get rid of old quake2 tga.c (11 years old workaround), fix #158

[illwieckz]

11 years ago, @lnussel added a workaround based on quake2 source code to be able to load some tga files that GdkPixbuf were not able to load. So, 11 years later, it seems this workaround is not needed. This patch removes the quake2 tga code and enlighten a little the code.

This tga.c were used to load map screenshots from Quake3, RTCW, ET and Doom3 (See #158).

I've checked it against Q3, RTCW and Wolf:ET maps, it works well, I've not tested Doom3 maps yet, but there is no reason it could fail.

[zturtleman]

The brightness modification is probably because Q3 and RTCW use a gamma ramp with overbight bits to brighten the assets. The actual image file is darker than displayed in-game. Gamma ramps are broken in windowed mode on GNU/Linux using Xorg or whatever, so compare with fullscreen. ET does not use overbright. I don't know if Doom 3 does. (I have not tested this pull request.)

[illwieckz]

With the brightness modification, all screenshots from all games where too bright, without this brightness modification, all screenshots from all suppported games (including quake3) seem to look fine. I need to test RTCW more because screenshots have a dark athmosphere, whatever the brightness setting, so I do'nt know yet if it's dark because the map is dark or because the brightness is wrong. I hope to not need per game brightness.

[illwieckz]

OK, map shots of Quake3, RTCW, ET and Doom3 are ok with these patches.

They all look better without the brightness modification.

[illwieckz]

Well, why I can't merge that o.O

[zturtleman]

I think tmp = p[0] + brightness; etc should be tmp = ((int)p[0]) << 1; in renderMemToGtkPixmap to match Q3 gamma ramps. (I haven't tested it.)

If the levelshots look fine and managing per-game brightness correction seems excessive, I guess it's not really important.

[illwieckz]

Ah, I can test it

[illwieckz]

What to do with the brightness value ?

[zturtleman]

Ignore it or rename it to overBrightBits and set it to 1. tmp = ((int)p[0]) << overBrightBits;

[illwieckz]

OK. with your changes, RTCW map shots looks better, but some other shots (like padman ones) are too brighty.

[illwieckz]

Doom3 mapshots are very nice too.

[zturtleman]

World of Padman would need to use overBrightBits 0.

[illwieckz]

yep (clickable image):

[illwieckz]

@zturtleman: I've included your code because it looks very nice, but currently it is disabled because we need to add some per-game code. Currently the mapshots are displayed without brightness modification, which is the safest choice.

[illwieckz]

@zturtleman: do you think Quake4 mapshots needs brightness bump ?

[zturtleman]

Okay. Yeah, would also need to find out what the values for all games should be. Spearmint would need per-mod setting, not hugely important just mentioning it. I think RTCW should actually use overBrightBits 0. I don't own Quake 4 and it's closed source, so I can't check.

[illwieckz]

Quake4 maps with overBrightBits 1 looks very nice
WolfET needs overBrightBits 0

[zturtleman]

The code looks good. OpenArena, Q3 Rally, Voyager Elite Force, Reaction, and Smokin' Guns should use overbrightbits 1 too. This isn't a complete list, I didn't check all the games.