This paper presents a new pipeline for rendering depth images entirely on GPU (graphics processing unit). The implementation exploits inherent parallelism of GPU to speed up the rendering of depth images. By the scheme, a novel forward 3D warping method is proposed for vertex shader to obtain high rendering performance. Furthermore, the hardware pipeline's rasterization function is utilized to conduct the image re-sampling efficiently to generate holes free rendering results. Per pixel lighting effect is implemented in pixel shader to get high image quality. The rendering shows rapid performance at full screen resolution, with correct self-occlusions and accurate silhouettes. Moreover, a real-time walkthrough system is implemented for the objects based on cylindrical depth image rendered by view-dependent dynamic LOD (level of detail) representation at runtime.