The first number in this statement is the sprite number. The
second number is the direction expressed as the number of
degrees to move in the clockwise direction, relative to the original
position of the sprite. The hash sign (#) signifies that the sprite is
moved at the specified angle and speed relative to a starting
position, instead of an absolute location, as in lines 70 and 80.
The final number specifies the speed in which the sprite moves
along its route on the screen, which ranges from 0 through 15.
The MOVSPR command has two alternative forms. See Chapter
V, BASIC 7.0 Encyclopaedia for these notations.
Sprites use an entirely different coordinate plane from bit-map
coordinates. The bit-map coordinates range from points 0,0 (the
top left corner) to 319,199 (bottom right corner). The visible sprite
coordinates start at point 50,24 and end at point 250,344. The
rest of the sprite coordinates are off the screen and are not
visible, but the sprite still moves according to them. The OFF-
screen locations allow sprites to move smoothly onto and off the
screen. Figure 6-7 illustrates the sprite coordinate and the visible
sprite positions.
0 (»00) 24 (»18)
VISIBLE VIEWING AREA
40 COLUMNS
25 ROWS
r
- - 229 (»ES)
320 (»140) 344 (dSt)
Figure 6-7. Visible Sprite Coordinates
6-22
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