Lissajous Trace

A canvas and a module script, nothing to install. Set canvas.dataset.tps from your stream, or call canvas.token() once per token.

<canvas id="shader-lissajous-trace" data-tps="9" data-color="#5ce1ff" style="display:block;width:100%;height:240px;border-radius:12px"></canvas>
<script type="module">
  // Set canvas.dataset.tps from your stream, or call canvas.token() per token.
  const canvas = document.getElementById("shader-lissajous-trace");
  const gl = canvas.getContext("webgl2", { alpha: false, antialias: false });
  const fragment = `#version 300 es
precision highp float;
uniform vec3 iResolution;
uniform float iTime;
uniform float uTokens;
uniform float uTps;
uniform vec3 uColor;
out vec4 outColor;
#define TAU 6.28318530718
float hash11(float p) { p = fract(p * 0.1031); p *= p + 33.33; p *= p + p; return fract(p); }
float hash12(vec2 p) { vec3 q = fract(vec3(p.xyx) * 0.1031); q += dot(q, q.yzx + 33.33); return fract((q.x + q.y) * q.z); }
// the accent, lifted so a dark pick still glows
vec3 accent() { return uColor / max(0.25, max(uColor.r, max(uColor.g, uColor.b))); }
// rotate a colour's hue around the grey axis, for a companion tone
vec3 hueRot(vec3 c, float a) {
  const vec3 k = vec3(0.57735027);
  float ca = cos(a);
  return max(c * ca + cross(k, c) * sin(a) + k * dot(k, c) * (1.0 - ca), 0.0);
}
// 0 at rest, toward 1 as the stream speeds up
float energy() { return 1.0 - exp(-max(uTps, 0.0) / 90.0); }
vec3 stage(vec2 uv) { return vec3(0.008, 0.009, 0.013) + accent() * 0.016 * exp(-dot(uv, uv) * 2.2); }
// soft shoulder so hot cores bloom toward white, plus a dither against banding
vec4 finish(vec3 c, vec2 fc) {
  c = 1.0 - exp(-max(c, 0.0) * 1.35);
  c += (hash12(fc) + hash12(fc + 17.13) - 1.0) / 255.0;
  return vec4(c, 1.0);
}

const vec2 AMP = vec2(0.82, 0.38);
vec2 curve(float s, float dl) { return AMP * vec2(sin(3.0 * s + dl), sin(2.0 * s)); }
vec2 dcurve(float s, float dl) { return AMP * vec2(3.0 * cos(3.0 * s + dl), 2.0 * cos(2.0 * s)); }

// nearest point on the figure near parameter s, by two Gauss-Newton steps
float nearest(vec2 p, float s, float dl) {
  for (int k = 0; k < 2; k++) {
    vec2 c = curve(s, dl) - p;
    vec2 t = dcurve(s, dl);
    s -= clamp(dot(c, t) / max(dot(t, t), 1e-3), -0.25, 0.25);
  }
  return s;
}

void mainImage(out vec4 fragColor, in vec2 fragCoord) {
  vec2 uv = (fragCoord - 0.5 * iResolution.xy) / iResolution.y;
  float px = 1.0 / iResolution.y;
  float e = energy();
  vec3 A = accent();
  vec3 B = hueRot(A, 1.0);
  vec3 col = stage(uv);

  // faint axes for the figure to sit in
  col += A * 0.05 * smoothstep(px, 0.0, abs(uv.y)) * step(abs(uv.x), 0.9);
  col += A * 0.05 * smoothstep(px, 0.0, abs(uv.x)) * step(abs(uv.y), 0.42);

  float dl = mod(iTime * 0.12, TAU);
  float S = mod(uTokens * 0.032 + iTime * 0.22, TAU);
  // the trail holds about half a second of travel, so speed lays down more ink
  float speed = 0.032 * uTps + 0.22;
  float len = clamp(0.5 + speed * 0.5, 0.6, 5.4);

  // the figure crosses each height four times: start from those, then refine
  float a = 0.5 * asin(clamp(uv.y / AMP.y, -1.0, 1.0));
  vec4 seeds = vec4(a, 1.5707963 - a, a + 3.1415927, 4.712389 - a);
  float I = 0.0, base = 0.0, age = 1.0;
  for (int i = 0; i < 4; i++) {
    float s = nearest(uv, seeds[i], dl);
    float d = length(curve(s, dl) - uv);
    float g = smoothstep(0.0024 + px, 0.0024 - px * 0.5, d) + exp(-d * 75.0) * 0.4 + exp(-d * 18.0) * 0.07;
    float ag = mod(S - s, TAU) / len;
    // at a blur of speed the whole figure glows, so the gradient never spins
    float fade = ag < 1.0 ? mix(pow(1.0 - ag, 1.4), 0.7, smoothstep(150.0, 700.0, uTps)) : 0.0;
    if (g * fade > I) { I = g * fade; age = ag; }
    base = max(base, smoothstep(0.0016 + px, 0.0016 - px * 0.5, d));
  }
  // the whole path, waiting to be drawn
  col += B * base * 0.12;
  col += mix(mix(A, vec3(1.0), 0.35), B, clamp(age, 0.0, 1.0)) * I * (0.75 + 0.45 * e);

