2

I'm working on a little GIS app using OSG, but i'm quite a newbie with it.

As the view is not changing a lot, i'm not struggling to keep a decent fps ratio.

I have to draw multiple layers on the same view. Layers may overlaps, but not always.

Right now, to be able to choose which layer is on top of the others, i'm using the PolygonOffet properties, but I don't like it.

Here is what I want to try : -put a clear node on my root to clear all the buffers -put a clear node on top of each layer node to clear only the depth buffer -find a way to force OSG to draw those layer in a specific order

So my question is : - Is it possible ? - How can I choose the rendering order of my layer's node ?

Krag
  • 79
  • 1
  • 9

1 Answers1

2

You can clear buffers with cameras. E.g. if your main camera draws everything and you want to only clear one buffer, you can add a second camera that does nothing than just having the same renderTargetImplementation, attach the DepthBuffer to it, having the GL_DEPTH_BUFFER_BIT clearMask and let it render after your main camera.

For cameras you can choose a rendering order via setRenderOrder and for nodes you can work with setRenderBin.

If you use the multiple camera solution, you have a multipass rendering though, that may get costly, since in your case you would probably draw each layer with it's own camera.

On a sidenote, what you want is to avoid z-fighting and there are several techniques to do so. Maybe with this keyword you can find an answer.

Tare
  • 482
  • 1
  • 9
  • 25