Real-scale planet terrain implementation
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Posted 29 December 2012 - 11:31 AM
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Posted 29 December 2012 - 01:10 PM
You might want to look into geo clip mapping. http://www.gamedev.net/topic/432126-geoclipmapping-paper/ It was designed and has been use for what you intend.
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Posted 30 December 2012 - 12:14 PM
Check out the project 'Infinity - The Quest for Earth'
here's their screenshots page: http://www.infinity-universe.com/Infinity/index.php?option=com_zoom&Itemid=90&catid=4&PageNo=1
A full procedural planet engine, where you can fly up to a planet, through its atmosphere, and to the landscape itself.. There are videos here:
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Posted 30 December 2012 - 06:47 PM
One of the problems with generating near-realistic detailed terrain for a water/land planet - the erosion patterns (air or water), the rivers/water drainage is a complex and high processing cyclic mutation of the base seed generated data. All those continuous features that are the cumulative result of interaction across a usually large area. You often have to calculate the whole (hard to do it ''in parts' because of use of intermediate data from outside the desired 'part'. If you suddenly need an adjactent 'part' to be generated it may turn out disjoint with the existing 'part' and you can get trapped in a non-deterministic series of 'patchings' to try to resolve the inconsistancies.
The ecosystems (including weather) are dependant on altitude/slopes/latitudes/proximity to water.
Take a look at a topo map of the earth to see the complex patterns (some river systems drain land areas of a significant percentatge of the surface)
Depending on how often you come and go from a 'planet' (or a set of them) you may want to build the resulting data and cache that to avoid the huge processing cost/delays.
Of course if that kind of detail level or need for cohesion in the extended patterns isnt needed, then generating the final terrain in 'parts' is possible (you just have to decide how much adjacent recursive stepped data is needed.to be 'good enough'.
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Posted 31 December 2012 - 02:34 AM
Eric Bruneton has done a lot of work on procedural water and land, I think he also has freely available code and publications for a procedural planet renderer, you might want to google that. At least his ocean demo really stuck in my head.
The slowsort algorithm is a perfect illustration of the multiply and surrender paradigm, which is perhaps the single most important paradigm in the development of reluctant algorithms. The basic multiply and surrender strategy consists in replacing the problem at hand by two or more subproblems, each slightly simpler than the original, and continue multiplying subproblems and subsubproblems recursively in this fashion as long as possible. At some point the subproblems will all become so simple that their solution can no longer be postponed, and we will have to surrender. Experience shows that, in most cases, by the time this point is reached the total work will be substantially higher than what could have been wasted by a more direct approach.
- Pessimal Algorithms and Simplexity Analysis
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Posted 31 December 2012 - 03:50 AM
regarding c#/xna: its possible, have a look at this:
it should give you a great overview of things that can be done.
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Posted 31 December 2012 - 07:51 AM