★ SGL User's Manual ★ PROGRAMMER'S STRUCT
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8-2. Scroll unit

A scroll is a collection of minute dots that are displayed on a monitor. In order to handle this point efficiently, SGL uses a scroll unit system as shown in the figure below.

A set of points of 8 x 8 dots is called a cell, and when dealing with scrolling, we will proceed with this cell as the smallest unit. These cells are further gathered to form a character pattern, which are further gathered to form pages, pages are gathered to form planes, and planes are gathered to form a map.

<Fig. 8-3 Scroll screen configuration unit>

note)
All are displayed horizontally x vertically (unit).

About scroll building blocks

Sega Saturn's hardware also includes a function that handles scrolling in dot units (called bitmaps) instead of cell units, but this manual does not explain it.
However, some functions that support scrolling functions, including bitmaps, are included in the SGL library, and these functions are described in the "Function Reference in the Reference Manual", although they are simple.
Please refer to "HARDWARE MANUAL vol.2" and "Function reference of reference manual" for some functions including bitmap mode.

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★ SGL User's Manual ★ PROGRAMMER'S STRUCT
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