Hi all. I'm writing my first OpenGL 3d engine at the moment, and I have a question about rendering objects. A couple of years ago I coded a crappy 3d engine using Watcom C++, I remember that I needed to write some code that made sure that objects outside the viewingspace, wouldn't be rendered. This resulted in a nice fps improval. Can someone tell me if openGL does this for you, when you use it correctly (GLulookat, modelview matrices etc.)? Thank you for the help. [Edited by - cozzie on October 14, 2004 7:39:30 AM]

OpenGL Does its own Frustum Culling BUT, You can do it faster and more effecient since you dont have to pass 1 million polies down the pipeline.

Frustum Culling is Easy in concept!

Create Bounding Boxes for the entire world which in turn is subdivided into 8 more boxes and so on.

Then By simple culling the boxes you will be clipping the correct polies also.

Bottom Line:When Passing Small amounts of polies(100-400) you dont need to clip when talking 6000 like in a typical quake map it will realy speed up things!

NOTE:If you implement your octree properly the real speed up comes when you only check collision with a couple of polies instead of 6000 each frame!!

Regards Dawid,
go to gametutorials.com and check for frustum culling!

hi,
thanks for the answer, it sounds really clear to me.
Since I'm new on this forum, can you tell me where I can select on which forum (for example: OpenGL) I can post my topic.

Quote:

Original post by cozzie can you tell me where I can select on which forum (for example: OpenGL) I can post my topic.

OpenGL.org has math & algorithms forum specifically for that. This forum is also pretty good.

Check out the Frustum Culling tutorial at GameTutorials:

http://www.gametutorials.com/Tutorials/opengl/OpenGL_Pg5.htm
(scroll down)