terrain LOD problem with camera

zenoid · Post by **zenoid** » Mon Sep 12, 2005 6:38 am

quickly ; my app merge newton and irrlicht, got a vehicle on a terrain. All the scene is prepared before entering the rendering loop. 3 cameras are set up there ; cockpit cam, fps cam and a mayacam. Then the vehicle is created and the cockpit cam is attached to it. What I see is that there is a LOD problem using only the cockpit cam (can switch bethween cam at run time). It seems that the reference camera position for the LOD rendering stayed at the origin of the terrain(not the point of view) and if I move the vehicle far away, I sometime drive under the ground and the landscape is ugly(low lod). But the vehicle still collide coerently with the terrain. Don't know if it's clear there...

anyone noticed that ?
THX.

Spintz · Post by **Spintz** » Mon Sep 12, 2005 4:47 pm

not sure why that would happen. The camera that's used for culling in the terrain node is whatever is returned by smgr->getActiveCamera(). I'd look into that, and make sure the camera you're using is active, maybe there's a bug there.

Fred · Post by **Fred** » Mon Sep 12, 2005 6:12 pm

Sounds like you're using the wrong camera.

zenoid · Post by **zenoid** » Wed Sep 14, 2005 6:37 am

I've read my code again and did not find something wrong but anyway I'am not an experienced C++ coder.

To help you Spintz, my heightmap is scaled 400 times on both x&y axes. I've tried other cam class found and this furum and all show the same pb as soon as attach those one to the vehicle. (vehicle : parent node + 2 billboard for the cam pos and cam dir).

did you find anything ?

Spintz · Post by **Spintz** » Wed Sep 14, 2005 1:53 pm

I wasn't looking for anything. I was suggesting you look to make sure the proper camera is being used by the TerrainNode to do cullling.

I'll try and setup an example with multiple cameras and test that out.

puh · Post by **puh** » Wed Sep 14, 2005 7:08 pm

in file CTerrainSceneNode.cpp change line 232 from:
core::vector3df cameraPosition = SceneManager->getActiveCamera()->getPosition ( );
to
core::vector3df cameraPosition = SceneManager->getActiveCamera()->getAbsolutePosition ( );

The problem with your code is that you set your camera as child, and in that case getPosition() returns the offset from the parent not the position in global space... getAbsolutePosition will help IMHO.

Spintz · Post by **Spintz** » Wed Sep 14, 2005 8:27 pm

Nice puh, never noticed that one!

zenoid · Post by **zenoid** » Thu Sep 15, 2005 7:41 am

thx all for your help.

This forum is a very good help.