Commodore 128D - Page 131

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• Line 99 is another delay so the capsule can continue to move
across the screen.
• Line 100 returns you to text mode.
Working with adjoining sprites can be more interesting than working
with a single sprite. The main points to remember are: (1) Make sure
you position the SSHAPE coordinates at the correct locations on the
screen, so you save the picture data properly; and (2) be certain to '
position the sprite coordinates in the correct location when you are
joining them with the MOVESPR statement. In this example, you posi
tioned sprite 2 at a location 24 pixels to the right of sprite 1.
Once you master the technique of adjoining two sprites, try more
than two. The more sprites you join, the better the detail and anima
tion will be in your programs.
The C128 has two additional SPRITE commands, SPRCOLOR and
COLLISION, which are not covered in this chapter. To learn about
these commands, refer to Chapter V, the BASIC 7.0 Encyclopedia.
Storing Sprite Data in Binary Files
The Commodore 128 has two new commands, BLOAD and BSAVE,
which make handling sprite data neat and easy. The "B" in BLOAD
and BSAVE stand for BINARY. The BSAVE and BLOAD commands
save and load binary files to and from disk. A binary file consists of
either a portion of a machine language program, or a collection of
data within a specified address range. You may be familiar with the
SAVE Command within the built-in machine language monitor. When
you use this SAVE command, the resulting file on disk is considered
a binary file. A binary file is easier to work with than an object code
file since you can load a binary file without any further preparation.
An object code file must be loaded with a loader, as in the Commo
dore 64 Assembler Development System; then the SYSTEM com
mand (SYS) must be used to execute it.
You're probably wondering what this has to do with sprites. Here's
the connection. The Commodore 128 has a dedicated portion of
memory ranging from decimal address 3584 ($0E00) through 4095
($0FFF), where sprite data is stored. This portion of memory takes
up 512 bytes. As you know, a sprite is 24 pixels wide by 21 pixels tall.
Each pixel requires one bit of memory. If the bit in a sprite is off
(equal to 0), the corresponding pixel on the screen is considered off
and it takes on the color of the background. If a pixel within a sprite is
123 USING C128 MODE—Color, Animation and Sprite Graphics Statements