Missing pixels of 1 × Size magnification on the left and right side of the image when using the HQ2x filter

[Ocatopuss]

None filer.

LQ2x

HQ2x

The HQ2x filter has its own advantages, especially when used in combination with some partial shader(s). Is there any chance that we could enjoy the full image with this filter? Thanks for your wonderful work.

[Screwtapello]

I know HQ2x (and related filters) work by looking at the eight neighbours of a given input pixel to determine what the output pixel should be. At the left and right edges, there aren't eight neighbours, so it wouldn't surprise me that it can't filter the edges properly.

However, I'd expect the same to be true on the top and bottom, and maybe true of the LQ2x filter too. This probably deserves looking into.

On the other hand, the HQ2x code is very old and widely used, this might just be how it's supposed to work.

[Ocatopuss]

I know HQ2x (and related filters) work by looking at the eight neighbours of a given input pixel to determine what the output pixel should be. At the left and right edges, there aren't eight neighbours, so it wouldn't surprise me that it can't filter the edges properly.

However, I'd expect the same to be true on the top and bottom, and maybe true of the LQ2x filter too. This probably deserves looking into.

On the other hand, the HQ2x code is very old and widely used, this might just be how it's supposed to work.

Thanks for your expertise to increase my knowledge.

However in my limited experience, HQ2x does not appear to display incompletely on other emulators such as VBA-M, mGBA, Snes9x, Mesen, desmume, etc. Is it possible that this is due to HQ2x version or rather code and/or emulator structure differences, or maybe operating methods (some via the CPU, some via the GPU)?