Game Developement

[Realeg]

This is the code i write to manipulate the *.exe file path extractor:

program TextureLoad;


uses crt,SDL2,SDL2_image,SysUtils;


type R=array[1..100] of pSDL_Renderer;
	 T=array[1..100] of pSDL_Texture;


var window:pSDL_Window; Render:R; Texture:T; i:byte;


procedure Graphic_Initialisation;
begin
	clrscr;
	if SDL_INIT(SDL_INIT_VIDEO)<0 then
		begin
			writeln('The graphic mode could not be initializated');
			writeln('The application will now exit');
			exit;
		end
	else
		window:=SDL_CreateWindow('Texture Window',50,50,600,480,SDL_WINDOW_SHOWN);
end;


Procedure Load_Texture(ExePath:AnsiString);
begin
	T[1]:=IMG_LOADTEXTURE(R[1],ExePath+'data\space_armada1.bmp');
	T[2]:=IMG_LOADTEXTURE(R[2],ExePath+'data\space_armada2.bmp');
	T[3]:=IMG_LOADTEXTURE(R[3],ExePath+'data\space_armada3.bmp');
end;




Procedure ComposerFrame;
var Path:AnsiString;
begin
	Path:=ExtractPathFile('Texture.exe');
	Load_Texture(Path);	
end;
			
	
	
procedure Graphic_Destruction;
begin
	SDL_DestroyWindow(window);
	SDL_QUIT;
end;


Begin
	Graphic_Initialisation;
	SDL_Delay(2000);
	ComposerFrame;
	Graphic_Destruction;
end.

And the error is this: Arg no 2: AnsiString found but expected PChar.
How do i solve it? Is there some kind of function that convert a AnsiString to a PChar? Or something like this?

[Realeg]

This is the code i just write to handle the files. The error i recive is that the path variable gets an AnsiString and the parameter for the IMG_LoadTexture is a pChar. How do i convert them?

program grafica;


uses SysUtils,crt,SDL2,SDL2_image;


type Textures=array[1..100] of pSDL_Texture;


var Window:pSDL_Window; var Tex:Textures; Ren:pSDL_Renderer;


procedure Graphic_Initialisation(var Window:pSDL_Window);
begin
	if SDL_INIT(SDL_INIT_VIDEO)<0 then
		writeln('An error ocurred, the program will now quit')
	else
		begin
			writeln('Graphic mode succesfully initialisated');
			Window:=SDL_CreateWindow('Test',50,50,600,400,SDL_WINDOW_SHOWN);
		end;
end;


procedure Texture_Loading;
var path:pChar;
begin
	Ren:=SDL_CreateRenderer(window,-1,0);
	path:=ExtractFilePath('grafica.exe');
	Tex[1]:=IMG_LoadTexture(Ren,path+'\monster.bmp');
	Tex[2]:=IMG_LoadTexture(Ren,path+'\monster1.bmp');;
end;


procedure Graphic_Composer;
var i:byte;
begin
	Texture_Loading;
	for i:=1 to 100 do
		begin
			if (i mod 2)=1 then
				begin
					SDL_RenderCopy(Ren,Tex[1],nil,nil);
					SDL_RenderPresent(Ren);
					SDL_DELAY(50);
				end
			else
				begin
					SDL_RenderCopy(Ren,Tex[2],nil,nil);
					SDL_RenderPresent(Ren);
					SDL_Delay(50);
				end;
		end;
end;


procedure Graphic_Destroy;
var i:byte;
begin
	for i:=1 to 100 do	
		SDL_DestroyTexture(Tex[i]);
	SDL_DestroyRenderer(Ren);
	SDL_DestroyWindow(Window);
	SDL_QUIT;
end;




begin
    clrscr;
	Graphic_Initialisation(Window);
	Graphic_Composer;
	Graphic_Destroy;
end.

[SilverWarior]

This is the code i just write to handle the files. The error i recive is that the path variable gets an AnsiString and the parameter for the IMG_LoadTexture is a pChar. How do i convert them?

Wrap the code defining path into PChar method:

    Tex[1]:=IMG_LoadTexture(PChar(Ren,path+'\monster.bmp'));

[Realeg]

Tried your solution, it dosen't work...

