[lua] inertialUnit Class

inertialUnit = {
    ['x'] = 0,
    ['y'] = 0,
    ['z'] = 0,
    ['d'] = 0,
    ['mouv'] = {
        [0]   = { 0, 0, 1},
        [1]   = { 1, 0, 0},
        [2]   = { 0, 0,-1},
        [3]   = {-1, 0, 0},
        ['u'] = { 0, 1, 0},
        ['d'] = { 0,-1, 0}
    }
}
function inertialUnit:new (o)
    o = o or {}   -- create object if user does not provide one
    setmetatable(o, self)
    self.__index = self
    return o
end
function inertialUnit.__tostring(self)
    return "[ Object inertialUnit {x : ".. self.x ..", y : ".. self.y ..", z : ".. self.z ..", delta : ".. self.d .."} ]"
end
function inertialUnit:getPos()
  local o = {}
  o.x, o.y, o.z, o.d = self.x, self.y, self.z, self.d
  return o
end
function inertialUnit:setPos(x, y, z, d)
  self.x = x
  self.y = y
  self.z = z
  self.d = d
end
function inertialUnit:deplace (mouv)
    self.x = self.x + mouv[1]
    self.y = self.y + mouv[2]
    self.z = self.z + mouv[3]
end
function inertialUnit:tourne (angle)
    self.d = ( self.d + angle ) % 4
end
function inertialUnit:forward()
    self:deplace( self.mouv[ self.d ] )
end
function inertialUnit:back()
    self:deplace( self.mouv[ ( self.d + 2 ) % 4 ] )
end
function inertialUnit:up()
    self:deplace( self.mouv[ 'u' ] )
end
function inertialUnit:down()
    self:deplace( self.mouv[ 'd' ] )
end
function inertialUnit:right()
    self:tourne( 1 )
end
function inertialUnit:left()
    self:tourne( -1 )
end