def readDepthMap(x, y):
    view = omUI.M3dView.active3dView()
    width = view.portWidth()
    height = view.portHeight()

    width = 1
    height = 1

    numPixels = width*height*4
    depth = [0.0]*numPixels
    util = om.MScriptUtil()
    util.createFromList(depth, numPixels)
    utilPtr = util.asUcharPtr()

    view.readDepthMap(x, y, width, height, utilPtr, omUI.M3dView.kDepth_Float)

    b1 = om.MScriptUtil.getUcharArrayItem(utilPtr, 0)
    b2 = om.MScriptUtil.getUcharArrayItem(utilPtr, 1)
    b3 = om.MScriptUtil.getUcharArrayItem(utilPtr, 2)
    b4 = om.MScriptUtil.getUcharArrayItem(utilPtr, 3)

    data = [b1,b2,b3,b4]
    b = struct.pack('4B', *data)
    floatDepth = struct.unpack('<f', b)[0]
    print "depth: ",floatDepth
    return floatDepth


def projectPointToViewZDepth(p):
    # take a world space point, bring it into screen-space, look up its camera depth
    # then project it back into world-space using that depth

    scriptUtil = om.MScriptUtil()
    ptr = scriptUtil.asShortPtr()

    scriptUtil2 = om.MScriptUtil()
    ptr2 = scriptUtil2.asShortPtr()

    view = omUI.M3dView.active3dView()
    stat = view.worldToView(p, ptr, ptr2)

    x = scriptUtil.getShort(ptr)
    y = scriptUtil.getShort(ptr2)

    depth = readDepthMap(x,y)
    ray = om.MVector()
    wp = om.MPoint()

    view.viewToWorld(x,y,wp, ray)

    pProjected = wp + ray * depth
    return pProjected