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Forum » SpaceEngine » Feedback and Suggestions » Seasonal Planet Textures (Simulating seasonal effects on planets in SpaceEngine)
Seasonal Planet Textures
curiousepicDate: Wednesday, 21.12.2011, 03:49 | Message # 1
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http://www.nasa.gov/mission_pages/fires/main/modis-10-overview.html

It would be glorious for planets in Space Engine to pulsate with such life, even in the absense of real life (at least the snow/ice cycle).





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SpaceEngineerDate: Wednesday, 21.12.2011, 10:23 | Message # 2
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That might be a bit hard to implement, however, I have some ideas.




 
HarbingerDawnDate: Tuesday, 04.09.2012, 06:57 | Message # 3
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I just realized myself how much SpaceEngine could benefit from seasonal planet textures. I was contemplating making another new Saturn texture for southern winter (I had already done one for equinox) when I thought about how inconvenient it is to switch such textures every season (not as much for Saturn of course wink ). Then I thought about a way that this might be implemented. It would be crude, but it seemed like it might be fairly easy to implement.

Similar to the way corona textures cycle now, with one smoothly fading into the next, something similar could be done with planet textures. Here's the idea I had in mind for how it could be called in the catalog files.

There would be a parameter called perhaps SeasonalDiffMap, with a value of true or false (if not specified, assumed to be false). Similar parameters could exist for CloudMap and BumpMap. Then there could be another parameter called SeasonalMapNumber which would specify how many textures would be cycled through (may not be necessary, I'm not sure), and would have an integer value greater than 1. Then there would be parameters to specify the textures to be used in the seasons, like DiffMap0, DiffMap1, DiffMap2 and so on. The same could be done for Bump and Cloud maps. The engine would cycle these textures at regular intervals until it came to the last map, at which point it would cycle back to the beginning.

There could also be parameters to specify the start and end dates and to specify whether the cycle should repeat (specifying a long time scale and non-repeating progression could be used to simulate terraforming in addons). Before the start date, the planet would use the earliest set of maps, and after the end date, it would use the last set. For cycling textures, a SeasonalEpoch parameter can be specified to set the date at which the cycle starts (it would cycle both before and after this date, however at this date the cycle would be exactly at its starting point). The times would be specified by the Julian date.

So a sample code for a terraforming Mars could look like this.

Code
SeasonalDiffMap true
SeasonalMapNumber 10

DiffMap0 "Mars.*"
DiffMap1 "MarsTF1.*"
DiffMap2 "MarsTF2.*"
DiffMap3 "MarsTF3.*"
DiffMap4 "MarsTF4.*"
DiffMap5 "MarsTF5.*"
DiffMap6 "MarsTF6.*"
DiffMap7 "MarsTF7.*"
DiffMap8 "MarsTF8.*"
DiffMap9 "MarsTF_final.*"

SeasonalMapStart 2451545
SeasonalMapEnd 3182030
SeasonalMapCycle false


And a code for Saturn might look like this:

Code
SeasonalDiffMap true
SeasonalMapNumber 4

DiffMap0 "SaturnNWinter.*"
DiffMap1 "SaturnEquinox.*"
DiffMap2 "SaturnSWinter.*"
DiffMap3 "SaturnEquinox.*"

SeasonalEpoch 2463334
SeasonalMapCycle true


If this process could be translated to procedural worlds, then it could be used to change sunspot patterns on stars as well.



I was about to create a new thread with a similar topic when I found this one. SpaceEngineer, is it okay if I rename it to "Seasonal Planet Textures" and move it to Feedback and Suggestions? It seems like it would be more appropriate there.





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Edited by HarbingerDawn - Tuesday, 04.09.2012, 07:01
 
SpaceEngineerDate: Tuesday, 04.09.2012, 09:13 | Message # 4
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Such a feature may be a bit overwhelming to the engine. At each time there should be 2 sets of textures in the VRAM to blend between them. The new set of textures should be loaded/generated every few frames, if user increases the timerate to see seasonal changes (well, this can't be a problem in multiplayer). This is like reloading the planet every few frames or seconds, the artifacts caused by the gradual increased level of detail from the new loaded textures will be noticeable. The landscape engine should be optimized greatly in generation/loading speed and memory consumption to use this approach.

Together with huge memory usage, there will be a huge disk space usage for catalog planets. For example, NASA have 12 full Earth color textures for every month. SE uses only the June (or July) texture, and it takes 3 Gb, so 12 textures will use 36 Gb.

Instead of this, I have ideas to implement procedural real-time recolouring of the planet at render time. The diffmap will have material ID instead of color, and color will be applied to it according to color table at render shader. This table will be changed over time. For example, green plant colors being changed to red, then to white (with specular in alpha), then back to green. This approach doesn't requires extra memory use and will eliminate transition artifacts.

Also, teraforming sequence should be separated from seasonal sequence, otherwise a terraformed Mars can't show seasonal effects.

Quote (HarbingerDawn)
I was about to create a new thread with a similar topic when I found this one. SpaceEngineer, is it okay if I rename it to "Seasonal Planet Textures" and move it to Feedback and Suggestions? It seems like it would be more appropriate there.

You're right, that will be good.

*





 
SnowfallDate: Tuesday, 25.11.2014, 01:31 | Message # 5
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I really like the idea of seasonal changes, it would be wonderful and make a lot of sense for planets and moons with highly elliptical orbits and tilts, worlds would feel a lot less static.
I have dreamed of something like this in Celestia for years now though nothing has come of it.
Even if the textures just switched and changed abruptly i would be happy at this point, though i can completely understand why smooth transitions would be nice.

Another thing to keep in mind during seasonal changes, is other factors like atmosphere pressure, albedo, colour and cloud coverage. for example: on an earth like planet with a highly elliptical orbit, the oceans would boil over into the atmosphere as it gets near to its star making it thicker, and then freeze as bright ice when it cools off farther from the star.

Though after all this i can see why it would be quite a challenge to add, i could never imagine programing it. the .SC files would have a lot more data to follow too, never mind all the math on how to calculate for procedurally generated planets.

Still fun to think about for now though. smile (sorry if this topic is old)





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FaceDeerDate: Tuesday, 25.11.2014, 06:00 | Message # 6
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A while back in another thread, I proposed using a stationary cloud heightfield with an opaque texture to simulate an ice cap that could be expanded and contracted smoothly with seasonal changes, exposing or hiding the terrain underneath. Using a second heightfield to add an "underside" to the ice cap would even allow it to float in an ocean such that the camera could navigate down under it. Perhaps that would be a useful approach for basic seasonality.
 
Forum » SpaceEngine » Feedback and Suggestions » Seasonal Planet Textures (Simulating seasonal effects on planets in SpaceEngine)
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