Attached is yet another 3D clouds patch, to fix the following:
1) The 3D clouds were not modified by the cloud coverage, due to some problems with osg::Switch
2) METAR changes to cloud coverage were not obeyed.
3) Making changes via the Cloud dialog had no effect unless 3D clouds were toggled.
4) Cloud cover was too sparse.
5) 3D Stratus clouds caused performance issues on some hardware (fixed by removing 3D stratus from cloudlayers.xml - it will now be a 2D layer).
- Removes the cloud type re-use code - I think they aren't worth the graphical artefacts that they cause in light of Tim's improvements
- Changes the transparency of the clouds. Previously, the clouds were transparent at 0m distance, opaque at 200m, then gradually more transparent to the fog limits. This meant they were generally quite transparent. Now, they are opaque from 200m to 15km, then become transparent at 20km. A side effect of this is that the current textures could probably benefit from being made slightly transparent to improve the blending of the sprites against each other.
- Replaces simple shader attributes with vectors (this was missed out of the last patch by mistake)
- Includes Yon's Fog update code (Thanks!)
- Fixes a bug since 1.0 where --enable-real-weather-fetch stopped the other weather scenarios from working.
This provides the following enhancements & bug fixes
- Fix the chequer-board bug.
- Add proper cloud coverage function - so scattered clouds are now truly scattered.
- Add real-time control for visibility range.
- Use a limited set of clouds rather than generating a completely new Geode for each cloud. This saves sorting and display time.
- Add controls to Rendering dialog to allow fine-tuning of the number of sprites, cloud visibility and the number of different types of cloud.
- Add some variance to the sort back-off to avoid all clouds being sorted at the same time.
- Pack attributes into vectors for performance
- Re-order the cloud type determination code so that if a cloud layer could either be stratus or cumulus, cumulus is used.
- Lowered the cloud level in the standard cloud configuration slightly so a cumulus layer is generated rather than stratus.
These last two mean that you should see some 3D cumuli if disabling real weather fetch.
My thanks to Yon Uriarte for his help with performance work.
Attached is another clouds patch. This does the following:
1) Puts the 3D clouds in a cloud rendering bin, to reduce the transparent edge problem. Viewing 3d clouds against a 2D layer _above_ it now blends correctly. There is still a problem when viewing a layer below the 3d clouds, and I'm not sure if/how I'll manage to solve that. Thanks to Tim for pointing me at the correct code (again).
2) Performance improvement by calculating the Bounding box when the cloud is generated rather than ever time it is requested.
> Something has changed in the environment manager which means that clouds
> generateion is now inconsistent. I'm still tracking it down, as my recent
> changes shouldn't have affected this.
Well, the cause was a bug in my code, but it didn't expose itself until we moved
to multiple cameras. The attached patch fixes the problem.
I've also put in a new heuristic to improve the frame-rate. Clouds that are already sorted
are likely to still be sorted in subsequent frames. Therefore I've put in a back-off
mechanism for the bubble-sort pass. This should mean that if you stay completely
stationary, once the clouds become sorted they will eventually only perform a
bubble sort pass every 128 frames.
> Warning: detected OpenGL error 'valeur non valide' after RenderBin::draw(,)
Fixed in the patch below. For some reason the shader didn't like index 16 being used...
The patch also fixes the chequer-board effect that was causing very sparse cloud cover.
Attached is a small patch for 3D clouds.
It provide the following:
1) Proper spherical distribution of sprites (previously they were distributed cylindrically - whoops)
2) Better shading, so the bottom of the cloud is darker than the top.
3) Fixed a couple of texture sizing bugs.
Attached is a small fix for the sorting in CloudShaderGeometry.cxx.
I think the sorting problem stems from the osg idiosyncracy
to store transposed matrices...so the intuitive
osg::Vec4f p = vm * osg::Vec4f(_cloudsprites[i]->position.osg(), 1.0f);
needs to be replaced with...
osg::Vec4f p = vm.preMult(osg::Vec4f(_cloudsprites[i]->position.osg(), 1.0f);
The patch also optimizes the distance calculation - it evaluates the distances
in model space instead of eye space, which reduces computation to a dot-
product instead of a matrix multiplication.
It fixes the following issues (to a greater or lesser extent):
1) Performance. Quad trees used to improve culling, and the sprites are placed on the surface of a sphere rather than
randomly throughout the cloud, requiring fewer textures. This saves about 5-10fps on my machine.
2) Disabled 3D clouds have no performance impact. Previously they were still in the scenegraph. Now they are removed.
3) Clouds are now loaded on start-up, and don't require the scenario to be changed, they also work with METAR.
4) The cloud field is shifted as you travel. There's a small bug in that the clouds "jump" as you reach the edge of the field.
5) Iterative sorting of sprites. This doesn't appear to solve the alpha blending problem completely, but may help a bit.