  // the pen, softer once it is a blur
  vec2 head = curve(S, dl);
  float dh = length(uv - head);
  float sharp = 1.0 - 0.6 * smoothstep(100.0, 500.0, uTps);
  col += vec3(1.0) * smoothstep(0.009 + px, 0.009 - px, dh) * sharp;
  col += A * (exp(-dh * 45.0) * 0.6 + exp(-dh * 12.0) * 0.15) * (0.6 + 0.4 * e);
  fragColor = finish(col, fragCoord);
}

void main() {
  mainImage(outColor, gl_FragCoord.xy);
  outColor.a = 1.0;
}
`;
  const vertex = `#version 300 es
void main() {
  vec2 p = vec2((gl_VertexID << 1) & 2, gl_VertexID & 2);
  gl_Position = vec4(p * 2.0 - 1.0, 0.0, 1.0);
}
`;
  const compile = (type, src) => {
    const s = gl.createShader(type);
    gl.shaderSource(s, src);
    gl.compileShader(s);
    if (!gl.getShaderParameter(s, gl.COMPILE_STATUS)) throw new Error(gl.getShaderInfoLog(s));
    return s;
  };
  const program = gl.createProgram();
  gl.attachShader(program, compile(gl.VERTEX_SHADER, vertex));
  gl.attachShader(program, compile(gl.FRAGMENT_SHADER, fragment));
  gl.linkProgram(program);
  gl.useProgram(program);
  const u = (n) => gl.getUniformLocation(program, n);
  const [res, time, tokens, rate, color] = ["iResolution", "iTime", "uTokens", "uTps", "uColor"].map(u);
  const hex = parseInt((canvas.dataset.color || "#7c5cff").slice(1), 16);
  gl.uniform3f(color, ((hex >> 16) & 255) / 255, ((hex >> 8) & 255) / 255, (hex & 255) / 255);

  // canvas.token(): count real tokens and derive the rate from the last second.
  const stamps = [];
  canvas.token = () => {
    stamps.push(performance.now());
    canvas.dataset.tps = "auto";
  };
  const still = matchMedia("(prefers-reduced-motion: reduce)").matches;
  let count = 0, last = performance.now(), visible = true, frame = 0;
  new IntersectionObserver(([e]) => {
    visible = e.isIntersecting;
    if (visible && !frame) frame = requestAnimationFrame(draw);
  }).observe(canvas);

  function draw(now) {
    frame = 0;
    const dt = Math.min((now - last) / 1000, 0.1);
    last = now;
    while (stamps.length && now - stamps[0] > 1000) stamps.shift();
    const wobble = 1 + 0.25 * Math.sin(now / 588) + 0.15 * Math.sin(now / 233 + 1) + 0.08 * Math.sin(now / 91 + 2);
    const tps = canvas.dataset.tps === "auto" ? stamps.length : Number(canvas.dataset.tps) * wobble;
    count += tps * dt;
    const dpr = Math.min(devicePixelRatio || 1, 2);
    const w = Math.round(canvas.clientWidth * dpr), h = Math.round(canvas.clientHeight * dpr);
    if (canvas.width !== w || canvas.height !== h) { canvas.width = w; canvas.height = h; }
    gl.viewport(0, 0, w, h);
    gl.uniform3f(res, w, h, 1);
    gl.uniform1f(time, still ? 2 : now / 1000);
    gl.uniform1f(tokens, still ? Number(canvas.dataset.tps) * 2 : count);
    gl.uniform1f(rate, tps);
    gl.drawArrays(gl.TRIANGLES, 0, 3);
    if (visible && !still) frame = requestAnimationFrame(draw);
  }
  frame = requestAnimationFrame(draw);
</script>

// Inputs the site passes in, as constants for Shadertoy.
// uTps: tokens per second. uTokens: tokens so far. uColor: the accent.
#define uTps 9.0
#define uTokens (iTime * uTps)
#define uColor vec3(0.361, 0.882, 1.000)

