Sprites respect the window they are seen through

DUKK's floor-to-ceiling white sliver, decoded: the sprite gate only
asked "did this column's ray warp?" — so a REAL body standing in front
of a warp mouth was clipped out of the mouth's columns (leaving a
baffling sliver of a huge close sprite), and a body virtualized
through warp A could paint columns bent by warp B. Every column now
remembers WHICH warp bent its ray and how far away that mouth stood;
a real body paints a column only nearer than its mouth (in front of
the window), and a virtual one only through its own warp's columns,
beyond the mouth. Projectile legs carry the same identity.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

packages/web/src/fpv/fx3d.ts

@@ -13,8 +13,8 @@ import type { GameEvent, GameView } from "@wizwar/engine";
 export type FpFx =
   | { id: number; kind: "projectile"; art: string; from: { x: number; y: number }; to: { x: number; y: number }; t0: number; dur: number;
       /** This leg flies in a warp mouth's virtual space: visible only
-       * through the opening, on columns whose rays bent. */
-      warped?: boolean }
+       * through THAT warp's opening, beyond its mouth. */
+      warped?: boolean; warpId?: number }
   | { id: number; kind: "impact"; art: string; at: { x: number; y: number }; t0: number; dur: number;
       /** Lifted off the floor (fireworks burst overhead); default 0.3. */
       rise?: number }
@@ -62,19 +62,20 @@ const IMPACT_ART: Record<string, string> = {
  * clipped by the depth buffer to the side the camera stands on. */
 function projectileLegs(
   view: GameView, a: { x: number; y: number }, b: { x: number; y: number },
-): { from: { x: number; y: number }; to: { x: number; y: number }; warped?: boolean }[] {
+): { from: { x: number; y: number }; to: { x: number; y: number }; warped?: boolean; warpId?: number }[] {
   const len = Math.hypot(b.x - a.x, b.y - a.y);
   if (len < 0.05) return [{ from: a, to: b }];
   const direct = castRay(view, a.x, a.y, Math.atan2(b.y - a.y, b.x - a.x));
   if (!direct.warped && direct.dist >= len - 0.4) return [{ from: a, to: b }];
-  for (const w of view.board.warps) {
+  for (let wi = 0; wi < view.board.warps.length; wi++) {
+    const w = view.board.warps[wi]!;
     const motion = warpMotion(w);
     const vt = motion.toVirtual(b);
     const vlen = Math.hypot(vt.x - a.x, vt.y - a.y);
     const hit = castRay(view, a.x, a.y, Math.atan2(vt.y - a.y, vt.x - a.x));
     if (hit.warped && hit.dist >= vlen - 0.4) {
       return [
-        { from: a, to: vt, warped: true },
+        { from: a, to: vt, warped: true, warpId: wi },
         { from: motion.toReal(a), to: b },
       ];
     }
@@ -96,7 +97,7 @@ export function fpFxForEvents(
         out.push({
           fx: {
             id: nextId++, kind: "projectile", art,
-            from: leg.from, to: leg.to, warped: leg.warped,
+            from: leg.from, to: leg.to, warped: leg.warped, warpId: leg.warpId,
             t0: 0, dur: PROJECTILE_DUR[art]!,
           },
           delay,