中文摘要：

提出了一种GPU加速的实时基于图像的绘制算法．该算法利用极坐标系生成对物体全方位均匀采样的球面深度图像；然后根据推导的两个预变换公式将单幅球面深度图像预变换到物体包围球的一个与视点相关的切平面上，以生成中间图像；再利用纹理映射生成最终目标图像．利用现代图形硬件的可编程性和并行性，将预变换移植到Vertex Shader来加快绘制速度；利用硬件的光栅化功能来完成图像的插值，以得到连续无洞的结果图像．此外，还在Pixel Shader上进行逐像素的光照以及环境映射的计算，生成高质量的光照效果．最终，文章解决了算法的视点受限问题，并设计了一种动态LOD（Level of Details）算法，实现了一个实时漫游系统，保持了物体间正确的遮挡关系．

英文摘要：

This paper presents an image-based real-time rendering algorithm on GPU. By the alorithm, we uniformly sample an object in all directions in a polar coordinates system, to construct a Spherical Depth Image. With two deduced Warping Equations, we then pre-warp the image onto a view-dependent tangent plane of the bounding sphere of the object to get an intermediate image, which can be further rendered onto the target image plane using standard texture mapping. By exploiting the inherent parallelism of modern programmable GPU, we transport the pre-warping process into Vertex Shader. Furthermore, the hardware pipeline＇ s rasterization function is utilized to conduct the image re-sampling efficiently to generate hole-free rendering results. Besides, Per-pixel lighting and Environment mapping effect is implemented in Pixel Shader to get high quality lighting effect. Finally, we solve the problem of limited field of view, and design a LOD （Level of Detail） algorithm to implement a real-time walkthrough system, in which all the rendered objects are occluded by each other correctly.