"use client";
import { Renderer, Program, Mesh, Color, Triangle, RenderTarget } from "ogl";
import { useEffect, useRef, CSSProperties } from "react";
import { useAnimationLoop, type Metrics } from "@/hooks/use-animation-loop";
const MAX_STRANDS = 12;
const MAX_COLORS = 8;
const VERT = `#version 300 es
in vec2 position;
void main() {
gl_Position = vec4(position, 0.0, 1.0);
}
`;
const FRAG = `#version 300 es
precision highp float;
uniform float uTime;
uniform vec2 uResolution;
uniform vec3 uColors[${MAX_COLORS}];
uniform int uColorCount;
uniform int uStrandCount;
uniform float uSpeed;
uniform float uAmplitude;
uniform float uWaviness;
uniform float uThickness;
uniform float uGlow;
uniform float uTaper;
uniform float uSpread;
uniform float uHueShift;
uniform float uIntensity;
uniform float uOpacity;
uniform float uScale;
uniform float uSaturation;
uniform float uEnvWidth;
uniform float uBrightTaper;
out vec4 fragColor;
const float PI = 3.14159265;
vec3 spectrum(float t) {
return 0.5 + 0.5 * cos(2.0 * PI * (t + vec3(0.00, 0.33, 0.67)));
}
vec3 samplePalette(float t) {
t = fract(t);
float scaled = t * float(uColorCount);
int idx = int(floor(scaled));
float blend = fract(scaled);
int nextIdx = idx + 1;
if (nextIdx >= uColorCount) nextIdx = 0;
return mix(uColors[idx], uColors[nextIdx], blend);
}
vec3 strandColor(float t) {
if (uColorCount > 0) return samplePalette(t);
return spectrum(t);
}
void main() {
vec2 uv = (gl_FragCoord.xy - 0.5 * uResolution) / uResolution.y;
uv /= max(uScale, 0.0001);
float e = 0.06 + uIntensity * 0.94;
// Envelope half-width in strand uv-space — when the glass is on it equals the
// lens rim, so strand tips land exactly on the glass edge. Amplitude keeps the
// full taper (waves converge to the center line, which meets the circle at
// x = ±r). Brightness falloff is mode-aware via uBrightTaper: a gentle power
// under glass so tips stay visible until they touch the rim, the full taper
// without glass so light dissolves in a soft gradient instead of hitting the
// envelope clamp at near-full strength.
float nx = clamp(abs(uv.x) / uEnvWidth, 0.0, 1.0);
float envCos = cos(nx * PI * 0.5);
float env = pow(envCos, uTaper);
float bright = pow(envCos, uBrightTaper);
vec3 col = vec3(0.0);
for (int i = 0; i < ${MAX_STRANDS}; i++) {
if (i >= uStrandCount) break;
float fi = float(i);
float ph = fi * 1.7 * uSpread;
float freq = (2.0 + fi * 0.35) * uWaviness;
float spd = 1.4 + fi * 1.2;
float tt = uTime * uSpeed;
float w = sin(uv.x * freq + tt * spd + ph) * 0.60
+ sin(uv.x * freq * 1.1 - tt * spd * 0.7 + ph * 1.7) * 0.40;
float amp = (0.1 + 0.02 * e) * env * uAmplitude;
float y = w * amp;
float d = abs(uv.y - y);
float thick = (0.001 + 0.05 * e) * (0.35 + env) * uThickness;
float g = thick / (d + thick * 0.45);
g = g * g;
float h = fi / float(uStrandCount) + uv.x * 0.30 + uTime * 0.04 + uHueShift;
col += strandColor(h) * g * bright;
}
col *= 0.45 + 0.7 * e;
col = 1.0 - exp(-col * uGlow);
float gray = dot(col, vec3(0.2126, 0.7152, 0.0722));
col = max(mix(vec3(gray), col, uSaturation), 0.0);
float lum = max(max(col.r, col.g), col.b);
float alpha = clamp(lum, 0.0, 1.0) * uOpacity;
fragColor = vec4(col * uOpacity, alpha);
}
`;
const GLASS_FRAG = `#version 300 es
precision highp float;
uniform sampler2D uScene;
uniform vec2 uResolution;
uniform float uRadius;
uniform float uRefraction;
uniform float uDispersion;
out vec4 fragColor;
vec2 toUv(vec2 p) {
return p * (uResolution.y / uResolution) + 0.5;
}
void main() {
vec2 p = (gl_FragCoord.xy - 0.5 * uResolution) / uResolution.y;
float d = length(p);
float r = uRadius;
float edge = fwidth(d) * 1.5;
float mask = 1.0 - smoothstep(r - edge, r + edge, d);
if (mask <= 0.0) {
fragColor = vec4(0.0);
return;
}
// sphere height: 0 at the rim, 1 at the center
float z = sqrt(max(r * r - d * d, 0.0)) / r;
float nd = d / r; // 0 at the center, 1 at the rim
// refraction is confined to a narrow band near the rim; the rest stays undistorted
