Hi,I am using OSG in a multi-wall stereo rendering environment. We have three walls, and we render both a left and right eye view for each wall. To do this, in my application I create six osg::Cameras and update their projection and view matrices each frame based on head-tracking. I add the same subgraph under each camera, and I get a seamless 3D scene across the three walls. So far so good.
My problem is with lighting. Although the 3D geometry is rendered in the right place, it isn't lit correctly. For example, sometimes the left view might be much brighter than the center view, which in turn is brighter than the right view. This has me confused because all six cameras are rendering the exact same scene, and the light is part of the scene (rather than a head-light of the viewer for example).
My scene graph is set up basically like this (just showing three rather than six cameras). The cameras all share the same child subgraph, and just render to viewports next to each other across a window.
root -- camera (mv & proj for left wall) --- model --- lightsource -- camera (mv & proj for center wall) --- model --- lightsource -- camera (mv & proj for right wall) --- model --- lightsourceI've attached a picture of the effect I'm getting. What I expected would be that the object (just a long red box) would be smoothly lit along its length. However, when it spans across my three views, you can see it's darker or lighter in each view, suggesting that the lightsource isn't in the same place within each rendering.
Am I putting my lightsource in the wrong place in the scene graph? I thought it should be a sibling to what you want lit? Even though the projection and view matrices are different for each camera, the lighting should be consistent, right?
I'm using a composite viewer, and each view I create I've set the lighting mode to NO_LIGHT, so I don't think it's a default light causing any trouble. The only light should be the one in my scene.
If you have any ideas why this is happening I would really appreciate hearing them! :-)
Thanks, Julian.
<<inline: lighting.jpg>>
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