[pitfiend]

program grafica;

uses SysUtils,crt,SDL2,SDL2_image;

type Textures=array[1..100] of pSDL_Texture;

var Window:pSDL_Window; var Tex:Textures; Ren:pSDL_Renderer;

procedure Graphic_Initialisation(var Window:pSDL_Window);
begin
    if SDL_INIT(SDL_INIT_VIDEO)<0 then
        writeln('An error ocurred, the program will now quit')
    else
        begin
            writeln('Graphic mode succesfully initialisated');
            Window:=SDL_CreateWindow('Test',50,50,600,400,SDL_WINDOW_SHOWN);
        end;
end;

procedure Texture_Loading;
var path:pChar;
begin
    Ren:=SDL_CreateRenderer(window,-1,0);
    path:=ExtractFilePath('grafica.exe');
    Tex[1]:=IMG_LoadTexture(Ren,path+'\monster.bmp');
    Tex[2]:=IMG_LoadTexture(Ren,path+'\monster1.bmp');;
end;

procedure Graphic_Composer;
var i:byte;
begin
    Texture_Loading;
    for i:=1 to 100 do
        begin
            if (i mod 2)=1 then
                begin
                    SDL_RenderCopy(Ren,Tex[1],nil,nil);
                    SDL_RenderPresent(Ren);
                    SDL_DELAY(50);
                end
            else
                begin
                    SDL_RenderCopy(Ren,Tex[2],nil,nil);
                    SDL_RenderPresent(Ren);
                    SDL_Delay(50);
                end;
        end;
end;

procedure Graphic_Destroy;
var i:byte;
begin
    for i:=1 to 100 do    
        SDL_DestroyTexture(Tex[i]);
    SDL_DestroyRenderer(Ren);
    SDL_DestroyWindow(Window);
    SDL_QUIT;
end;

begin
    clrscr;
    Graphic_Initialisation(Window);
    Graphic_Composer;
    Graphic_Destroy;
end.

I think you must validate that ExtractFilePath didn't gets you a string path with '\' at the end. That could produce unexpected results as you are having.

[User137]

I wonder, how could i make games in Turbo Pascal using graphics? I tried to use the "graph unit" integrated with pascal, but i can't use the keyboard in the graphic window.
So, i'm here to ask you, what i need to start create a graphic game using Pascal language?

I would recommend installing Lazarus for that kind of stuff. Turbo pascal is only for learning basics, starting to use graphics on it won't lead anywhere, and gives you too much information you don't need. No modern time games can be made with Turbo Pascal.

[phibermon]

What Silverwarrior suggested :

Tex[1]:=IMG_LoadTexture(PChar(Ren,path+'\monster.bmp'));

should read :

Tex[1]:=IMG_LoadTexture(Ren,PChar(path+'\monster.bmp'));

[SilverWarior]

What Silverwarrior suggested :

Tex[1]:=IMG_LoadTexture(PChar(Ren,path+'\monster.bmp'));

should read :

Tex[1]:=IMG_LoadTexture(Ren,PChar(path+'\monster.bmp'));

You are absolutely correct. How could I have made such trivial mistake

[Realeg]

I've tried the the second solution from the very beginning. The error is now that i got a short string instead of pChar. I've tried this solution, but it had the same result.

path:=pChar(ExtractFilePath('grafica.exe'));

EDIT: The fact is that i just realise that by writing the upper instruction, the path variable is empty. Only if you write the whole path it is kept in the variable, the problem i want to avoid. In the problem with the short-string to pChar, i solved, the problem is this thing now. Getting the file path, without writing the whole path

If i write

path:=pChar(ExtractFilePath('C:\Pascal\Projects\grafica.exe');

the variable will keep C:\Pascal\Projects\, otherwise it will be empty.

[SilverWarior]

When you use

ExtractFilePath('grafica.exe');

your program tires to search for file named grafica.exe in your current directory also know as working directory which may not be the folder from which your application was launched and then extract its path. If the file can't be found in current directoy you will get empty path as a result.

So extract your program path using

MyAppPath := ExtractFilePath(Application.ExeName);

as I have suggested to you in the first place.

Now you already know what ExtractFilePath method does right.
And Application.ExeName property returns the full filename of your program executable from which you can extract path to the folder in which your executable resides.