mesh with triangle adjacency in 3.0

[bishopnator]

This is a follow-up post from Development Talk (ogre 1.x) where the changes where accepted and merged in 1.x, but they were not added to 2.x (and 3.0). There in that thread I posted link to pull request for 2.3 and here I added link for 3.0 (there were some merge conflicts already when I tried to just take the changes from the mentioned pull request so I rather created new one).

Here is the link for 3.0 branch: https://github.com/OGRECave/ogre-next/pull/455
I based the changes on the https://github.com/OGRECave/ogre/pull/830 - please review it carefully as I didn't verify the changes - I just went file by file from the pull request targeted ogre 1.x and ported the changes which were possible to port so the OGRE is compiling.

[dark_sylinc]

Ahhh thanks for the reminder. I completely forgot.

I should be able to look at it this weekend, I hope.

[bishopnator]

I finally could also text the changes with my Hlms implementation and found still missing handling of the newly introduced OperationType values in both render systems. Now it seems to work correctly with both HLSL and GLSL geometry shaders. Let me know whether you think it is needed also in 2.3 branch, while the pull request for the ogre-next 2.3 I didn't update. If it is not needed, I will close the PR.

[dark_sylinc]

I'm not sure if I want to include it in 3.0 branch since it's very close to shipping.

But it definitely should not be included in 2.3; as it would break ABI & API. Even though we make no API/ABI guarantees before 3.0; we're trying to avoid unnecessary friction.

It will definitely go into master though (which will become 4.0)