gistfile1.py

import maya.cmds as cmds
from pymel.core import *
from pymel.core.datatypes import *
import maya.api.OpenMaya as om
import maya.api.OpenMayaUI as omui

class SamsClass():
	
	def __init__(self):
		pass

	def pointLocator(self, *args):
		'''
		pass in the name of a mesh, or just select one
		'''

		self.meshSelection = cmds.ls( type='mesh' )
		self.Context = 'Context'

		# clear any previous contexts
		if cmds.draggerContext( self.Context, ex=1 ):
			print 'deleting'
			cmds.deleteUI( self.Context )
		cmds.setToolTo( 'selectSuperContext' )

		# create context and set tool
		cmds.draggerContext( self.Context, pressCommand=self.onPress, dragCommand=self.onDrag, name=self.Context, cursor='crossHair' )
		cmds.setToolTo( self.Context )
		
	def onDrag( self ):
		vpX, vpY, _ = cmds.draggerContext( self.Context, q=1, dp=1 )
		cp = om.MPoint()
		dir = om.MVector()
		omui.M3dView().active3dView().viewToWorld( int(vpX), int(vpY), cp, dir )

		minpos = None
		mindist = float("inf")
		clmsh = None

		for mesh in self.meshSelection:
			selectionList = om.MSelectionList()
			selectionList.add( mesh )
			dagPath = selectionList.getDagPath(0)
			self.fnMesh = om.MFnMesh(dagPath)

			self.intersection = self.fnMesh.closestIntersection( om.MFloatPoint( cp	), om.MFloatVector( dir ), om.MSpace.kWorld, 99999, False )

			if self.intersection : 
				hitPoint, hitRayParam, hitFace, hitTriangle, hitBary1, hitBary2 = self.intersection

				if hitTriangle != -1:
					
					pos = Point( *hitPoint )
					if minpos == None:
						clmsh = mesh
						minpos = pos
						mindist = hitRayParam
					else:
						if hitRayParam < mindist:
							clmsh = mesh
							minpos = pos
							mindist = hitRayParam
		
		if ( mindist < float("inf") ):					
		#	self.loc1.setTranslation( minpos , space='world' )
		#	print( clmsh )
			cmds.hilite( clmsh, r=1 )
			cmds.refresh()
			

	def onPress( self ):
		vpX, vpY, _ = cmds.draggerContext( self.Context, q=1, ap=1 )
		cp = om.MPoint()
		dir = om.MVector()
		omui.M3dView().active3dView().viewToWorld( int(vpX), int(vpY), cp, dir )

		minpos = None
		mindist = float("inf")

		for mesh in self.meshSelection:
			selectionList = om.MSelectionList()
			selectionList.add( mesh )
			dagPath = selectionList.getDagPath(0)
			self.fnMesh = om.MFnMesh(dagPath)

			self.intersection = self.fnMesh.closestIntersection( om.MFloatPoint( cp	), om.MFloatVector( dir ), om.MSpace.kWorld, 99999, False )

			if self.intersection : 
				hitPoint, hitRayParam, hitFace, hitTriangle, hitBary1, hitBary2 = self.intersection

				if hitTriangle != -1:
					
					pos = Point( *hitPoint )
					if minpos == None:
						minpos = pos
						mindist = hitRayParam
					else:
						if hitRayParam < mindist:
							minpos = pos
							mindist = hitRayParam
		
#		if ( mindist < float("inf") ):					
		#	self.loc1 = spaceLocator()
		#	self.loc1.setTranslation( minpos , space='world' )
		#	cmds.refresh()


a = SamsClass()
a.pointLocator()