added dmc2gym conversion and example how to leverage DMPs

alr_envs/dmc/Ball_in_the_cup_mp_wrapper.py

@@ -0,0 +1,27 @@
+from typing import Union
+
+import numpy as np
+
+from mp_env_api.env_wrappers.mp_env_wrapper import MPEnvWrapper
+
+
+class BallInCupMPWrapper(MPEnvWrapper):
+
+    @property
+    def active_obs(self):
+        # Besides the ball position, the environment is always set to 0.
+        return np.hstack([
+            [False] * 2,  # cup position
+            [True] * 2,  # ball position
+            [False] * 2,  # cup velocity
+            [False] * 2,  # ball velocity
+        ])
+
+    @property
+    def start_pos(self) -> Union[float, int, np.ndarray]:
+        return np.hstack([self.physics.named.data.qpos['cup_x'], self.physics.named.data.qpos['cup_z']])
+
+    @property
+    def dt(self) -> Union[float, int]:
+        # Taken from: https://github.com/deepmind/dm_control/blob/master/dm_control/suite/ball_in_cup.py#L27
+        return 0.02