updated the collision for jumps and terrain

src/game/playerJump.test.ts

@@ -1,13 +1,16 @@
 import { describe, expect, it } from "vitest";
 import {
   PLAYER_GROUND_MIN_NORMAL_Y,
+  PLAYER_AIRBORNE_PRESENTATION_DELAY_MS,
   PLAYER_JUMP_BUFFER_MS,
   PLAYER_JUMP_COYOTE_MS,
   bufferPlayerJump,
   cancelBufferedPlayerJump,
   characterVerticalMotion,
+  createCharacterVerticalPresentationTiming,
   createPlayerJumpTiming,
   isWalkableGroundHit,
+  updateCharacterVerticalPresentation,
   updatePlayerJumpTiming,
 } from "./playerJump";
 
@@ -63,4 +66,38 @@ describe("player jump timing", () => {
     expect(characterVerticalMotion(true, 0, 100, 150)).toBe("landing");
     expect(characterVerticalMotion(true, 0, 150, 150)).toBe("grounded");
   });
+
+  it("hides brief terrain gaps without playing a landing animation", () => {
+    const timing = createCharacterVerticalPresentationTiming();
+    expect(updateCharacterVerticalPresentation(timing, false, -0.1, 1_000, false))
+      .toBe("grounded");
+    expect(updateCharacterVerticalPresentation(
+      timing,
+      true,
+      0,
+      1_000 + PLAYER_AIRBORNE_PRESENTATION_DELAY_MS - 1,
+      false,
+    )).toBe("grounded");
+  });
+
+  it("presents real falls and intentional jumps, then lands once", () => {
+    const falling = createCharacterVerticalPresentationTiming();
+    expect(updateCharacterVerticalPresentation(falling, false, -1, 2_000, false))
+      .toBe("grounded");
+    expect(updateCharacterVerticalPresentation(
+      falling,
+      false,
+      -2,
+      2_000 + PLAYER_AIRBORNE_PRESENTATION_DELAY_MS,
+      false,
+    )).toBe("falling");
+    expect(updateCharacterVerticalPresentation(falling, true, 0, 2_200, false))
+      .toBe("landing");
+    expect(updateCharacterVerticalPresentation(falling, true, 0, 2_400, false))
+      .toBe("grounded");
+
+    const jumping = createCharacterVerticalPresentationTiming();
+    expect(updateCharacterVerticalPresentation(jumping, false, 7.2, 3_000, true))
+      .toBe("rising");
+  });
 });

src/game/playerJump.ts

@@ -3,7 +3,8 @@ export const PLAYER_JUMP_COYOTE_MS = 100;
 export const PLAYER_JUMP_BUFFER_MS = 120;
 export const PLAYER_JUMP_LANDING_UNLOCK_MS = 80;
 export const PLAYER_LANDING_PRESENTATION_MS = 180;
-export const PLAYER_GROUND_PROBE_DISTANCE = 0.14;
+export const PLAYER_AIRBORNE_PRESENTATION_DELAY_MS = 100;
+export const PLAYER_GROUND_PROBE_DISTANCE = 0.22;
 export const PLAYER_GROUND_MIN_NORMAL_Y = 0.55;
 
 export type CharacterVerticalMotion = "grounded" | "rising" | "falling" | "landing";
@@ -15,6 +16,12 @@ export interface PlayerJumpTiming {
   lockedUntilLanding: boolean;
 }
 
+export interface CharacterVerticalPresentationTiming {
+  airborneStartedAtMs: number;
+  airbornePresented: boolean;
+  landingUntilMs: number;
+}
+
 export interface GroundProbeHit {
   readonly timeOfImpact: number;
   readonly normal: { readonly y: number };
@@ -29,6 +36,14 @@ export function createPlayerJumpTiming(nowMs = Number.NEGATIVE_INFINITY): Player
   };
 }
 
+export function createCharacterVerticalPresentationTiming(): CharacterVerticalPresentationTiming {
+  return {
+    airborneStartedAtMs: Number.NEGATIVE_INFINITY,
+    airbornePresented: false,
+    landingUntilMs: Number.NEGATIVE_INFINITY,
+  };
+}
+
 export function bufferPlayerJump(timing: PlayerJumpTiming, requestedAtMs: number): void {
   if (!Number.isFinite(requestedAtMs)) return;
   timing.bufferedUntilMs = requestedAtMs + PLAYER_JUMP_BUFFER_MS;
@@ -92,3 +107,38 @@ export function characterVerticalMotion(
   if (grounded) return nowMs < landingUntilMs ? "landing" : "grounded";
   return verticalVelocity > 0.15 ? "rising" : "falling";
 }
+
+/**
+ * Keeps tiny terrain gaps from interrupting locomotion with a fall/land pair.
+ * An intentional jump is presented immediately; an incidental loss of ground
+ * must persist before it becomes visible, and only visible airtime may land.
+ */
+export function updateCharacterVerticalPresentation(
+  timing: CharacterVerticalPresentationTiming,
+  grounded: boolean,
+  verticalVelocity: number,
+  nowMs: number,
+  intentionalJump: boolean,
+): CharacterVerticalMotion {
+  if (!Number.isFinite(nowMs)) {
+    return characterVerticalMotion(grounded, verticalVelocity, 0, Number.NEGATIVE_INFINITY);
+  }
+
+  if (!grounded) {
+    if (!Number.isFinite(timing.airborneStartedAtMs)) timing.airborneStartedAtMs = nowMs;
+    if (
+      intentionalJump
+      || nowMs - timing.airborneStartedAtMs >= PLAYER_AIRBORNE_PRESENTATION_DELAY_MS
+    ) timing.airbornePresented = true;
+    return timing.airbornePresented
+      ? characterVerticalMotion(false, verticalVelocity, nowMs, timing.landingUntilMs)
+      : "grounded";
+  }
+
+  if (timing.airbornePresented) {
+    timing.landingUntilMs = nowMs + PLAYER_LANDING_PRESENTATION_MS;
+  }
+  timing.airborneStartedAtMs = Number.NEGATIVE_INFINITY;
+  timing.airbornePresented = false;
+  return characterVerticalMotion(true, verticalVelocity, nowMs, timing.landingUntilMs);
+}