基于未加权区域采样的直线反走样算法

直线作为组成图形的基本元素,其生成方法一直是计算机图形学研究的基础内容之一.针对非垂直且非水平直线在光栅图形显示器存在的走样现象,结合经典的Bresenham算法和未加权区域采样思想,提出一种新的反走样直线生成算法.相比于传统的未加权区域采样以及Wu算法,该算法主要利用整数加减运算完成直线的反走样,计算简单,利于FPGA(Field Programmable Gate Array)硬件实现.仿真结果表明:新算法的仿真速度约为传统未加权区域采样的3倍,与Wu算法仿真速度相当;利用Wu算法生成的直线平滑性较好,但是沿着直线方向的某些相邻像素灰度值相差较大,而新算法生成的直线不但平滑效果好,而且沿直线方向相邻像素灰度值相差不大,因此,相比于Wu算法,新算法反走样效果更佳.

New anti-aliasing straight line drawing algorithm based on unweighted area sampling

Line is a basic element of graphics. Its drawing algorithm is always one of the basic content of computer graphics research. In order to solve the aliasing phenomenon generated when drawing a non-vertical and non-horizontal straight line on a raster graphics monitor, based on Bresenham algorithm and the thought of the traditional unweighted area sampling algorithm, a new anti-aliasing straight line drawing algorithm was put forward. Compared to the traditional algorithm and the well-known Wu algorithm, the new algorithm principally used integer addition and subtraction to draw anti-aliasing straight lines. The calculation of the new algorithm was simple and the new algorithm could be easily implemented in FPGA hardware platform. Experimental results show that the simulation speed obtained by the new algorithm when drawing lines is nearly three times as fast as that obtained by the traditional algorithm and is almost equivalent to that obtained by Wu algorithm. Although the straight line generated by Wu algorithm has good smooth effect, along the straight line direction adjacent pixels- grey values sometimes have large difference. However, the new algorithm not only has good smooth effect, but also can find a good solution to solve the problem Wu algorithm has. Therefore, compared with Wu algorithm, the new algorithm-s anti-aliasing effect is much better.