vec2 dir = d > 0.0 ? p / d : vec2(0.0);
float lens = smoothstep(0.85, 1.0, nd) * pow(nd, 6.0);
vec2 offset = -dir * lens * uRefraction * 0.15;
vec2 disp = -dir * lens * uDispersion * 0.012;
vec3 light;
light.r = texture(uScene, toUv(p + offset - disp)).r;
light.g = texture(uScene, toUv(p + offset)).g;
light.b = texture(uScene, toUv(p + offset + disp)).b;
// neutral fresnel rim (no color tint so the glass stays clear)
float fres = pow(1.0 - z, 3.0);
vec3 rim = vec3(1.0) * fres * 0.18;
// specular highlight from the upper-left
vec2 lightDir = normalize(vec2(-0.55, 0.6));
float spec = pow(max(dot(p / max(r, 1e-4), lightDir), 0.0), 6.0);
spec *= smoothstep(r, r * 0.55, d);
vec3 emissive = light + rim + vec3(spec) * 0.4;
float emissiveA = clamp(max(max(emissive.r, emissive.g), emissive.b), 0.0, 1.0);
// almost clear glass body: only a faint neutral darkening, mostly near the rim
float bodyA = 0.05 + fres * 0.05;
// composite emissive light over the clear body (premultiplied)
float outA = emissiveA + bodyA * (1.0 - emissiveA);
vec3 outRGB = emissive;
outRGB *= mask;
outA *= mask;
fragColor = vec4(outRGB, outA);
}
`;
export interface StrandsProps {
colors?: string[];
count?: number;
speed?: number;
amplitude?: number;
waviness?: number;
thickness?: number;
strandWidth?: number;
glow?: number;
taper?: number;
spread?: number;
hueShift?: number;
intensity?: number;
saturation?: number;
opacity?: number;
scale?: number;
glass?: boolean;
refraction?: number;
dispersion?: number;
glassSize?: number;
paused?: boolean;
className?: string;
style?: CSSProperties;
}
const buildPalette = (colors: string[]): number[][] => {
const filled = colors && colors.length ? colors : ["#ffffff"];
const padded: number[][] = [];
for (let i = 0; i < MAX_COLORS; i++) {
const hex = filled[i] ?? filled[filled.length - 1];
const c = new Color(hex);
padded.push([c.r, c.g, c.b]);
}
return padded;
};
export default function Strands({
colors = ["#FF4242", "#7C3AED", "#06B6D4", "#EAB308"],
count = 13,
speed = 0.8,
amplitude = 1.25,
waviness = 1,
thickness = 1.55,
strandWidth = 100,
glow = 0.25,
taper = 3,
spread = 1.65,
hueShift = 0,
intensity = 1,
saturation = 1,
opacity = 0.9,
scale = 0.9,
glass = true,
refraction = 1.3,
dispersion = 0.5,
glassSize = 1,
paused = false,
className = "",
style,
}: StrandsProps) {
const propsRef = useRef<
Required<Omit<StrandsProps, "className" | "style" | "paused">>
>({
colors,
count,
speed,
amplitude,
waviness,
thickness,
strandWidth,
glow,
taper,
spread,
hueShift,
intensity,
saturation,
opacity,
scale,
glass,
refraction,
dispersion,
glassSize,
});
propsRef.current = {
colors,
count,
speed,
amplitude,
waviness,
thickness,
strandWidth,
glow,
taper,
spread,
hueShift,
intensity,
saturation,
opacity,
scale,
glass,
refraction,
dispersion,
glassSize,
};
const ctnDom = useRef<HTMLDivElement>(null);
const pausedRef = useRef(paused);
pausedRef.current = paused;
const drawRef = useRef<((t: number) => void | false) | null>(null);
const measureRef = useRef<((m: Metrics) => void) | null>(null);
const glRef = useRef<WebGLRenderingContext | WebGL2RenderingContext | null>(
null,
);
const loop = useAnimationLoop({
target: ctnDom,
halted: paused,
dpr: 2,
onResize: (metrics) => measureRef.current?.(metrics),
onFrame: ({ now }) => (drawRef.current ? drawRef.current(now) : false),
gl: () => glRef.current,
});
useEffect(() => {
const ctn = ctnDom.current;
if (!ctn) return;
const renderer = new Renderer({
alpha: true,
premultipliedAlpha: true,
antialias: true,
});
const gl = renderer.gl;
gl.clearColor(0, 0, 0, 0);
gl.enable(gl.BLEND);
gl.blendFunc(gl.ONE, gl.ONE_MINUS_SRC_ALPHA);
gl.canvas.style.backgroundColor = "transparent";
const geometry = new Triangle(gl);
if (geometry.attributes.uv) {
delete geometry.attributes.uv;
}
const bw = gl.drawingBufferWidth || ctn.offsetWidth;
const bh = gl.drawingBufferHeight || ctn.offsetHeight;
const program = new Program(gl, {
vertex: VERT,
fragment: FRAG,
uniforms: {
uTime: { value: 0 },
