Draw a sphere: Difference between revisions

[[File:Cpcbasic sphere.png|thumb|Output in CPCBasic]]

The program above can also be adapted to produce graphical output in MODE 2 instead:

<syntaxhighlight lang="locobasic">10 MODE 2:ORIGIN 320,200:INK 0,0:INK 1,26

20 DIM v(2),vec(2)

30 v(0)=30:v(1)=30:v(2)=-50

40 lung=SQR(v(0)*v(0)+v(1)*v(1)+v(2)*v(2))

50 v(0)=v(0)/lung

60 v(1)=v(1)/lung

70 v(2)=v(2)/lung

80 r=180:k=1.5:ambient=0.03

90 FOR i=INT(-r) TO INT(r)

100 x=i

110 FOR j=INT(-2*r) TO INT(2*r)

120 y=j/2

130 IF (x*x+y*y<=r*r) THEN GOSUB 1000

140 NEXT j

160 NEXT i

170 END

1000 vec(0)=x

1010 vec(1)=y

1020 vec(2)=SQR(r*r-x*x-y*y)

1030 GOSUB 2000

1040 GOSUB 3000

1050 b=(d^k+ambient)/(1+ambient)

1060 IF b>rnd THEN PLOT x,-y

1100 RETURN

2000 lung=SQR(vec(0)*vec(0)+vec(1)*vec(1)+vec(2)*vec(2))

2010 vec(0)=vec(0)/lung

2020 vec(1)=vec(1)/lung

2030 vec(2)=vec(2)/lung

2040 RETURN

3000 d=v(0)*vec(0)+v(1)*vec(1)+v(2)*vec(2)

3010 IF d<0 THEN d=-d ELSE d=0

3020 RETURN</syntaxhighlight>