Hello. What should I do to load png?
I have allegro 4.2.2(last stable version) and I downloaded libpng,and zlib.
I link to alleg.lib, loadpng.lib, zdll.lib. But if I only write after initialize allegro BITMAP *png = load_png("name.png",NULL);
The Compiler (msvc2008 c++ express) said he cant find:
Verweis auf nicht aufgelöstes externes Symbol "_png_error" in Funktion "_read_data".
Verweis auf nicht aufgelöstes externes Symbol "_png_get_io_ptr" in Funktion "_read_data".
and so on... Had I link some false?
I hope someone can help me.

Greetz,
Tibo

my problem is... i havent got a data named loadpng.lib only have zdll.lib and libpng.lib.... where do i get support for MSVC... i only find linux and unix support...
If i download loadpng from here:
http://tjaden.strangesoft.net/loadpng/
ldpng15.zip (90.8k)
there are only some make files examples and headers but no library....
please help me guys.

Best Regards,
Tibo

Here see the code:

#include <WinAllegro.h>
#include "loadpng.h"
#include <png.h>
#include <zlib.h>

int main(int argc, char **argv)
{
allegro_init();
install_keyboard();
set_color_depth(32);
set_gfx_mode(GFX_AUTODETECT_WINDOWED,640,480,0,0);



BITMAP *bmp;
register_png_file_type();

return 0;
} END_OF_MAIN()

and I link to alleg.lib, zdll.lib, and libpng.lib

here is the error message only for register_png_file_type()

1>main.obj : error LNK2001: Nicht aufgelöstes externes Symbol "_register_png_file_type".
1>C:\Users\Tibo\pngtest\pngtest\Debug\pngtest.exe : fatal error LNK1120: 1 nicht aufgelöste externe Verweise.

nicht aufgelöste externe verweise = unresolved extern symbol... so he cant find the function... but if i write the function in msvc he find the function...

ah and I found out that register_png_file() is only declared not defined... where is the definition of register_png_file() usually?

Tibo

and if i include regpng.c he said:
Verweis auf nicht aufgelöstes externes Symbol "_load_png" in Funktion "_register_png_file_type".
Verweis auf nicht aufgelöstes externes Symbol "_save_png" in Funktion "_register_png_file_type".
Verweis auf nicht aufgelöstes externes Symbol "_load_memory_png" in Funktion ""void * __cdecl load_datafile_png(struct PACKFILE *,long)" (?load_datafile_png@@YAPAXPAUPACKFILE@@J@Z)".

I dont know... do loadpng really work?....

whats a .o file? I found a libpng-bcc.lib data and i linked to it.. but my compiler said this data is damaged or not valid...
I downloaded libpng from here
http://gnuwin32.sourceforge.net/packages/libpng.htm
i downloaded the complete package without sources...

Tibo

does nobody know the problem?
Nobody use loadpng with MSVC?

These are probably not for MSVC.

I'd make WinAllegro.h on my self... without WinAllegro allegro doesnt work with MSVC. Allegro havent got much support for windows... thats very bad. I'm not a windows fan but the IDE is very good...

Yes i added all loadpng sources. regpng savepng and so on...

To Milan Mimica:
So there arent any loadpng libpng files for MSVC?...

Compile them yourself. A C programmer should be used to compile things.

what should i compile? the regpng loadpng savepng sources?
WTF? Without my code allegro doesnt work... and I dont use Winapi:
See whats written in my code:
#ifdef _MSC_VER
#pragma warning(push)
#pragma warning(disable: 312)
#include "allegro.h"
#pragma warning(pop)
#else
#include "allegro.h"
#endif

And winalleg including doesnt work right. I tried everything but without this code allegro doesnt work by me.

Hey guys... its working now.... thank you soo much for help. I dont know what was my fault but after i installed all allegro and libpng zlib again it works fine.
Thanks

Greetz,
Tibo

ya without the WinAllegro.h allegro doesnt work^^ I only have to include loadpng.h
If I include the others error message appear^^ so thanks for your help Edgar and the others. It's working fine now.

Edit: Omfg sry next problem. Why does transparency doesnt work?
I only can use alpha blending on pngs? or is there a special method to do png transparent.

Greetz,
Tibo

I'm dumb! brother I have 2 gfx in my project folder both are the same images only the format isnt the same. One is .bmp and the other is .png if I draw them both using draw_sprite the bmp is transparent but the png isnt transparent....
So its not my fault...

Here is the error code without WinAllegro.h and with allegro.h

1>d:\lib\allegro v4.2.2\include\allegro\internal\alconfig.h(397) : warning C4312: 'Typumwandlung': Konvertierung von 'unsigned int' in größeren Typ 'unsigned char *'
1>d:\lib\allegro v4.2.2\include\allegro\internal\alconfig.h(404) : warning C4312: 'Typumwandlung': Konvertierung von 'unsigned int' in größeren Typ 'unsigned char *'
1>d:\lib\allegro v4.2.2\include\allegro\inline\draw.inl(421) : warning C4312: 'Typumwandlung': Konvertierung von 'unsigned int' in größeren Typ 'unsigned char *'
1>d:\lib\allegro v4.2.2\include\allegro\inline\draw.inl(435) : warning C4312: 'Typumwandlung': Konvertierung von 'unsigned int' in größeren Typ 'unsigned char *'
1>d:\lib\allegro v4.2.2\include\allegro\inline\draw.inl(446) : warning C4312: 'Typumwandlung': Konvertierung von 'unsigned int' in größeren Typ 'unsigned short *'
1>d:\lib\allegro v4.2.2\include\allegro\inline\draw.inl(460) : warning C4312: 'Typumwandlung': Konvertierung von 'unsigned int' in größeren Typ 'unsigned short *'
1>d:\lib\allegro v4.2.2\include\allegro\inline\draw.inl(471) : warning C4312: 'Typumwandlung': Konvertierung von 'unsigned int' in größeren Typ 'unsigned short *'
1>d:\lib\allegro v4.2.2\include\allegro\inline\draw.inl(485) : warning C4312: 'Typumwandlung': Konvertierung von 'unsigned int' in größeren Typ 'unsigned short *'
1>d:\lib\allegro v4.2.2\include\allegro\inline\draw.inl(521) : warning C4312: 'Typumwandlung': Konvertierung von 'unsigned int' in größeren Typ 'unsigned int *'
1>d:\lib\allegro v4.2.2\include\allegro\inline\draw.inl(535) : warning C4312: 'Typumwandlung': Konvertierung von 'unsigned int' in größeren Typ 'unsigned int *'

have fun^^.

Konvertierung von 'unsigned int' in größeren Typ 'unsigned int * =
Convert from unsigned int in bigger type unsigned int*.

Thanks for help.

One way or the other, it is your fault, because both are Allegro BITMAPs after they've been loaded. At that time, the on-disk format is no longer relevant.
Attach both images so we can have a look at them.

I see no errors, just warnings.