fix: implement monotonic transition shortening to prevent respawn wipe replay during input mashing

Author: CoolSpring8

src/GameScene.ts

@@ -20,7 +20,7 @@ import { PlayerView } from "./view/PlayerView";
 import {
   baseTransitionDuration,
   type DeathRespawnSequenceKind,
-  retimedTransitionDuration,
+  shortenedTransitionDuration,
   transitionTimings,
   SPAWN_WIPE_VISUALS,
 } from "./view/deathRespawn";
@@ -686,7 +686,11 @@ export class GameScene extends Phaser.Scene {
       return;
     }
 
-    transition.totalDuration = retimedTransitionDuration(transition.kind, transition.elapsed);
+    transition.totalDuration = shortenedTransitionDuration(
+      transition.kind,
+      transition.totalDuration,
+      transition.elapsed,
+    );
   }
 
   private tryApplyBufferedSkip(): void {

src/view/deathRespawn.ts

@@ -44,6 +44,14 @@ export function retimedTransitionDuration(
   );
 }
 
+export function shortenedTransitionDuration(
+  kind: DeathRespawnSequenceKind,
+  currentTotalDuration: number,
+  elapsed: number,
+): number {
+  return Math.min(currentTotalDuration, retimedTransitionDuration(kind, elapsed));
+}
+
 export function transitionTimings(
   kind: DeathRespawnSequenceKind,
   totalDuration = baseTransitionDuration(kind),

tests/model/death-respawn.test.ts

@@ -3,6 +3,7 @@ import { PLAYER_INTRO_TIMING } from "../../src/player/intro.ts";
 import {
   baseTransitionDuration,
   retimedTransitionDuration,
+  shortenedTransitionDuration,
   transitionTimings,
 } from "../../src/view/deathRespawn.ts";
 import { sampleStartIntro } from "../../src/view/startIntro.ts";
@@ -52,4 +53,12 @@ describe("Death and intro presentation math", () => {
     expect(spike.wipeCoverAt).toBeGreaterThan(spike.explodeAt);
     expect(spike.wipeRevealAt).toBeGreaterThan(spike.wipeCoverAt);
   });
+
+  test("skip shortening is monotonic, so repeated confirm presses cannot replay the wipe", () => {
+    const once = shortenedTransitionDuration("normal", 1, 0.1);
+    const mashedLater = shortenedTransitionDuration("normal", once, 0.55);
+
+    expect(once).toBeCloseTo(0.6, 5);
+    expect(mashedLater).toBeCloseTo(once, 5);
+  });
 });