.7); let band = dist + noiseD - ringR; let g = exp(-band * band / (2.0 * sigma * sigma)); var fade = 1.0 - smoothstep(params.rippleDuration * 0.4, params.rippleDuration, elapsed); fade *= fade; let radialFade = 1.0 - smoothstep(params.rippleMaxRadius * 0.75, params.rippleMaxRadius, ringR); let contrib = g * fade * radialFade; ringContrib += contrib; let zone = smoothstep(params.impactRadius, 0.0, dist); let zoneFade = 1.0 - smoothstep(0.0, params.rippleDuration * 0.35, elapsed); impactBoost += zone * zoneFade; let dir = select(vec2f(0.0), toHit / dist, dist > 0.0001); let core = smoothstep(0.0, sigma * 2.5, dist) * smoothstep(0.0, sigma * 1.5, ringR); pushVec += dir * g * fade * radialFade * core; } ringContrib = min(ringContrib, 1.5); impactBoost = min(impactBoost, 1.0); let fieldSt = st - pushVec * (params.refraction * 1.4 / minAxis); let info = cellInfo(fieldSt * params.cellScale); let lineDist = info.x; let halfSize = info.y; let cellId = info.zw; let line = smoothstep(halfSize - params.lineWidth, halfSize, lineDist); let flash = cellFlash(cellId); var flowNoise = 0.0; var hazeVec = vec2f(0.0); if (params.flowIntensity > 0.001 || params.haze > 0.001) { let t = params.time * params.flowSpeed; let fn1 = snoise(vec3f(st * params.flowScale, t * 0.5)); let fn2 = snoise(vec3f(st * params.flowScale * 2.1 + 7.3, -t * 0.35)); flowNoise = (fn1 * 0.6 + fn2 * 0.4) * 0.5 + 0.5; hazeVec = vec2f(fn1, fn2) * params.haze; } let bp = min(frag, params.resolution - frag) / minAxis; let rr = max(params.edgeFalloff, 0.02); let hmix = clamp(0.5 + 0.5 * (bp.y - bp.x) / rr, 0.0, 1.0); let edgeDist = mix(bp.y, bp.x, hmix) - rr * hmix * (1.0 - hmix); let fresnel = pow(1.0 - smoothstep(0.0, params.edgeFalloff, edgeDist), 1.6) * params.edgeGlow; let pageMouse = vec2f(params.mouse.x, params.mouse.y - params.scroll); let mouseSt = pageMouse / minAxis; let mouseD = distance(pageFrag, pageMouse); var hover = exp(-mouseD * mouseD / (params.hoverRadius * params.hoverRadius * 0.5)) * params.hoverGlow; let hoverCell = cellInfo(mouseSt * params.cellScale).zw; let sameCell = 1.0 - step(0.5, distance(hoverCell, cellId)); var charge = sameCell * params.hoverCharge; hover *= 1.0 - params.hideOnHover; charge *= 1.0 - params.hideOnHover; let revealHover = select(0.0, 1.0, params.gridRevealMode == 1.0 || params.gridRevealMode == 3.0); let revealClick = select(0.0, 1.0, params.gridRevealMode == 2.0 || params.gridRevealMode == 3.0); let allowHover = max(revealHover, select(0.0, 1.0, params.gridRevealMode == 0.0)); charge *= allowHover; var hoverMask = 1.0 - smoothstep(params.gridRevealRadius * (1.0 - params.gridFade), params.gridRevealRadius, mouseD); hoverMask *= 1.0 - params.hideOnHover; let gridBoost = (revealHover * hoverMask + revealClick * impactBoost) * params.gridRevealStrength; let gridEnergy = line * (params.gridOpacity + gridBoost + charge + flash + ringContrib * params.rippleIntensity * 5.0); var energy = gridEnergy * (0.35 + fresnel * 0.4) + fresnel * 0.5 + flash * 0.5 + flowNoise * params.flowIntensity * (0.12 + fresnel * 0.25 + line * 0.15) + hover * (0.25 + line * 0.75 * allowHover) + ringContrib * params.rippleIntensity; let hide = 1.0 - params.hideOnHover * (1.0 - smoothstep(params.hoverRadius * 0.35, params.hoverRadius * 1.4, mouseD)); let warp = (-pushVec * params.refraction * 0.7 + hazeVec * 6.0) * revealMask * hide; let refr = warp; let texel = 1.0 / params.resolution; let baseUv = clamp(inUv + refr * texel * vec2f(1.0, -1.0), vec2f(0.0), vec2f(1.0)); var content: vec4f; if (params.hasContent > 0.5) { content = textureSampleLevel(uContent, uSampler, baseUv, 0.0); let ab = params.aberration * min(length(warp), 24.0) / 24.0; if (ab > 0.01) { let abOff = normalize(warp + vec2f(1e-5)) * ab * texel * 3.0; content.r = textureSampleLevel(uContent, uSampler, clamp(baseUv + abOff, vec2f(0.0), vec2f(1.0)), 0.0).r; content.b = textureSampleLevel(uContent, uSampler, clamp(baseUv - abOff, vec2f(0.0), vec2f(1.0)), 0.0).b; } if (params.pageReact > 0.001) { let pageL = dot(content.rgb, vec3f(0.2126, 0.7152, 0.0722)); energy *= mix(1.0, 0.3 + pageL * 1.6, params.pageReact * revealMask); } } else { content = vec4f(0.0); } energy *= revealMask * hide; let dimEff = params.dim * revealMask * (1.0 - hover * 0.5); var col = content.rgb * (1.0 - dimEff); if (params.tint > 0.001) { let membrane = params.color / max(max(params.color.r, max(params.color.g, params.color.b)), 0.001); col *= mix(vec3f(1.0), membrane * 0.92 + 0.08, params.tint * revealMask); } let fieldGlow = params.color * energy * params.opacity; let dissolveGlow = params.edgeColor * dissolveEdge * params.dissolveGlow * hide; let dark = 1.0 - params.pageLum; let darkMix = clamp(dark * 1.4 - 0.2, 0.0, 1.0); let rawAdd = fieldGlow + dissolveGlow; let additive = rawAdd / (1.0 + 0.45 * max(max(rawAdd.r, rawAdd.g), rawAdd.b)); let aMax = max(max(additive.r, additive.g), additive.b); let inked = col * exp(-(vec3f(aMax) - additive) * 1.7) * (1.0 - 0.18 * min(aMax, 1.0)); col = mix(inked, col + additive, darkMix); let alpha = max(content.a, clamp(energy * params.opacity + dissolveEdge, 0.0, 1.0)); col = clamp(col, vec3f(0.0), vec3f(max(alpha, 0.001))); var out: FieldOut; out.color = vec4f(col, alpha); out.emission = vec4f(rawAdd, 1.0); return out; }`; const BRIGHT_SHADER = /* wgsl */ ` struct BrightParams { threshold: f32, } @group(0) @binding(0) var params: BrightParams; @group(0) @binding(1) var uScene: texture_2d; @group(0) @binding(2) var uSampler: sampler; @fragment fn fs_main(@location(0) uv: vec2f) -> @location(0) vec4f { let c = textureSampleLevel(uScene, uSampler, uv, 0.0); let lum = dot(c.rgb, vec3f(0.2126, 0.7152, 0.0722)); let gate = smoothstep(params.threshold, params.threshold + 0.25, lum); return vec4f(c.rgb * gate, 1.0); }`; const KAWASE_DOWN_SHADER = /* wgsl */ ` struct BlurParams { texel: vec2f, } @group(0) @binding(0) var params: BlurParams; @group(0) @binding(1) var uScene: texture_2d; @group(0) @binding(2) var uSampler: sampler; @fragment fn fs_main(@location(0) uv: vec2f) -> @location(0) vec4f { let o = params.texel; var sum = textureSampleLevel(uScene, uSampler, uv, 0.0) * 4.0; sum += textureSampleLevel(uScene, uSampler, uv - o, 0.0); sum += textureSampleLevel(uScene, uSampler, uv + o, 0.0); sum += textureSampleLevel(uScene, uSampler, uv + vec2f(o.x, -o.y), 0.0); sum += textureSampleLevel(uScene, uSampler, uv - vec2f(o.x, -o.y), 0.0); return sum * 0.125; }`; const KAWASE_UP_SHADER = /* wgsl */ ` struct BlurParams { texel: vec2f, } @group(0) @binding(0) var params: BlurParams; @group(0) @binding(1) var uScene: texture_2d; @group(0) @binding(2) var uBase: texture_2d; @group(0) @binding(3) var uSampler: sampler; @fragment fn fs_main(@location(0) uv: vec2f) -> @location(0) vec4f { let o = params.texel; var sum = textureSampleLevel(uScene, uSampler, uv + vec2f(-o.x * 2.0, 0.0), 0.0); sum += textureSampleLevel(uScene, uSampler, uv + vec2f(-o.x, o.y), 0.0) * 2.0; sum += textureSampleLevel(uScene, uSampler, uv + vec2f(0.0, o.y * 2.0), 0.0); sum += textureSampleLevel(uScene, uSampler, uv + vec2f(o.x, o.y), 0.0) * 2.0; sum += textureSampleLevel(uScene, uSampler, uv + vec2f(o.x * 2.0, 0.0), 0.0); sum += textureSampleLevel(uScene, uSampler, uv + vec2f(o.x, -o.y), 0.0) * 2.0; sum += textureSampleLevel(uScene, uSampler, uv + vec2f(0.0, -o.y * 2.0), 0.0); sum += textureSampleLevel(uScene, uSampler, uv + vec2f(-o.x, -o.y), 0.0) * 2.0; let base = textureSampleLevel(uBase, uSampler, uv, 0.0); return mix(base, sum / 12.0, 0.62); }`; const COMPOSITE_SHADER = /* wgsl */ ` struct CompositeParams { resolution: vec2f, bloomStrength: f32, grain: f32, time: f32, pageLum: f32, } @group(0) @binding(0) var params: CompositeParams; @group(0) @binding(1) var uScene: texture_2d; @group(0) @binding(2) var uBloom: texture_2d; @group(0) @binding(3) var uSampler: sampler; fn grainNoise(p: vec2f, t: f32) -> f32 { var v = fract(vec3f(p.xyx) * vec3f(443.897, 441.423, 437.195) + t); v += dot(v, v.yzx + 19.19); return fract((v.x + v.y) * v.z) - 0.5; } @fragment fn fs_main(@location(0) uv: vec2f, @builtin(position) pos: vec4f) -> @location(0) vec4f { let scene = textureSampleLevel(uScene, uSampler, uv, 0.0); let bloom = textureSampleLevel(uBloom, uSampler, uv, 0.0).rgb * params.bloomStrength; let darkMix = clamp((1.0 - params.pageLum) * 1.4 - 0.2, 0.0, 1.0); let bMax = max(max(bloom.r, bloom.g), bloom.b); let inked = scene.rgb * exp(-(vec3f(bMax) - bloom) * 1.1) * (1.0 - 0.1 * min(bMax, 1.0)); var col = mix(inked, scene.rgb + bloom, darkMix); let bloomLum = dot(bloom, vec3f(0.2126, 0.7152, 0.0722)); let alpha = clamp(scene.a + bloomLum, 0.0, 1.0); let g = grainNoise(vec2f(pos.x, params.resolution.y - pos.y), fract(params.time) + 0.1); col += g * params.grain * (0.15 + alpha * 0.25); col = clamp(col, vec3f(0.0), vec3f(max(alpha, 0.001))); return vec4f(col, alpha); }`; export function supportsHtmlInCanvas(): boolean { if (typeof document === "undefined" || isHtmlInCanvasBlocked()) return false; const probe = document.createElement("canvas") as PaintableCanvas; const ctx = probe.getContext("2d") as ElementImageContext | null; return Boolean( ctx && typeof ctx.drawElementImage === "function" && typeof probe.requestPaint === "function", ); } /** True when the browser exposes WebGPU. The device itself is requested lazily. */ export function supportsWebGPU(): boolean { return typeof navigator !== "undefined" && Boolean(navigator.gpu); } let sharedGpu: Promise | null = null; /** One WebGPU device per page, shared by every ForceField instance. */ function acquireGpu(): Promise { if (!sharedGpu) { sharedGpu = init().catch((error) => { sharedGpu = null; throw error; }); } return sharedGpu; } const SHAPE_INDEX: Record = { hexagon: 0, triangle: 1, square: 2, }; const REVEAL_INDEX: Record = { always: 0, hover: 1, click: 2, both: 3, }; const clamp = (value: number, min: number, max: number) => Math.min(Math.max(value, min), max); function destroyTarget(t: Target | null) { (t as unknown as { destroy?: () => void } | null)?.destroy?.(); } export function createForceField( elements: ForceFieldElements, options: ForceFieldOptions = {}, ): ForceFieldInstance | null { if (!supportsWebGPU()) return null; const config = { ...DEFAULTS, ...options }; const { source, content, output } = elements; const sourceCtx = source.getContext("2d") as ElementImageContext | null; const paintable = source as PaintableCanvas; const htmlInCanvas = Boolean( !isHtmlInCanvasBlocked() && source.contains(content) && sourceCtx && typeof sourceCtx.drawElementImage === "function" && typeof paintable.requestPaint === "function", ); if (htmlInCanvas) prepareHtmlInCanvas(source, content); let gpu: Gpu | null = null; let screen: Surface | null = null; let fieldFx: Effect | null = null; let brightFx: Effect | null = null; let downFx: Effect | null = null; let upFx: Effect | null = null; let compositeFx: Effect | null = null; let sceneTarget: Target | null = null; let brightTarget: Target | null = null; const downTargets: Target[] = []; const upTargets: Target[] = []; let contentTexture: Texture | null = null; let fallback2d: CanvasRenderingContext2D | null = null; let contentDirty = false; let pageLum = 0; let wake = () => {}; function readPageLum(): number { try { const probe = document.createElement("canvas"); probe.width = probe.height = 1; const pctx = probe.getContext("2d", { willReadFrequently: true }); if (!pctx) return 0; let el: Element | null = content; while (el instanceof Element) { const bgColor = getComputedStyle(el).backgroundColor; if (bgColor && bgColor !== "transparent") { pctx.clearRect(0, 0, 1, 1); pctx.fillStyle = bgColor; pctx.fillRect(0, 0, 1, 1); const d = pctx.getImageData(0, 0, 1, 1).data; if (d[3] > 128) { return (0.2126 * d[0] + 0.7152 * d[1] + 0.0722 * d[2]) / 255; } } el = el.parentElement; } } catch {} return 0; } if (htmlInCanvas) { paintable.onpaint = () => { try { sourceCtx!.reset(); drawHtmlInCanvas(source, sourceCtx!, content); contentDirty = true; wake(); } catch {} }; } const hitData: [number, number, number, number][] = Array.from( { length: MAX_HITS }, () => [0, 0, -999, 0], ); let hitIndex = 0; let mouseX = -9999; let mouseY = -9999; let dpr = 1; function resizeGpuTargets(width: number, height: number) { if (!sceneTarget || !brightTarget) return; if (sceneTarget.size[0] !== width || sceneTarget.size[1] !== height) { sceneTarget.resize([width, height]); } let bw = Math.max(1, width >> 1); let bh = Math.max(1, height >> 1); if (brightTarget.size[0] !== bw || brightTarget.size[1] !== bh) { brightTarget.resize([bw, bh]); } for (let i = 0; i < MIPS; i++) { bw = Math.max(1, bw >> 1); bh = Math.max(1, bh >> 1); const down = downTargets[i]; if (down.size[0] !== bw || down.size[1] !== bh) down.resize([bw, bh]); } for (let i = MIPS - 1; i >= 0; i--) { const up = i === 0 ? brightTarget : downTargets[i - 1]; const targetUp = upTargets[i]; if (targetUp.size[0] !== up.size[0] || targetUp.size[1] !== up.size[1]) { targetUp.resize([up.size[0], up.size[1]]); } } } function syncCanvasSize() { dpr = getCanvasPixelRatio(output); const width = Math.max(1, Math.round(output.clientWidth * dpr)); const height = Math.max(1, Math.round(output.clientHeight * dpr)); if (screen) { const [w, h] = screen.size; if (w !== width || h !== height) screen.resize([width, height]); } else if (output.width !== width || output.height !== height) { output.width = width; output.height = height; } resizeGpuTargets(width, height); if (htmlInCanvas) { const sourceWidth = Math.max(1, Math.round(source.clientWidth * dpr)); const sourceHeight = Math.max(1, Math.round(source.clientHeight * dpr)); if ( source.width !== sourceWidth || source.height !== sourceHeight ) { source.width = sourceWidth; source.height = sourceHeight; } paintable.requestPaint!(); } } syncCanvasSize(); function ensureContentTexture(): Texture { const w = Math.max(1, source.width); const h = Math.max(1, source.height); if ( !contentTexture || contentTexture.size[0] !== w || contentTexture.size[1] !