restore render support for mujoco<3 (#750)

gymnasium/envs/mujoco/mujoco_rendering.py

@@ -610,6 +610,14 @@ def _create_overlay(self):
         self.add_overlay(topleft, "Toggle geomgroup visibility", "0-4")
 
         self.add_overlay(bottomleft, "FPS", "%d%s" % (1 / self._time_per_render, ""))
+        if mujoco.__version__ >= "3.0.0":
+            self.add_overlay(
+                bottomleft, "Solver iterations", str(self.data.solver_niter[0] + 1)
+            )
+        elif mujoco.__version__ < "3.0.0":
+            self.add_overlay(
+                bottomleft, "Solver iterations", str(self.data.solver_iter + 1)
+            )
         self.add_overlay(
             bottomleft, "Solver iterations", str(self.data.solver_niter[0] + 1)
         )

pyproject.toml

@@ -41,7 +41,7 @@ classic-control = ["pygame >=2.1.3"]
 classic_control = ["pygame >=2.1.3"]  # kept for backward compatibility
 mujoco-py = ["mujoco-py >=2.1,<2.2", "cython<3"]
 mujoco_py = ["mujoco-py >=2.1,<2.2", "cython<3"]       # kept for backward compatibility
-mujoco = ["mujoco >=3.0.0", "imageio >=2.14.1"]
+mujoco = ["mujoco >=2.1.5", "imageio >=2.14.1"]
 toy-text = ["pygame >=2.1.3"]
 toy_text = ["pygame >=2.1.3"]         # kept for backward compatibility
 jax = ["jax >=0.4.0", "jaxlib >=0.4.0"]
@@ -67,7 +67,7 @@ all = [
     "mujoco-py >=2.1,<2.2",
     "cython<3",
     # mujoco
-    "mujoco >=3.0.0",
+    "mujoco >=2.1.5",
     "imageio >=2.14.1",
     # toy-text
     "pygame >=2.1.3",