Raise exception in a CreateIntFImage
lazarus / 39-Graphics

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BlueIcaro · 2012-08-18 15:10

Hello, I trying to load a PNG file, as make the example, that come
with Lazarus, OpenGlControlDemo.
So I copy the function LoadflTextImage2DfromPNG, and for Test I wrote
this small program.
Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i program
project1; {$mode objfpc}{$H+} uses  {$IFDEF UNIX}{$IFDEF UseCThreads} 
cthreads,  {$ENDIF}{$ENDIF}  Classes  { you can add units after this
},  Graphics, IntfGraphics,Gl,Fpimage;  TYpe   { TglTexture
}  TglTexture= class    public      width ,Height : Longint;      Data
         : Pointer;      destructor Destroy;Override;   end; var  P:
TPortableNetworkGraphic;  InfImage: TLazIntfImage;  Textura :
TglTexture;  Pb: PByte;  X,Y: Integer;  c : TFpColor;{ TglTexture
} destructor TglTexture.Destroy;begin  Data := Nil;  //Data.Free; 
inherited Destroy;end; begin  Textura := TglTexture.Create;  InfImage
:= nil;   P := TPortableNetworkGraphic.Create; 
P.LoadFromFile('Texture1.png');  InfImage := P.CreateIntfImage; 
Textura.width:= P.Width;   Textura.Height:=P.Height; 
Getmem(Textura.Data,Textura.width * Textura.Height * 3);  Pb := PByte
(Textura.Data);   For Y := 0 To P.Height-1 do  Begin    For X := 0 To
P.Width do    Begin      c:=InfImage.Colors[x,y];      Pb^:= c.red shr
8;      inc(pb);      Pb^:=c.Green shr 8;      inc(pb);     
Pb^:=c.blue shr 8;      inc(pb);    end;  end;  ReadLn;  P.Free; 
InfImage.Free;  Textura.Free;end.     But in the line
Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i InfImage :=
P.CreateIntfImage; I got a exception of the debugger: Extenal SigSev.
But If I run the example that come with Lazarus, every thing goes ok.
I don't know what I doing wrong.
Any idea?

Thank
/BlueIcaro

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Blaazen · 2012-08-18 15:26

This is starnge. I didn't see the demo, but here:
Code: [Select]  P: TPortableNetworkGraphic;
  InfImage: TLazIntfImage;
are two different types and you create like this:
Code: [Select]InfImage := P.CreateIntfImage;

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BlueIcaro · 2012-08-18 16:59

Yes Blaazen, it's very strange, but I copy and paste de original
function, and I got the same problema.
Also I add the same requiered packaged  .

But it's doesn't work.

/BLueIcaro

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Blaazen · 2012-08-18 20:24

Sorry, my mistake. "InfImage := P.CreateIntfImage;" is not a
constructor.

I can see that original code is in try..except construction. You
should do it too.
Code: [Select]function LoadglTexImage2DFromPNG(PNGFilename: string;
Image: TglTexture
  ): boolean;
var
  png: TPortableNetworkGraphic;
  IntfImg: TLazIntfImage;
  y: Integer;
  x: Integer;
  c: TFPColor;
  p: PByte;
begin
  Result:=false;
  png:=TPortableNetworkGraphic.Create;
  IntfImg:=nil;
  try
    png.LoadFromFile(PNGFilename);
    IntfImg:=png.CreateIntfImage;
    Image.Width:=IntfImg.Width;
    Image.Height:=IntfImg.Height;
    GetMem(Image.Data,Image.Width*Image.Height * 3);
    p:=PByte(Image.Data);
    for y:=0 to IntfImg.Height-1 do begin
      for x:=0 to IntfImg.Width-1 do begin
        c:=IntfImg.Colors[x,y];
        p^:=c.red shr 8;
        inc(p);
        p^:=c.green shr 8;
        inc(p);
        p^:=c.blue shr 8;
        inc(p);
      end;
    end;
  finally
    png.Free;
    IntfImg.Free;
  end;
  Result:=true;
end;             

Unfortunally, this demo does not work here on my laptop.

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BlueIcaro · 2012-08-18 21:27

Hi Blaazen, I copied the function and it doesn't work.
But I found something interesting. I was making my test in a Program.
I selected a Program from  Proyect/New Proyect, the Program and it's
doesn't work.

But If I make a application, it's works find. I don't know why, but
this code works
Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i unit
Unit1; {$mode objfpc}{$H+} interface uses  Classes, SysUtils,
FileUtil, Forms, Controls, Graphics, Dialogs, StdCtrls, 
IntfGraphics,Gl,FPimage; type   { TForm1 }   TForm1 = class(TForm)   
Button1: TButton;    procedure Button1Click(Sender: TObject); 
private    { private declarations }  public    { public declarations
}  end;TYpe { TglTexture } TglTexture= class  public    width ,Height
: Longint;    Data          : Pointer;    destructor
Destroy;Override; end; varP: TPortableNetworkGraphic;InfImage:
TLazIntfImage;Textura : TglTexture;Pb: PByte;X,Y: Integer;c :
TFpColor; var  Form1: TForm1; implementation{ TglTexture } destructor
TglTexture.Destroy;beginData := Nil;//Data.Free;inherited
Destroy;end;{$R *.lfm} { TForm1 }function
LoadglTexImage2DFromPNG(PNGFilename: string; Image: TglTexture  ):
boolean;var  png: TPortableNetworkGraphic;  IntfImg: TLazIntfImage; 
y: Integer;  x: Integer;  c: TFPColor;  p: PByte;  Cadena:
String;begin  Result:=false;  png:=TPortableNetworkGraphic.Create; 
IntfImg:=nil;  Cadena := ExpandFileNameUTF8(PNGFilename);  try   
png.LoadFromFile(ExpandFileNameUTf8 (PNGFilename));   
IntfImg:=png.CreateIntfImage;    Image.Width:=IntfImg.Width;   
Image.Height:=IntfImg.Height;   
GetMem(Image.Data,Image.Width*Image.Height * 3);   
p:=PByte(Image.Data);    for y:=0 to IntfImg.Height-1 do begin     
for x:=0 to IntfImg.Width-1 do begin        c:=IntfImg.Colors[x,y];  
    p^:=c.red shr 8;        inc(p);        p^:=c.green shr 8;       
inc(p);        p^:=c.blue shr 8;        inc(p);      end;    end; 
finally    png.Free;    IntfImg.Free;  end; 
Result:=true;end; procedure TForm1.Button1Click(Sender: TObject);var 
Tex: TglTexture;begin  Tex := TglTexture.Create;  IF
LoadglTexImage2DFromPNG('Texture1.png',Tex) Then   
 ShowMessage('si')  ELSE    ShowMessage ('No');  IF Tex <> nil Then  
 ShowMessage('No nil')  ELSE      ShowMessage('Nil');end; end.       
                                                                     
I think there is some importan diference between a Application and a
Program.

/BlueIcaro

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BlueIcaro · 2012-08-18 21:35

I don't know why, but if this code doesn't run into a GUI Application
(Application with forms) it doesn't work 

/BlueIcaro