fix: Adding color fade-in for tile reveal

public/src/game.js

@@ -50,6 +50,38 @@ export const teamCooldownEndMs = { blue: 0, red: 0 };
 let rafId = 0;
 let lastPointerEvent = null;
 
+// ── Tile fade-in animation ────────────────────────────────────────────────────
+
+/** key → timestamp (ms) when the tile was first revealed */
+const tileRevealTime = new Map();
+const TILE_FADE_MS = 500;
+let fadeRafId = 0;
+
+function markTileReveal(key) {
+  tileRevealTime.set(key, Date.now());
+  if (!fadeRafId) scheduleFadeFrame();
+}
+
+function scheduleFadeFrame() {
+  fadeRafId = requestAnimationFrame(() => {
+    fadeRafId = 0;
+    draw();
+    // Keep looping while any tile is still fading
+    const now = Date.now();
+    const stillFading = [...tileRevealTime.values()].some(t => now - t < TILE_FADE_MS);
+    if (stillFading) scheduleFadeFrame();
+  });
+}
+
+/** Returns the fill opacity multiplier for a tile (0–1). */
+function tileAlpha(key) {
+  const t = tileRevealTime.get(key);
+  if (t === undefined) return 1;
+  const progress = (Date.now() - t) / TILE_FADE_MS;
+  if (progress >= 1) { tileRevealTime.delete(key); return 1; }
+  return progress;
+}
+
 // ── Zoom / Pan state ──────────────────────────────────────────────────────────
 
 const MIN_ZOOM = 1;
@@ -594,10 +626,13 @@ export function draw() {
       if (!isExploitable(x, y)) continue;
       const k = cellKey(x, y);
       const meta = cellMeta(k);
+      const alpha = tileAlpha(k);
+      ctx.globalAlpha = alpha;
       if (!meta)                                   ctx.fillStyle = COLOR_RING_IDLE;
       else if (meta.discoveredBy !== currentTeam)  ctx.fillStyle = COLOR_OPPONENT_GREY;
       else ctx.fillStyle = currentTeam === "blue" ? COLOR_BLUE_DISCOVERED : COLOR_RED_DISCOVERED;
       ctx.fillRect(x * cw, y * ch, cw, ch);
+      ctx.globalAlpha = 1;
     }
   }
 
@@ -670,7 +705,9 @@ function refreshCursorFromLast() {
 // ── Selection display ─────────────────────────────────────────────────────────
 
 function applyRevealPayload(cell) {
-  cells.set(cellKey(cell.x, cell.y), {
+  const _revealKey = cellKey(cell.x, cell.y);
+  markTileReveal(_revealKey);
+  cells.set(_revealKey, {
     discoveredBy: cell.discoveredBy ?? currentTeam,
     hasPlanet:    Boolean(cell.hasPlanet),
     planet:       cell.planet ?? null,
@@ -774,6 +811,7 @@ async function onCanvasClick(ev) {
         else                        milDeductRed  = data.deductions.red  ?? milDeductRed;
         // Transfer tile in local cells Map
         const existing = cells.get(key);
+        markTileReveal(key);
         cells.set(key, { ...existing, discoveredBy: currentTeam });
         hint.textContent = `⚔️ Tuile (${cell.x},${cell.y}) conquise !`;
         updateEconomyDisplay();