Talk:Planar

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Perhaps some drawn images would better show how planar graphics are stored in ram

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Can someone explain why planar images are easier to scroll in hardware? It's not obvious to me. Mr2001 12:50, 16 July 2005 (UTC)

Agreed, outside of being more space efficient in most cases of the time, therefore requiring less data moving, it doesn't seem to make sense. In fact having eight pixels partially represented in one byte would make horizontal scrolling somewhat nightmarish in software. In hardware the Amiga had support for scrolling, which outside for what I imagine to be a complexity boost in hardware support for that, has no appreciable effect on ease of pointer-adjusting-based scrolling versus chunky representations.

Being a former Amiga programmer myself (although not a very good one), the only reason I can see why planar is better than chunky is that it allows for any number of colours that is a power of 2: 2, 4, 8, 16, 32, 64, 128, 256, etc., not just 256 or 65536. In the days of the Amiga and the Atari ST this was very important, as the colour of a pixel was usually only an index to a palette which included RGB information, and did not contain the RGB information in itself. Currently the vast amounts of computer memory available seem to have made this concern obsolete. JIP | Talk 22:15, 23 January 2006 (UTC)

I imagine that planar images are easier to scroll because you can simply apply a rotate operation on the screen data, and that will scroll the screen by x pixels horizontally. I believe that this operation is free using the Amiga's clever chipset. The Mekon 03:00, 29 January 2006 (UTC)