Commodore VIC-20 User Manual page 235

Chapter 6: Graphics
221
memory. Since the first row is a repeating pattern of "01" bit pairs, it is
displayed as four dots in the character color. The second row, being a
repeated series of "10" pairs, is displayed as four dots in the border color,
producing a set of eight horizontal stripes.
You can simplify your experimentation by typing the following imme-
diate mode command:
10 POJ(E 646,14
Location 646 contains the value that BASIC puts in color memory for each
character it displays on the screen. By changing this value you can put
characters into the work area, and BASIC will leave them in multicolor
mode. This makes any messages displayed by BASIC multicolor too, but
you should have little difficulty recognizing them.
MIxing Multlcolor Characters
WIth Other Modes
Because multicolor mode is turned on or off for each character on the
screen, you can put multicolor characters, custom characters, and normal
text on the same screen. For example, try putting the three generations of
stick man characters together on a single display.
This ability gives you a great deal of versatility for designing players
and playfields. Multicolor mode can be useful for both players and play-
fields which are relatively static, while high-resolution custom characters
can be used at the same time to create the more active players, with standard
characters for text display.
ADVANCED VIC CHIP TOPICS
In this section we will cover some aspects of the VIC chip that you will
find helpful as you develop more sophisticated programs. If you find some
of the information too difficult, just skip over it for now. As you become
more familiar with the VIC, this section will become easier to understand.
VIC Chip's Window Into Memory
When it comes to memory addresses, the VIC chip and the rest ofthe
computer are quite different. The 6502 microprocessor in the VIC computer