by Graf Zahl » Tue Feb 05, 2019 9:05 am
This was caused by a oversight in ZDoom's original stacked sector code. When building the visplanes it checked all the texture properties of two sectors and if identical merged them. But what it forgot was to check if a sector even had a portal! Remember, this stuff way quickly slapped together and even more quickly abandoned when it became clear that it wasn't going to work out that well.
As a result any sector that lies completely within a portal sector but has no portal itself but the same plane properties would be automatically merged into the portal. The GL renderer has no concept of visplanes so wouldn't do such a thing. I had some hacky workaround for this in the renderer but had to ultimately disable it for compatibility issues. I had known of only one map needing this (KDIZD's Z1M1, which I fixed in the map before the release) so I didn't consider this a needed fix. But this map ran into the same issue so I had to bring back that hacky fix in a less problematic reincarnation.
This was caused by a oversight in ZDoom's original stacked sector code. When building the visplanes it checked all the texture properties of two sectors and if identical merged them. But what it forgot was to check if a sector even had a portal! Remember, this stuff way quickly slapped together and even more quickly abandoned when it became clear that it wasn't going to work out that well.
As a result any sector that lies completely within a portal sector but has no portal itself but the same plane properties would be automatically merged into the portal. The GL renderer has no concept of visplanes so wouldn't do such a thing. I had some hacky workaround for this in the renderer but had to ultimately disable it for compatibility issues. I had known of only one map needing this (KDIZD's Z1M1, which I fixed in the map before the release) so I didn't consider this a needed fix. But this map ran into the same issue so I had to bring back that hacky fix in a less problematic reincarnation.