MipMap Filtering in 3dsmax
OpenGL, Texel Lookup: Nearest, MipMap Lookup: None
The texture is taken as is (256x256). The screen pixel shows the nearest texel found in the texture. As the texels go away from the camera, the nearest texel taken to fill in the screen pixel might not be the right choice. Notice the dotted appearance on the left and right side of the plane. Sometimes a black texel is taken, sometimes a white one...
OpenGL, Texel Lookup: Linear , MipMap Lookup: None
In this case, the texel chosen for every screen pixel is calculated by linear interpolation between the possible candidates using the original 256x256 texture. Notice that in the close-up area, the central black line is perfectly smooth on both sides (compare to Nearest/None!), but as it gets farther, it gets unprecise.
OpenGL, Texel Lookup: Nearest , MipMap Lookup: Nearest
This is a perfect demonstration of pure mipmapping without any interpolation. What you see here are decresing resolution textures (256x256, 128x128, 64x64, 32x32, 16x16 and 8x8) used with increasing distance. Still, the next possible texel is used for each screen pixel, without any interpolation.
OpenGL, Texel Lookup: Linear , MipMap Lookup: Nearest
Very similar to the previous, but here the texel is chosen by linear interpolation between the closest texels around the screen pixel to be shaded. This smooths the line in horizontal direction, but still leaves the vertical borders visible.(where the texture resolution changes)
OpenGL, Texel Lookup: Nearest , MipMap Lookup: Linear
This is exactly the opposite of the above example - there is no linear interpolation between the texels of a single texture resolution, but there is linear interpolation between the textures with different resolution! So the line is blurred vertically, making the change of resolution less noticeable, but without a horizontal blur.
OpenGL, Texel Lookup: Linear , MipMap Lookup: Linear
This is the best quality OpenGL can provide in 3dsmax viewports. The texels are linearly interpolated inside a mipmap level texture with the same resolution, AND between texture resolution levels, giving a blur in both the horizontal and vertical direction. Compare this to the Pyramidal Filtering in 3dsmax and you will notice the similarity!
Scanline, Pyramidal filtering, equivalent to (Linear/Linear)
This is the result of the scanline rendering with Pyramidal filtering. Compare to the previous image!
Scanline, Summed Area filtering, no equivalent in OpenGL viewports.
This is how you would like it to be... Precise and smooth.