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Horizontal resolution.
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Vertical resolution, or interlacing.
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Data fetch and modulo, which tell the system how much data to put on a hor-
izontalline and how to fetch data from memory to the screen.
In addition, you need to allocate memory to store the playfield, set pointers to tell the
system where to find the data in memory, and (optionally) write a Copper routine to
handle redisplay of the playfield.
HEIGHT AND WIDTH OF THE PLAYFIELD
To create a playfield that is the same size as the screen, you can use a width of either
320 pixels or 640 pixels, depending upon the resolution you choose. The height is either
200 lines or 400 lines, depending upon whether or not you choose interlaced mode.
BIT-PLANES AND COLOR
You define playfield color by:
1. Deciding how many colors you need and how you want to color each pixel.
2. Loading the colors into the color registers.
3. Allocating memory for the number of bit-planes you need and setting a pointer
to each bit-plane.
4.
Writing instructions to place a value in each bit in the bit-planes to give you the
correct color.
Table 3-1 shows how many bit-planes to use for the color selection you need.
34 Playfield Hardware
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