使用GPU编程的光线投射体绘制算法

Ray-Casting-Based Volume Rendering Algorithm Using GPU Programming

将传统的光线投射体绘制算法在具有可编程管线的图形处理器(GPU)上重新实现.首先将体数据作为三维纹理保存在显存中,然后通过编写顶点程序和片段程序将光线进入点/离开点计算和光线遍历的计算移入GPU中执行,最后根据不同的采样点颜色混合公式实现不同的绘制效果.文中算法仅需绘制一个四边形即可完成三维重建.实验结果表明:在进行光照效果的重建时,该算法能够达到实时交互的绘制要求,并能实现半透明等复杂绘制效果.

In this work, we implement the traditional ray-casting-based volume rendering algorithm on the programmable graphics processing unit （GPU）. By the algorithm, at first the volume data is transferred into the video RAM as 3D texture, then the ray＇s entry point, leave point and the ray traversal in the GPU are calculated by the vertex program and the fragment program. Finally, different rendering effects are achieved according to various blending functions of the sampling points. Our implementation only needs to render one quadrangle for 3D reconstruction. The experiment shows that when reconstructing with shading effect, the GPU-based ray-casting algorithm can meet the requirements of real-time interactive rendering, and it can also realize some complex effects such as translucency.