Does anyone have an idea, how to create seamless portal effect (linked portal door)?
I have a raw idea, to do everything by hand, but it's very dirty

Anyway, I found a nice video demostraiting what I want to archive:
World Portals - What's the big deal?
And one thread from blender forums (with some little explanation, which is close to what I have in my mind):
Seamless transition between scenes


Any ideas are welcome! Best regards!

Edit: I found old posts made by Rackscha, he used to play with portals as I can see, and well as far as I see transition made the way I see it too, but he used shader to draw the portals if I got it correctly. And he used clipping shader, to cut off part of the model that went through the portal.

I once played around with it aswell.
If you're aiming for portals that can NOT be dynamically placed by the player like in Valve's 'Portal' it shouldn't be too hard (collision is going to be muuuch easier).

For it to work you basically have to render two scenes, one for the portal view and one from the player's perspective.

This is how I see it (transition):

So when I move player to the linked portal, I set his new position to the linked portal position, but with offset which is relative to the first portal (so it's like mirroring his position relative to the portals, cause they are the same).

BUT I have two problems in my head with all this...

FiRST - how do I transit other objects, I mean how to handle visual part? I need to duplicate them, so it looks like object actually passing through the portal. To do this, I need to cut the object which penetrates the portal, and the rest of it in the linked portal as well (part which still didn't go through the portal yet).

Take a look at this picture.

Sure, I won't need this for the player (as he won't see himself in the game mechanics that I'm thinking off), but for other objects I will need them, especially in situations when the portal let's say placed in the middle of the room, so it's backside is visible.

SECOND - is performance. I imagine this like: view for each portal, view that shows what linked portal currently sees (relative to it's position and angle). But this is going to be pretty slow I guess... What do you guys think??


Best regards!

http://stackoverflow.com/questions/13167192/portal-effect-in-opengl

clipping planes

Will this article about opengl help me, since acknex uses direcx?

Edit: also I found out that using same model for two portals will lead into a problem with setting different views on skin of the each model, cause it seems that the skin of the second portal automatically changes by the skin of the first one. Using 'ent_clone' or 'ent_clonesk in' did not help so far.

Edit2: actually it seems, that I used 'ent_cloneskin' wrongly It works now.

Edit3: Kartoffel, can you explain more? I got views showing what linked portal see, but I need to add 'scene from player's perspective' I guess.

I'm sure someone implemented it with 3dgs, then switched to Unity.

You can see that Rackscha got it working, here take a look at this video:
3D Gamestudio A8 Seamless Portal

I want to understand how it works but myself, but unfortunately I'm not that good as I expected. I can't get math part to work (adding player's perspective to the view angles/positions). I've read this old thread, and got angles working (thanks to Uhrwerk), but I can't get vector calculations.. the way they should work. And I can't pick right words to search internet for proper algorithm...

Best regards!

well , clipping planes aren't an opengl principle , thought you might start with research ,through questions from others with the same topic..

anyway directx has this https://msdn.microsoft.com/en-us/library/windows/desktop/bb174426(v=vs.85).aspx

but I am sure you need a shader , maby contact that guy .

Thank you for links man, yes I wrote him a PM.

My best regards!

i like portale style games , this method i tried to create it before but i stuck in views , i do all calculation for the mouvement exept the views i get problem in it .
i think the view need special shader

This is what i did before :


so the camera portal 1 it move and rotate a l aid of player view .

i ask Rackscha before about the method and this what he say :