Random pixelated fonts

[ghost]

After few changes in font rendering engine, some text looks worse than before in some resolutions.

Few examples:

[krzys-h]

Define 'some resolutions'. I don't seem to be able to reproduce this.

[ghost]

First two are default 800x600 windowed screen mode. The third screenshot is also default 800x600, but I maximized the window while I was in main menu before I started any level.

[krzys-h]

I tried the exact same resolutions and couldn't reproduce this. Maybe show your graphics settings?

[ghost]

Well, I tested with some graphic settings - it doesn't really depends on texture filtering, MSAA, etc. Experimenting with window size helps to fix readable of some words, but starting with default settings there's still some places that text is messed up.

[ghost]

It also have nothing to do with the game's UI language. I changed the language, restarted the game and still the "Missions" button is messed up in 800x600 window from very beginning.

I guess it's something wrong with refreshing text resolution in few places, because most of the text is looking good in any resolution.

[piotrdz]

@RaptorParkowsky: can you check if this issue occurred before my commit 8baccb0? It's possible that I broke something when optimizing texture generation in text rendering.

[krzys-h]

@piotrdz: He already said that this occurs since text rendering changes

[ghost]

@piotrdz Yeah, I can confirm that occured after your fixes. I also remember that "Missions" button in main menu even long before that commit was a little strange, but possibly this is more related to UI though.

This is how it was looking before on standard 800x600 window:

A little bit strange, but still readable. The new one that's in latest dev build is almost completely unreadable in standard 800x600 window.

[piotrdz]

@RaptorParkowsky: Just like @krzys-h , I can't reproduce it on my machine. I'll look over my code later and see what could be causing this.

[krzys-h]

I just got some similar text rendering artifacts after resizing window from 1280x1024 to 800x600 while having mission 1.3 loaded. Those are most visible on the black background of the debug stats, but if you look closely you can see them in other places too.

[piotrdz]

Please check if my last commit fixes this problem.If it still occurs, then it may be a problem with using GL_NEAREST or with float rounding of texture coords and I can prepare a separate branch for testing that.
In either case, I'm trying to fix this blindly because I haven't been able to reproduce the issue on my hardware.

[ghost]

Unfortunately after that fixes this pixelated fonts still occurs in the same locations.

Now I also found it also occurs here, in the ending splashscreen, if it would be helpful to know (it was also before yours totay fixes):

[krzys-h]

I managed to reproduce it again by randomly switching resolutions. @piotrdz, could you see if you can reproduce it like that?
It's still a lot less visible than for @RaptorParkowsky though, mostly as single pixels near the edge of the characters (in this case it looks to be the space character?).
Now that I think about it, my one might be a completly different issue, as it appears for all characters of given type on screen.

[krzys-h]

I've managed to "fix" my issue, but it's not the cleanest fix ever...

-        Math::Point texCoord1(static_cast<float>(tex.charPos.x) / FONT_TEXTURE_SIZE.x,
-                              static_cast<float>(tex.charPos.y) / FONT_TEXTURE_SIZE.y);
-        Math::Point texCoord2(static_cast<float>(tex.charPos.x + tex.tileSize.x) / FONT_TEXTURE_SIZE.x,
-                              static_cast<float>(tex.charPos.y + tex.tileSize.y) / FONT_TEXTURE_SIZE.y);
+        float dx = 0.5f/FONT_TEXTURE_SIZE.x;
+        float dy = 0.5f/FONT_TEXTURE_SIZE.y;
+        Math::Point texCoord1(static_cast<float>(tex.charPos.x) / FONT_TEXTURE_SIZE.x + dx,
+                              static_cast<float>(tex.charPos.y) / FONT_TEXTURE_SIZE.y + dy);
+        Math::Point texCoord2(static_cast<float>(tex.charPos.x + tex.tileSize.x) / FONT_TEXTURE_SIZE.x - dx,
+                              static_cast<float>(tex.charPos.y + tex.tileSize.y) / FONT_TEXTURE_SIZE.y - dy);

[piotrdz]

@krzys-h: well, with your fix I get pixelated text everywhere.
Instead, I think that my commit 4e331f1 will solve this as a kind of workaround. Now, only characters will be rendered, not characters and their surrounding tiles. There should be no overlap, unless the width of character falls exactly on power of 2 boundary, which is unlikely.

[ghost]

Well, that's true. After that fix it get even more pixelated bugs:

[krzys-h]

My fix didn't even get applied in the repo (and it does not cause pixelated text for me). @piotrdz's fix made no noticeable difference at all for me

[muzscaly]

I can confirm this bug (graphics engine: gl14 | res: 800x600)
But for me appears in another form...

[tomangelo2]

@Davivad: which OS do you have?

[muzscaly]

Windows 7 Home Premium x64

[MrSimbax]

Not sure if this is related, but guess what, odd font rendering happened for me too.

[piotrdz]

I've finally reproduced this issue by using software renderer. It should be fixed by 72f966b.

[MrSimbax]

It's better, but there are still little bugs.

edit:

In SatCom they are more noticeable, although on other font sizes there is less bugs.

[krzys-h]

I can't reproduce this issue anymore, although in my case there was never any text deforming, only characters from neighboring tiles being visible.

[piotrdz]

As I suspected, the root cause of the remaining rendering artifacts is floating-point rounding. I have a very ugly fix for this which I will commit once I clean it up a little bit.
However, to clean this up properly and avoid similar problems in the future means rewriting UI positioning and size calculations everywhere. I wonder if this is worth the effort if we are to move to CEGUI anyway.

[krzys-h]

After 71a77c7, the text looks a lot different than it used to. Additionally, underlines on links in SatCom are invisible.

Before:

After:

[piotrdz]

@krzys-h: I've fixed the display of highlights.

It's not surprising that the text looks different because now it is actually aligned to pixel boundaries, as it should be. Previously, it was almost always rendered at some uneven pixel position and blended onto the surrounding pixels which made it look a bit thicker than it would normally be.

[MrSimbax]

This issue no longer occurs for me.

[krzys-h]

Yup, everything seems to be fine now.