unit Rocket;

interface

uses FMX.Objects, FMX.Ani, FMX.Types, FMX.Graphics, SysUtils, System.Types;

const
   ANGLE_INC = 2;
   TICS_TILL_DIR_CHANGE = 30;
   TICS_TILL_EXLODE = 170;

type
   TRocket = class
   private
      fPosition, fVelocity: TPointF;
      fAngle, fToAngle, fSpeed: Single;
      ExplosionType: Byte;
      TicsTillDirectionChange, TicsTillExlosion: Integer;
      fCurrentExplosionTics, fCurrentDirectionTics: Integer;
      fRocketImg, fExplodeImg: TImage;
      fExlosionAni, fRocketAnimationAni: TBitmapListAnimation;
      fDestroyed: Boolean;
   public
      Constructor Create; overload;
      Destructor Destroy; overload;
      Constructor Create(pX, pY, pAngle, pSpeed: Single); overload;
      procedure SetPosition(pPosition: TPointF);
      procedure SetVelocity(pVelocity: TPointF);
      procedure SetAngle(pDeg: Single);
      procedure SetToAngle(pDeg: Single);
      procedure SetSpeed(pSpeed: Single);
      procedure FreeRocket(Sender: TObject);
      procedure Update;
      property Destroyed: Boolean read fDestroyed;
      property Position: TPointF read fPosition write SetPosition;
      property Angle: Single read fAngle write SetAngle;
      property ToAngle: Single read fToAngle write SetToAngle;
      property CurrentExplosionTics: Integer read fCurrentExplosionTics;
      property CurrentDirectionTics: Integer read fCurrentDirectionTics;
      property Speed: Single read fSpeed write SetSpeed;
      property Velocity: TPointF read fVelocity write SetVelocity;
   end;

implementation

uses Animation;

procedure TRocket.SetVelocity(pVelocity: TPointF);
begin
   fVelocity := pVelocity;
end;

procedure TRocket.SetToAngle(pDeg: Single);
begin
   fToAngle := pDeg;
end;

procedure TRocket.SetAngle(pDeg: Single);
begin
   fAngle := pDeg;
end;

procedure TRocket.SetPosition(pPosition: TPointF);
begin
   fPosition := pPosition;
end;

procedure TRocket.Update;
var
   AnglesComparsion: Single;
begin
   fRocketImg.RotationAngle := Angle;
   Velocity := TPointF.Create(Speed * cos((Angle - 90) * PI / 180),
     -Speed * sin((Angle + 90) * PI / 180));
   with Position do
   begin
      Position := TPointF.Create(X + Velocity.X, Y + Velocity.Y);
      fRocketImg.Position.X := X;
      fRocketImg.Position.Y := Y;
   end;
   Inc(fCurrentExplosionTics);
   Inc(fCurrentDirectionTics);
   if (fCurrentExplosionTics = TicsTillExlosion) then
   begin
      Speed := 0;
      fRocketImg.Visible := False;
      with fPosition do
      begin
         fExplodeImg.Position.X := X;
         fExplodeImg.Position.Y := Y;
      end;
      fExlosionAni.Enabled := True;
   end;
   if fCurrentDirectionTics = TicsTillDirectionChange then
   begin
      fCurrentDirectionTics := 0;
      ToAngle := 180 - Random(360);
   end
   else
   begin
      AnglesComparsion := Angle - ToAngle;
      if Abs(AnglesComparsion) > 3 then
      begin
         if AnglesComparsion < 0 then
            Angle := Angle + ANGLE_INC
         else
            Angle := Angle - ANGLE_INC;
      end;
   end;
end;

procedure TRocket.SetSpeed(pSpeed: Single);
begin
   fSpeed := pSpeed;
end;

constructor TRocket.Create;
begin
   inherited Create;
end;

destructor TRocket.Destroy;
begin
   fRocketAnimationAni.Free;
   fRocketImg.Free;
   fExlosionAni.Free;
   fExplodeImg.Free;
   inherited Destroy;
end;

procedure TRocket.FreeRocket(Sender: TObject);
begin
   fDestroyed := True;
end;

constructor TRocket.Create(pX, pY, pAngle, pSpeed: Single);
begin
   inherited Create;
   Position := TPointF.Create(pX, pY);
   Self.fAngle := pAngle;
   ToAngle := pAngle;
   Speed := pSpeed;
   fDestroyed := False;
   ExplosionType := 1 + Random(2);
   TicsTillExlosion := 100 + Random(TICS_TILL_EXLODE);
   TicsTillDirectionChange := TICS_TILL_DIR_CHANGE;
   fCurrentExplosionTics := 0;
   fCurrentDirectionTics := 0;
   fRocketImg := TImage.Create(MainForm);
   with fRocketImg do
   begin
      Parent := MainForm;
      Position := TPosition.Create(TPointF.Create(pX, pY));
      RotationAngle := pAngle;
      Scale.X := 2;
      Scale.Y := 2;
   end;
   fRocketAnimationAni := TBitmapListAnimation.Create(fRocketImg);
   with fRocketAnimationAni do
   begin
      Parent := fRocketImg;
      AnimationBitmap := TBitmap.CreateFromFile('rocket.png');
      PropertyName := 'Bitmap';
      AnimationCount := 4;
      AnimationRowCount := 1;
      Duration := 0.3;
      Delay := 0;
      Loop := True;
      Enabled := True;
   end;
   fExplodeImg := TImage.Create(MainForm);
   with fExplodeImg do
   begin
      Scale.X := 3;
      Scale.Y := 3;
      Parent := MainForm;
   end;
   fExlosionAni := TBitmapListAnimation.Create(fExplodeImg);
   with fExlosionAni do
   begin
      Parent := fExplodeImg;
      AnimationBitmap := TBitmap.CreateFromFile('expl' + Inttostr(ExplosionType)
        + '.png');
      PropertyName := 'Bitmap';
      AnimationCount := 41;
      AnimationRowCount := 9;
      Duration := 4;
      Delay := 0;
      OnFinish := FreeRocket;
   end;
end;

end.