Max2012的世界坐标转屏幕坐标

Max2012使用Nitrous作为显示驱动的时候会有个Bug，就是MaxScript无法用GW.TransPoint来将世界坐标转换为屏幕坐标.这个Bug在2013中已经修复，2012可以换用Direct3D来解决，当不能换的时候，可以用该函数凑合解决一下:)。

Fn WorldPositionToScreen inputPos =
(
    viewMatrix = GetViewTM()
    viewCameraMatrix = Inverse viewMatrix
    screenRange2D = GetViewSize()
    refPosition = inputPos * viewMatrix
    screenOrigin = mapScreenToView [0,0] refPosition.z screenRange2D
    screenEnd = mapScreenToView screenRange2D refPosition.z screenRange2D
    worldSize = screenOrigin - screenEnd
    aspectX = screenRange2D.x/(abs worldSize.x)
    aspectY = screenRange2D.y/(abs worldSize.y)
    screenX = (aspectX * (refPosition.x - screenOrigin.x)) as Integer
    screenY = (abs(aspectY*(refPosition.y - screenOrigin.y))) as Integer
    [screenX,screenY]    
)