Commodore 16 - Page 71

SCNCLR
SCNCLH
Clears the current
screen, whether graphics, text, or both
(split
screen).
SOUND
SOUND voice
#,
frequency control, duration
This statement produces
a
SOUND using one at three voices with
a
frequency
control
in the range
0-1023
lor a duration
ot -
65535 60ths
oi
a second
Voice
1
2
3
Voice 1
(tone)
Voice
2
(tone)
Voice 2 (white
noise)
It
a
SOUND (or voice
N
is requested, and the previous
SOUND tor the
same N is still playing. BASIC watts for the previous SOUND lo
oomplete.
SOUND with a duration of is
a
special case. It causes
BASIC to turn
oft the current
SOUND
for
that
voice
immediately,
regardless of the time remaining on the previous
SOUND See the
MUSIC
NOTE TABLE In the appendix for the frequency control values
that correspond
to
real notes
EXAMPLE:
SOUND 2, 800, 3600
Plays a
note using
voice 2 with
frequency
set at 800
for one
minute
138
I
SSHAPE/GSHAPE
SSHAPE
and GSHAPE
are used to
save and
restore rectangular
areas
of multicolour or high resolution
screens
using
BASIC string variables.
The
command
lo
save an area Is;
SSHAPE string variable,
a1
,bt
t.a2,b2|
stnng
variable
a1.bl
...
a2,b2 ....
.Siring
name to save data
In
.
.Corner coordinate (scaled)
.
.Corner coordinate opposite (at ,bl
)
(default «s the
PC)
Because BASIC
limits siring
lengths to 255
characters, the size
of the
area
you may save
is limited. The string size required can be
calculatea using one of (he following (unsealed) formulas:
L<mcm)
-
INT( (ABS(a1-a2)
+
1) I 4 + 99)
•
<ABS(b1-b2> + 1)
+
4
Uh-0
-
INT((ABS<ai-a2)
+
1J/8+
.99)
•
(ABS(b1-b2> +
1)
+
4
(mem) refers
lo
multi-colour
mode;
(h-r) Is high tesolulion
The shape is saved row by row. The last
four
bytes ol the
string
contain the column and row lengths less one
(I.e.:
A8S (a1-a2) )
in low/
high byte format (if scaled divide the lengths by 3.2 (X) and 5.1 2
(Y)
).
The command lo
display
a saved
shape
on
any area of the screen
GSHAPE
string variable name
[. la.b]
[.mode]
J
string . . Contains shape to be
drawn
a.b . .Top
let! coordinate telling where to draw the shape
(scaled
-
the
default is the PC)
mode Replacement mode:
0. place shape as
is (default)
1 :
place
field
Inverted
shape
2;
OR shape with area
3; AND shape
with area
4: XOH
shape
with
area
(
139