Add camera support to jaxsim.mujoco visualizer

src/jaxsim/mujoco/loaders.py

@@ -423,6 +423,36 @@ def convert(
                 pos="1 0 5",
             )
 
+        # -------------------------------------------------------
+        # Add a camera following the CoM of the worldbody element
+        # -------------------------------------------------------
+
+        worldbody_element = None
+
+        # Find the <worldbody> element of our model by searching the one that contains
+        # all the considered joints. This is needed because there might be multiple
+        # <worldbody> elements inside <mujoco>.
+        for wb in mujoco_element.findall(".//worldbody"):
+            if all(
+                wb.find(f".//joint[@name='{j}']") is not None for j in considered_joints
+            ):
+                worldbody_element = wb
+                break
+
+        if worldbody_element is None:
+            raise RuntimeError("Failed to find the <worldbody> element of the model")
+
+        # Camera attached to the model
+        _ = ET.SubElement(
+            worldbody_element,
+            "camera",
+            name="track",
+            mode="trackcom",
+            pos="1 0 5",
+            zaxis="0 0 1",
+            fovy="60",
+        )
+
         # --------------------------------
         # Return the resulting MJCF string
         # --------------------------------

src/jaxsim/mujoco/visualizer.py

@@ -54,14 +54,16 @@ def reset(
 
     def render_frame(self, camera_name: str | None = None) -> npt.NDArray:
         """"""
+        camera_name = camera_name or "track"
 
         mujoco.mj_forward(self.model, self.data)
-        self.renderer.update_scene(data=self.data)  # TODO camera name
+        self.renderer.update_scene(data=self.data, camera=camera_name)
 
         return self.renderer.render()
 
     def record_frame(self, camera_name: str | None = None) -> None:
         """"""
+        camera_name = camera_name or "track"
 
         frame = self.render_frame(camera_name=camera_name)
         self.frames.append(frame)