by TDRR » Thu Jan 31, 2019 12:32 am
I think you are using either Truecolor Softpoly or plain old Software Render (not truecolor), which don't support filtering.
To use filtering, you need to change your renderer to the Truecolor Software renderer (NOT SOFTPOLY) and then go into Display Options, go into the Software submenu and then into the Truecolor submenu, set all three options there to "On"