Texture smoothing override (and how to deal with it)

[code4240]

So I implemented the ole vertex tilemap example into my game project today, and ran into the dreaded "lines appearing between tiles" problem.

(click to show/hide)

I read about a billion threads on the topic and spent a good while wrangling with it, tossing std::floor all over the place, until I narrowed it down to one problem: the view size. When the view is the same size as the window, everything works perfectly. But when I change the size of the view (or the window) it goes to hell.
(btw I am using a letterboxing algorithm when the window is resized https://github.com/SFML/SFML/wiki/Source:-Letterbox-effect-using-a-view)

EDIT:
It turns out this was happening because texture smoothing was being forced, so texture.setSmooth(false) had no effect. I didn't notice because my tiles were solid color, but when drew shapes in them I realized the textures were blurry... so it looks like this is my real issue and I'll have to figure out the fix. I can fix it on my own computer but I can't go onto any user's computer to make them turn off smoothing override...

[fallahn]

A possible solution mentioned on the IRC channel (by Jonny I think) is to render an area of the map, unzoomed, using the working view, to a render texture. Then you can zoom in/out on the rendered area and draw it to the window using a sprite or a single quad via vertex array.

[code4240]

A possible solution mentioned on the IRC channel (by Jonny I think) is to render an area of the map, unzoomed, using the working view, to a render texture. Then you can zoom in/out on the rendered area and draw it to the window using a sprite or a single quad via vertex array.

That sounds like a good idea. After I send the program to some friends to see whether they get the error I'll investigate this. I'm still trying to figure out why it happens on some computers but not others...

EDIT: I had another friend with AMD run it and they similarly did not experience issues. Now I just need someone with nvidia that isn't me to run it.

[code4240]

Okay I had a friend with an nvidia gpu test it and they didn't see lines either. it seems to be a problem with my system specifically. I'll look into it when I get home but, does anyone have any clues as to what might be going on?

[code4240]

REVALATION:
When I call setSmooth(true) on the computers that didn't have the error, it creates the error.

I think the computer having the issues is overriding the smooth option in the driver settings and forcing it true, causing this error.

Is there anyway I can deal with this besides just telling the user they need to turn that off?