Disable Frustrum Culling Entirly

[paul424]

Hello, I wrote the culling code for my application. Now I don't need ogre3d culling anymore. How do I disable frustrum culling entirely ? The createSceneManager() MUST take some arguments which enables some form of culling. Either by type :

• ST_GENERIC - Generic scene manager (Octree if you load Plugin_OctreeSceneManager, DotScene if you load Plugin_DotSceneManager)
  ST_EXTERIOR_CLOSE - old Terrain Scene Manager
  ST_EXTERIOR_FAR - Nature scene manager (this mode is not present anymore in Ogre 1.0. Use "Terrain", or "Paging Landscape" instead)
  ST_EXTERIOR_REAL_FAR - Paging Scene Manager
  ST_INTERIOR - BSP scene manager

or by name :

• DefaultSceneManager
  OctreeSceneManager
  BspSceneManager
  PCZSceneManager

How do I get away with that ?

[dark_sylinc]

Use the DefaultSceneManager to avoid overhead.

However Ogre is still going to do some Camera vs Aabb culling. How it is coded in v1.x makes it almost impossible to disable. In v2.x the code was refactored, and though we don't support skipping frustum culling out of the box, it would be relatively easy to modify the source code to avoid culling (which shouldn't matter much anyway because it's now below 0.5ms for 64k objects on modern CPUs in Ogre 2.x).

But for Ogre 1.x there is no way I'm afraid.

[mkultra333]

I've been using Ogre since 1.6, currently on 1.10, and I was always fighting the culling system since I have my own custom lighting and shadowing system, and a custom zone-based culling system.

What I generally do is set a really huge bounding box for everything so that Ogre always thinks everything is in the frustum. For instance, on manually created meshes, I always do the following.

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m_pDynamicSpotMesh->_setBounds(AxisAlignedBox(-1000000,-1000000,-1000000,1000000,1000000,1000000));
m_pDynamicSpotMesh->_setBoundingSphereRadius(1000000);

For Ogre::Rectangle2D I always use

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miniScreen_VR_L->setBoundingBox(AxisAlignedBox(-100000.0*Vector3::UNIT_SCALE, 100000.0*Vector3::UNIT_SCALE)); 

I had a problem with manually created banks of general purpose triangles (used dynamically every frame for doing blood splats and such) culling, so when I initially create the triangle bank, I set the first 8 triangles to be at the far corners of a massive cube like this, where SPLAT_BANKDISTANCE is 32767 and all my action happens well within the bounds of the cube that creates.

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		for(nLoop=0 ; nLoop<MAXDYNAMICSPOT ; nLoop++)
		{
			// Ogre is incorrectly culling stuff after I modify the mesh, regardless of how I set the bounding boxes.
			// to get around this 8 of the triangles are set to the extreme corners of a massive bounding box.
			// the rest of the triangles are just put in a line off in the distance.
			switch(nLoop)
			{
				case 0: flXPosA= SPLAT_BANKDISTANCE ; flYPosA= SPLAT_BANKDISTANCE ; flZPosA= SPLAT_BANKDISTANCE ; break ;
				case 1: flXPosA=-SPLAT_BANKDISTANCE ; flYPosA= SPLAT_BANKDISTANCE ; flZPosA= SPLAT_BANKDISTANCE ; break ;
				case 2: flXPosA= SPLAT_BANKDISTANCE ; flYPosA=-SPLAT_BANKDISTANCE ; flZPosA= SPLAT_BANKDISTANCE ; break ;
				case 3: flXPosA=-SPLAT_BANKDISTANCE ; flYPosA=-SPLAT_BANKDISTANCE ; flZPosA= SPLAT_BANKDISTANCE ; break ;
				case 4: flXPosA= SPLAT_BANKDISTANCE ; flYPosA= SPLAT_BANKDISTANCE ; flZPosA=-SPLAT_BANKDISTANCE ; break ;
				case 5: flXPosA=-SPLAT_BANKDISTANCE ; flYPosA= SPLAT_BANKDISTANCE ; flZPosA=-SPLAT_BANKDISTANCE ; break ;
				case 6: flXPosA= SPLAT_BANKDISTANCE ; flYPosA=-SPLAT_BANKDISTANCE ; flZPosA=-SPLAT_BANKDISTANCE ; break ;
				case 7: flXPosA=-SPLAT_BANKDISTANCE ; flYPosA=-SPLAT_BANKDISTANCE ; flZPosA=-SPLAT_BANKDISTANCE ; break ;
				default: 
					//flXPosA=nXPos ; flYPosA=-SPLAT_BANKDISTANCE ; flZPosA=0 ;
					flXPosA=nXPos ; flYPosA=0 ; flZPosA=0 ;
			}

Note that this only had to be done on the initial creation, after that I was free to move any of the triangles anywhere and they still wouldn't be culled.

For entities, I do the following

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aabb.setExtents(-SPLAT_BANKDISTANCE, -SPLAT_BANKDISTANCE, -SPLAT_BANKDISTANCE, SPLAT_BANKDISTANCE, SPLAT_BANKDISTANCE, SPLAT_BANKDISTANCE) ;
m_pEntityInfo[nEntity].pEnt->getMesh()->_setBounds(aabb,false);

I have found the above tricks work for circumventing Ogre culling. But I did find it frustrating that there was no easy way just to turn it off.