Gym adapter

GymAdapter exposes the simulator as a Gym-style reset() / step() loop, the natural interface for driving a robot from a policy. It speaks ActionCall in and Observation out.

import cadenza_lab as cadenza
from cadenza_lab import ActionCall

env = cadenza.GymAdapter(robot="go1", headless=True)
obs = env.reset()

for _ in range(20):
    obs, info = env.step(ActionCall("walk_forward", distance_m=0.5))
    if not env.is_open:           # property, not a method
        break

env.close()

Constructor

GymAdapter(robot, *, xml_path=None, scene=None, headless=False,
           render_camera=False, cam_distance=0.0, cam_elevation=-15.0,
           cam_azimuth=270.0, max_action_seconds=30.0)

Param	Description
`robot`	`"go1"` or `"g1"`.
`scene`	An optional `Scene`.
`headless`	`True` to run without a viewer (CI-safe).
`render_camera`	Populate `Observation.camera` each step.
`max_action_seconds`	Per-action wall-clock cap.

Methods

Method	Returns	Description
`reset()`	`Observation`	Reset to the start state.
`step(call)`	`(Observation, info: dict)`	Execute one `ActionCall`.
`add_box / add_slope / add_sphere(...)`	`GymAdapter`	Add geometry before `reset()` (same args as `Scene`).
`clear_scene()`	None	Remove added geometry.
`is_open`	`bool`	Property. Whether the viewer/sim is still open.
`close()`	None	Shut down the sim/viewer.

Scene geometry is baked at reset(). Add boxes/slopes/spheres before the first reset() (or call reset() again after changing the scene).

GymAdapter.step() returns (Observation, info), not the 5-tuple Gym returns. For the standard (obs, reward, terminated, truncated, info) loop tied to a CLI mission, use CustomEnv.

`ActionCall`

The action passed to step(). Parameterizes a named action.

ActionCall(action_name, speed=1.0, extension=1.0, repeat=1,
           distance_m=0.0, rotation_rad=0.0, duration_s=0.0,
           speed_override=0.0, height_override=0.0)

Field	Description
`action_name`	A base action, e.g. `"walk_forward"` (see Actions).
`distance_m`	Target distance for locomotion actions.
`rotation_rad`	Target rotation for turn actions.
`speed`, `extension`, `repeat`	Gait/scale modifiers.
`duration_s`, `speed_override`, `height_override`	Fine-grained overrides.

`Observation`

Returned by reset() / step().

Attribute	Description
`pos`, `rpy`, `body_height`	Base pose (numpy arrays / float).
`qpos`, `qvel`	Full generalized position / velocity.
`foot_contacts`	Tuple of per-foot ground contact bools.
`terrain_ahead`, `obstacles_ahead`	Raycast sensing dicts (see Simulation).
`camera`	RGB frame, shape `(224, 224, 3)` (when `render_camera=True`).
`depth`	Depth frame.
`to_dict()`	Serialize the observation to a plain dict.

Demo: drive a scene through a Gym loop

"""demo_gym.py: headless reset/step loop with obstacles + camera (CI-safe)."""
import cadenza_lab as cadenza
from cadenza_lab import ActionCall

env = cadenza.GymAdapter(robot="go1", headless=True, render_camera=True)
env.add_box(position=(-1.2, 0.0, 0.08), size=(0.15, 0.15, 0.08))
env.add_slope(position=(-2.5, 0.0, 0.0), size=(0.6, 0.6, 0.05), angle_deg=12)

obs = env.reset()
print("start:", obs.pos.round(2), "camera:", obs.camera.shape)

plan = [
    ActionCall("walk_forward", distance_m=0.6),
    ActionCall("turn_left", rotation_rad=0.8),
    ActionCall("walk_forward", distance_m=0.6),
    ActionCall("sit"),
]
for call in plan:
    obs, info = env.step(call)
    print(f"{call.action_name:<14} moved={info['moved_m']:.2f}  ok={info['ok']}")
    if not env.is_open:
        break

env.close()

python demo_gym.py

Get started

Features

Tutorial

Constructor

Methods

`ActionCall`

`Observation`

Demo: drive a scene through a Gym loop

​Constructor

​Methods

​ActionCall

​Observation

​Demo: drive a scene through a Gym loop

Constructor

Methods

`ActionCall`

`Observation`

Demo: drive a scene through a Gym loop