the difference between linear & point filter

shuipi

Newcomer
When doing full screen post effects, if the size of the texture and the size of the render target match, using linear and point filter for the texture should be the same, however, is this only true when you are sampling the exact center of the texels (like Gaussian Blur or plain averge)? How about when doing something like Poisson Blur where the random sample points are not necessarily on the center of the texel? Does linear filter make a difference in this case, even though the texel/pixel ratio is still 1:1?
 
Yea, and if you align the pixel centers and texel centers properly, you will only get weights of 1 and 0, hence one pixel is used completely, and its neighbours aren't used at all.
So you effectively get a pointsample.

What I got from the opening post is that he was asking whether the linear filter was turned off altogether when the texture and rendertarget are the same size (1:1 ratio). This is not the case. The linear filtering is still performed, it just yields the same result as pointsampling when your pixels and texels are aligned exactly.
 
I would have thought "Weighted average" was the best way to express it.
(Not native english though.)
 
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