[FEATURE REQUEST] use half blocks (quadrants) to increase doomfire resolution

[plasmoduck]

You could double the fire resolution by using half blocks (quadrants). So you can at least double the resolution with half blocks (the same difference as between mpv --vo=tct and then also adding --vo-tct-algo=plain) (by default it uses half blocks).

[nullgemm]

We use dotted blocks to perform some basic halftoning, so we can't keep the same blending "quality" with half-blocks. I think decent blending is what makes the fire effect visually acceptable, so I don't plan on changing the effect to use half-blocks :)