Commodore 128 Programmer's Reference Manual page 298

288 COMMODORE 128
To expand more than one sprite, add two raised to the bit position for the sprite
numbers you want to expand, and store the result in the expansion registers.
To return the sprites to their original size, clear the bits in the expansion
registers.
SPRITE DISPLAY PRIORITIES
In your sprite programs, you have the option of displaying sprites in front of or behind
other sprites or objects on the screen. This is known as defining the sprite's display
priorities. The VIC chip defines two distinct sprite display priorities:
1. Sprite-to-sprite
2. Sprite-to-data
SPRITE-TO-SPRITE DISPLAY PRIORITIES
Each of the eight sprites available on the Commodore 128 is assigned its own plane in
which it moves independent of other sprites or of the pictures on the screen background.
Visualize the sprite planes as in Figure 9-9.
Screen
Background ■
Plane
Sprite plane 7
Sprite plane 6
Sprite plane 5
Sprite plane 4
Sprite plane 3
Sprite plane 2
Sprite plane 1
Sprite plane 0
Figure 9-9. Relationship of Sprite Planes
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I )
u
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I t
II
The display priority of each sprite plane depends on the sprite number. The
sprite-to-sprite display priorities are predefined according to the sprite number. This
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