Raise exception in a CreateIntFImage

[BlueIcaro]

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][+][-]

1. program project1;
2.  
3. {$mode objfpc}{$H+}
4.  
5. uses
6.   {$IFDEF UNIX}{$IFDEF UseCThreads}
7.   cthreads,
8.   {$ENDIF}{$ENDIF}
9.   Classes
10.   { you can add units after this },
11.   Graphics, IntfGraphics,Gl,Fpimage;
12.   TYpe
13.  
14.   { TglTexture }
15.  
16.  TglTexture= class
17.     public
18.       width ,Height : Longint;
19.       Data          : Pointer;
20.       destructor Destroy;Override;
21.  
22.   end;
23.  
24. var
25.   P: TPortableNetworkGraphic;
26.   InfImage: TLazIntfImage;
27.   Textura : TglTexture;
28.   Pb: PByte;
29.   X,Y: Integer;
30.   c : TFpColor;
31. { TglTexture }
32.  
33. destructor TglTexture.Destroy;
34. begin
35.   Data := Nil;
36.   //Data.Free;
37.   inherited Destroy;
38. end;
39.  
40. begin
41.   Textura := TglTexture.Create;
42.   InfImage := nil;
43.    P := TPortableNetworkGraphic.Create;
44.   P.LoadFromFile('Texture1.png');
45.   InfImage := P.CreateIntfImage;
46.   Textura.width:= P.Width;
47.    Textura.Height:=P.Height;
48.   Getmem(Textura.Data,Textura.width * Textura.Height * 3);
49.   Pb := PByte (Textura.Data);
50.  
51.   For Y := 0 To P.Height-1 do
52.   Begin
53.     For X := 0 To P.Width do
54.     Begin
55.       c:=InfImage.Colors[x,y];
56.       Pb^:= c.red shr 8;
57.       inc(pb);
58.       Pb^:=c.Green shr 8;
59.       inc(pb);
60.       Pb^:=c.blue shr 8;
61.       inc(pb);
62.     end;
63.   end;
64.   ReadLn;
65.   P.Free;
66.   InfImage.Free;
67.   Textura.Free;
68. end.    
69.  

But in the line

Code: Pascal  [Select][+][-]

1. InfImage := P.CreateIntfImage;
2.  

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

[Blaazen]

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;


[BlueIcaro]

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

[Blaazen]

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.

[BlueIcaro]

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][+][-]

1. unit Unit1;
2.  
3. {$mode objfpc}{$H+}
4.  
5. interface
6.  
7. uses
8.   Classes, SysUtils, FileUtil, Forms, Controls, Graphics, Dialogs, StdCtrls,
9.   IntfGraphics,Gl,FPimage;
10.  
11. type
12.  
13.   { TForm1 }
14.  
15.   TForm1 = class(TForm)
16.     Button1: TButton;
17.     procedure Button1Click(Sender: TObject);
18.   private
19.     { private declarations }
20.   public
21.     { public declarations }
22.   end;
23. TYpe
24.  
25. { TglTexture }
26.  
27. TglTexture= class
28.   public
29.     width ,Height : Longint;
30.     Data          : Pointer;
31.     destructor Destroy;Override;
32.  
33. end;
34.  
35. var
36. P: TPortableNetworkGraphic;
37. InfImage: TLazIntfImage;
38. Textura : TglTexture;
39. Pb: PByte;
40. X,Y: Integer;
41. c : TFpColor;
42.  
43. var
44.   Form1: TForm1;
45.  
46. implementation
47. { TglTexture }
48.  
49. destructor TglTexture.Destroy;
50. begin
51. Data := Nil;
52. //Data.Free;
53. inherited Destroy;
54. end;
55. {$R *.lfm}
56.  
57. { TForm1 }
58. function LoadglTexImage2DFromPNG(PNGFilename: string; Image: TglTexture
59.   ): boolean;
60. var
61.   png: TPortableNetworkGraphic;
62.   IntfImg: TLazIntfImage;
63.   y: Integer;
64.   x: Integer;
65.   c: TFPColor;
66.   p: PByte;
67.   Cadena: String;
68. begin
69.   Result:=false;
70.   png:=TPortableNetworkGraphic.Create;
71.   IntfImg:=nil;
72.   Cadena := ExpandFileNameUTF8(PNGFilename);
73.   try
74.     png.LoadFromFile(ExpandFileNameUTf8 (PNGFilename));
75.     IntfImg:=png.CreateIntfImage;
76.     Image.Width:=IntfImg.Width;
77.     Image.Height:=IntfImg.Height;
78.     GetMem(Image.Data,Image.Width*Image.Height * 3);
79.     p:=PByte(Image.Data);
80.     for y:=0 to IntfImg.Height-1 do begin
81.       for x:=0 to IntfImg.Width-1 do begin
82.         c:=IntfImg.Colors[x,y];
83.         p^:=c.red shr 8;
84.         inc(p);
85.         p^:=c.green shr 8;
86.         inc(p);
87.         p^:=c.blue shr 8;
88.         inc(p);
89.       end;
90.     end;
91.   finally
92.     png.Free;
93.     IntfImg.Free;
94.   end;
95.   Result:=true;
96. end;
97.  
98. procedure TForm1.Button1Click(Sender: TObject);
99. var
100.   Tex: TglTexture;
101. begin
102.   Tex := TglTexture.Create;
103.   IF LoadglTexImage2DFromPNG('Texture1.png',Tex) Then
104.      ShowMessage('si')
105.   ELSE
106.     ShowMessage ('No');
107.   IF Tex <> nil Then
108.      ShowMessage('No nil')
109.   ELSE
110.       ShowMessage('Nil');
111. end;
112.  
113. end.
114.                                                                                
115.  

I think there is some importan diference between a Application and a Program.

/BlueIcaro

[BlueIcaro]

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

/BlueIcaro