# 2D Physics Playground

rigid bodies, a character, one-way platforms, and joints.

```{raw} html
<a class="example-run-button" href="../demos/features_physics_playground2d.html">▶ Run in browser</a>


```

**Tags:** `physics` `2d` `character` `joints`

One scene exercising the 2D physics stack end to end. Dynamic boxes and circles fall
and pile on a static segment floor, a two-link pendulum swings from pin joints, a bead
slides along a groove joint, and a player-controlled character walks, jumps, and lands
on a one-way platform it can also jump up through from below. An Area2D trigger zone
reports every body passing through it, the character included: a CharacterBody2D is an
ordinary kinematic body, so it fires the same signals a falling box does.

This is a Y-down pixel world (``gravity = Vec2(0, +g)``, +Y rendered downward), so
falling reads as falling on screen. The character's ``up_direction`` and the one-way
platform's solid side are flipped to -Y to match.

Engine features shown:
  - PhysicsBody2D in DYNAMIC and STATIC modes with PhysicsMaterial friction and
    restitution; each body carries a CollisionShape2D plus a visual child that
    inherits the body transform the physics sync writes each fixed step.
  - CharacterBody2D driven by velocity + move_and_slide, with is_on_floor gating jumps.
  - A one-way platform: solid from above, pass-through from below.
  - Area2D body_entered / body_exited signals updating the HUD live, including the
    body_exited a DESTROYED body still owes: press X and the zone names what it lost.
  - PinJoint2D (a pendulum chain) and GrooveJoint2D (a bead pinned to a slide rail and
    kicked along it at start).

Controls:
    A / D             - move the character left / right
    Hold click or tap - walk the character toward the pointer (mouse / touch)
    Space, click, tap - jump
    R                 - respawn the falling batch
    X                 - destroy whatever is inside the trigger zone
    Escape            - quit

Run: uv run python examples/features/physics/playground2d.py
Headless self-check: uv run python examples/features/physics/playground2d.py --test

## Source

```{literalinclude} ../../examples/features/physics/playground2d.py
:language: python
:linenos:
```