快速高精度的可见面选择

Fast Selecting Visible Surfaces in High Precision

高效地选取可见面,对于复杂场景的快速绘制是非常重要的.提出一种可见面的选择方法,能将基于图像空间或基于物体空间的可见面选择进行高效的结合,实现可见面的快速高精度的选取.首先,它对场景中的面片进行基于法向的分类,并根据面片的空间位置,为每一类面片分别建立一种层次形式的索引结构进行管理;然后在绘制过程中,基于像素驱动对可见面片进行由近及远的选取.由于索引结构对面片进行了有序的管理,这种选取计算很快,并能将可见面都选取出来,而已绘制的可见面的集合又能自动地成为遮挡者,隐含地剔除了大量的不可见面.与目前国际上关于可见性处理的方法相比,新方法对可见面的选取具有很高的精度,速度很快,并且能够方便地处理带有动态物体的场景.

It is very important to efficiently select visible surfaces in rendering complex scenes. As for this, a method is presented in this paper by combining the strategies for image-based selection and object-based selection. First, it classifies the surfaces by their normals, and manages every class of surfaces in hierarchical indexing structures by their positions in 3D space. Then, the visible surfaces are pixel-driven searched from near to far. As the index structures can manage the surfaces orderly, this search can be calculated quickly and all visible surfaces can be obtained. Meanwhile, the selected visible surfaces can be fused automatically to act as the occluders to implicitly cull the occluded surfaces in large quantities. Compared with existing methods for selecting visible surfaces, the new method is fast and in high precision, and can conveniently handle the scenes with dynamic objects.