Yes, I too remember the memory savings being the key aspect of bitplane design choices in the early and mid 80s. The increased granularity in varying the trade-off between memory for graphics vs program code being the secondary aspect. The downside to bitplanes vs chunky pixel formats was having to write to four different memory addresses to fully change one 16 color pixel.
One case where bitplanes could be faster was high-res bitmapped text. As long as your text was monochrome (all in one bitplane), you could write an 8 pixel wide character with one byte. This was a big deal when it came to scrolling a screen full of bitmapped text.
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Yes, I too remember the memory savings being the key aspect of bitplane design choices in the early and mid 80s. The increased granularity in varying the trade-off between memory for graphics vs program code being the secondary aspect. The downside to bitplanes vs chunky pixel formats was having to write to four different memory addresses to fully change one 16 color pixel.
One case where bitplanes could be faster was high-res bitmapped text. As long as your text was monochrome (all in one bitplane), you could write an 8 pixel wide character with one byte. This was a big deal when it came to scrolling a screen full of bitmapped text.