Unity3d Editor script to put pivot point in ProBuilder objects back on the mesh after manipulating the faces/edges/verts

FixProBuilderPivot.cs

/* Fix ProBuilder Pivot
 * An action to move the pivot back to the mesh in cases where you've
 * manipulated the edges/faces of a mesh and left the pivot far behind
 * Author: Levi Lansing (https://github.com/levilansing)
 * Feb 2018
 */

using UnityEngine;
using UnityEditor;
using ProBuilder2.Common;
using ProBuilder2.EditorCommon;

namespace Zephlabs.Actions
{
	/**
	 *	This class is responsible for loading the pb_MenuAction into the toolbar and menu.
	 */
	[InitializeOnLoad]
	static class RegisterCustomAction {
		/**
		 *	Static initializer is called when Unity loads the assembly.
		 */
		static RegisterCustomAction()
		{
			// This registers a new MakeFacesDoubleSided menu action with the toolbar.
			pb_EditorToolbarLoader.RegisterMenuItem(InitCustomAction);
		}

		/**
		 *	Helper function to load a new menu action object.
		 */
		static pb_MenuAction InitCustomAction()
		{
			return new FixProBuilderPivot();
		}

		/**
		 *	Usually you'll want to add a menu item entry for your action.
		 * 	https://docs.unity3d.com/ScriptReference/MenuItem.html
		 */
		[MenuItem("Tools/ProBuilder/Fix Pivot %#&F", true)]
		static bool MenuVerifyDoSomethingWithPbObject()
		{
			// Using pb_EditorToolbarLoader.GetInstance keeps MakeFacesDoubleSided as a singleton.
			FixProBuilderPivot instance = pb_EditorToolbarLoader.GetInstance<FixProBuilderPivot>();
			return instance != null && instance.IsEnabled();
		}

		[MenuItem("Tools/ProBuilder/Fix Pivot %#&F", false, pb_Constant.MENU_GEOMETRY + 3)]
		static void MenuDoDoSomethingWithPbObject()
		{
			FixProBuilderPivot instance = pb_EditorToolbarLoader.GetInstance<FixProBuilderPivot>();

			if(instance != null)
				pb_EditorUtility.ShowNotification(instance.DoAction().notification);
		}
	}

	/**
	 *	This is the actual action that will be executed.
	 */
	public class FixProBuilderPivot : pb_MenuAction
	{
		public override pb_ToolbarGroup group { get { return pb_ToolbarGroup.Geometry; } }
		public override Texture2D icon { get { return null; } }
		public override pb_TooltipContent tooltip { get { return _tooltip; } }

		/**
		 *	What to show in the hover tooltip window.  pb_TooltipContent is similar to GUIContent, with the exception that it also
		 *	includes an optional params[] char list in the constructor to define shortcut keys (ex, CMD_CONTROL, K).
		 */
		static readonly pb_TooltipContent _tooltip = new pb_TooltipContent
		(
			"Fix Pivot",
			"Moves the pivot to a vertex on the edge of the mesh."
		);

		/**
		 *	Determines if the action should be enabled or grayed out.
		 */
		public override bool IsEnabled()
		{
			// `selection` is a helper property on pb_MenuAction that returns a pb_Object[] array from the current selection.
			return pb_Editor.instance != null && selection != null && selection.Length > 0;
		}

		/**
		 *	Determines if the action should be loaded in the menu (ex, face actions shouldn't be shown when in vertex editing mode).
		 */
		public override bool IsHidden()
		{
			return pb_Editor.instance == null || pb_Editor.instance.editLevel != EditLevel.Geometry;
		}

		/**
		 *	Do the thing.  Return a pb_ActionResult indicating the success/failure of action.
		 */
		public override pb_ActionResult DoAction()
		{
			pbUndo.RecordObjects(selection, "Fix Pivot");

			foreach(pb_Object pb in selection)
			{
				// find bottom-most, left-most, nearest vertex
				var index = 0;
				var mf = pb.GetComponent<MeshFilter>();
				if (mf != null) {
					var mesh = mf.sharedMesh;
					if (mesh) {
						var minY = mesh.vertices[0].y;
						for (int i = 0; i < mesh.vertices.Length; i++) {
							var vert = mesh.vertices[i];
							if (minY > vert.y) {
								minY= vert.y;
								index = i;
							}
						}
						var minX = mesh.vertices[index].x;
						for (int i = 0; i < mesh.vertices.Length; i++) {
							var vert = mesh.vertices[i];
							if (Mathf.Approximately(vert.y, minY) && minX > vert.x) {
								minX = vert.x;
								index = i;
							}
						}
						var minZ = mesh.vertices[index].z;
						for (int i = 0; i < mesh.vertices.Length; i++) {
							var vert = mesh.vertices[i];
							if (Mathf.Approximately(vert.y, minY) && Mathf.Approximately(vert.x, minX) && minZ > vert.z) {
								minZ = vert.z;
								index = i;
							}
						}
					}
				}

				pb_EditorUtility.SetPivotAndSnapWithPref(pb, new int[] { index });

				pb.ToMesh();
				pb.Refresh();
				pb.Optimize();
			}

			// This is necessary!  Otherwise the pb_Editor will be working with caches from
			// outdated meshes and throw errors.
			pb_Editor.Refresh();
			
			return new pb_ActionResult(Status.Success, "Fix Pivot");
		}
	}
}