Commodore Amiga A1000, Hardware Reference Manual

Page: 127 / 380

Sprites can be attached in the following combinations:
Sprite 1 to sprite 0
Sprite 3 to sprite 2
Sprite 5 to sprite 4
Sprite 7 to sprite 6
Any or all of these attachments can be active during the same displayfield. As an example,
assume that you wish to have more colors in the spaceship sprite and you are using sprite
DMA channels 0 and 1. There are five colors plus transparent in this sprite.
0000154444510000
0001564444651000
0015676446765100
0001564444651000
0000154444510000
The first line in this sprite requires the four data words shown in Table 4-4 to form the
correct binary color selector numbers.
Table 4-4: Data Words for First Line of Spaceship Sprite
PIXEL NUMBER
15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
----------------------------------------------------------------------
Line 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
Line 2 0 0 0 0 0 1 1 1 1 1 1 0 0 0 0 0
Line 3 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
Line 4 0 0 0 0 1 1 0 0 0 0 1 1 0 0 0 0
The highest numbered sprite (number 1, in this example) contributes the highest order
bits (left-most) in the binary number. The high-order data word in each sprite contributes
the leftmost digit. Therefore, the lines above are written to the sprite data structures as
follows:
Line 1 Sprite 1 high-order word for sprite line 1
Line 2 Sprite 1 low-order word for sprite line 1
Line 3 Sprite 0 high-order word for sprite line 1
Line 4 Sprite 0 low-order word for sprite line 1
See Figure 4-7 for the order these words are stored in memory. Remember that this data
is contained in two sprite structures.
- 118 Sprite Hardware -