== h ) { // A new wrapper invalidates vgpu's cached bindings to the old texture. contentTexture?.destroy(); contentTexture = gpu!.device.createTexture({ size: [w, h], format: "rgba8unorm", usage: ["texture_binding", "copy_dst", "render_attachment"], label: "force-field.content", }); } return contentTexture; } function uploadContent() { if (!htmlInCanvas || !contentDirty || !gpu) return; contentDirty = false; pageLum = readPageLum(); const texture = ensureContentTexture(); gpu.gpu.queue.copyExternalImageToTexture( { source }, { texture: texture.gpu }, [source.width, source.height], ); fieldFx?.set({ uContent: texture }); sourceCtx!.clearRect(0, 0, source.width, source.height); } function renderFallback() { if (!fallback2d || !htmlInCanvas || !contentDirty) return; contentDirty = false; fallback2d.clearRect(0, 0, output.width, output.height); fallback2d.drawImage(source, 0, 0, output.width, output.height); sourceCtx!.clearRect(0, 0, source.width, source.height); } let time = 3.7; function render() { if ( !gpu || !screen || !fieldFx || !brightFx || !downFx || !upFx || !compositeFx || !sceneTarget || !brightTarget ) return; uploadContent(); const width = output.width; const height = output.height; fieldFx.set({ params: { hits: hitData, resolution: [width, height], time, shape: SHAPE_INDEX[config.shape] ?? 0, color: config.color, edgeColor: config.edgeColor, opacity: clamp(config.opacity, 0, 1), cellScale: clamp(config.cellScale, 4, 80), lineWidth: clamp(config.lineWidth, 0.005, 0.2), gridOpacity: clamp(config.gridOpacity, 0, 1), gridRevealMode: REVEAL_INDEX[config.gridReveal] ?? 2, gridRevealStrength: clamp(config.gridRevealStrength, 0, 3), gridRevealRadius: clamp(config.gridRevealRadius, 60, 800) * dpr, gridFade: clamp(config.gridFade, 0.02, 1), flashSpeed: clamp(config.flashSpeed, 0, 4), flashIntensity: clamp(config.flashIntensity, 0, 1), flowScale: clamp(config.flowScale, 0.5, 12), flowSpeed: clamp(config.flowSpeed, 0, 4), flowIntensity: clamp(config.flowIntensity, 0, 4), edgeGlow: clamp(config.edgeGlow, 0, 4), edgeFalloff: clamp(config.edgeFalloff, 0.02, 0.6), reveal: clamp(config.reveal, 0, 1), dissolveScale: clamp(config.dissolveScale, 0.5, 12), dissolveWidth: clamp(config.dissolveWidth, 0.005, 0.2), dissolveGlow: clamp(config.dissolveGlow, 0, 12), rippleSpeed: clamp(config.rippleSpeed, 0.1, 4), rippleWidth: clamp(config.rippleWidth, 0.01, 0.4), rippleBlend: clamp(config.rippleBlend, 0, 1), rippleDuration: clamp(config.rippleDuration, 0.3, 5), rippleIntensity: clamp(config.rippleIntensity, 0, 8), rippleMaxRadius: clamp(config.rippleMaxRadius, 0.1, 2), impactRadius: clamp(config.impactRadius, 0, 0.5), refraction: clamp(config.refraction, 0, 60), aberration: clamp(config.aberration, 0, 8), haze: clamp(config.haze, 0, 2), pageReact: clamp(config.pageReact, 0, 1), tint: clamp(config.tint, 0, 1), mouse: [mouseX * dpr, height - mouseY * dpr], hoverGlow: clamp(config.hoverGlow, 0, 3), hoverRadius: clamp(config.hoverRadius, 40, 600) * dpr, hoverCharge: clamp(config.hoverCharge, 0, 2), hideOnHover: config.hideOnHover ? 1 : 0, scroll: content.scrollTop * dpr, dim: clamp(config.dim, 0, 1), hasContent: htmlInCanvas ? 1 : 0, pageLum, }, }); const bloomOn = config.bloom > 0.001; gpuFrame(gpu, (f) => { f.pass(sceneTarget!, fieldFx!); if (bloomOn) { brightFx!.set({ uScene: sceneTarget!.colors[1], params: { threshold: clamp(config.bloomThreshold, 0, 1) }, }); f.pass(brightTarget!, brightFx!); let src: Target = brightTarget!; for (let i = 0; i < MIPS; i++) { const dst = downTargets[i]; downFx!.set({ uScene: src, params: { texel: [0.5 / src.size[0], 0.5 / src.size[1]] }, }); f.pass(dst, downFx!); src = dst; } for (let i = MIPS - 1; i >= 0; i--) { const base = i === 0 ? brightTarget! : downTargets[i - 1]; const dst = upTargets[i]; upFx!.set({ uScene: src, uBase: base, params: { texel: [1 / src.size[0], 1 / src.size[1]] }, }); f.pass(dst, upFx!); src = dst; } } compositeFx!.set({ uScene: sceneTarget!, uBloom: bloomOn ? upTargets[0] : sceneTarget!, params: { resolution: [width, height], bloomStrength: bloomOn ? clamp(config.bloom, 0, 3) : 0, grain: clamp(config.grain, 