When I visited Bremen last year, I photographed many brickwalls because I wanted to make some textures for quake. I talked about it in the inpiration thread and khreathor showed interest.
Here's a dropbox link for some samples:
https://www.dropbox.com/s/1x338wm7glu9wpe/Bricks.zip?dl=0
I've still got a few others in store... 

I did one texture from DSC01759.JPG, because it was the worst "scenario", from what you have provided. I'm working on a tutorial, should be ready tomorrow.
Bricks
as WAD
in-game screenshot

I haven't fixed all flaws in this texture. Bricks are too wide and white mortar doesn't look good. From my experience bright colors don't work well in Quake.
But you'll be able to fix this. 

That one was the worst szenario because the shot is from an angle, am I right? Or was the colour the problem?
When this is 'finished' I should upload it to Quaddicted. 

Screenshot from the game: http://i.imgur.com/5EnM15i.png
The gray rectangle is a nodraw texture, you can see other parts of level through it. But it's a part of 1 brush which looks in the editor like this: http://i.imgur.com/4jL0oCS.png
How can quake make 1 face with two different textures, and how to fix it? 

That's actually just a good old-fashioned HOM ("hall of mirrors") glitch, which qbsp will occasionally shart out for no obvious reason.

The "fix" is to try rearranging your brushes in an attempt to make qbsp chop them up in a different way. 

Alternatively, turn the troubled brush it into a func_wall or some other entity. Of course, that might also lead to a leak if the brush is touching the void. 

Hey, if anybody knows where to look at existing map hacks, if those are documented?

In case of vanilla quake, I wish I could make triggers be active after certain events, like the area you once passed through but now it has triggers that activates certain things. 

Sorry I might have been too busy reading these, I guess Dormant triggers is what I'm looking for.
https://quakewiki.org/wiki/Map_based_hacks 

Point your face towards: https://tomeofpreach.wordpress.com/category/map-hacks/ 

There's also a thread on this board called "Teaching Old Progs.dat New Tricks." 

Thank you~

It seems like it has all the existing hacks? Is all working hacks going to get there, which are discussed on that thread "Teaching Old Progs.dat New Tricks"? don't know why but it seems to be pretty busy thread in overall. 

Logic gate triggers using spikeshooters are the classic way of having "triggered" triggers. I've used them several times with no problem. They do require extra entities and models to implement. 

And the idea of doing it with spikeshooters looks even more terrible when you can just use the neat solution linked in post #18192 

I had at least one version of a Radiant based editor that didn't get along well with the brush based info_notnull method, but other than that it has worked fine for me. 

Quake uses lightmaps, correct? Is it not possible to edit the luxel density? 

"_lightmap_scale" "n"
Forces all surfaces+submodels to use this specific lightmap scale. Removes "LMSHIFT" field.

I believe this is what you're looking for? its in tyrutils-ericw. 

requires engine support too.
and by that, I mean it only works with fteqw. 

It's only possible to control lightmaps globally, and even then only in one engine? 

Quake uses lightmaps, and the luxel scale is hardcoded at 1 lightmap sample per 16 texels.
Since you can control the texture scale in your map editor, this give control over the lightmap scale as a side effect of changing the texture scale, but you can't change them independently (in vanilla quake). Skacky's map jam5 map is an example using 128x128 textures and a texture scale of 0.5 (iirc), so it has double the normal lightmap resolution: https://www.quaddicted.com/reviews/func_mapjam5.html

The flag mukor mentioned, and some others in my light tool, are more or less FTEQW-only extensions 

Thanks, that makes sense. Do you have a Steam account? I have some more questions, don't want to pollute the thread with running dialog. 

Yep, I'm just "ericw" on steam. I wouldn't worry about posting here though, since other people may have the same questions too :)
(or http://celephais.net/board/view_thread.php?id=61211&start=701 if it's about tyrutils-ericw) 

I think I added you, found an ericw with negke on the friends list. 

How do you make noise gate or blocker in Quake1? 

Surrounding the monster...