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View Full Version : games where you're inside a cube...



MarsuGL
07-15-2001, 11:31 AM
hello, i have noticied few games like
serious sam or some unreal T levels where if you look the sky, you see the edges of a cube.

can you explain what is it and what is the utility of this.
maybe it has a name http://www.opengl.org/discussion_boards/ubb/smile.gif

Marsu

DFrey
07-15-2001, 11:45 AM
That's a poorly made skybox.

zed
07-15-2001, 12:54 PM
use 'terragen' to generate skyboxes for natural outdoor scenes

mcbastian
07-16-2001, 02:48 AM
Is there a tutorial out there, how to make skyboxes with terragen and use them in gl?

(ok, use them in gl shouldn't be the problem. draw 6 planes (cube http://www.opengl.org/discussion_boards/ubb/wink.gif ), put texture on it http://www.opengl.org/discussion_boards/ubb/smile.gif )

the problem would be: how to get the 6 textures (top,bottom,left,right,front,back) out of terragen so that you wouldn't really ses any edges of the cube......

thanks 4 help!

Bastian

DFrey
07-16-2001, 03:12 AM
I'd be interested in that too. The only similar thing I've seen along those lines, is instructions on how to use Bryce to make skyboxes. Or maybe terragen defaults to a 90 degree FOV. I couldn't find any way to specify or change it in the terragen demo. If it does default to 90 degrees, it should be trivial to make the skybox. Just generate the terrain, then make 6 pictures (one for each direction). In Bryce you do that as well, but because of a bug you have to specify some crazy number (I think 112 or something like that) to get the 90 degree FOV. I know a while back there was a thread on the topic that gave precise instructions on how to use Bryce.

DFrey
07-16-2001, 03:26 AM
Ask Google (http://google.com) and ye shall receive.
http://holodeck.st.usm.edu/vrcomputing/vrc_cs/tutorials/skybox.shtml

RedZen
07-16-2001, 03:53 AM
Well the best way is to create a dome, and then flat parts for the side. Dome for the top http://www.opengl.org/discussion_boards/ubb/smile.gif You obviously want movins clouds and stuff so you don't physically apply textures to the dome http://www.opengl.org/discussion_boards/ubb/smile.gif You creat layers and apply the sky textures to those. The distant stuff (flat parts) you just apply a normal texture you, as easy as that. http://www.opengl.org/discussion_boards/ubb/smile.gif

DFrey
07-16-2001, 04:13 AM
Yep, making the skybox itself is trivial. Getting proper textures for the skybox involves some additional work. That's what Terragen and Bryce can be used for (if the skybox is a cube).

RedZen
07-16-2001, 04:27 AM
Yeah sure thing. But for the sky itself. To for instance get the clous or something going. I reckon the best is to have three or so layers of textures, that's blended except for the upper most one. If you keep the top layer static, and you move the following two in opposite directions then you get a really cool effect. Or if you move them in the same direction but at different speeds. I saw that volumetric cloud thing on the homepage which looked pretty cool. I'm assuming it works the same as volumetric fog.

Tim Stirling
07-16-2001, 11:45 PM
Centre the camera and then rotate the camera to one of the 6 directions all at 90 degrees(front, left, top etc.) and adjust the zoom until it is exactly focuses on the whole of the edge of the map (if you are looking forewards, make sure each side of the FOV goes through the top left and top right of the heightmap respectively).

Do a test render at low quality and low res to test before you waste hours of rendering time. Then put the quality up to max and use the highest resolution, once rendered reduce the size to about 512*512, touch up a bit, maybe a very slight blue and then you are done.

[This message has been edited by Tim Stirling (edited 07-17-2001).]