1. A method of image processing for projecting a three-dimensional (3D) image onto a two-dimensional (2D) screen, wherein at least one object is formed with at least one plane existing in 3D space, the method comprising: setting a viewing range and boundaries which enclose the viewing range; clipping by checking if any face of the object intersects with the boundaries, and, if so, calculating an intersecting plane of the face and the viewing range, so that the intersecting plane is a clipped plane corresponding to the face, and each clipped plane has a plurality of vertices; and integrating by recording the plurality of vertices of the clipped planes in a same vertex list in accordance with a triangle-list primitive after performing clipping of the object and calculating at least one clipped plane, such that the vertices of the clipped planes are represented by the same vertex list.