Directly painting textures on top of 3D objects in 3D perspective viewport is a new issue of Human Computer Interface (HCI).This paper presents a method to solve this issue.It converts the position information of the texture pixels of texture map into color information

and then transfers both the coordinates and the color of texture pixels into screen through texture mapping at the same time.Only is the color information of texture pixels converted into illumination by calculating the normal and the angle of ray incidence of the screen pixel in the method.The texture coordinates are firstly converted into the color information by generating another texture map

which is called information Map whose pixels' color represents the coordinates information.And then the corresponding texture coordinates are mapped into screen reference frame by texture mapping and stored into information buffer for later use.So we can obtain the texture coordinates of screen pixels correspondingly by decoding from information buffer.After optimizing

we can paint textures on top of 3D objects in 3D perspective viewport in real time.The paper also gives some examples and related definitions of using additional information of 2D texture map for 3D graph generating.