' Turtle Graphics Library by Angelo Rosina 1995
' Ported to Freebasic by Angelo Rosina 2007
'
'(RIGH and LEF because RIGHT and LEFT are reserved keywords, of course)

Declare Sub LEF (gradi As Integer)
Declare Sub SETCOL (C As Integer)
Declare Sub SETSIZE (C As Integer)
Declare Sub RIGH (gradi As Integer)
Declare Sub FORW (passi As Integer)
Declare Sub BACK (passi As Integer)
Declare Sub TURTLE (numero As Integer)
Declare Sub UP ()
Declare Sub DOWN ()
Declare Sub DTurtle ()

Dim Shared As Integer graph, dimen, angulo, N, dis, su, pasos
Dim Shared As Integer colore(10), figura(5000,10), figura2()
Dim Shared As Long X(10), Y(10)
Dim Shared As String comando

Sub BACK (passi As Integer)
    pasos = passi
    comando = "d " & Str(passi)
    DTurtle
    comando = ""
    pasos = 0
End Sub

Sub DOWN
    su = 0
End Sub

Sub DTurtle Static
    Dim As Integer rifa, lavora, XX, YY, scher(), FX, FY
    Dim As String R

    If rifa = 0 Then rifa = 1: Redim scher(5000)
    If lavora Then Put (XX - dimen * 4, YY - dimen * 2), scher, Pset
    'SCREEN graph
    If su Then comando = "b" & comando
    FX = X(N)
    FY = Y(N)
    R = "s" & Str(dimen) & "bm" & Str(FX) & "," & Str(FY) & "c" & Str(colore(N)) & "Ta" & Str(angulo) & comando
    Draw R
    X(N) = X(N) + Sin(angulo / 57.2957) * dimen / 4 * pasos
    Y(N) = Y(N) + Cos(angulo / 57.2957) * dimen / 4 * pasos
    XX = X(N)
    YY = Y(N)
    Get (X(N) - dimen * 4, Y(N) - dimen * 2)-(X(N) + dimen * 4, Y(N) + dimen * 2), scher: lavora = 1
    If dis = 0 Then
        R = "bm" & Str(XX) & "," & Str(YY) & "Ta" & Str(angulo) & "r1 ta " & Str(angulo + 15 + 360 * (angulo + 15 > 360)) & "u7 ta " & Str(angulo + 165 + 360 * (angulo + 165 > 360)) & "u7 ta" & Str(angulo) & " m" & Str(XX) & "," & Str(YY)
        Draw R
    Else
        Put (XX, YY), figura2, Or
    End If
End Sub

Sub FORW (passi As Integer)
    pasos = -passi
    comando = "u " & Str(passi)
    DTurtle
    comando = ""
    pasos = 0
End Sub

Sub LEF (gradi As Integer)
    angulo += gradi
    Do Until angulo <= 360
        angulo -= 360
    Loop
    DTurtle
End Sub

Sub RIGH (gradi As Integer)
    angulo -= gradi
    Do Until angulo >= 0
        angulo += 360
    Loop
    DTurtle
End Sub

Sub SETCOL (C As Integer)
    colore(N) = C
    DTurtle
End Sub

Sub SETSIZE (C As Integer)
    dimen = C
    DTurtle
End Sub

Sub TURTLE (numero As Integer) Static
    Dim As Integer i, NN, j
    Dim As Integer ang()

    Redim figura2(dis)
    If dis <> 0 And graph <> 0 Then
        For i = 0 To dis
            figura2(i) = figura(i, numero)
        Next i
    End If
    NN = N
    N = numero
    If j = 0 Then j = 1: Redim ang(10): dimen = 4
    If X(numero) = 0 Then X(numero) = 320
    If Y(numero) = 0 Then Y(numero) = 100: colore(numero) = 15
    ang(NN) = angulo
    angulo = ang(N)
    DTurtle
End Sub

Sub UP
    su = 1
End Sub