Cauldron

// Cauldron over a wood fire — 48x48, top-down 3/4, key light top-left.// Loop: 12 frames @ 10 fps. Bubbles swell and pop, the brew swirls, the sigil pulses, steam drifts, fire flickers.// Variants: brew colour green / violet / blue (ramp swap — no new colours).const CX = 24, GROUND = 45;const BODY = { cx: 24, cy: 29, rx: 16, ry: 12 };const LIP = { cy: 16, rx: 17, ry: 6 };const MOUTH = { cy: 16, rx: 14, ry: 4 };const IRON = ["n0", "n1", "n2", "n3"];function edgeDist(x, y, cx, cy, rx, ry) {  // approximate distance (px) from the ellipse boundary, inside only  const nx = (x + 0.5 - cx) / rx, ny = (y + 0.5 - cy) / ry;  const r = Math.sqrt(nx * nx + ny * ny);  return (1 - r) * Math.min(rx, ry) * 1.15;}function body(g, t) {  const { cx, cy, rx, ry } = BODY;  g.field({ x: [cx - rx, cx + rx], y: [cy - ry, cy + ry] }, (x, y) => {    const i = litIndex(x, y, cx, cy, rx, ry, 4, -0.05);    if (i < 0) return null;    const nx = (x + 0.5 - cx) / rx, ny = (y + 0.5 - cy) / ry;    // warm rim light from the fire along the underside    if (ny > 0.5 && Math.abs(nx) < 0.55 && edgeDist(x, y, cx, cy, rx, ry) < 1.2) return Math.abs(nx) < 0.3 ? "r1" : "r0";    // soft specular: a short curved highlight on the upper-left shoulder    const sx = nx + 0.5, sy = ny + 0.28;    if (sx * sx * 3 + sy * sy * 9 < 0.07) return "n4";    return IRON[i];  });}function band(g, t) {  // riveted iron band following the belly's curvature, with a pulsing sigil plate at the front  const { cx, cy, rx } = BODY;  const yAt = (x) => { const u = (x + 0.5 - cx) / (rx - 0.5); return Math.round(cy - 3 + (1 - Math.sqrt(Math.max(0, 1 - u * u))) * -3); };  g.part("band", () => {    for (let x = cx - rx + 1; x <= cx + rx - 1; x++) {      const y = yAt(x), u = (x - cx) / rx;      g.pixel(x, y, u < -0.3 ? "n3" : u < 0.5 ? "n2" : "n1");      g.pixel(x, y + 1, "n0");    }    for (const u of [-0.8, -0.45, 0.45, 0.8]) {      const x = Math.round(cx + u * (rx - 1));      g.pixel(x, yAt(x) + 1, u < 0 ? "n4" : "n3");    }  });  const pulse = 0.5 + 0.5 * Math.cos(TAU * t);  const hot = pulse > 0.66 ? "brew3" : pulse > 0.33 ? "brew2" : "brew1";  const y0 = yAt(cx) - 1;  g.part("sigil", () => {    g.fillPoly([[cx, y0 - 1], [cx + 3, y0 + 2], [cx, y0 + 5], [cx - 3, y0 + 2]], "n1");    g.poly([[cx, y0 - 1], [cx + 3, y0 + 2], [cx, y0 + 5], [cx - 3, y0 + 2], [cx, y0 - 1]], "g1");    g.pixel(cx - 1, y0, "g2"); g.pixel(cx - 2, y0 + 1, "g2");    g.pixel(cx, y0 + 1, "brew1"); g.pixel(cx - 1, y0 + 2, "brew1"); g.pixel(cx + 1, y0 + 2, "brew1"); g.pixel(cx, y0 + 3, "brew1");    g.pixel(cx, y0 + 2, hot);    if (pulse > 0.5) { g.pixel(cx, y0 + 1, "brew2"); g.pixel(cx, y0 + 3, "brew2"); }  });}function lip(g) {  const { cy, rx, ry } = LIP;  g.part("lip", () => {    // outer thickness (seen on the near side) then the lit top face    g.ellipse({ x: [CX - rx, CX + rx], y: [cy - ry + 1, cy + ry] }, "n1", { fill: "n1" });    g.field({ x: [CX - rx, CX + rx], y: [cy - ry, cy + ry - 1] }, (x, y) => {      const nx = (x + 0.5 - CX) / rx, ny = (y + 0.5 - (cy - 0.5)) / (ry - 0.5);      if (nx * nx + ny * ny > 1) return null;      const a = -0.7 * nx - 0.3 * ny;      // top-left of the ring catches the light      return a > 0.45 ? "n4" : a > 0.05 ? "n3" : a > -0.45 ? "n2" : "n1";    });  });  for (const s of [-1, 1]) {    const hx = CX + s * (rx + 1);    g.part(s < 0 ? "handleL" : "handleR", () => {      g.strokeEllipse({ x: [hx - 2, hx + 2], y: [cy + 4, cy + 9] }, s < 0 ? "n2" : "n1");      g.pixel(hx - 1, cy + 4, s < 0 ? "n4" : "n2");    });  }}function brew(g, t) {  const { cy, rx, ry } = MOUTH;  const L = { cx: CX, cy: cy + 1, rx: rx - 1, ry: ry - 1 };  g.part("brew", () => {    // inner wall of the far side, then the liquid surface    g.field({ x: [CX - rx, CX + rx], y: [cy - ry, cy + ry] }, (x, y) => {      const nx = (x + 0.5 - CX) / rx, ny = (y + 0.5 - cy) / ry;      if (nx * nx + ny * ny > 1) return null;      const lx = (x + 0.5 - L.cx) / L.rx, ly = (y + 0.5 - L.cy) / L.ry;      if (lx * lx + ly * ly > 1) return nx > 0.35 ? "n1" : "n0";   // inner wall: its right side catches light      if (ly > 0.55 && Math.abs(lx) < 0.8) return "brew2";          // meniscus along the near edge      if (ly < -0.3) return "brew0";      return "brew1";    });    // swirl: two arms, 2-fold symmetric so a half turn per loop closes the loop    for (let arm = 0; arm < 2; arm++) {      for (let s = 0.25; s < 0.9; s += 0.09) {        const a = Math.PI * t + arm * Math.PI + s * 2.8;        const x = Math.round(L.cx + Math.cos(a) * s * L.rx);        const y = Math.round(L.cy + Math.sin(a) * s * L.ry);        g.pixel(x, y, s > 0.6 ? "brew2" : "brew0");      }    }    g.line([CX - 9, cy], [CX - 6, cy], "brew3");               // glint of the key light  });}function bubbles(g, t) {  const spots = [[-6, 1, 0.0], [3, 2, 0.34], [8, 0, 0.68]];  g.detached("bubbles", () => {    for (const [dx, dy, ph] of spots) {      const p = (t + ph) % 1;      const x = CX + dx, y = MOUTH.cy + dy;      if (p < 0.2) g.pixel(x, y, "brew2");      else if (p < 0.45) { g.rect({ x: [x - 1, x], y: [y - 1, y] }, "brew2", { fill: "brew2" }); g.pixel(x - 1, y - 1, "brew3"); }      else if (p < 0.62) {        g.ellipse({ x: [x - 2, x + 1], y: [y - 2, y] }, "brew2", { fill: "brew2" });        g.pixel(x - 1, y - 2, "brew3"); g.pixel(x - 2, y - 1, "brew3"); g.pixel(x + 1, y, "brew0");      } else if (p < 0.75) {        for (const [ox, oy] of [[-3, 0], [2, 0], [-1, -3], [0, 1]]) g.pixel(x + ox, y + oy, "brew3");      }    }  });}function steam(g, t) {  g.detached("steam", () => {    for (let i = 0; i < 4; i++) {      const p = (t + i / 4) % 1;      const x0 = CX + [-6, -1, 4, 8][i] + Math.round(Math.sin(TAU * (p * 0.8 + i * 0.3)) * 2);      const y0 = LIP.cy - 4 - Math.round(p * 12);      if (p < 0.35) { g.rect({ x: [x0, x0 + 1], y: [y0, y0 + 1] }, "brew3", { fill: "brew3" }); g.pixel(x0 + 1, y0 + 1, "brew2"); }      else if (p < 0.7) { g.pixel(x0, y0, "brew2"); g.pixel(x0 + 1, y0 - 1, "brew2"); }      else if (chk(x0, Math.floor(t * 12))) g.pixel(x0, y0, "brew1");    }  });}function logs(g) {  g.part("logs", () => {    // back log (angled), front log (level) with end grain facing the viewer    g.rect({ x: [18, 31], y: [39, 41] }, "w1", { fill: "w1" });    g.pixel(31, 39, "w3");    g.rect({ x: [15, 34], y: [41, 44] }, "w2", { fill: "w2" });    g.line([16, 41], [33, 41], "w3");    g.line([16, 44], [33, 44], "w1");    g.ellipse({ x: [12, 16], y: [40, 45] }, "w3", { fill: "w3" });    g.strokeEllipse({ x: [12, 16], y: [40, 45] }, "w1");    g.pixel(14, 42, "w1"); g.pixel(13, 41, "w4");    g.line([22, 42], [26, 42], "w1"); g.pixel(30, 43, "w1");  });}function fire(g, t) {  g.part("fire", () => {    flame(g, 19, 40, 5, 8, t, 0.1, ["r1", "r2", "r3", "g3"]);    flame(g, 29, 40, 5, 7, t, 0.55, ["r1", "r2", "r3", "g3"]);    flame(g, 24, 41, 7, 11, t, 0.3, ["r1", "r2", "r3", "g3"]);  });  g.detached("embers", () => {    for (let k = 0; k < 3; k++) {      const p = (t * 2 + k / 3) % 1;      const x = 24 + Math.round(Math.sin(TAU * (p + k * 0.4)) * 7), y = 37 - Math.round(p * 5);      if (p < 0.7) g.pixel(x, y, p < 0.35 ? "g2" : "r2");    }  });}function foot(g, fx, lit) {  g.part(lit ? "footL" : "footR", () => {    g.fillPoly([[fx - 2, 37], [fx + 2, 37], [fx + 3, 43], [fx - 3, 43]], "n1");    g.line([fx - 2, 38], [fx - 3, 42], lit ? "n3" : "n2");    g.line([fx - 3, 43], [fx + 3, 43], "n0");    g.pixel(fx - 1, 43, "n2"); g.pixel(fx + 1, 43, "n2");  // toes  });}const Cauldron = sprite(pal, (g, t) => {  contactShadow(g, CX, GROUND, 18, 2);  g.outlined("ink", () => {    foot(g, 12, true);    foot(g, 36, false);    g.part("body", () => body(g, t));    lip(g);  });  band(g, t);  brew(g, t);  bubbles(g, t);  g.outlined("ink", () => { logs(g); fire(g, t); });  steam(g, t);});submit(Cauldron, {  size: [48, 48], origin: "top-left", kind: "icon", scale: 1,  animate: { fps: 10, duration: 1.2, loop: true },  anchor: { x: 24, y: 45 },  variants: [    { name: "idle-green" },    { name: "idle-violet", repalette: swap("brew", "v") },    { name: "idle-blue", repalette: swap("brew", "b") },  ],});