A Minecraft mod which replaces vanilla portals with better ones. These better portals allow one to see the other side and pass through them without any pesky loading screens.

Video

Flat and arbitrarily shaped portals are supported as well:

And so are end portals:

(Side note: How tf do I make unordered lists in this mess of a markdown renderer?!)

Supported portals:

1. - Vanilla Nether and End portal
2. - Twilight Forest portal (as of BP 0.2, disabled by default in 0.1, BP 0.2.6+ supports TF 3.9+, BP 0.2.5 or below supports TF 3.8 or below)
3. - The Aether portal (as of BP 0.2)
4. - Mekanism Teleporter (as of BP 0.2, disabled by default as there are known issues for short distance (less than view-distance) teleportation within the same dimension which will require significant changes to BP to be resolved (#151), fixed and enabled by default as of BP 0.3)
5. - Travel Huts (as of BP 0.3)
6. - AbyssalCraft portals (as of BP 0.3.1)

Notes regarding compatibility:

1. - Cubic Chunks requires BP 0.2.2 or above and CC 970 or above (#20)
2. - Portal Gun requires BP 0.2.4 or above (mixed recursive rendering cannot be supported, see #69)
3. - Tails requires BP 0.2 or above (#77)
4. - Server-side JourneyMap requires journeymap-1.12.2-5.5.5b9 or above (#38)
5. - Twilight Forest requires TF 3.9 or above (BP prior to 0.2.6 required TF 3.8 or below)
6. - SereneSeasons must be at least 1.2.17, otherwise it will cause the world to repeatedly be re-loaded (SereneSeasons#153)
7. - SpongeForge requires BP 0.3.4 (BP 0.3.7 for plugin worlds) and a recent SpongeForge (1.12.2-2825-7.1.6 is too old, 1.12.2-2838-7.1.7-RC3910 should do), additionally enhanced third-party transfers are disabled when Sponge is installed (#338)
8. - Valkyrien Warfare is incompatible, likely fixed in VW 1.0 (#179)
9. - LittleTiles must be at least v1.5.0-pre159 (LittleTiles#237)
10. - Vivecraft requires BP 0.3.7, barely tested (I lack the necessary hardware), third-person/MR mode is not yet fully supported (it works fine but portal rendering is disabled), Optifine caveats apply (only default settings have been tested), Multiplayer is untested

Caveats when using Optifine:

1. - Fast Render must be disabled (and Minecraft might need to be restarted afterwards)
2. - It's either Shaders or see-through portals (It may be possible to fix this for shader packs which use the same shaders for both dimensions. For all other shader packs, substantial changes to OF would be required which won't be happening in the near future.) Note that portals may not render correctly if shaders have just been turned off, if that's the case, re-join the world.
3. - The Render Region feature must not be toggled while near a portal (to be safe, change it from the main menu, otherwise the game might crash). As of BP 0.3, toggling of the Render Region feature in-game should now be supported.
4. - Smooth World should be turned off because it will disable mobs' AI when they're far away, e.g. on the remote side of a portal (this is intended behavior and will probably not change, see #374)

1.14.x?

Eventually. Probably. I'm aware of the demand, please don't leave a comment for it. The plan atm is to get it fully working on 1.12.2 first. ~At this point (BP 0.2) a re-write of one large part (client-side seamless world transition) of the mod is in progress and I can think of at least two more parts (server-side portal visibility tracking and the Portal.Mutable API) that need to be re-written, so porting the mod now would just double that work.~ Done. I've begun with the 1.14.4 update in late August and might be done with it before 2020 with first usable alpha versions probably (at current pace, subject to change) late October / early November (also still blocked on Mixin 0.8 release).

DO NOT REPORT ISSUES ON CURSEFORGE, USE THE ISSUE TRACKER INSTEAD!