Ngui Click and scene click to judge

Note: Add Boxcollider to the NGUI component and set the area size

public void OnMouseDown ()
{

if (Uicamera.hoveredobject = = null)//Scene Click
{
A = Gameobject.find ("box");

if (b = = false)
{

A.renderer.material.color = color.red;
B = true;
}

else if (b = = true)
{

A.renderer.material.color = Color.yellow;
b = false;
}
}

}

or with radiographic testing

Ray Ray=uicamera.maincamera.screenpointtoray (input.mouseposition);//Launch line to screen
Raycasthit hit;
if (Physics.raycast (ray,out hit,200))//Ray collision detection
{
Print ("point to Ngui");
}

Ngui Click and scene click to judge