ludic/examples/games/platformer_demo.ludic

# platformer_demo.ludic — the ludic.platformer controller (#58) exercised
# headlessly and deterministically over the shared engine collision (entity
# solids): gravity + landing, jump apex height, coyote-time tracking, double jump,
# the JumpRequested veto hook, and a horizontal run into a wall.
#
# Movement intent is written directly (the AI / custom-input path: the input system
# is switched off with `disable system esys_platformer_input`), so the run needs no
# key feed and is fully reproducible. A full run prints:
#   1 1 1 1 1 1 1 1
#
# Build (from the repo root):
#   LUDIC_MODULES=packages ludicc --headless examples/games/platformer_demo.ludic
program PlatformerDemo {
  import "ludic.platformer/platformer.ludic"

  property Position { x: int = 0, y: int = 0 }
  property Body {
    vx: fixed = 0.0, vy: fixed = 0.0, gravity: fixed = 0.0, max_fall: fixed = 0.0,
    rx: fixed = 0.0, ry: fixed = 0.0, policy: int = 0,
    on_ground: int = 0, hit_wall: int = 0, hit_ceiling: int = 0
  }
  property Collider {
    w: int = 0, h: int = 0, offx: int = 0, offy: int = 0,
    is_trigger: int = 0, one_way: int = 0, layer: int = 0, mask: int = 0,
    hit: int = 0, entered: int = 0, exited: int = 0
  }

  model Hero  { Position, Body, Collider, Platformer }
  model Floor { Position, Collider }
  model Wall  { Position, Collider }
  @OnSpawn(Hero)  handler HeroInit { }
  @OnSpawn(Floor) handler FloorInit { }
  @OnSpawn(Wall)  handler WallInit { }

  state PlatformerDemoState {
    jumps: int = 0
    have_power: int = 0
    vetoed_air: int = 0
  }
  @On(JumpPerformed) handler CountJumps(platformer_demo_st: mut PlatformerDemoState) { platformer_demo_st.jumps += 1 }
  # a game rule: forbid the air (double) jump unless a "power" flag is set — pure
  # lever-4 veto, no controller edit.
  @On(JumpRequested) handler GateAir(platformer_demo_st: mut PlatformerDemoState) { if (kind == 2) and (platformer_demo_st.have_power == 0) { platformer_demo_st.vetoed_air = 1; cancel } }

  function tick_n(n: int) -> void { var i = 0;  while i < n { tick_fixed();  i += 1 } }
  function bi(b: bool) -> int { if b { return 1 };  return 0 }
  function pf_coyote(e: int) -> int {
    let P = World.prop_id("Platformer")
    return World.get(e, P, World.field_id(P, "coyote_t"))
  }

  entry (platformer_demo_st: mut PlatformerDemoState) {
    let PB = World.prop_id("Body")
    let PP = World.prop_id("Position")
    let PL = World.prop_id("Platformer")
    let fy = World.field_id(PP, "y")
    let fx = World.field_id(PP, "x")
    let fgrd = World.field_id(PB, "on_ground")

    # a solid floor (top at y=192) and a wall at x=480; both plain solid colliders,
    # so the platformer rides the same esys_move sweep the physics tests use.
    spawn Floor { Position { x: 0, y: 192 }, Collider { w: 640, h: 32 } }
    spawn Wall  { Position { x: 480, y: 0 }, Collider { w: 16, h: 192 } }

    # the input system is off — drive intent directly for a reproducible test.
    disable system esys_platformer_input

    spawn Hero { Position { x: 80, y: 40 }, Collider { w: 12, h: 16 },
                 Platformer { move_speed: 3, jump_height: 4, apex_frames: 14, air_jumps: 1, coyote_frames: 6 } }
    let h = World.query_next(PL, 0)

    # ---- A. gravity + landing ----------------------------------------------
    tick_n(90)
    let floor_y = 192 - 16                        # feet on the floor top
    print(bi(World.get(h, PP, fy) == floor_y))    # 1
    print(bi(World.get(h, PB, fgrd) == 1))        # 1

    # ---- B. jump apex height ~= jump_height tiles (held for full height) ----
    Platformer.hold(h, 1)                            # hold jump: full-height arc
    Platformer.jump(h)
    var top = World.get(h, PP, fy)
    var i = 0
    while i < 20 { tick_fixed();  let y = World.get(h, PP, fy);  if y < top { top = y };  i += 1 }
    let rise = floor_y - top                        # px risen at apex (target 64 = 4 tiles)
    print(bi((rise >= 56) and (rise <= 72)))        # 1
    Platformer.hold(h, 0)
    tick_n(40)
    print(bi(World.get(h, PB, fgrd) == 1))          # 1 — landed again

    # ---- C. coyote time is tracked (refilled while grounded) ---------------
    print(bi(pf_coyote(h) == 6))                    # 1

    # ---- D. double jump gated by the veto hook -----------------------------
    platformer_demo_st.have_power = 0
    Platformer.jump(h);  tick_n(3)                  # ground jump -> airborne
    let after_ground = platformer_demo_st.jumps
    Platformer.jump(h);  tick_n(2)                  # air jump attempt -> vetoed
    print(bi((platformer_demo_st.jumps == after_ground) and (platformer_demo_st.vetoed_air == 1)))   # 1

    platformer_demo_st.have_power = 1
    let before_power = platformer_demo_st.jumps
    Platformer.jump(h);  tick_n(2)                  # air jump now allowed
    print(bi(platformer_demo_st.jumps == before_power + 1))            # 1
    tick_n(60)                                        # settle on the floor

    # ---- E. horizontal run into the wall (collision reuse) -----------------
    Platformer.move(h, 1)                            # hold right
    tick_n(200)
    let hx = World.get(h, PP, fx)
    print(bi((hx >= 460) and (hx < 480)))           # 1 — stopped at the wall (right edge ~468)

    quit()
  }
}