Shaders on GIT - some feedback

[Thorsten]

I've pulled the up-to-date GIT yesterday to investigate a cloud-drawing issue, and while I was on it, I found some time to experiment with the shaders.

Flightgear running under Linux, on my laptop powered with an NVIDIA GeForce 8600M GT GPU and an Intel Core 2 Duo T9300 with 2.5 GHz.

Local weather was usually on, so absolute framerates are probably less meaningful than relative framerate changes. The scenery was around Lake Tahoe.

Urban shader: I tested that on a higher quality vs. performance level the artefacts of urban terrain where much reduced. The impact on my framerate was almost none (I lost 2 fps with the higher quality shader) - so I am fine here. I have not encountered any condition so far in which the urban shader rendered my system useless.

Landmass shader: Here I have *massive* problems. With quality set below 3.5, this is what I get - a Martian landscape of some reddish black desert dust



If I switch the landmass effect off, I get yellow-green hills instead, likewise if I increase quality to 4.0. The weird thing is that using the landmass effect, my framerate is cut in half (in this particular situation and scenery, from 22 down to 10, I have observed 33 going down to 6 close to Las Vegas though) without any notable change in the visible scenery. About the only thing I did see with the landmass shader is that I can get snowcover if I set the snow line low enough - but the pricetag in framerate seems excessively heavy.

Transition effects: These work well for me, with a very modest impact on framerate, usually I lost between 3-4 fps. Somewhat funny - with landmass effects off, the transition effects still contain snow in 'their' terrain, but not anywhere else, which looks a bitt eerie... easily fixed. I know some people are not too happy with the 'artificial' landcover that is generated with these shaders, but as far as I am concerned, please make more for yet more terrain types!

In general, I find the menu a bit counter-intuitive - I wonder if it would be much bother to do the 'quality vs. performance' for each different type of effect rather than for all of them, because I might want to run the 'old' water shader from 2.0.0 but the new urban shader with less artifacts, and currently I have to buy either into a package, or I can switch one effect completely off.