问题描述
我想自己在GLSL着色器中实现纹理过滤(最小和磁过滤器)(因为我想使用image_load_and_store而不是采样器，并且我想以特殊方式处理未定义的像素)，我正在寻找用于讨论过滤过程的文章.
我可以回想起如何从我曾经写过的raytracer中实现纹理过滤-我认为您需要考虑每个像素的UV梯度，并取决于那些以某种方式缩放采样栅格的长度.一个49个样本的圆形内核，我认为这太重了.
我认为我可以使用dFdx()和dFdy()获得UV渐变-但我想知道什么样的内核openGL用于过滤，并以相同的方式在我的glsl着色器中实现. /p>
还-如何区分是否需要应用minfilter或magfilter?过滤过程是否不同?
最后但并非最不重要的一点:如果将其缩小过滤，如何根据UV梯度选择合适的mipmap级别?
Codeproject上有一篇文章，该文章在GLSL中实现了不同的过滤器(包括双线性过滤器):链接
I would like to implement texture filtering (min and magfilter) myself in a GLSL shader (as i want to use image_load_and_store and not a sampler, and also I want to handle undefined pixels in a special way) and I'm looking for an article or so that discusses the filtering process.
I can recall on how to implement texturefiltering from a raytracer I once wrote - I think you need to take into consideration the UV gradients at each pixel and depending on the length of those somehow scale your sampling raster.. but there I used a 49-samples circular kernel, I think that's too heavy.
I think the UV gradients i can get using dFdx() and dFdy() - but I'd like to know how what kind of kernel openGL is using for the filtering and implement it in my glsl shader the same way.
also - how to distinguish whether a minfilter or a magfilter needs to be applied? and is the filtering process different?
last but not least: if its minification filtering, how to choose the appropriate mipmap level based on the UV gradients?
There's an article over at Codeproject which implements different filters (among them bi-linear) in GLSL: link
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