forums.ps2dev.org

[ragnarok2040]

I recently hacked in png/dat support for gskit, because I wanted a simple way to render alpha blended/transparent fonts. I couldn't get the spacing quite right as I had to multiply the gsFont->Additional values by 1.5 in the gskit_font_print_scaled function(). That's a ttf font converted with Bitmap Font Builder. It only takes up 6.61 kb's of space :D.

http://homebrew.thewaffleiron.net/ragnarok2040/snap006.PNG

If anyone wants it, I can fix up the code and supply a patch later.

Edit:
Nevermind, heh. I had some free time so I grabbed the latest version of gsKit and made a patch :D. I included all the #ifdef HAVE_LIBPNG #endif's as well.

http://homebrew.thewaffleiron.net/ragnarok2040/gsKit_pngdatfont.tar.gz

To use:
I added gsFont->Path_PNG and GSKIT_FTYPE_PNG_DAT so you pretty much just use them like normal bmp/dat files. I haven't tested rendering in persistent mode, just one shot.

[cosmito]

Thanks, it seems useful.

[Neovanglist]

Thanks a bunch!

This will go into SVN very soon, I'll review it all and make sure it's merged in SVN head.

Nice work :)
_________________
Regards,
Neovanglist

[ooPo]

I've added this patch the repository.

[ragnarok2040]

Nice, thanks :D.

Oh yeah, before I forget. I've been running into a NULL pointer exception error when compiling with the latest version of gsKit. I haven't been able to get printf() output from ps2link/ps2client or xlink, lately, so I'm not sure where it's occurring just that it's prior to anything being displayed on screen. It seems only to affect my v6 PS2 with a network adapter/hdd in it and not my v7 without a network adapter/hdd.

The list of functions I call prior to drawing something on screen in order (arguments clipped so it's more readable):

[Lukasz]

If you get an exception, try building with -g flag and using ee-addr2line to locate the problem in the source. I wrote a short tutorial on how to do so: http://lukasz.dk/programming/playstation-2/ps2link-debugging/
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Lukasz.dk

[ragnarok2040]

I tried using ps2client netdump, but all ps2link would do afterwards is stall at executing the elf file without any output from either side. I couldn't use -g on all the files, as this created a 5 megabyte elf file, and ps2link would stall while executing it. I did a bunch of builds with -g on the core emulator code and -g on the ps2 frontend code, logged the exception errors I was getting from the output on the screen, and plugged them into the ee-addr2line command after compiling a full compile with -g on every source file.

The results came back to pngrtran.c:0 in libpng every time, but the source file may not be accurate if gsKit passes a null pointer to a function residing within that file. I compiled without png support in gsKit, and the exception disappears. I tried compiling libpng with the -g flag, but ps2link kept stalling when executing the elf. I commented out all the gsKit_texture_png() function calls in my program, but the exception was still occurring even though no png relevant code was called.

I hope this information helps, heh.

[Lukasz]

I'd just add printfs to debug libpng, as it seems to be causing the exception and find the bug the that way.

Alternatively, you can use ee-objdump to disassemble the ELF and find the EPC address and see if you can locate the function where the exception occours, since ee-addr2line isn't working for you.
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Lukasz.dk

[ragnarok2040]

All the exceptions just take me to different labels like 1834dc:
001834d8 <$LC127>:
1834d8: 322d5347 andi t5,s1,0x5347
1834dc: 00333130 tge at,s3,0xc4

Depending on the way I compile, the offset is always a few bytes around there. Unfortunately, it doesn't look like it says much :/. I'm guessing that's at or near the operation that causes the exception, and addr2line traces it back further... I tried tracing it back manually, but my understanding of mips assembly is pretty much nil, heh.

[dlanor]

[ragnarok2040]

I think I found the problem. This time I cleaned my code, and rebuilt gskit the way it was, and setup everything as it was when it first occurred. The exception occurred again, then I just used a full + source intermixed objdump, then looked up the epc address, and saw that it was occurring during the switch() statement in fread, the second instruction listed in the disassembly under <fread>. This told me that fread was being passed a NULL pointer as the file stream, so I searched for all the fopen() functions in gsKit, since it returns a NULL pointer on fail. Adding a check to gsKit_texture_png() to see if File was NULL before doing anything else and returning -1 if it was, fixed the exceptions I was getting.

Lines 93, 276, 608, and 707 of gsTexture.c all use fopen(), but don't check if File is NULL prior to using the File pointer. I wasn't getting any exceptions after adding the check to gsKit_texture_png(), so I think the -g flag was making my program unstable for some reason.

I made a patch:
http://homebrew.thewaffleiron.net/ragnarok2040/gskit_fopen.tar.gz

It just adds "if (File == NULL)" statements after the fopen calls, print's an error message and returns -1 if the condition returns true.

[ooPo]

I've added this patch to the repository.