From 4310af9c4bc782dab2ae5e2e7432c6f00a7390e7 Mon Sep 17 00:00:00 2001
From: Nitish89847 <girinitishkumar11@gmail.com>
Date: Sat, 16 Aug 2025 00:53:40 +0530
Subject: [PATCH] Fix MyCustomEnv: environment initialization, loader, and test
 block

- Fixed MyCustomEnv class to properly initialize with config
- Moved load(), get_default_config(), and get_domain_randomizer outside the class
- Consolidated test block into a single __main__ section
- Verified step(), reset(), and loader functionality
---
 mujoco_playground/_src/my_custom_env.py | 95 +++++++++++++++++++++++++
 mujoco_playground/_src/registry.py      | 10 ++-
 2 files changed, 104 insertions(+), 1 deletion(-)
 create mode 100644 mujoco_playground/_src/my_custom_env.py

diff --git a/mujoco_playground/_src/my_custom_env.py b/mujoco_playground/_src/my_custom_env.py
new file mode 100644
index 000000000..8613fa482
--- /dev/null
+++ b/mujoco_playground/_src/my_custom_env.py
@@ -0,0 +1,95 @@
+import ml_collections
+from mujoco_playground._src import mjx_env
+import numpy as np
+
+ALL_ENVS = ("MyCustomEnv",)
+class MjxEnv:
+    def __init__(self, config=None):
+        pass
+
+class MyCustomEnv(MjxEnv):
+    def __init__(self, config=None):
+        super().__init__(config)
+        self.state = 0.0
+
+    @property
+    def action_size(self):
+        return 1
+
+    @property
+    def mj_model(self):
+        return None
+
+    @property
+    def mjx_model(self):
+        return None
+
+    @property
+    def xml_path(self):
+        return None
+
+    def reset(self):
+        self.state = 0.0
+        return np.array([self.state], dtype=np.float32)
+
+    def step(self, action):
+        self.state += float(action[0])
+        obs = np.array([self.state], dtype=np.float32)
+        reward = -abs(self.state)
+        done = abs(self.state) > 10
+        info = {}
+        return obs, reward, done, info
+def load(env_name: str, config=None, config_overrides=None) -> mjx_env.MjxEnv:
+        if env_name != "MyCustomEnv":
+            raise ValueError(f"Unknown env: {env_name}")
+
+        if config is None:
+            config = get_default_config(env_name)
+        if config_overrides:
+            config.update(config_overrides)
+
+        return MyCustomEnv()
+    
+def get_domain_randomizer(env_name: str):
+    if env_name == "MyCustomEnv":
+        return None
+    return None
+    
+def get_default_config(env_name: str) -> ml_collections.ConfigDict:
+    if env_name == "MyCustomEnv":
+        cfg = ml_collections.ConfigDict()
+        cfg.obs_dim = 1
+        cfg.action_dim = 1
+        return cfg
+    raise ValueError(f"Unknown env: {env_name}")
+
+if __name__ == "__main__":
+    # Instantiate environment
+    env = MyCustomEnv()
+
+    # Reset environment and print initial observation
+    obs = env.reset()
+    print("Initial observation:", obs)
+
+    # Step through the environment
+    for i in range(15):
+        action = [1.0]  # test action
+        obs, reward, done, info = env.step(action)
+        print(f"Step {i+1} | obs: {obs}, reward: {reward}, done: {done}")
+        if done:
+            print("Environment reached terminal state")
+            break
+
+    # Test loader function
+    try:
+        loaded_env = load("MyCustomEnv")
+        obs = loaded_env.reset()
+        print("Loaded environment initial obs:", obs)
+        print("Loader test passed!")
+    except Exception as e:
+        print("Loader test failed:", e)
+
+    # Simple assertions for sanity check
+    assert isinstance(obs, (list, np.ndarray)), "Observation must be array-like"
+    assert hasattr(env, "step"), "Environment must have step() method"
+    print("Sanity checks passed!")
diff --git a/mujoco_playground/_src/registry.py b/mujoco_playground/_src/registry.py
index a2d988279..8e9b0fb4f 100644
--- a/mujoco_playground/_src/registry.py
+++ b/mujoco_playground/_src/registry.py
@@ -14,6 +14,8 @@
 # ==============================================================================
 """Registry for all environments."""
 from typing import Any, Callable, Dict, Optional, Tuple, Union
+from mujoco_playground._src import my_custom_env
+
 
 import jax
 import ml_collections
@@ -31,7 +33,7 @@
 
 # A tuple containing all available environment names across all suites.
 ALL_ENVS = (
-    dm_control_suite.ALL_ENVS + locomotion.ALL_ENVS + manipulation.ALL_ENVS
+    dm_control_suite.ALL_ENVS + locomotion.ALL_ENVS + manipulation.ALL_ENVS + my_custom_env.ALL_ENVS
 )
 
 
@@ -42,6 +44,8 @@ def get_default_config(env_name: str):
     return locomotion.get_default_config(env_name)
   elif env_name in dm_control_suite.ALL_ENVS:
     return dm_control_suite.get_default_config(env_name)
+  elif env_name in my_custom_env.ALL_ENVS:
+        return my_custom_env.get_default_config(env_name)
 
   raise ValueError(f"Env '{env_name}' not found in default configs.")
 
@@ -57,6 +61,8 @@ def load(
     return locomotion.load(env_name, config, config_overrides)
   elif env_name in dm_control_suite.ALL_ENVS:
     return dm_control_suite.load(env_name, config, config_overrides)
+  elif env_name in my_custom_env.ALL_ENVS:
+        return my_custom_env.load(env_name, config, config_overrides)
 
   raise ValueError(f"Env '{env_name}' not found. Available envs: {ALL_ENVS}")
 
@@ -67,5 +73,7 @@ def get_domain_randomizer(env_name: str) -> Optional[DomainRandomizer]:
 
   if env_name in locomotion.ALL_ENVS:
     return locomotion.get_domain_randomizer(env_name)
+  if env_name in my_custom_env.ALL_ENVS:
+        return my_custom_env.get_domain_randomizer(env_name)
 
   return None