Don't know if this helps, but I noticed a similar problem when I have alpha func turned on or if I'm using a blend function. Also this will happen if you are using the transparent render bin. Are you using a texture rectangle or texture 2d? If you are using a texture rectangle, use GL_FLOAT_RGBA32_NV instead of GL_RGB32F_ARB. (this assumes you have an nvidia card) I found I get better performance using an osg::TextureRectangle on nvidia. And some of those weird problems go away too. If you can get away with half floats (GL_RGB16F_ARB for tex2d and GL_FLOAT_RGBA32_NV for texrect), you can always fall back to that and I'd bet your problem will go away. Dennis
________________________________ From: [EMAIL PROTECTED] on behalf of David Spilling Sent: Fri 3/2/2007 7:18 AM To: openscenegraph Subject: [osg-users] Plea for help / strange performance problems with RTTand RGB32F Hello All. I don't normally like posting this kind of plea for help, but I'm completely stuck. I am using OSG1.2, to do HDR RTT. I have a CameraNode (PRE_RENDER) with a RGB32F texture attached. Under this I have something simple - i.e. the OSG shiny cow. Alongside, I also have a NESTED_RENDER absolute projection camera, with a full-screen quad with the RTT texture on it. The quad has no tone-mapping shader at all. So far, pretty normal. Performance is fine and stable. However, if I add fog to the cow's stateset, performance gets much much worse; in fact, as you zoom in on the cow (i.e. as the cow occupies more of the texture) the frame rate gets lower and lower until it's effectively stopped. If I remove the RTT bits from the SG - i.e. detach the RGB32F texture, don't draw the quad - everything is fine. If the RTT texture is RGB8, everything is fine. This is all buried in a complex application; I haven't yet been able to duplicate this behaviour based on one of the examples, but I was hoping somebody might be able to tell me where to start looking. I have the following possibilites, in order of likelihood. I guess that it could be driver issues, or application memory management (e.g. not using ref_ptrs where I should have been, not clearing up, array bounds, that sort of thing), or the lack of a tone-mapping shader doing something funny on-card... I don't think it's worth me explaining any more, as its so app dependent, and consequently I'd quite understand if I got no replies at all. However, if anybody has seen this before, or has any ideas of where to start looking, or has any useful diagnostic tricks, I'd be grateful. Thanks, David
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