Simba 1.5 - Planetary rotation around sun

program new;
{$R-}

const
  SPEEDSCALE := 500;
  G = 6.674*10**-11;
  Middle: TPoint = [500,500];

type
  TPlanet = record
    Distance, Diameter, Mass: Double;

    Pos: record Distance, Angle: Single; end;
    Color: TColor;
    pathrad: Int32;
  end;


var
  Sun: TPlanet;
  image: TImage;
  Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune: TPlanet;
  year: Int32;

function TPlanet.Velocity(): Double;
begin
  Result := Sqrt((G*Sun.Mass) / (Self.Distance*1000));
end;

function TPlanet.SizeScaled(): Int32;
begin
  Result := Max(1,Trunc(Self.Diameter ** 0.35 / 5));
end;

function TPlanet.Tick(Image: TImage): TPoint;
var
  speed: Single;
  size: Int32;
begin
  speed := Self.Velocity();
  size  := Self.SizeScaled();

  if Self.Diameter = Earth.Diameter then
  begin
    if Modulo(Self.Pos.Angle + speed/Self.Distance*speedscale, 2*PI) <> Self.Pos.Angle + speed/Self.Distance*speedscale then
      year += 1;

    Image.DrawText('Earth years: '+ ToStr(year), [50,50], $FFFFFF);
  end;

  Self.Pos.Distance := Self.Distance ** 0.27;
  Self.Pos.Angle := Modulo(Self.Pos.Angle + speed/Self.Distance*speedscale, 2*PI);

  Result.x := Round(Middle.x + Self.Pos.Distance * Cos(Self.Pos.Angle));
  Result.y := Round(Middle.y + Self.Pos.Distance * Sin(Self.Pos.Angle));

  if Self.pathrad = 0 then Self.pathrad := Ceil(Result.DistanceTo(Middle));
  image.DrawCircleAA(middle, Self.pathrad, $222222, 1);

  image.DrawCircleAA(Result, size, Self.Color, size);
end;

procedure Update(Image: TImage);
begin
  Mercury.Tick(image); Venus.Tick(image); Earth.Tick(image); Mars.Tick(image);
  Jupiter.Tick(image); Saturn.Tick(image); Uranus.Tick(image); Neptune.Tick(image);
end;

var
  tmp: TImage;
begin
  Sun.Diameter     := 696340*2;
  Sun.Mass         := 2*10**30;
  Sun.Distance     := 0;


  Mercury.Diameter := 2440*2;
  Mercury.Mass     := 3.3010*10**23;
  Mercury.Distance := 57.9*10**6;
  Mercury.Color    := Colors.SLATEGREY;

  Venus.Diameter   := 6052*2;
  Venus.Mass       := 4.1380*10**24;
  Venus.Distance   := 108.2*10**6;
  Venus.Color      := Colors.PALE_VIOLETRED;

  Earth.Diameter   := 6371*2;
  Earth.Mass       := 5.97*10**24;
  Earth.Distance   := 149.6*10**6;
  Earth.Color      := Colors.SKYBLUE;

  Mars.Diameter    := 3390*2;
  Mars.Mass        := 6.4273*10**23;
  Mars.Distance    := 228.0*10**6;
  Mars.Color       := Colors.RED;

  Jupiter.Diameter := 69911*2;
  Jupiter.Mass     := 1.89852*10**27;
  Jupiter.Distance := 778.5*10**6;
  Jupiter.Color    := Colors.MEDIUM_BLUE;

  Saturn.Diameter  := 58232*2;
  Saturn.Mass      := 5.6846*10**26;
  Saturn.Distance  := 1432.0*10**6;
  Saturn.Color    := Colors.BEIGE;

  Uranus.Diameter  := 25362*2;
  Uranus.Mass      := 8.6819*10**25;
  Uranus.Distance  := 2867.0*10**6;
  Uranus.Color     := Colors.SKYBLUE;

  Neptune.Diameter := 24622*2;
  Neptune.Mass     := 1.02431*10**26;
  Neptune.Distance := 4515.0*10**6;
  Neptune.Color    := Colors.DARK_BLUE;

  image := TImage.Create(1000,1000);

  while True do
  begin
    image.DrawCircleAA(Middle, Sun.SizeScaled(), $88FFFF, Sun.SizeScaled());
    Update(image);
    //tmp := image.ResizeBilinear(image.GetWidth() div 4, image.GetHeight() div 4);
    image.Show(False);
    //tmp.Free();
    image.Clear();
    //TerminateScript;
  end;
  image.Free();
end.