Got an issue with the graph unit in my Pascal program - pascal

Question

I'm new to this forum. I'm here to ask you guys your help.
I have an assignment where I have to code a game in Pascal, which is a brick breaker in my case. Though I stumbled upon a problem that I don't quite manage to solve and it's probably related to the graph unit.
It's supposed to display a wall of bricks of various colours in the graphic interface (generated by the graph unit) but nothing appears. The window stays all black. And I know it's not due to having wrtiten a wrong path to the BGI graphic file in the initialisation of the graph unit as I used the same initalisation in an other program where I managed to draw things in the graphic interface.
Finally, my game is in french, so just a few words that you'll need to know: Niveau means level, Jouer means play and Règles means rules. You'll see by choosing a level in the menu that the application will compile but nothing will be displayed in the graph window.
I'd be very glad if you help me out (please).
Here is the main program:
program principal;
uses
Crt, Keyboard, sysutils, jeu, graph;
var
t : TKeyEvent;
c : char;
x, y, mur : Integer;
F , F2 : Text;
V: r;
GraphicsDriver, GraphicsMode, ErrCode : Smallint;
s : String;
begin
x := 62;
y := 12;
GoToXY(47, 4);
writeln('CASSE BRIQUE STPI EDITION');
GoToXY(55, y);
writeln('Niveaux');
GoToXY(55, y + 2);
writeln('Regles');
GoToXY(x, y);
InitKeyBoard();
repeat //boucle pour déplacer le curseur de haut en bas dans la première fenêtre du menu
t := GetKeyEvent();
t := TranslateKeyEvent(t);
c := GetKeyEventChar(t);
if c = 's' then
begin
GoToXY(x - 1, y + 2);
x := 61;
end;
if c = 'z' then
begin
GoToXY(x, y);
x := 62;
end;
until c = 'm';
ClrScr();
case x of
62: begin
GoToXY(47, 4);
writeln('CASSE BRIQUE STPI EDITION');
GoToXY(55, y);
writeln('Niveau 1');
GoToXY(55, y + 2);
writeln('Niveau 2');
GoToXY(55, y + 4);
writeln('Niveau 3');
GoToXY(63, 14);
end;
61: begin //affichage des règles
DoneKeyBoard();
assign(F2, 'Regles.txt');
reset(F2);
while not eof(F2) do
begin
readln(F2, S);
writeln(S);
end;
RetourArriereMenu(X, Y, mur, T, C, f, f2, V, GraphicsDriver, GraphicsMode, ErrCode, s);
end;
end;
x := 63;
repeat //boucle pour déplacer le curseur de ahut en bas dans la fenêtre de la séléction des niveau
t := GetKeyEvent();
t := TranslateKeyEvent(t);
c := GetKeyEventChar(t);
if c = 's' then
begin
if y < 16 then
begin
GoToXY(x, y + 2);
y := y + 2;
end;
end;
if c = 'z' then
begin
if y > 12 then
begin
GoToXY(x, y - 2);
y := y - 2;
end;
end;
until (c = 'm') or (c = 'w');
if c = 'm' then
begin
DoneKeyboard();
case y of //pour chaque niveau séléctionné, une valeur est assignée à mur (ça serivira au déroulement des procédures ci-dessous)
12: mur := 1;
14: mur := 2;
16: mur := 3;
end;
ClrScr();
GraphicsDriver := Detect; //initialisation de l'unité graph
InitGraph(GraphicsDriver, GraphicsMode,'C:\PP\BGI');
ErrCode := GraphResult;
If GraphResult <> grOK Then //affichage d'un message d'erreur si ça n'arrive pas à trouver le fichier graphique dans le répertoire indiqué ci-dessus
Begin
Writeln('Une erreur graphique s est produite: ', GraphErrorMsg(ErrCode));
Writeln('Le fichier graphique (.BGI) n a pas ete trouve, donc veuillez changer le chemin dans InitGraph');
Readln;
Halt(1);
End
Else
begin
remplissageDoc(mur,F);
MiseEnPlaceMur(mur,F,V);
end;
readln;
closegraph;
end;
if c= 'w' then
RetourArriereMenu(X,Y,mur,T,C,f,f2,V, GraphicsDriver, GraphicsMode, ErrCode,s);
end.
