Delphi Tutorial 4: Reaction Timer

In this tutorial you will create a simple game that measures reaction time. The interface makes extensive use of panel objects as status indicators. It also uses a timer control, an image control and two SpeedButtons. This exercise requires great attention to detail in setting the properties of the objects on the screen.

Operation

The program shows and hides an image at random locations within an invisible grid on the screen. While the image is visible it can be “hit” by clicking on it with the mouse button. If the mouse button is clicked on any other part of the screen a “miss” is recorded. If no attempt to click the mouse button is made while the image is visible a “timeout” is recorded. A timer event is used control the rate at which the image moves. “Hits”, “misses” and “timeouts” are recorded in status boxes at the bottom of the screen. After a set number of images are shown the program stops and the average “hit time” is shown.

Program Interface

The main form for the program is shown in the screenshot . There are seven panel components on the form although it is possible to see only six of them. Panel1 is used as a container for panels 2-6 and it is essential, when creating the form, to place these panels “inside” panel 1.

Create the form as follows

• Size the form according to

• Place the first panel component (Panel1) on the blank form. Set the properties as follows

• THIS IS IMPORTANT. Panels 2-6 MUST BE PLACED ON PANEL1 - NOT ON THE FORM ITSELF
• Arrange panels 2-6 as follows

Note the Align property of each panel - Panel6 is aligned to the client (Panel1) - this is to say it fills the space between the right margin of Panel1 (which is effectively the right margin of the form) and the right margin of Panel5.

• Complete the addition of panels by adding Panel7 TO THE FORM with the following properties

Panel7 is the container for the SpeedButtons and the Edit Box. These controls must not be added to the form itself.

• Select Panel7 and add the SpeedButtons and Edit Box. The properties are as follows

Edit1: Left = 5 Top = 67 Width = 25 Height = 21 Hint = 'Delay = value x 100 (ms)'

Text = '20'

SpeedButton1: Left = 5 Top = 6 Width = 25 Height = 25 Hint = 'Start Game'

NumGlyphs = 2 ParentShowHint = True ShowHint = True OnClick = StartClick

SpeedButton2: Left = 5 Top = 36 Width = 25 Height = 25 Hint = 'Stop Game'

NumGlyphs = 2 ParentShowHint = True ShowHint = True OnClick = StopClick

• To place the picture on SpeedButton1, select its “Glyph” property and load the file “Bulbon.bmp” from the Delphi/Images/Buttons directory (Drive L).
• For SpeedButton2 use the picture “Bulboff.bmp”

• Select the form and add a timer component (Timer1). Set its Interval property to 2000
• Select the form and add an image component. Set the Name propety to “Ball” and the Height and Width to 32. Click on the Picture property and load the file “smiley.bmp” from the Delphi/Images/Buttons directory (Drive L).

Program Code

procedure TForm1.MoveBall;

var

NewSlot: Integer;

begin

repeat

NewSlot := Random (144);

until NewSlot <> slot;

slot := NewSlot;

Ball.Left := (slot mod 12) * dx + Panel7.Width;

Ball.Top := (slot div 12) * dy;

Ball.Show;

end;

procedure TForm1.FormCreate(Sender: TObject);

begin

dx := Ball.Height;

dy := Ball.Width;

total_hit:=0;total_miss:=0;

ClientWidth := dx * 12 + Panel7.Width;

ClientHeight := dy * 12 + Panel1.Height;

Randomize;

Panel2.Caption:='';

Panel3.Caption:='';

Panel4.Caption:='';

Panel5.Caption:='';

Panel6.Caption:='';

Ball.Hide;

end;

procedure TForm1.BallClick(Sender: TObject);

var this_time:longint;

begin

if running then

begin

this_time:=GettickCount-tstart;

if sender is TForm1 then

begin

Inc(Misses);

total_miss:=total_miss+this_time;

Panel4.Caption:=' Misses:'+InttoStr(Misses);

Panel6.Caption:=' Miss in '+InttoStr(this_time)+' ms';

end

else if Sender is TImage then

begin

Inc(Hits);

total_hit:=total_hit+this_time;

Panel3.Caption:=' Hits:'+InttoStr(Hits);

Panel6.Caption:=' Hit in '+InttoStr(this_time)+' ms';

Messagebeep(0);

end;

running:=false;

Ball.Hide;

end;

end;

procedure TForm1.StartClick(Sender: TObject);

begin

Balls:=10;

hits:=0;

misses:=0;

total_hit:=0;

total_miss:=0;

timeouts:=0;

Panel2.Caption:=' Targets:'+InttoStr(Balls);

Panel3.Caption:=' Hits:'+InttoStr(Hits);

Panel4.Caption:=' Misses:'+InttoStr(Misses);

Panel5.Caption:=' Timeouts:'+InttoStr(Timeouts);

Panel6.Caption:=' ';

Timer1.Interval:=Trunc(StrtoFloat(Edit1.Text)*100);

Moveball;

Timer1.Enabled:=true;

running:=true;

tstart:=GetTickCount;

end;

procedure TForm1.StopClick(Sender: TObject);

begin

Timer1.Enabled:=False;

end;

procedure TForm1.Timer1Timer(Sender: TObject);

var average:real;

begin

if running then

begin

Inc(Timeouts);

Panel5.Caption:=' Timeouts:'+InttoStr(Timeouts);

running:=false;

end;

Dec(Balls);

Panel2.Caption:=' Targets:'+InttoStr(Balls);

if Balls > 0

then

begin

Moveball;

tstart:=GetTickCount;

running:=true;

end

else

begin

timer1.Enabled:=false;

running:=false;

Panel2.Caption:=' Finished';

if hits>0 then

begin

average:=total_hit/hits;

Panel6.Caption:=' Average Hit Time = '

+FloattoStrF(average,fffixed,8,2)+ ' ms';

end;

Ball.Hide;

end;

end;

end.