uResolution: { value: [bw, bh] },
uColors: { value: buildPalette(propsRef.current.colors) },
uColorCount: {
value: Math.min(propsRef.current.colors.length, MAX_COLORS),
},
uStrandCount: { value: Math.min(propsRef.current.count, MAX_STRANDS) },
uSpeed: { value: speed },
uAmplitude: { value: amplitude },
uWaviness: { value: waviness },
uThickness: { value: thickness },
uGlow: { value: glow },
uTaper: { value: taper },
uSpread: { value: spread },
uHueShift: { value: hueShift },
uIntensity: { value: intensity },
uOpacity: { value: opacity },
uScale: { value: scale },
uSaturation: { value: saturation },
uEnvWidth: {
value:
(glass ? 0.46 * glassSize : 0.3846) *
Math.min(Math.max(strandWidth, 1), 100) *
0.01,
},
uBrightTaper: { value: taper * (glass ? 0.3 : 1) },
},
});
const mesh = new Mesh(gl, { geometry, program });
const renderTarget = new RenderTarget(gl, {
width: bw,
height: bh,
});
const glassProgram = new Program(gl, {
vertex: VERT,
fragment: GLASS_FRAG,
uniforms: {
uScene: { value: renderTarget.texture },
uResolution: { value: [bw, bh] },
uRadius: { value: 0.46 * glassSize * scale },
uRefraction: { value: refraction },
uDispersion: { value: dispersion },
},
});
const glassMesh = new Mesh(gl, { geometry, program: glassProgram });
gl.canvas.style.position = "absolute";
gl.canvas.style.top = "0";
gl.canvas.style.left = "0";
ctn.appendChild(gl.canvas);
glRef.current = gl;
measureRef.current = ({
width,
height,
dpr,
bufferWidth,
bufferHeight,
}) => {
renderer.dpr = dpr;
renderer.setSize(width, height);
const targetBw = gl.drawingBufferWidth || bufferWidth;
const targetBh = gl.drawingBufferHeight || bufferHeight;
program.uniforms.uResolution.value = [targetBw, targetBh];
renderTarget.setSize(targetBw, targetBh);
glassProgram.uniforms.uResolution.value = [targetBw, targetBh];
};
let lastT = -1;
let accum = 0;
const update = (t: number) => {
const dt = lastT >= 0 ? t - lastT : 0;
lastT = t;
const current = propsRef.current;
if (!pausedRef.current) accum += dt;
program.uniforms.uTime.value = accum * 0.001;
program.uniforms.uColors.value = buildPalette(current.colors);
program.uniforms.uColorCount.value = Math.min(
current.colors.length,
MAX_COLORS,
);
program.uniforms.uStrandCount.value = Math.min(
Math.max(Math.round(current.count), 1),
MAX_STRANDS,
);
program.uniforms.uSpeed.value = current.speed;
program.uniforms.uAmplitude.value = current.amplitude;
program.uniforms.uWaviness.value = current.waviness;
program.uniforms.uThickness.value = current.thickness;
program.uniforms.uGlow.value = current.glow;
program.uniforms.uTaper.value = current.taper;
program.uniforms.uSpread.value = current.spread;
program.uniforms.uHueShift.value = current.hueShift;
program.uniforms.uIntensity.value = current.intensity;
program.uniforms.uOpacity.value = current.opacity;
program.uniforms.uScale.value = current.scale;
program.uniforms.uSaturation.value = current.saturation;
program.uniforms.uEnvWidth.value =
(current.glass ? 0.46 * current.glassSize : 0.3846) *
Math.min(Math.max(current.strandWidth, 1), 100) *
0.01;
program.uniforms.uBrightTaper.value =
current.taper * (current.glass ? 0.3 : 1);
if (current.glass) {
renderer.render({ scene: mesh, target: renderTarget });
glassProgram.uniforms.uScene.value = renderTarget.texture;
glassProgram.uniforms.uRefraction.value = current.refraction;
glassProgram.uniforms.uDispersion.value = current.dispersion;
glassProgram.uniforms.uRadius.value =
0.46 * current.glassSize * current.scale;
renderer.render({ scene: glassMesh });
} else {
renderer.render({ scene: mesh });
}
if (pausedRef.current) return false;
};
drawRef.current = update;
loop.resize();
loop.start();
return () => {
drawRef.current = null;
measureRef.current = null;
if (ctn && gl.canvas.parentNode === ctn) {
ctn.removeChild(gl.canvas);
}
};
// eslint-disable-next-line react-hooks/exhaustive-deps
}, []);
return (
<div
ref={ctnDom}
className={`relative h-full w-full bg-transparent ${className}`}
style={style}
/>
);
}