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Understanding Rembrandt: Difference between revisions
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→Shadows at night time
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as far as I know it's doing shadows at night just as well. If you drive your ufo to a Rembrandt-defined light source, I think it will cast a shadow also at night. I don't think the shadow part is off just because the sun is down. | as far as I know it's doing shadows at night just as well. If you drive your ufo to a Rembrandt-defined light source, I think it will cast a shadow also at night. I don't think the shadow part is off just because the sun is down. | ||
Wrong, Rembrandt is not doing shadows at night time: | |||
https://gitorious.org/fg/flightgear/source/5ccc83566785c9b5b75e8d03579dbd1aa45d7237:src/Viewer/renderer.cxx#L938-939 | |||
The conceptual beauty of shadows in Rembrandt is that they're not faked, there's actually a physics computation going on where light in the scene reaches and where it doesn't. The downside is that unless there's a huge amount of filtering going on, that computation is suffering from numerical accuracy so much that it flickers all over the place. | The conceptual beauty of shadows in Rembrandt is that they're not faked, there's actually a physics computation going on where light in the scene reaches and where it doesn't. The downside is that unless there's a huge amount of filtering going on, that computation is suffering from numerical accuracy so much that it flickers all over the place. | ||
the thing about rembrandt & light sources is true, I remember seeing screen shots - but I cannot imagine that the amount of computations for a handful of airports light should be equal to have a "central" light source illuminating everything (aka the sun) ? | the thing about rembrandt & light sources is true, I remember seeing screen shots - but I cannot imagine that the amount of computations for a handful of airports light should be equal to have a "central" light source illuminating everything (aka the sun) ? | ||
I invit you to start FlightGear and enable the Rembrandt shadows and look at your framerate, | |||
then disable Rembrandt shadows and look again at your framerate. | |||
Conclusion: how many FPS costs the Rembrandt shadows ? | |||
(here the answer is 3~5 FPS, so Rembrandt shadows are not the "FPS killer" thing) | |||
Basically, it seems there's no "LOD for shadows" taking place, i.e. computations are heavy/complex despite having any light souces in your vicinity that could have an effect realistically. I would have expected that the corresponding shaders/effects specifically look for light source so that the computations kick in, but otherwise don't - unless, rembrandt is even doin moonlight shadow ? | Basically, it seems there's no "LOD for shadows" taking place, i.e. computations are heavy/complex despite having any light souces in your vicinity that could have an effect realistically. I would have expected that the corresponding shaders/effects specifically look for light source so that the computations kick in, but otherwise don't - unless, rembrandt is even doin moonlight shadow ? | ||
The shadow cascades are acting like "shadows LOD", | |||
you can tweak this setting at runtime and see how Rembrandt shadows are updated. | |||
After that you will conclude that "LOD for shadows" is implemented finally. | |||
== Zero Scenery Tests == | == Zero Scenery Tests == | ||