Van Horn R Brooks, Turk Greg
Georgia Institute of Technology, Atlanta, GA 30332-0760, USA.
IEEE Trans Vis Comput Graph. 2008 May-Jun;14(3):539-50. doi: 10.1109/TVCG.2007.70435.
Both image textures and procedural textures suffer from minification aliasing, however, unlike image textures, there is no good automatic method to anti-alias procedural textures. Given a procedural texture on a surface, we present a method that automatically creates an anti-aliased version of the procedural texture. The new procedural texture maintains the original texture's details, but reduces minification aliasing artifacts. This new algorithm creates a pyramid similar to MIP-Maps to represent the texture. Instead of storing per-texel color, our texture hierarchy stores weighted sums of reflectance functions, allowing a wider range of effects to be anti-aliased. The stored reflectance functions are automatically selected based on an analysis of the different reflectances found over the surface. When the texture is viewed at close range, the original texture is used, but as the texture footprint grows, the algorithm gradually replaces the texture's result with an anti-aliased one.
图像纹理和过程纹理都会受到缩小混叠的影响，然而，与图像纹理不同的是，目前还没有很好的自动方法来对过程纹理进行抗混叠处理。对于曲面上的过程纹理，我们提出了一种自动创建其抗混叠版本的方法。新的过程纹理保留了原始纹理的细节，但减少了缩小混叠伪影。这种新算法创建了一个类似于MIP映射的金字塔来表示纹理。我们的纹理层次结构存储的不是每个纹理元素的颜色，而是反射函数的加权和，从而能够对更广泛的效果进行抗混叠处理。基于对曲面上不同反射率的分析，自动选择存储的反射函数。当近距离查看纹理时，使用原始纹理，但随着纹理覆盖区域的增大，该算法会逐渐用抗混叠版本替换纹理的结果。
