Commodore Amiga A1000, Hardware Reference Manual

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CLIPPED SPRITES
As noted above, sprites will be partially or totally clipped if they pass across or beyond the
boundaries of the display window. The values of 64 (horizontal) and 44 (vertical) are
"normal" for a centred display on a standard NTSC video monitor. See Chapter 3,
"Playfield Hardware", for more information on display offsets. Information on PAL displays
will be found there. If you choose other values to establish your display window, your
sprites will be clipped accordingly.
SIZE OF SPRITES
Sprites are 16 pixels wide and can be almost any height you wish... as short as one line or
taller than the screen. You would probably move a very tall sprite vertically to display a
portion of it at a time.
Sprite size is based on a pixel that is 1/320th of a screen's width, 1/200th of a NTSC
screen's height, or 1/256 of a PAL screen's height. This pixel size corresponds to the low-
resolution and non-interlaced modes of the normal full-size playfield. Sprites, however,
are independent of playfield modes of display, so changing the resolution or interlace
mode of the playfield has no effect on the size or resolution of a sprite.
SHAPE OF SPRITES
A sprite can have any shape that will fit within the 16-pixel width. You define a sprite's
shape by specifying which pixels actually appear in each of the sprite's locations. For
example, Figures 4-3 and 4-4 show a spaceship whose shape is marked by Xs. The first
Figure shows only the spaceship as you might sketch it out on graph paper. The second
Figure shows the spaceship within the 16-pixel width. The 0s around the spaceship mark
the part of the sprite not covered by the spaceship and transparent when displayed.
x x
x x x x x
x x x x x x x x x x
x x x x x x x x x x
x x x x x x
x x
Figure 4-3: Shape of Spaceship
- Sprite Hardware 97 -