fix(camera): sticky focusPoint + per-frame camera loop (stop corner-snap mid-run)

The player-centered camera snapped the dungeon to the top-left corner after a while: the
renderer nulled focusPoint on a transient player-less frame, so the transform lost its
translate. Fix: focusPoint is now sticky (keep the last if the player is momentarily
absent), and the SP bridge re-applies the camera every frame via its own RAF loop, so a
canvas resize or a stale frame can no longer break centering.

html/js/render/isoRenderer.js

@@ -268,12 +268,12 @@
                 }
             }
         }
-        this.focusPoint = null;
         for (var i = 0; i < scene.entities.length; i++) {
             var e = scene.entities[i];
             p = this._project(e.x, e.y, originX, originY);
             items.push({ type: 'entity', e: e, sx: p.x, sy: p.y, depth: e.x + e.y + 0.55 });
-            if (e.you || e.kind === 'player') this.focusPoint = { x: p.x, y: p.y + this.tileH }; // SP camera target
+            // Sticky camera target (keep last if the player is momentarily absent).
+            if (e.you || e.kind === 'player') this.focusPoint = { x: p.x, y: p.y + this.tileH };
         }
         items.sort(function (a, b) { return a.depth === b.depth ? (a.y || 0) - (b.y || 0) : a.depth - b.depth; });
 

html/js/render/spGameRenderer.js

@@ -128,9 +128,22 @@
         host.style.display = 'block';
         toggleLegacy(true);
         SP._live = true;
+        SP._startCameraLoop();
         return true;
     };
 
+    // Re-apply the camera every frame while live — robust against the renderer resizing its canvas
+    // or a transient focusPoint, which was making the view snap to the corner mid-run.
+    SP._startCameraLoop = function () {
+        if (SP._camRaf != null) return;
+        function tick() {
+            if (!SP._live) { SP._camRaf = null; return; }
+            SP._applyCamera();
+            SP._camRaf = root.requestAnimationFrame(tick);
+        }
+        SP._camRaf = root.requestAnimationFrame(tick);
+    };
+
     // Back to the ROT view (splash / win / lose). Call on game end.
     SP.hide = function () {
         SP._live = false;

html/js/render/tileRenderer.js

@@ -284,9 +284,11 @@
 
         // Snapshot the base scene, then composite the torch light + vignette on top, and keep
         // an animation loop running so the light flickers and embers drift between renders.
-        // Where the player is on this canvas — the SP camera centers the view on it.
+        // Where the player is on this canvas — the SP camera centers on it. Sticky: keep the last
+        // point if the player is momentarily absent (level transition), so the view never snaps to
+        // the corner.
         var _fp = findPlayer(scene);
-        this.focusPoint = _fp ? { x: (_fp.x + 0.5) * cell, y: (_fp.y + 0.5) * cell } : null;
+        if (_fp) this.focusPoint = { x: (_fp.x + 0.5) * cell, y: (_fp.y + 0.5) * cell };
 
         this._lastScene = scene;
         this._collectEmitters(scene);