Here is the unit in which is stored all the procedures needed to run the main program
unit jeu;
interface
uses
sysutils, Crt, Keyboard, graph;
const
MAXtabX = 100;
MAXtabY = 50;
Type r = array [1..MAXtabX,1..MAXtabY] of Integer;
procedure remplissageDoc(m: Integer; var f: Text); //remplir les documents aléatoirement à chaque lancement de niveau. m correspond au niveau que le joueur a choisi
procedure MiseEnPlaceMur(m: Integer; var f: Text; res: r); //affichage du mur avec pour chaque bloque des vies (soit 1 soit 2 soit 3)
procedure RetourArriereMenu(X,Y: Integer; var m: Integer; var T: TkeyEvent; var C: char; var f,f2: Text; var res: r; var GraphicsDriver, GraphicsMode, ErrCode : Smallint; s: String); //pour retourner en arrière dans n'importe quel endroit du menu
procedure DessinerBrique(i,j: Integer; res: r; x1,y1,x2,y2: Integer); //dessine une brique
implementation
procedure DessinerBrique(i, j : Integer; res : r; x1, y1, x2, y2 : Integer);
begin
writeln(x1, ',', y1, ' ', x2, ',', y2, '-', res[i][j]);
setcolor(15);
rectangle(x1, y1, x2, y2);
if res[i][j]= 1 then
begin
setfillstyle(1,1);
floodfill((x1+x2)div 2,(y1+y2)div 2,15);
end;
if res[i][j] = 2 then
begin
setfillstyle(1, 2);
floodfill((x1 + x2) div 2, (y1 + y2) div 2, 15);
end;
if res[i][j]= 3 then
begin
setfillstyle(1,4);
floodfill((x1 + x2) div 2, (y1 + y2) div 2, 15);
end;
end;
procedure remplissageDoc(m : Integer; var f : Text);
var
a : Integer;
begin
if m = 1 then
begin
assign(f, 'Niveau 1.txt');
rewrite(f);
for a := 1 to 30 do //30 chiffres vont êtres saisis dans le fichier
begin
write(f, 1);
writeln;
end;
close(f);
end;
if m = 2 then
begin
assign(f, 'Niveau 2.txt');
rewrite(f);
randomize();
for a := 1 to 30 do
begin
write(f, random(2) + 1);
writeln;
end;
close(f);
end;
if m = 3 then
begin
assign(f, 'Niveau 3.txt');
rewrite(f);
randomize();
for a := 1 to 30 do
begin
write(f, random(3) + 1);
writeln;
end;
close(f);
end;
end;
procedure MiseEnPlaceMur(m : Integer; var f : Text; res : r);
var
i, j : Integer;
x1, y1, x2, y2 : Integer;
s : String;
begin
i := 1;
x1 := 200;
x2 := 245;
y1 := 0;
y2 := 25;
reset(f);
read(f, s);
while not eof do
begin
for j:= 1 to length(s) do
begin
res[i][j] := StrToInt(s[j]); //remplissage du tableau des vies
DessinerBrique(i, j, res, x1, y1, x2, y2);
x1 := x2;
x2 := x2 + 10;
if (j = 5) or (j = 10) or (j = 15) or (j = 20) or (j = 25) then //pour avoir des 6 lignes de 5 briques
begin
x1 := 200;
x2 := 245;
y1 := y2;
y2 := y1 + 25
end;
end;
end;
i := i + 1;
close(f);
end;
procedure RetourArriereMenu(X, Y : Integer; var m : Integer; var T : TkeyEvent; var C : char; var f, f2 : Text; var res : r; var GraphicsDriver, GraphicsMode, ErrCode : Smallint; s : String); //retourner en arrière à n'importe quel moment dans le menu
begin
InitKeyBoard();
T := GetKeyEvent();
T := TranslateKeyEvent(T);
C := GetKeyEventChar(T);
if C = 'w' then
begin
X := 62;
Y := 12;
ClrScr();
GoToXY(47, 4);
writeln('CASSE BRIQUE STPI EDITION');
GoToXY(55, Y);
writeln('Niveaux');
GoToXY(55, Y + 2);
writeln('Regles');
GoToXY(X,Y);
repeat
T := GetKeyEvent();
T := TranslateKeyEvent(t);
C := GetKeyEventChar(t);
if C = 's' then
begin
GoToXY(X - 1, Y + 2);
X := 61;
end;
if C = 'z' then
begin
GoToXY(X, Y);
X := 62;
end;
until C = 'm';
ClrScr();
case X of
62: begin
GoToXY(47, 4);
writeln('CASSE BRIQUE STPI EDITION');
GoToXY(55, Y);
writeln('Niveau 1');
