Make camera setting more robust

src/jaxsim/mujoco/loaders.py

@@ -159,9 +159,7 @@ def convert(
         considered_joints: list[str] | None = None,
         plane_normal: tuple[float, float, float] = (0, 0, 1),
         heightmap: bool | None = None,
-        cameras: (
-            list[dict[str, str, str, str, str]] | dict[str, str, str, str, str]
-        ) = None,
+        cameras: list[dict[str, str]] | dict[str, str] = None,
     ) -> tuple[str, dict[str, Any]]:
         """
         Converts a ROD model to a Mujoco MJCF string.
@@ -479,7 +477,7 @@ def convert(
         # Add user-defined camera
         cameras = cameras if cameras is not None else {}
         for camera in cameras if isinstance(cameras, list) else [cameras]:
-            _ = ET.SubElement(worldbody_element, "camera", **camera)
+            _ = ET.SubElement(worldbody_element, "camera", **_Camera(**camera))
 
         # ------------------------------------------------
         # Add a light following the  CoM of the first link
@@ -515,9 +513,7 @@ def convert(
         model_name: str | None = None,
         plane_normal: tuple[float, float, float] = (0, 0, 1),
         heightmap: bool | None = None,
-        cameras: (
-            list[dict[str, str, str, str, str]] | dict[str, str, str, str, str]
-        ) = None,
+        cameras: list[dict[str, str]] | dict[str, str] = None,
     ) -> tuple[str, dict[str, Any]]:
         """
         Converts a URDF file to a Mujoco MJCF string.
@@ -559,9 +555,7 @@ def convert(
         model_name: str | None = None,
         plane_normal: tuple[float, float, float] = (0, 0, 1),
         heightmap: bool | None = None,
-        cameras: (
-            list[dict[str, str, str, str, str]] | dict[str, str, str, str, str]
-        ) = None,
+        cameras: list[dict[str, str]] | dict[str, str] = None,
     ) -> tuple[str, dict[str, Any]]:
         """
         Converts a SDF file to a Mujoco MJCF string.
@@ -593,3 +587,24 @@ def convert(
             heightmap=heightmap,
             cameras=cameras,
         )
+
+
+class _Camera:
+    def __init__(self, name: str, mode: str, pos: str, xyaxes: str, fovy: str):
+        self.name = name
+        self.mode = mode
+        self.pos = pos
+        self.xyaxes = xyaxes
+        self.fovy = fovy
+
+    def __iter__(self):
+        if not all(isinstance(self.key, str) for key in self.__annotations__.keys()):
+            raise ValueError("Values must be strings")
+
+        if len(self.pos.split()) != 3:
+            raise ValueError("pos must have three values separated by space")
+
+        if len(self.xyaxes.split()) != 6:
+            raise ValueError("xyaxes must have six values separated by space")
+
+        return tuple(self.key for key in self.__annotations__.keys())