Platformer

Platformer2DBehavior and Platformer3DBehavior are kinematic character controllers with walk, run, jump (buffer, coyote time, multi-jump, jump-cut), gravity, and slope/autostep settings. The WASM runtime owns the character controller; your game writes $platformer2D or $platformer3D input each frame and reads state through the handle.

Minimal example (2D)

See website/snippets/behaviors/catalog/platformer.ts:

import { Platformer2DBehavior } from '@zylem/game-lib/behavior';

const platformer = player.use(Platformer2DBehavior, {
  walkSpeed: 8,
  runSpeed: 14,
  jumpForce: 12,
  maxJumps: 2,
});

player.onUpdate(({ inputs }) => {
  player.$platformer2D.moveX = inputs.p1.axes.Horizontal.value;
  player.$platformer2D.jump = inputs.p1.buttons.A.held > 0;
  player.$platformer2D.run = inputs.p1.shoulders.LTrigger.held > 0;
});

Options (high level)

Option	Default (2D)	Notes
walkSpeed / runSpeed	8 / 14	Horizontal speed on ground.
jumpForce, maxJumps	12 / 1	Multi-jump when maxJumps > 1.
gravity, coyoteTime, jumpBufferTime	20 / 0.1s / 0.1s	Feel tuning.
jumpCutMultiplier	0.5	Short-hop when releasing jump.
autostep, snapToGroundDistance	small step / 0.2	SNES-style step-ups and downhill glue.
useAttachedCollider	true	KCC shape from Rapier collider when true.

3D adds moveZ on $platformer3D and uses X/Z locomotion with the same jump feature set.

Handle

• getState() — FSM state (idle, walking, running, jumping, falling, landing).
• isGrounded(), getJumpCount().

Pitfalls

• Vertical motion for 2D platformer uses behavior-owned verticalVelocity; do not fight it with manual Y transforms.
• Attach a suitable capsule/box collider before spawn; optional shape override requires useAttachedCollider: false.
• For jump-only entities without full platformer locomotion, consider Jumper instead.

API reference

• Platformer2DBehavior, Platformer3DBehavior
• Platformer2DState, Platformer2DFSM
• Generated reference: API