For those of you who are lazy to download files form China with 5Kbs speed.
Spreadtrum ResearchDownload User Guide [v1.0.2][EN]
Original source (slow).
Friday, November 13, 2015
Sunday, November 8, 2015
There is an image Fig 3.6 in a book "Viewpoints"  which explains one-point perspective. An observer looks at a box (B1,B2,B3,B4) and the box projects to an image plane containing points V1 and V2. It is a one-point perspective because the close side of the box (B1,B4) is parallel to the image plane. The observer looks in OZ direction and OZ is parallel to (B4,B3). Hence V1 is the vanishing point for line (B4,B3). (O,V2) is parallel to the box's diagonal and hence V2 is the vanishing point for the line (B4,B2).