NTSC filter scanline interrogations

[twipley]

Following the spirit from http://www.snes9x.com/phpbb2/viewtopic.php?p=29571, we were asking ourselves why ZSNES seems to use a "custom blitter," which darkens every second scanline by 25%, contrary to Snes9x, more faithful to blargg's sample code.

OV2 of the linked-to forum told me that I would "have to ask the zsnes devs about this."

An off-topic thought: it hits me that Snes9x offers a different kind of NTSC emulation; I am used to using (bleed-fixed) RGB-preset NTSC filter in ZSNES, and am feeling strange to finding everything "overly illuminated" while using Snes9x's implementation of the RGB-preset NTSC filter.

[kode54]

Older sample code than that included a hard 75% scanlines effect integrated with the line doubling.