An enhanced image mapping algorithm is proposed for a real-time computer-generated (CG) integral imaging system. The proposed algorithm, viewpoint vector rendering, can be easily adapted to generate a set of elemental images from complex three-dimensional (3D) objects and is less affected by system factors and object image quality than previous methods. In addition, it can support all the display modes of the integral imaging system. The feasibility and efficiency of the proposed approach are verified and analyzed through rendering experiments. Using this technique, it is possible to realize an interactive CG integral imaging system which can be applied to virtual reality.