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Fix various bugs in NES NTSC filter and PPU palettes #31

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Commits on Jan 18, 2024

  1. Correct dot crawl phase offset calculation

    - Thanks lidnariq!
    - The new formula is based on the color generator clock cycle count per
      frame.
    Gumball2415 committed Jan 18, 2024
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  2. Use standard RGB-YIQ matrix coefficients

    https://forums.nesdev.org/viewtopic.php?p=172817#p172817
    
    Bisqwit originally intended to match a certain palette using different
    display primaries ("FCC D65"). This resulted in colors that looked off.
    The modification here is to more closely match Bisqwit's own palette
    generator, which uses a more standard RGB-YIQ matrix.
    at hue 0, saturation 1.0, contrast 1.0, brightness 1.0, gamma 2.2
    https://bisqwit.iki.fi/utils/nespalette.php
    
    IQ component coefficients are derived from the NTSC base matrix of
    luminance and color-difference. with color reduction factors and an
    additional 33 degree rotation of each respective component.
    https://www.nesdev.org/wiki/NTSC_video#Converting_YUV_to_signal_RGB
    Gumball2415 committed Jan 18, 2024
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