Im the last weeks, I've been working on integrating Lauri's skydome scattering shader in a seamless way with the rest of the environment. I have now a working version of the shaders available which could be committed.
This is: * the original skydome shader, with an added simulation of a low altitude constant density haze layer and meaningful response to the parameters /rendering/scene/overcast, /rendering/scene/scattering and /rendering/scene/saturation. * a matching terrain shader which connects to the skydome in a (mostly) seamless way * this can render everything from rather heavy fog on the ground to a near space view at high altitude with (mostly) seamless transitions * some additional code getting the sunrise/sunset plausible by darkening the haze where needed. See http://www.flightgear.org/forums/viewtopic.php?f=47&t=11274&start=135#p140031 for some recent pictures * a small change in 3dclouds.frag to let clouds fade into a matching horizon haze color. All this is conceptually independent of Local Weather - while it is supported and the relevant parameters are automatically set by Local Weather, they can be set from anywhere else. Now, I need some help. First, the combined effect of lots of 3d clouds and haze shading isn't fast. It isn't really slow either, with multiple layers of 6/8 clouds drawn to 45 km distance I still get ~20 fps out (36 without the haze and skydome shader for the same clouds), but I have the feeling it could go faster, there's too much redundant things happening. For instance, I get my altitude in model space by vec4 ep = gl_ModelViewMatrixInverse * vec4(0.0,0.0,0.0,1.0); alt = ep.z; in the vertex shader - but this could probably easily be passed as a uniform if I just would know how (lat, lon, alt) maps into model space. And so on. So if anyone with more experience in shader writing can look over it and smooth it a bit, that'd be very good. There is a writeup of the underlying ideas available, and I have tried to comment a lot, and I can also explain the underlying math. The second thing is - I can't get it into a distributable form myself. I don't understand the structure of effect files. In my current implementation, I have just overwritten the Flightgear defaults, used some really ugly hack at one point and distributing that in this form means either using my skydome/terrain or CPU rendering. I don't want to commit it in such a form, this should be optionally linked to the scattering shader on/off. Also, I run into other problems - I've tried to use the haze shader instead of object default, but they're not blended to the same final color when fully fogged, they come out too dark, and I don't know why. I suspect that something happens to objects later that doesn't happen to terrain... So, I'd need the help of someone who understands the effect file structure to create a structure which can be committed without wrecking everything else. If anyone is willing to help with either problem, please let me know and then we can take the bulk of the technical discussion off list (where I can use attachments). I have a pretty good idea what the issues are and in what direction one should probably go to address them - I'm just a bit out of my depth doing it myself. Thanks in advance, * Thorsten ------------------------------------------------------------------------------ All the data continuously generated in your IT infrastructure contains a definitive record of customers, application performance, security threats, fraudulent activity and more. Splunk takes this data and makes sense of it. Business sense. IT sense. Common sense. http://p.sf.net/sfu/splunk-d2d-oct _______________________________________________ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
