From e7a9447c03aa2aaac7b6ab664a1a72623d12c89c Mon Sep 17 00:00:00 2001
From: Benjamin Nauck <benjamin@nauck.se>
Date: Sun, 12 Feb 2023 21:59:31 +0100
Subject: [PATCH] Add gravcomp to body in unity plugin

The unity plugin is missing gravcomp which makes it impossible for buoyancy
---
 unity/Runtime/Components/Bodies/MjBody.cs | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/unity/Runtime/Components/Bodies/MjBody.cs b/unity/Runtime/Components/Bodies/MjBody.cs
index 8d6a8cd3..e29de5c0 100644
--- a/unity/Runtime/Components/Bodies/MjBody.cs
+++ b/unity/Runtime/Components/Bodies/MjBody.cs
@@ -20,17 +20,23 @@ namespace Mujoco {
 
   // The component represents the apex of hierarchy that defines a single rigid body.
   public class MjBody : MjBaseBody {
+
+    [Tooltip("Gravity compensation force, specified as fraction of body weight.")]
+    public float GravityCompensation;
+
     protected override void OnParseMjcf(XmlElement mjcf) {
       // Transform
       transform.localPosition =
           MjEngineTool.UnityVector3(mjcf.GetVector3Attribute("pos", defaultValue: Vector3.zero));
       transform.localRotation = MjEngineTool.UnityQuaternion(
           mjcf.GetQuaternionAttribute("quat", defaultValue: MjEngineTool.MjQuaternionIdentity));
+      GravityCompensation = mjcf.GetFloatAttribute("gravcomp", defaultValue: 0.0f);
     }
 
     protected override XmlElement OnGenerateMjcf(XmlDocument doc) {
       var mjcf = (XmlElement)doc.CreateElement("body");
       MjEngineTool.PositionRotationToMjcf(mjcf, this);
+      mjcf.SetAttribute("gravcomp", MjEngineTool.MakeLocaleInvariant($"{GravityCompensation}"));
       return mjcf;
     }