unit fPong;

interface

uses
  System.Classes,
  System.UITypes,
  System.SysUtils,
  System.Math,
  Vcl.Forms,
  Vcl.ExtCtrls,
  Vcl.Controls,
  Vcl.Dialogs,
  
  GLS.Scene,
  GLS.VectorTypes,
  GLS.Objects,
  GLS.Texture,
  GLS.VectorGeometry,
  GLS.Cadencer,
  GLS.SceneViewer,
  GLS.SpaceText,
  GLS.ShadowPlane,
  GLS.ShadowVolume,
 
  GLS.Material,
  GLS.Coordinates,
  GLS.BaseClasses;

type
  TFormPong = class(TForm)
    GLScene1: TGLScene;
    GLSceneViewer1: TGLSceneViewer;
    GLCamera1: TGLCamera;
    Plane1: TGLPlane;
    Cube1: TGLCube;
    Cube2: TGLCube;
    Cube3: TGLCube;
    Ball: TGLSphere;
    DummyCube1: TGLDummyCube;
	 GLLightSource1: TGLLightSource;
	 GLMaterialLibrary1: TGLMaterialLibrary;
    Pad: TGLCube;
    SpaceText1: TGLSpaceText;
    Timer1: TTimer;
    GLCadencer1: TGLCadencer;
    GLShadowVolume: TGLShadowVolume;
    procedure GLSceneViewer1MouseMove(Sender: TObject; Shift: TShiftState;
      X, Y: Integer);
    procedure FormCreate(Sender: TObject);
    procedure Timer1Timer(Sender: TObject);
    procedure GLCadencer1Progress(Sender: TObject; const deltaTime,
      newTime: Double);
  private
	 ballVector : TAffineVector;
	 score : Integer;
	 gameOver : Boolean;
	 procedure ResetGame;
  end;

var
  FormPong: TFormPong;

implementation

{$R *.DFM}

procedure TFormPong.FormCreate(Sender: TObject);
begin
	Randomize;
	GLSceneViewer1.Cursor:=crNone;
	ResetGame;
end;

procedure TFormPong.ResetGame;
var
	angle : Single;
begin
	// places the ball in the mat center, resets score and ball speed
	angle:=DegToRad(45+Random(90));
	MakeVector(ballVector, 4*cos(angle), 4*sin(angle), 0);
	score:=0;
	gameOver:=False;
	Ball.Position.AsVector:=NullHmgPoint;
end;

procedure TFormPong.GLSceneViewer1MouseMove(Sender: TObject;
  Shift: TShiftState; X, Y: Integer);
const
	cPadMinMax = 6.25;
var
	px : Single;
begin
	// the pad's position is directly calculated from the mouse position
	px:=(x-(GLSceneViewer1.Width/2))*0.035;
	if px<-cPadMinMax then
		px:=-cPadMinMax
	else if px>cPadMinMax then
		px:=cPadMinMax;
	Pad.Position.X:=px;
//   GLCadencer1.Reset;
   // update the whole stuff now!
   GLCadencer1.Progress;
end;

procedure TFormPong.GLCadencer1Progress(Sender: TObject; const deltaTime,
  newTime: Double);
var
	newBallPos : TGLVector;
begin
	// gameOver is True as soon as the ball is behind the pad, but we don't end
	// the game immediately so the user can realize he has lost
	if (not gameOver) and (deltaTime>0) then begin
		// calc expected new ball pos (if no bump occurs)
		// ( note : VectorCombine(v1, v2, f1, f2)=v1*f1+v2*f2 )
		newBallPos:=VectorCombine(Ball.Position.AsVector, ballVector, 1, deltaTime);
		// check collision with edges
		if newBallPos.X<-7.05 then
			ballVector.X:=-ballVector.X
		else if newBallPos.X>7.05 then
			ballVector.X:=-ballVector.X
		else if newBallPos.Y>4.55 then
			ballVector.Y:=-ballVector.Y;
		// check collision with pad
		if newBallPos.Y<-4 then begin
			if (newBallPos.X>Pad.Position.X-1.25) and (newBallPos.X<Pad.Position.X+1.25) then begin
				// when ball bumps the pad, it is accelerated and the vector
				// is slightly randomized
				ballVector.Y:=-ballVector.Y;
				ballVector.X:=ballVector.X+(Random(100)-50)/50;
				ballVector.Y:=ballVector.Y+0.1;
				// ...and of course a point is scored !
				Inc(score);
				SpaceText1.Text:=Format('%.3d', [score]);
			end else begin
				// ball missed !
				gameOver:=True;
            Exit;
         end
		end;
	end;
	// move the ball
	with Ball.Position do
		AsVector:=VectorCombine(AsVector, ballVector, 1, deltaTime);
end;

procedure TFormPong.Timer1Timer(Sender: TObject);
begin
	// update performance monitor
  //%s : Name,
	Caption:=Format('%.2f FPS', [GLSceneViewer1.FramesPerSecond]);
	GLSceneViewer1.ResetPerformanceMonitor;
	// display score window when game is over and the ball is well out of the board
	if gameOver and (Ball.Position.Y<-6) then begin
		// stop the timer to avoid stacking up Timer events
		// while the user makes up his mind...
		Timer1.Enabled:=False;
		if MessageDlg('Score : '+IntToStr(score)+#13#10#13#10+'Play again ?',
						  mtInformation, [mbYes, mbNo], 0)=mrYes then begin
			ResetGame;
			Timer1.Enabled:=True;
		end else Close;
	end;
end;

end.