区域求和表算法的改进

Use Texture Filtering With Summed Area Table in Hardware Rendering

查找表技术可以使纹理过滤变得容易处理,其计算精度不再依赖于纹理的密度。目前常用的有Mipmap技术和区域求和表技术。区域求和表技术使用一张预先计算的表格,该表格的每一个值代表由纹理图像左下角和当前点所确定的长方形区域的纹理值之和,它在相同性能的情况下能提供比mipmap过滤算法更好的视觉效果。由于该算法需要更多的内存空间和内存读写次数,本文对算法进行了改进,使之更适合于硬件实现。

Texture filtering computations can be made tractable through use of looku Ptables which allow computational costs independent of the texture density.There are two typical example of this technique at present,mipma Pand Summed Area Table.Summed Area Table using a single precalculated table in which each value representing the sum of the intensities of all pixels contained in the rectangle defined by the pixel of interest and the lower left comer of the texture image.It gives better visual quality than mipma Pat almost the same performance.Because this algorithm needs more memory space and memory reading.So this paper focuses on the optimizatin,to make it more suitable for hardware rendering.