GoToXY(55,Y + 2);
writeln('Niveau 2');
GoToXY(55,Y + 4);
writeln('Niveau 3');
GoToXY(63, 14);
x := 63;
end;
61: begin
DoneKeyBoard();
assign(F2, 'Regles.txt');
reset(F2);
while not eof(F2) do
begin
readln(F2, S);
writeln(S);
end;
RetourArriereMenu(X, Y, m, T, C, f, f2, res, GraphicsDriver, GraphicsMode, ErrCode, s);
end;
end;
x:=63;
repeat
t := GetKeyEvent();
t := TranslateKeyEvent(t);
c := GetKeyEventChar(t);
if c = 's' then
begin
if y < 16 then
begin
GoToXY(x, y + 2);
y := y + 2;
end;
end;
if c = 'z' then
begin
if y > 12 then
begin
GoToXY(x, y - 2);
y := y - 2;
end;
end;
until (c = 'm') or (c = 'w');
if c = 'm' then
begin
DoneKeyboard();
case y of
12: m := 1;
14: m := 2;
16: m := 3;
end;
ClrScr();
GraphicsDriver := Detect;
InitGraph(GraphicsDriver, GraphicsMode, 'C:\PP\BGI');
ErrCode := GraphResult;
If GraphResult <> grOK Then
Begin
Writeln('Une erreur graphique s est produite: ', GraphErrorMsg(ErrCode));
Writeln('Le fichier graphique (.BGI) n a pas ete trouve, donc veuillez changer le chemin dans InitGraph');
Readln;
Halt(1);
End
Else
begin
remplissageDoc(m, f);
MiseEnPlaceMur(m, f, res);
end;
readln;
closegraph;
end;
if c = 'w' then
RetourArriereMenu(X, Y, m, T, C, f, f2, res, GraphicsDriver, GraphicsMode, ErrCode, s);
end;
end;
end.

Answer 1

Graphics mode is failing to initialize but you are ignoring the result. Read GraphResult exactly once, and act on that.
Edit: put the BGI fonts in your .exe directory and use '' for the BGI path.
Code Organization
Your code is very disorganized and uses a lot of meaningless variable names — making it very hard to understand what you are trying to do. That and you keep trying to switch back and forth between graphics mode and text mode (and not quite getting it right).
This “answer” is designed to help you better organize your code.
Since this is a graphical game, forget WriteLn and everything else that is not graphical. The very first thing you should do is initialize graphics mode. Put that in a procedure if you wish:
procedure Initialiser;
var
gd, gm : integer;
begin
gd := Detect;
InitGraph( gd, gm, '' );
if GraphResult <> grOK then
begin
WriteLn( 'Impossible de démarrer le mode graphique.' );
Halt( 1 )
end;
ClearDevice
end;
begin
Initialiser;
end.
Next you want to do a menu. Make that a function:
type
ActionDeMenu = (Niveau1, Niveau2, Niveau3, Aider, Quitter);
function Menu : ActionDeMenu;
begin
// dessinez votre menu ici
// obtenir l'entrée de l'utilisateur
// retourner le choix de l'utilisateur
end;
You can then update your main program. You might as well put it in a loop; Break to quit.
begin
Initialiser;
repeat
case Menu of
Niveau1: Jouer( 1 );
Niveau2: Jouer( 2 );
Niveau3: Jouer( 3 );
Aider: Aider;
Quitter: Break
end
until false;
CloseGraph
end.
After that you need to write procedures to show help and to play the game at a specified level of difficulty:
procedure Aider;
begin
// afficher l'aide
// l'utilisateur doit appuyer sur Entrée (ou quelque chose) pour continuer
end;
procedure Jouer( niveau : integer );
begin
// initialiser le niveau de jeu
// jouer le jeu
// affichage gagné/perdu
end;
As you can see, we keep breaking tasks down into simpler tasks that:
do not need to be repeated
keep tasks separate
are simple
With just this organic sense of organization you can make the game much more understandable and easier to implement.