#define TAU 6.28318530718
float hash11(float p) { p = fract(p * 0.1031); p *= p + 33.33; p *= p + p; return fract(p); }
float hash12(vec2 p) { vec3 q = fract(vec3(p.xyx) * 0.1031); q += dot(q, q.yzx + 33.33); return fract((q.x + q.y) * q.z); }
// the accent, lifted so a dark pick still glows
vec3 accent() { return uColor / max(0.25, max(uColor.r, max(uColor.g, uColor.b))); }
// rotate a colour's hue around the grey axis, for a companion tone
vec3 hueRot(vec3 c, float a) {
  const vec3 k = vec3(0.57735027);
  float ca = cos(a);
  return max(c * ca + cross(k, c) * sin(a) + k * dot(k, c) * (1.0 - ca), 0.0);
}
// 0 at rest, toward 1 as the stream speeds up
float energy() { return 1.0 - exp(-max(uTps, 0.0) / 90.0); }
vec3 stage(vec2 uv) { return vec3(0.008, 0.009, 0.013) + accent() * 0.016 * exp(-dot(uv, uv) * 2.2); }
// soft shoulder so hot cores bloom toward white, plus a dither against banding
vec4 finish(vec3 c, vec2 fc) {
  c = 1.0 - exp(-max(c, 0.0) * 1.35);
  c += (hash12(fc) + hash12(fc + 17.13) - 1.0) / 255.0;
  return vec4(c, 1.0);
}

const vec2 AMP = vec2(0.82, 0.38);
vec2 curve(float s, float dl) { return AMP * vec2(sin(3.0 * s + dl), sin(2.0 * s)); }
vec2 dcurve(float s, float dl) { return AMP * vec2(3.0 * cos(3.0 * s + dl), 2.0 * cos(2.0 * s)); }

// nearest point on the figure near parameter s, by two Gauss-Newton steps
float nearest(vec2 p, float s, float dl) {
  for (int k = 0; k < 2; k++) {
    vec2 c = curve(s, dl) - p;
    vec2 t = dcurve(s, dl);
    s -= clamp(dot(c, t) / max(dot(t, t), 1e-3), -0.25, 0.25);
  }
  return s;
}

void mainImage(out vec4 fragColor, in vec2 fragCoord) {
  vec2 uv = (fragCoord - 0.5 * iResolution.xy) / iResolution.y;
  float px = 1.0 / iResolution.y;
  float e = energy();
  vec3 A = accent();
  vec3 B = hueRot(A, 1.0);
  vec3 col = stage(uv);

  // faint axes for the figure to sit in
  col += A * 0.05 * smoothstep(px, 0.0, abs(uv.y)) * step(abs(uv.x), 0.9);
  col += A * 0.05 * smoothstep(px, 0.0, abs(uv.x)) * step(abs(uv.y), 0.42);

  float dl = mod(iTime * 0.12, TAU);
  float S = mod(uTokens * 0.032 + iTime * 0.22, TAU);
  // the trail holds about half a second of travel, so speed lays down more ink
  float speed = 0.032 * uTps + 0.22;
  float len = clamp(0.5 + speed * 0.5, 0.6, 5.4);

  // the figure crosses each height four times: start from those, then refine
  float a = 0.5 * asin(clamp(uv.y / AMP.y, -1.0, 1.0));
  vec4 seeds = vec4(a, 1.5707963 - a, a + 3.1415927, 4.712389 - a);
  float I = 0.0, base = 0.0, age = 1.0;
  for (int i = 0; i < 4; i++) {
    float s = nearest(uv, seeds[i], dl);
    float d = length(curve(s, dl) - uv);
    float g = smoothstep(0.0024 + px, 0.0024 - px * 0.5, d) + exp(-d * 75.0) * 0.4 + exp(-d * 18.0) * 0.07;
    float ag = mod(S - s, TAU) / len;
    // at a blur of speed the whole figure glows, so the gradient never spins
    float fade = ag < 1.0 ? mix(pow(1.0 - ag, 1.4), 0.7, smoothstep(150.0, 700.0, uTps)) : 0.0;
    if (g * fade > I) { I = g * fade; age = ag; }
    base = max(base, smoothstep(0.0016 + px, 0.0016 - px * 0.5, d));
  }
  // the whole path, waiting to be drawn
  col += B * base * 0.12;
  col += mix(mix(A, vec3(1.0), 0.35), B, clamp(age, 0.0, 1.0)) * I * (0.75 + 0.45 * e);

  // the pen, softer once it is a blur
  vec2 head = curve(S, dl);
  float dh = length(uv - head);
  float sharp = 1.0 - 0.6 * smoothstep(100.0, 500.0, uTps);
  col += vec3(1.0) * smoothstep(0.009 + px, 0.009 - px, dh) * sharp;
  col += A * (exp(-dh * 45.0) * 0.6 + exp(-dh * 12.0) * 0.15) * (0.6 + 0.4 * e);
  fragColor = finish(col, fragCoord);
}

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