View Full Version : How is culling done

11-26-2005, 06:43 AM
Hi Everybody,

I am using FlightGear 0.9.4 Simulation Software.

We are reading a data file which is in binary format(*.btg) and adding every object
in scene graph(Tree structure).
Now our scene graph contains all the objects which will be used further for culling
and rendering
Object contained in the scene graph are: modal branch, aircraft branch , terrain branch
and different lightening.

We are using frustum culling technique . In constuctor we are setting the frustum values

I have lot of doubts……..
1. How are we setting the frustums six plane and where (are we placing in the scene
2. How are we selecting part of the objects from scene graph and placing it in frustum
Which is being used for further culling and rendering.
3. A concept called extend sphere over sphere is used. I didn’t get the concept.

If any one knows about culling and rendering plz explain me in detail .

Plz explain me the concept of Bounding Box also


Zulfiqar Malik
11-26-2005, 08:41 AM
First of all do not post on multiple forums! Secondly post on the appopriate forum. Thirdly, there is probably infinite information available on these topics, and you don't exactly need Einstein's brain to have it on your desktop within minutes.
I probably would have answered your question had you not exhibited such blatant ignorance of forum ethics!!!

11-28-2005, 03:03 AM
I am new to the Flightgear 0.9.4 s/w.(just as a freshers)
What is wrong if i ask my queries.
Dont discourage new people those who are intersted technically to know details in this forum.pls do guide me if u can do.

Zulfiqar Malik
11-28-2005, 03:47 AM
There is nothing wrong in asking questions. Its just who you direct it to!
Anyway, coming back to your question, its not related to OpenGL! I would suggest the following to you.
1. Maths refresher. Nothing fancy, just matrices, vectors and planes.
2. Use GOOGLE. Its your friend. You probably wasted a good 3 days waiting for a reply on this forum whereas you could have gotten much information within minutes, using google.
3. A thorough reading of OpenGL Programming Guide (freely available).
4. Read some scene graph docs. (again, use google).
and if you still don't get your answers ...
STUDY FlightGear 0.9.4 documentation or visit its forums!
But lets end this discussion here. I am sure i have done enough violation of forum rules already!