Resonance ping: right click with the drill lights up nearby veins through fog (t50)

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

src/render/overlays.js

@@ -109,6 +109,42 @@ function drawFlowRates() {
   }
   ctx.restore();
 }
+// The resonance ping's echo: a ring spreading from the bot, the veins it found lighting up inside
+// it, then fading once it has gone out. The veins are drawn once into a small image, so each
+// frame is one clipped drawImage however many there are. Drawn over fog, so unexplored rock shows.
+const PING_SPEED = 160, PING_FADE = 4500;
+function pingImage(p) {
+  const size = p.r * 2 + 1, c = document.createElement('canvas'); c.width = c.height = size;
+  const g = c.getContext('2d'), img = g.createImageData(size, size), d = img.data, ox = Math.floor(p.x - p.r), oy = Math.floor(p.y - p.r);
+  for (const i of p.cells) {
+    const x = i % W - ox, y = ((i / W) | 0) - oy;
+    if (x < 0 || y < 0 || x >= size || y >= size) continue;
+    const k = (y * size + x) * 4, m = mat[i];
+    d[k] = Math.min(255, COLR[m] + 90); d[k + 1] = Math.min(255, COLG[m] + 90); d[k + 2] = Math.min(255, COLB[m] + 90); d[k + 3] = 220;
+  }
+  g.putImageData(img, 0, 0);
+  return { c, ox, oy };
+}
+function drawPing() {
+  const p = GAME.ping;
+  if (!p) return;
+  const ms = performance.now() - p.t0, front = ms / 1000 * PING_SPEED, done = p.r / PING_SPEED * 1000;
+  if (ms > done + PING_FADE) { GAME.ping = null; return; }
+  if (!p.img) p.img = pingImage(p);
+  const ctx = R.ctx, zp = R.zp, c = worldToScreenPx(p.x, p.y), o = worldToScreenPx(p.img.ox, p.img.oy);
+  ctx.save();
+  ctx.beginPath(); ctx.arc(c.x, c.y, Math.min(front, p.r + 1) * zp, 0, Math.PI * 2); ctx.clip();
+  ctx.globalAlpha = ms < done ? 1 : Math.max(0, 1 - (ms - done) / PING_FADE);
+  ctx.imageSmoothingEnabled = false;
+  ctx.drawImage(p.img.c, o.x, o.y, p.img.c.width * zp, p.img.c.height * zp);
+  ctx.restore();
+  if (front < p.r) {
+    ctx.save();
+    ctx.strokeStyle = `rgba(160,225,255,${0.85 * (1 - front / p.r)})`; ctx.lineWidth = Math.max(2, zp * 0.8);
+    ctx.beginPath(); ctx.arc(c.x, c.y, front * zp, 0, Math.PI * 2); ctx.stroke();
+    ctx.restore();
+  }
+}
 // Outline a run of blocks: strong while it is being edited, faint when pointed at
 function drawRunOutline(run, strong) {
   if (!run || !run.length) return;