Planetary System Animation

[James D Jarvis]

A simple program that randomly generates a planetary system showing the main star, some planets, and moons.  There's no physics here and sizes are exaggerated so there is something to see.

EDIT: corrected the value to generate nump so it's the same in both locations in the program.

Code: (Select All)

'planetary system animation
'by James D, Jarvis 10/10/2022
'
' a simple planetary system animation generator, planets and moons orbiting a star
' <esc> to exit
' press "n" for a new system
'feel free to modify for your own use as you wish
Screen _NewImage(1200, 800, 32)
_FullScreen _SquarePixels
Randomize Timer
_Define K As _UNSIGNED LONG
stars& = _NewImage(1200, 800, 32)
_Dest stars&
For s = 1 To 1200
    PSet (Rnd * _Width, Rnd * _Height), _RGB32(240 + Rnd * 15, 240 + Rnd * 15, 240 + Rnd * 15)
Next s
_Dest 0
Type planet_type
    orbit As Double
    size As Double
    kp As _Unsigned Long
    rate As Double
    ppos As Double
End Type
Dim Shared sunx, suny, mooncount(20)
sunx = _Width / 2: suny = _Height / 2: sunr = 10 + Int(Rnd * 40): Ksun = _RGB32(250, 200 + sunr, 0)
Dim Shared planet(20) As planet_type
Dim Shared moon(20, 12) As planet_type
Nump = Int(1 + Rnd * 20)
For p = 1 To Nump
    planet(p).orbit = p * (sunr * 1.5) + Rnd * 10
    planet(p).size = 1 + Int(Rnd * 8)
    planet(p).kp = _RGB32(Int(5 + Rnd * 250), Int(5 + Rnd * 250), Int(5 + Rnd * 250))
    planet(p).rate = (5 / p) / (50 / Sqr(sunr))
    planet(p).ppos = Int(Rnd * 360)
    If p > 1 Then
        nm = (Int(Rnd * (p + 3)))
        If nm > 12 Then nm = Int(nm / 2)
        mooncount(p) = nm
        For m = 1 To mooncount(p)
            moon(p, m).orbit = m * (planet(p).size * 1.5) + Rnd * 10
            moon(p, m).size = .5 + Int(Rnd * (planet(p).size / 3))
            moon(p, m).kp = _RGB32(Int(200 + Rnd * 53), Int(200 + Rnd * 53), Int(200 + Rnd * 53))
            moon(p, m).rate = ((5 / p) / _Pi) * (1 + Rnd * 3)
            moon(p, m).ppos = Int(Rnd * 360)
        Next m
    End If
Next p


Do
    _Limit 60
    Cls
    _PutImage , stars&, 0
    circleBF sunx, suny, sunr, Ksun
    For n = 1 To Nump
        drawplanet n
    Next
    _Display
    kk$ = InKey$
    If kk$ = "n" Then
        stars& = _NewImage(800, 800, 32)
        _Dest stars&
        For s = 1 To 1200
            PSet (Rnd * _Width, Rnd * _Height), _RGB32(240 + Rnd * 15, 240 + Rnd * 15, 240 + Rnd * 15)
        Next s
        _Dest 0
        sunr = 10 + Int(Rnd * 40): Ksun = _RGB32(100 + sunr * 2 + Rnd * 50, sunr * 4 + Rnd * 50, 0)
        Nump = Int(1 + Rnd * 20)
        For p = 1 To Nump
            planet(p).orbit = p * (sunr * 1.5) + Rnd * 10
            planet(p).size = 1 + Int(Rnd * 8)
            planet(p).kp = _RGB32(Int(5 + Rnd * 250), Int(5 + Rnd * 250), Int(5 + Rnd * 250))
            planet(p).rate = (5 / p) / (50 / Sqr(sunr))
            planet(p).ppos = Int(Rnd * 360)
            If p > 1 Then
                nm = (Int(Rnd * (p + 3)))
                If nm > 12 Then nm = Int(nm / 2)
                mooncount(p) = nm
                For m = 1 To mooncount(p)
                    moon(p, m).orbit = (planet(p).size * 1.5) + m * planet(p).size
                    moon(p, m).size = .5 + Int(Rnd * (planet(p).size / 3))
                    moon(p, m).kp = _RGB32(Int(200 + Rnd * 53), Int(200 + Rnd * 53), Int(200 + Rnd * 53))
                    moon(p, m).rate = ((5 / p) / _Pi) * (1 + Rnd * 3)
                    moon(p, m).ppos = Int(Rnd * 360)
                Next m
            End If
        Next p
    End If
Loop Until kk$ = Chr$(27)

_FreeImage stars&

Sub circleBF (cx As Long, cy As Long, r As Long, klr As _Unsigned Long)
    rsqrd = r * r
    y = -r
    While y <= r
        x = Sqr(rsqrd - y * y)
        Line (cx - x, cy + y)-(cx + x, cy + y), klr, BF
        y = y + 1
    Wend
End Sub


Sub drawplanet (p)
    x = planet(p).orbit * Sin(0.01745329 * planet(p).ppos)
    y = planet(p).orbit * Cos(0.01745329 * planet(p).ppos)
    x2 = (planet(p).orbit - planet(p).size / 2) * Sin(0.01745329 * planet(p).ppos)
    y2 = (planet(p).orbit - planet(p).size / 2) * Cos(0.01745329 * planet(p).ppos)
    x3 = (planet(p).orbit - planet(p).size / 3) * Sin(0.01745329 * planet(p).ppos)
    y3 = (planet(p).orbit - planet(p).size / 3) * Cos(0.01745329 * planet(p).ppos)
    pr = _Red(planet(p).kp)
    pg = _Green(planet(p).kp)
    pb = _Blue(planet(p).kp)
    planet(p).ppos = planet(p).ppos + planet(p).rate
    circleBF sunx + x, suny + y, planet(p).size, planet(p).kp
    circleBF sunx + x2, suny + y2, planet(p).size / 2.5, _RGB32(pr * 1.1, pg * 1.1, pb * 1.05)
    circleBF sunx + x3, suny + y3, planet(p).size / 4, _RGB32(pr * 1.2, pg * 1.2, pb * 1.1)
    If mooncount(p) > 0 Then
        For m = 1 To mooncount(p)
            mx = moon(p, m).orbit * Sin(0.01745329 * moon(p, m).ppos)
            my = moon(p, m).orbit * Cos(0.01745329 * moon(p, m).ppos)
            circleBF sunx + x + mx, suny + y + my, moon(p, m).size, moon(p, m).kp
            moon(p, m).ppos = moon(p, m).ppos + moon(p, m).rate
        Next m
    End If
End Sub