I'd bet the farm on this being the graphics driver.

And since you provided the version #, maybe I have a shot in addressing it.

(I've seen DarkPlaces users mention certain driver #s being bad several times. I didn't expect this kind of thing to enter my world of "classic Quake appearance engines" but if this driver # can cause the problem, maybe I can target it. Nvidia used to have the reputation of providing stability and ATI was the shoddy/incompatible vendor. I don't claim to know much about graphics card drivers but things I have read makes it sound like they traded places.) 

In the gl version, type gl_clear 1

Does this fix the sky issue?

[The r_oldwater 0 issue is separate deal, I have plan to fix.] 

Setting this through console unfortunately doesn't have any visible effect, sky on start map still looks like in post #533.

My driver settings in nvidia control panel:

Anisotropic Filtering: Application-controlled
Antialiasing - FXAA: Off
Antialiasing - Setting: Application-controlled
Antialiasiang - Gamma correction: On
Antialiasing Mode: Application-controlled
Antialiasing Transparency: Off
Refresh Rate: Application-controlled
CUDA-GPUs: All
DSR Factors: Off
DSR Smoothing: Off
Triple Buffering: Off
Energy Saving Mode: Adaptive
Max amount of prerendered frames: Use settings of 3D application
Shader cache: On
Texture Filtering: Anisotropic Pattern Optimization: Off
Texture Filtering - Negative LOD Bias: Allow
Texture Filtering Quality: High Quality
Texture Filtering - Trilinear Optimization: On
Threaded Optimization: Auto
SSAO: Off
Vertical Sync: Use settings of 3D application
Prerendered VR frames: 1

My monitor refresh rate is at 120 Hz, if that matters at all. 

Mark V Beta 3

r_oldwater 0 issue gone. Was trying to resize warp image buffer before valid screen width/height determined. 

Fix confirmed, works. ^^ Now all that's left to do is looking up to the sky!

Btw, before you release the final version, is there any chance to add a menu toggle between gl_nearest_mipmap_linear ("classic") and gl_linear_mipmap_linear ("smooth") texture filtering? Currently, you still need to put this into autoexec.cfg if you prefer the "pixel look". 

My pc is saying it's a virus. :D 

I just turned off the virus protection to download it. When I turned the virus protection on again the files were deleted.

Windows 8 doesn't like your program there Baker! 

I think that's rather an issue with your AV. :P I am using Panda Free AV on Win 8.1 here without issues. 

http://quakeone.com/proquake/interims/mark_v_20150410_without_dx8.zip

The DX8 version (but not the GL version and not the WinQuake version)) somehow triggers Microsoft (and only Microsoft's) malware detection as some old Trojan from 2006.

61 other virus scanners say the dx8 version is not malware.

Go figure ...

https://www.virustotal.com/en/url/b4f88f7ed8a4eac7b57dc4804229437d9a8a4de6dbd75e4b80ee6f853f399fcf/analysis/1428796006/ 

No silly virus warnings.

Looks like the skybox problem (drawing the sky in front of geometry) and the external mp3's not playing bugs are both still not fixed.

Also, had to start from a clean install as something in my config is crashing the program back to desktop... 

Water is working now with "r_oldwater 0". I still can't reproduce any problem with the sky. Also tried the config.cfg NightFright posted.

Here is my gl_info:
GL_VENDOR: NVIDIA Corporation
GL_RENDERER: GeForce GT 650M/PCIe/SSE2
GL_VERSION: 4.5.0 NVIDIA 347.52

We have the same driver version, so it could be a 6xx series card vs 7xx issue. 

external mp3s not playing ... please provide more information.

Note: Mark V doesn't support mp3s playing from inside a pak. 

@ericw I see the driver # is same as NightFright's --- so isn't the driver. Hmmm. GeForce 7 series. 

Reupdated contents of Beta 3 zip with a interpolation bug fixed for the WinQuake build. 

My guess is also that it must be something with the graphics card model. As I wrote above, these builds work fine on an older system with an nvidia card running on the same driver. I doubt it has anything to do with the OS. Also as a reminder: Mark V before 20141010 is still running fine with the Geforce 700 series. So whatever got changed in the meantime is something those cards apparently don't like. 

sorry, but mp3's don't play. They're not inside of a pak. I'm sure they used to work once upon a time. To be honest it has been broke in a lot of builds for me, I know I'm not the only person because I talked to Sock about it (it's one of the reasons he uses quakespasm over fitz)

I still use fitz regardless of this but it'd be nice to hear music again. 

map start;
r_shadows 1; wait; r_shadows 0

sky is now b0rked, despite switching r_shadows back to 0. 

You can't just switch it off...

You could try vid_reset though? 

in GL_DrawAliasShadow, change the arguments of the following functions to match the values given here:
eglStencilFunc(GL_EQUAL,0,~0);
eglClearStencil(0);

sky bug now fixed.

actually, that clearstencil call becomes redundant as 0 is the default anyway and nothing else changes it.
also, consider only clearing the stencil buffer once per frame for entity shadows, so that you don't get tripple-whammys with gibs etc.
using ~0 instead of 2 means that the shadows don't glitch until you have (typically) 256 overlaps, rather than merely 3. which is important if you're doing what I just recommended. 

Excellent, thanks Spike. 

I should have another revision sometime this evening. @fifth -- I'll see if I can reproduce that on a Windows 8 machine. 

Just for the record: I don't have issues with MP3 playback on Win 8.1. My issues are purely about graphics. Curious to see if next build will be fully usable for me. 

I have never updated them myself... for the record quakespasm uses .ogg files which work fine. 

I'm not sure why music isn't working for you, but I'll give the old college try to fix, and I have feeling it's gonna get solved.

Re: ogg and stuff

My understanding is that Quakespasm uses software rendering for MP3 music playback rendering.

It should be very reliable, but software rendering is slow and is quite a CPU hit. Mark V uses API that provide hardware acceleration.

An my opinion on music works like this: there is MP3 and nothing else and here's why:

1) The MP3 patents are expiring
2) Hardware API on every platform from Windwos to Mac to mobile platforms is optimized for MP3.
3) ogg is "free software" and I support free software, but the last decoding patent for MP3 expires in September 2015.

I think ogg was a great idea, but I don't think ogg has a rational use this in world in the year 2015.

Spirit and I used to have debates over video codecs and I favored free codecs while he supported the ones that worked well (H.264). Spirit won!

I see no place in this world for ogg.

/One opinion and I'm often wrong about these kinds of things. 

Oh, either I did not post a lot about how much I tried to prefer free video codecs or you forgot. I just gave up at some point. Maybe we talked after that. I can even spell Ptalarbvorm...

Ogg beats MP3 quality-wise. Opus would be even better. There should be nice libraries for all the Xiph stuff, including FLAC.