SmallBasic Turtle Logo Source Code

Just how hard is it to code a turtle? Not hard at all, if one hour is all it takes to code this. I'm still missing Show and Hide Turtle, but hey, it's only one hour!

'Turtle Logo in Small Basic

'by Harry Hardjono

'Turtle angle speed x1 y1 x0 y0

'Turtle move moveto penup pendown

'Turtle turn turnleft turnright

' Only took me 1 hour to do this. :)

'

GraphicsWindow.Show()

GraphicsWindow.Clear()

cmd1="init"

Toitle()

cmd1="move"

cmd2="50"

Toitle()

cmd1="turnright"

cmd2="90"

Toitle()

cmd1="move"

cmd2="50"

Toitle()

cmd1="turnright"

cmd2="90"

Toitle()

cmd1="move"

cmd2="50"

Toitle()

cmd1="turnright"

cmd2="90"

Toitle()

cmd1="move"

cmd2="150"

Toitle()

cmd1="turnleft"

cmd2="90"

Toitle()

cmd1="move"

cmd2="50"

Toitle()

cmd1="turnright"

cmd2="90"

Toitle()

cmd1="moveto"

cmd2="20"

cmd3="50"

Toitle()

cmd1="turn"

cmd2="20"

Toitle()

cmd1="move"

cmd2="1500"

Toitle()

cmd1="turnright"

cmd2="100"

Toitle()

cmd1="move"

cmd2="1500"

Toitle()

cmd1="turnright"

cmd2="100"

Toitle()

cmd1="move"

cmd2="1500"

Toitle()

cmd1="turnright"

cmd2="100"

Toitle()

cmd1="move"

cmd2="1500"

Toitle()

Sub Toitle

'cmd1=command (input)

'cmd2=param1 (input)

'cmd3=param2 (input)

If (cmd1="init") then

sy=GraphicsWindow.Height

sx=GraphicsWindow.Width

x1=sx/2

y1=sy/2

x0=x1

y0=y1

p=1

angle=90

elseif (cmd1="penup") then

p=0

elseif (cmd1="pendown") then

p=1

elseif (cmd1="move") then

'forward

x0=x1

y0=y1

x1=x0+cmd2*Math.Sin(Math.GetRadians(angle))

y1=y0+cmd2*Math.Cos(Math.GetRadians(angle))

draw()

elseif (cmd1="moveto") then

x0=x1

y0=y1

x1=cmd2

y1=cmd3

draw()

elseif (cmd1="turn") then

angle=cmd2

elseif (cmd1="turnleft") then

angle=angle+cmd2

elseif (cmd1="turnright") then

angle=angle-cmd2

endif

'These really need to be Mod

'Seems buggy - doesn't work with negative number?

RemBugFix2()

x1=Math.Remainder(x1,sx)

y1=Math.Remainder(y1,sy)

angle=Math.Remainder(angle,360)

endsub

Sub RemBugFix

While (px<0)

px=px+sx

EndWhile

While (py<0)

py=py+sy

EndWhile

endsub

Sub RemBugFix2

While (x1<0)

x1=x1+sx

EndWhile

While (y1<0)

y1=y1+sy

EndWhile

While (angle<0)

angle=angle+360

EndWhile

endsub

'Draw

Sub Draw

If (p>0) then

If (x0<>x1 or y0<>y1) then

m=math.Max(math.Abs(x1-x0),math.Abs(y1-y0))

mx1=0

mx3=m

For i=0 To m

my1=x0

my3=x1

mx2=i

map()

px=my2

my1=y0

my3=y1

mx2=i

map()

py=my2

RemBugFix()

px=Math.Remainder(px,sx)

py=Math.Remainder(py,sy)

GraphicsWindow.SetPixel(px,py,"blue")

EndFor

endif

endif

endsub

'map function

Sub map

'x1-x2-x3 y1-y2-y3

'(x2-x1)/(x3-x1)=(y2-y1)/(y3-y1)

'(y3-y1)*(x2-x1)/(x3-x1)=(y2-y1)

'y1+(y3-y1)*(x2-x1)/(x3-x1)=y2

my2=((my3-my1)*(mx2-mx1)/(mx3-mx1))+my1

EndSub