0, 1), time, pageLum, }, }); f.pass(screen!, compositeFx!); }); } let raf = 0; let lastTime = performance.now(); let lastDraw = 0; let lastInput = 0; let destroyed = false; let running = false; let visible = true; const motionQuery = window.matchMedia("(prefers-reduced-motion: reduce)"); let reducedMotion = motionQuery.matches; function frame(now: number) { if (destroyed) return; if (!visible) { running = false; return; } if (fallback2d) { renderFallback(); running = false; return; } if (!gpu) { running = false; return; } const delta = Math.min((now - lastTime) / 1000, 1 / 30); lastTime = now; if (!reducedMotion) time += delta; let ripplesLive = false; for (let i = 0; i < MAX_HITS; i++) { if ( hitData[i][2] > -900 && time - hitData[i][2] < config.rippleDuration + 0.3 ) { ripplesLive = true; break; } } const active = ripplesLive || now - lastInput < 500 || reducedMotion || contentDirty; if (active || now - lastDraw >= 31) { render(); lastDraw = now; } if (reducedMotion && !contentDirty) { running = false; return; } raf = requestAnimationFrame(frame); } function start() { if (destroyed || running || !visible) return; running = true; lastTime = performance.now(); raf = requestAnimationFrame(frame); } wake = start; acquireGpu() .then((device) => { if (destroyed) return; gpu = device; screen = surface(gpu, output, { autoResize: false, alphaMode: "premultiplied", label: "force-field", }); sceneTarget = target(gpu, { size: [Math.max(1, output.width), Math.max(1, output.height)], colors: [{ format: "rgba8unorm" }, { format: "rgba16float" }], label: "force-field.scene", }); brightTarget = target(gpu, { size: [2, 2], format: "rgba16float", label: "force-field.bright", }); for (let i = 0; i < MIPS; i++) { downTargets.push( target(gpu, { size: [2, 2], format: "rgba16float", label: `force-field.down-${i}`, }), ); upTargets.push( target(gpu, { size: [2, 2], format: "rgba16float", label: `force-field.up-${i}`, }), ); } const linear = sampler(gpu, { minFilter: "linear", magFilter: "linear", addressModeU: "clamp-to-edge", addressModeV: "clamp-to-edge", }); fieldFx = effect(gpu, FIELD_SHADER, { label: "force-field.field", set: { uSampler: linear, uContent: ensureContentTexture() }, }); brightFx = effect(gpu, BRIGHT_SHADER, { label: "force-field.bright", set: { uSampler: linear }, }); downFx = effect(gpu, KAWASE_DOWN_SHADER, { label: "force-field.down", set: { uSampler: linear }, }); upFx = effect(gpu, KAWASE_UP_SHADER, { label: "force-field.up", set: { uSampler: linear }, }); compositeFx = effect(gpu, COMPOSITE_SHADER, { label: "force-field.composite", set: { uSampler: linear }, }); syncCanvasSize(); start(); }) .catch((error) => { if (destroyed) return; console.warn( "ForceField: WebGPU unavailable, showing content without the effect.", error, ); fallback2d = output.getContext("2d"); contentDirty = true; start(); }); function spawnHit(x: number, y: number) { const idx = hitIndex % MAX_HITS; hitIndex++; hitData[idx][0] = x * dpr; hitData[idx][1] = output.height - y * dpr - content.scrollTop * dpr; hitData[idx][2] = time; lastInput = performance.now(); start(); } function onPointerDown(event: PointerEvent) { if (!config.clickRipples) return; const rect = output.getBoundingClientRect(); const x = event.clientX - rect.left; const y = event.clientY - rect.top; spawnHit(x, y); config.onHit?.