Ball vom Paddle abprallen

[DeddyH]

Oder erstell mal ein neues Projekt, benenne das Formular frmDemo und die Unit uDemoMain. Die überschreibst Du dann komplett mit dem folgenden Code und weist im Objektinspektor dem OnCreate-Ereignis die FormCreate-Methode zu.

Delphi-Quellcode:

unit uDemoMain;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, ExtCtrls;

type
  TfrmDemo = class(TForm)
    procedure FormCreate(Sender: TObject);
  private
    { Private-Deklarationen }
    FPaddle: TPanel;
    FBall: TImage;
    FTimer: TTimer;
    procedure DoOnTimer(Sender: TObject);
    function Collision(FirstRect, SecondRect: TRect): Boolean;
  public
    { Public-Deklarationen }
  end;

var
  frmDemo: TfrmDemo;

implementation

{$R *.dfm}

const
  STEP = 2;

{ TfrmDemo }

function TfrmDemo.Collision(FirstRect, SecondRect: TRect): Boolean;
var
  OutRect: TRect;
begin
  Result := IntersectRect(OutRect, FirstRect, SecondRect);
end;

procedure TfrmDemo.DoOnTimer(Sender: TObject);
var
  PaddleRect, BallRect: TRect;
begin
  FBall.Top := FBall.Top + STEP;
  PaddleRect := Rect(FPaddle.Left, FPaddle.Top, FPaddle.Left + FPaddle.Width,
    FPaddle.Top + FPaddle.Height);
  BallRect := Rect(FBall.Left, FBall.Top, FBall.Left + FBall.Width,
    FBall.Top + FBall.Height);
  if Collision(PaddleRect, BallRect) then
    begin
      FTimer.Enabled := false;
      ShowMessage('Kollision');
    end;
end;

procedure TfrmDemo.FormCreate(Sender: TObject);
const
  EDGELENGTH = 20;
var
  FBitmap: TBitmap;
begin
  //Paddel erzeugen
  FPaddle := TPanel.Create(self);
  FPaddle.Parent := self;
  FPaddle.Top := ClientHeight - FPaddle.Height;
  FPaddle.Left := (ClientWidth - FPaddle.Width) div 2;
  //Ball erzeugen
  FBall := TImage.Create(self);
  FBall.Parent := self;
  FBall.Width := EDGELENGTH;
  FBall.Height := EDGELENGTH;
  FBall.Top := 0;
  FBall.Left := (ClientWidth - FBall.Width) div 2;
  //Ball malen und darstellen
  FBitmap := TBitmap.Create;
  try
    FBitmap.Width := EDGELENGTH;
    FBitmap.Height := EDGELENGTH;
    FBitmap.Canvas.Brush.Color := clRed;
    FBitmap.Canvas.Ellipse(0, 0, FBitmap.Width, FBitmap.Height);
    FBall.Picture.Assign(FBitmap);
  finally
    FBitmap.Free;
  end;
  //Timer erzeugen
  FTimer := TTimer.Create(self);
  FTimer.Interval := 20;
  FTimer.OnTimer := DoOnTimer;
end;

end.