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");
+  });
 });