Portal/skybox visual bug

[abbuw]

If you're looking down on the bottom half of a portal from the top half that has a visible sky, the bottom of the skybox clips in the portal's view. Using the latest version of GZDoom (g3.3pre-11-g4f5b459). Using integrated Intel HD5500 graphics, using the latest drivers. Example map.

---

[abbuw]

Another version of the map that's been altered a bit to show off the glitch more, and a video demonstrating the glitch.

[ZZYZX]

I had similar issue with my map. Looking at a skybox through a portal causes..kind of a "shadow" of one of the portal sectors to be drawn over the skybox, at 32k height or something similar. I don't have an example map, but have full map that has this reproducing reliably

edit: actually this stopped happening in recent GZDooms.

[abbuw]

Discovered the same glitch happens with reflective floors and ceilings, using the most recent GZDoom beta (gzdoom-x64-g3.4pre-46-g7bd281ddc). I forgot to include more information about my system in the OP, I'm using a laptop with an Intel i5-5200u, with an integrated Intel HD Graphics 5500 and the latest drivers.

Code: Select all

GL_VENDOR: Intel
GL_RENDERER: Intel(R) HD Graphics 5500
GL_VERSION: 4.4.0 - Build 20.19.15.4835 (Core profile)
GL_SHADING_LANGUAGE_VERSION: 4.40 - Build 20.19.15.4835

Another map here.

[Graf Zahl]

Right now I'm at a loss why this happens. I know precisely which element is not being rendered properly but I have no idea why.

[Graf Zahl]

Finally found it. This was some incorrect writes to the depth buffer that made parts of nested portals disappear.

[Rachael]

Oh wow, this one was in the game for YEARS. I thought it was unfixable.

[Graf Zahl]

This one had been in the game ever since portals could be nested - and yes, it was a very minor, very subtle oversight. It finally hit me when I changed the height of the cap polygon for some testing and the results were not what I would have expected. That gave me the needed clue to find the real cause.

[abbuw]

This one had been in the game ever since portals could be nested - and yes, it was a very minor, very subtle oversight. It finally hit me when I changed the height of the cap polygon for some testing and the results were not what I would have expected. That gave me the needed clue to find the real cause.

Woo! Thank you! This little glitch was the bane of my existence.