Irrlicht Engine

... hi. here is my problem: as soon as a skybox texture tile is bigger than 512 px, the thin boundary lines of the skybox can clearly be seen. the problem applies only to OPENGL. it does not occur, if Directx is used. also, if the tile is reduced to 512 or smaller, the effect is gone.

by the way: mipmas are off... when creating the skybox and switched on again after creation (just like in the examples).

strangely enough: if the graphics card config is changed to: (antialias off) the box borders become invisible. otherwise they are visible. even more strange: if the SIrrlichtCreationParameters method is used instead of createDevice, and if param.Antialias is set to true, the borders are invisible again. So the solution seems to be: configure graphics card adapter to let the application decide (if antialias) and set param.Antialias to true.

well, I can live with that. but it would be nice if someone here had an explanation for that kind of strange skybox mapping behavior.

regards, eric GY

I'm not sure about those bugs I noticed it in irredit.

turn on mipmapping solves it I think.

in the future add it to the sourceforge tracker and these might get fixed.

thanks for the quick response.

I tried the simple skybox on a different graphics system, using NVIDIA instead of ATI to eliminate that it could be an OPENGL driver bug. It isn't. The skybox borders are visible, no matter if it is ATI or NVIDIA. Even more: the bigger the map tiles, the stronger the effect. A neat looking skybox cannot really be accomplished - to my experience - unless your tiles are at least 960x960. I usually use tiles 1280x1280 - and here the borders are visible in a way, that makes it almost impossible to use the Irrlicht skybox option. As I want my app to run OPENGL and DirectX, I switched to rendering my own cube and mapping it. In a way a solution, but I would have loved to use the addSkybox routine. Also I did find out that the visibility strongly depends on the angle of the camera. You can tell my moving, for instance, an FPS slowly around. Moving it to the left or right by only 0.01f makes the effect appear and disappear again. Has anyone else experienced these strange phenomena ?

Just use power-of-two sizes, i.e. 512 or 1024

Yes, indeed. Resizing the textures from 1280/960 to 1024 solved the problem . The skybox does no longer show the border lines and the textures still look pretty neat. Thanks a million.

ooops... no, it didn't. Putting anti-alias back to life and the borders are back to life as well, even with 1024 sizes. Only resizing the textures to 512 is a remedy - but that is completely out of the question for me. It looks kind of ugly. Sigh ... so it has definitely something to do with anti-aliasing and true/false.

I had this problem too and fixed it in irredit by selecting texture_clamp_clamp instead of texture_clamp_repeat