Add bindings generation for mjOption, mjVisual, and mjStatistic.

Fixes #2076.

PiperOrigin-RevId: 677789263
Change-Id: Ie1bda40af62c5ac9bbba541668a50adfc59d3f7c

python/mujoco/codegen/generate_spec_bindings.py

@@ -43,6 +43,13 @@ def _value_binding_code(
       fulltype = fulltype + '&'  # plugin and orientation are not pointers
     else:
       fulltype = fulltype + '*'
+  # non-mjs structs
+  rawclassname = rawclassname.replace('mjOption', 'raw::MjOption')
+  rawclassname = rawclassname.replace('mjVisual', 'raw::MjVisual')
+  rawclassname = rawclassname.replace('mjStatistic', 'raw::MjStatistic')
+  fulltype = fulltype.replace('mjOption', 'raw::MjOption')
+  fulltype = fulltype.replace('mjVisual', 'raw::MjVisual')
+  fulltype = fulltype.replace('mjStatistic', 'raw::MjStatistic')
 
   def_property_args = (
       f'"{varname}"',
@@ -68,6 +75,9 @@ def _array_binding_code(
     raise NotImplementedError()
   innertype = field.inner_type.decl()
   rawclassname = classname.replace('mjs', 'raw::Mjs')
+  rawclassname = rawclassname.replace('mjOption', 'raw::MjOption')
+  rawclassname = rawclassname.replace('mjVisual', 'raw::MjVisual')
+  rawclassname = rawclassname.replace('mjStatistic', 'raw::MjStatistic')
   fullvarname = varname
   if classname == 'mjSpec':  # raw mjSpec has a wrapper
     rawclassname = classname.replace('mjS', 'MjS')
@@ -209,12 +219,17 @@ def _ptr_binding_code(
         }}
     }}, py::return_value_policy::reference_internal);"""
 
-  raise NotImplementedError()
+  raise NotImplementedError(
+      'Unsupported array type: ' + vartype + ' in ' + classname
+  )
 
 
 def _binding_code(field: ast_nodes.StructFieldDecl, key: str) -> str:
   if isinstance(field.type, ast_nodes.ValueType):
     return _value_binding_code(field.type, key, field.name)
+  elif isinstance(field.type, ast_nodes.AnonymousStructDecl):
+    field.type = ast_nodes.ValueType(name='mjVisual'+field.name.title())
+    return _value_binding_code(field.type, key, field.name)
   elif isinstance(field.type, ast_nodes.PointerType):
     return _ptr_binding_code(field.type, key, field.name)
   elif isinstance(field.type, ast_nodes.ArrayType):
@@ -224,7 +239,10 @@ def _binding_code(field: ast_nodes.StructFieldDecl, key: str) -> str:
 
 def generate() -> None:
   for key in structs.STRUCTS.keys():
-    if (key.startswith('mjs') or key == 'mjSpec') and key != 'mjsElement':
+    if (
+        key.startswith('mjs')
+        or key in ['mjSpec', 'mjOption', 'mjVisual', 'mjStatistic']
+    ) and key != 'mjsElement':
       print('\n  // ' + key)
       for field in structs.STRUCTS[key].fields:
         code = _binding_code(field, key)

python/mujoco/specs.cc

@@ -109,6 +109,9 @@ PYBIND11_MODULE(_specs, m) {
   py::class_<raw::MjsPlugin> mjsPlugin(m, "MjsPlugin");
   py::class_<raw::MjsOrientation> mjsOrientation(m, "MjsOrientation");
   py::class_<raw::MjsWrap> mjsWrap(m, "MjsWrap");
+  py::class_<raw::MjOption> mjOption(m, "MjOption");
+  py::class_<raw::MjStatistic> mjStatistic(m, "MjStatistic");
+  py::class_<raw::MjVisual> mjVisual(m, "MjVisual");
 
   // ============================= MJSPEC =====================================
   mjSpec.def(py::init<>());

python/mujoco/specs_test.py

@@ -717,5 +717,30 @@ class SpecsTest(absltest.TestCase):
     self.assertIsNotNone(model)
     self.assertEqual(model.nplugin, 0)
 
+  def test_access_option_stat_visual(self):
+    spec = mujoco.MjSpec()
+    spec.from_string(textwrap.dedent("""
+      <mujoco model="MuJoCo Model">
+        <option timestep="0.001"/>
+        <statistic meansize="0.05"/>
+        <visual>
+          <quality shadowsize="4096"/>
+        </visual>
+      </mujoco>
+    """))
+    self.assertEqual(spec.option.timestep, 0.001)
+    self.assertEqual(spec.stat.meansize, 0.05)
+    self.assertEqual(spec.visual.quality.shadowsize, 4096)
+
+    spec.option.timestep = 0.002
+    spec.stat.meansize = 0.06
+    spec.visual.quality.shadowsize = 8192
+
+    model = spec.compile()
+
+    self.assertEqual(model.opt.timestep, 0.002)
+    self.assertEqual(model.stat.meansize, 0.06)
+    self.assertEqual(model.vis.quality.shadowsize, 8192)
+
 if __name__ == '__main__':
   absltest.main()