Version 2.1.2: Python bindings, OBJ assets support, bugfixes.

PiperOrigin-RevId: 434731612
Change-Id: I0cfda3e7a3d1c72036764986efc252ffa1b8c6b0

unity/Runtime/Tools/MjEngineTool.cs

@@ -35,6 +35,10 @@ public static class MjEngineTool {
     return name.Replace('/', '_');
   }
 
+  public static string MakeLocaleInvariant(FormattableString interpolated) {
+    return FormattableString.Invariant(interpolated);
+  }
+
   // Loads a model from the specified file.
   // `filename` should contain an absolute path to the file.
   public static unsafe MujocoLib.mjModel_* LoadModelFromFile(string fileName) {
@@ -190,11 +194,11 @@ public static class MjEngineTool {
   }
 
   public static string Vector3ToMjcf(Vector3 vec) {
-    return $"{vec.x} {vec.y} {vec.z}";
+    return MakeLocaleInvariant($"{vec.x} {vec.y} {vec.z}");
   }
 
   public static string QuaternionToMjcf(Quaternion quat) {
-    return $"{quat.w} {quat.x} {quat.y} {quat.z}";
+    return MakeLocaleInvariant($"{quat.w} {quat.x} {quat.y} {quat.z}");
   }
 
   // We can't use transform.localPosition because we allow arbitrary deep gameObject hierarchies
@@ -230,12 +234,20 @@ public static class MjEngineTool {
 
   // Converts an array of floats to an Mjcf.
   public static string ArrayToMjcf(float[] array) {
-    return String.Join(" ", array);
+    String ret = "";
+    foreach (float entry in array) {
+      ret += MakeLocaleInvariant($"{entry} ");
+    }
+    return ret.Substring(startIndex:0, length:ret.Length - 1);
   }
 
   // Converts a list of floats to an Mjcf.
   public static string ListToMjcf(List<float> list) {
-    return String.Join(" ", list);
+    String ret = "";
+    foreach (float entry in list) {
+      ret += MakeLocaleInvariant($"{entry} ");
+    }
+    return ret.Substring(startIndex:0, length:ret.Length - 1);
   }
 
   // Generates an Mjcf of the specified component's transform.

unity/Runtime/Tools/MjcfGenerationContext.cs

@@ -70,7 +70,7 @@ public class MjcfGenerationContext {
     var optionMjcf = (XmlElement)mjcf.AppendChild(doc.CreateElement("option"));
     optionMjcf.SetAttribute(
         "gravity", MjEngineTool.Vector3ToMjcf(MjEngineTool.MjVector3(Physics.gravity)));
-    optionMjcf.SetAttribute("timestep", $"{Time.fixedDeltaTime}");
+    optionMjcf.SetAttribute("timestep", MjEngineTool.MakeLocaleInvariant($"{Time.fixedDeltaTime}"));
 
     var sizeMjcf = (XmlElement)mjcf.AppendChild(doc.CreateElement("size"));
     sizeMjcf.SetAttribute("nuser_sensor", $"{_nuserSensor}");