_Title "Globe Spin - Space Bar For Another One - Esc To End"



Screen _NewImage(800, 600, 32)

Do

    start:

    Cls

    Input "XRADIUS (10-500)="; XRADIUS

    If XRADIUS < 10 Or XRADIUS > 500 Then GoTo start

    Input "YRADIUS (10-500)="; YRADIUS

    If YRADIUS < 10 Or YRADIUS > 500 Then GoTo start

    Input "ZRADIUS (10-500)="; ZRADIUS

    If ZRADIUS < 10 Or ZRADIUS > 500 Then GoTo start

    Input "SPEED (-20 to 20)"; speed

    If speed < -20 Or speed > 20 Then GoTo start

    II = 0

    speed2 = speed / 100

    Do

        For I = 0 To _Pi Step .2 ' Latitude angle (from pole to pole)

            For K = II To 2 * _Pi + II Step .2 ' Longitude angle (rotation)

                X = XRADIUS * Sin(I) * Cos(K)

                Y = YRADIUS * Cos(I)

                Z = ZRADIUS * Sin(I) * Sin(K)

                XPLOT = X + Z / 5 + 400

                YPLOT = Y + Z / 5 + 300

                Line -(XPLOT, YPLOT)

            Next K

        Next I



        ' Draw longitudinal lines (pole to pole)

        For LON = 0 To 2 * _Pi Step .4

            For LAT = 0 To _Pi Step .2

                X = XRADIUS * Sin(LAT) * Cos(LON + II)

                Y = YRADIUS * Cos(LAT)

                Z = ZRADIUS * Sin(LAT) * Sin(LON + II)

                XPLOT = X + Z / 5 + 400

                YPLOT = Y + Z / 5 + 300

                Line -(XPLOT, YPLOT)

            Next LAT

        Next LON



        II = II + speed2

        Locate 1, 1: Print "XRADIUS: "; XRADIUS

        Locate 2, 1: Print "YRADIUS: "; YRADIUS

        Locate 3, 1: Print "ZRADIUS: "; ZRADIUS

        Locate 4, 1: Print "SPEED: "; speed

        _Delay .1

        If a$ = Chr$(27) Then End

        _Display

        Cls

        a$ = InKey$

    Loop Until a$ = " "

Loop