[Feature Request] Add option for bilinear downscaling

[EPeanutG]

Would it be possible to implement a downscaling algorithm that can actually downsample? (ex: bilinear downsampling) The default downscaling in ShaderGlass right now (with the "Pixel Size" option) looks pretty jagged, without much anti-aliasing.

Comparison:

• Original image
• Downscaled with ShaderGlass
• Downscaled with Photoshop (bilinear resampling option)

With crt-royale applied:

• ShaderGlass downscaling
• Photoshop bilinear downscaling

The difference is particularly noticeable on Bowser's spikes, which are much more smooth with bilinear downsampling.