(x, y); } const rectCache = createRectCache(output); function onPointerMove(event: PointerEvent) { const rect = rectCache.current; mouseX = event.clientX - rect.left; mouseY = event.clientY - rect.top; lastInput = performance.now(); start(); } function onPointerLeave() { mouseX = -9999; mouseY = -9999; } content.addEventListener("pointerdown", onPointerDown); content.addEventListener("pointermove", onPointerMove, { passive: true }); content.addEventListener("pointerleave", onPointerLeave); function onMotionChange() { reducedMotion = motionQuery.matches; start(); } motionQuery.addEventListener("change", onMotionChange); function onScroll() { lastInput = performance.now(); start(); } content.addEventListener("scroll", onScroll, { passive: true }); const observer = createCanvasResizeObserver(() => { syncCanvasSize(); start(); }); observer.observe(output); observer.observe(content); const intersection = new IntersectionObserver((entries) => { visible = entries[entries.length - 1]?.isIntersecting ?? true; if (visible) start(); }); intersection.observe(output); return { setOptions(next) { let changed = false; for (const [key, value] of Object.entries(next)) { if (typeof value === "function") continue; const prev = config[key as keyof typeof config]; if (Array.isArray(value) && Array.isArray(prev)) { if ( value.length !== prev.length || value.some((item, i) => item !== prev[i]) ) { changed = true; break; } } else if (prev !== value) { changed = true; break; } } Object.assign(config, next); if (!changed) return; syncCanvasSize(); start(); }, impact(x, y) { spawnHit(x, y); }, resize() { syncCanvasSize(); start(); }, destroy() { destroyed = true; rectCache.destroy(); cancelAnimationFrame(raf); observer.disconnect(); intersection.disconnect(); motionQuery.removeEventListener("change", onMotionChange); content.removeEventListener("scroll", onScroll); content.removeEventListener("pointerdown", onPointerDown); content.removeEventListener("pointermove", onPointerMove); content.removeEventListener("pointerleave", onPointerLeave); contentTexture?.destroy(); destroyTarget(sceneTarget); destroyTarget(brightTarget); for (const target of [...downTargets, ...upTargets]) destroyTarget(target); screen?.dispose(); if (htmlInCanvas) paintable.onpaint = null; }, }; } function useSyncExternalStore( subscribe: (onStoreChange: () => void) => () => void, getSnapshot: () => T, ): T { const [value, setValue] = useState(getSnapshot); useEffect(() => { const unsubscribe = subscribe(() => setValue(getSnapshot())); return unsubscribe; }, [subscribe, getSnapshot]); return value; } export interface ForceFieldProps extends ForceFieldOptions { children: ComponentChildren; className?: string; style?: JSX.CSSProperties; } const emptySubscribe = () => () => {}; export function ForceField({ children, className, style, ...options }: ForceFieldProps) { const sourceRef = useRef(null); const contentRef = useRef(null); const outputRef = useRef(null); const instanceRef = useRef(null); const [initialOptions] = useState(options); const [failed, setFailed] = useState(false); const supported = useSyncExternalStore(emptySubscribe, supportsHtmlInCanvas); const native = supported && !failed; useEffect(() => { const source = sourceRef.current; const content = contentRef.current; const output = outputRef.current; if (!source || !content || !output) return; instanceRef.current = createForceField( { source, content, output }, initialOptions, ); if (native && !instanceRef.current) setFailed(true); return () => { instanceRef.current?.destroy(); instanceRef.current = null; }; }, [initialOptions, native]); useEffect(() => { instanceRef.current?.setOptions(options); }); const sourceRefCallback = useCallback((el: HTMLCanvasElement | null) => { sourceRef.current = el; if (el) el.setAttribute("layoutsubtree", "true"); }, []); return (

{!native ? (

{children}

) : null}

); } export default ForceField;