How can i get how much of the plane is visible on the 0.0 z axis? Because when drawing, i have translated back 5.0 so that more is in view on the 0.0 z axis, however this has stuffed up my winMouse -> glMouse coordinates. Heres the code i'm using atm to get the mouse coordinates in ogl: --- --- --- void GetGLMouse(int wx, int wy){ pX = (((double)wx / (double)windowWidth) * 2.0) - 1.0; pY = -(((double)wy / (double)windowHeight) * 2.0) - 1.0; } --- --- --- Can anyone tell me how to get how much is in view on the 0.0z axis, or a better way for converting the winMouse -> glMouse coordinates?