Fix: Handle non-parallelized scenes in _get_genesis_link_transform

- Check if scene is parallelized before passing envs_idx parameter
- Fixes GenesisException: 'envs_idx is not supported for non-parallelized scene'
- Ensures compatibility with both parallelized and non-parallelized scenarios

Author: Roushelfy

genesis/engine/couplers/ipc_coupler.py

@@ -1689,10 +1689,15 @@ def _get_genesis_link_transform(self, link_idx, env_idx):
         import numpy as np
 
         rigid_solver = self.rigid_solver
+        is_parallelized = self.sim._scene.n_envs > 0
 
         # Get current link state from Genesis
-        link_pos = rigid_solver.get_links_pos(links_idx=link_idx, envs_idx=env_idx)
-        link_quat = rigid_solver.get_links_quat(links_idx=link_idx, envs_idx=env_idx)
+        if is_parallelized:
+            link_pos = rigid_solver.get_links_pos(links_idx=link_idx, envs_idx=env_idx)
+            link_quat = rigid_solver.get_links_quat(links_idx=link_idx, envs_idx=env_idx)
+        else:
+            link_pos = rigid_solver.get_links_pos(links_idx=link_idx)
+            link_quat = rigid_solver.get_links_quat(links_idx=link_idx)
 
         link_pos = link_pos.detach().cpu().numpy()
         link_quat = link_quat.detach().cpu().numpy()