Re: [Algorithms] 2D Side Terrain generation

[Andy F. <pad...@ob...>]

An alternative take to random/quasi-stochastic methods I'll mention
an exercise we did with my London undergraduates for a Lunar Lander
terrain.  The problem was to make the terrain controllable, in order to
insert plausible landing sites, (or IIRC "defender" well, you might
want to create volatile terrain to nicely hide ground based missle silos)

Rather than starting with a Perlin source and filtering as Megan suggests,
we found a great way was to Fourier construct with about 5 or 6 sine components.
By setting the frequency and amplitude coefficients the terrain could have
a useful "roughness" parameter, with local consistency, without unexpected 
dicontinuities (effectively band limiting the terrain within the frame 
resolution) and remain well bounded in height. Compared to a pink or
Perlin source and IIR filter it's swings and roundabouts in terms of cost.

- Andy


On Tue, 9 Aug 2011 07:49:44 -0600
Megan Fox <sha...@gm...> wrote:

> I'd also recommend Perlin - once you start mixing high or low passed
> low-frequency Perlin noise with high/low-passed high-frequency noise, you
> get some very, very interesting results.
> 
> The key, and what will define your continents and the feel of the resultant
> shape, is the number of layers of noise, and how you scale or cut (high/low
> pass) each layer.
> 
> Hugo Elias's page is an oldy, but it has some really great info on this
> topic: http://freespace.virgin.net/hugo.elias/models/m_clouds.htm - that
> page is the one that turned me on to how cool noise could be in the first
> place (my version of his cloud algorithm:
> http://www.youtube.com/watch?v=kHvJqPxXUXM).  I realize he's working in a
> slightly different space, but those basic techniques can be applied from a
> side view just as they can from a top-down view.
> 
> On Mon, Aug 8, 2011 at 11:34 PM, Marc Hernandez <ma...@gm...> wrote:
> 
> >  The big revelation for me was that I realized I could use fractals
> > as input functions to other fractals, as well as composing them from
> > adding or multiplying.
> >
> >  I tend to start with the standard perlin noise to define the major
> > continents, then use things like rigid multifractal to build mountains
> > into it.
> >  From there I use another perlin noise to add smaller hills and
> > valleys, and use yet another to define where to place all those.
> >
> >  Here's a 2d example of the output.
> > http://redmine.alephnought.com/projects/cubit/wiki/World#Pretty-pictures
> >  I didnt have a terrain renderer yet, so I dont know what the
> > landscape looked like, but I liked the start of it.
> >
> >  For something like you're mentioning, I think I might treat it as a
> > strip of a standard 2d heightmap.  That way you might get some neat
> > parallax as the ship flys through it.
> >
> > On Mon, Aug 8, 2011 at 8:39 PM, Brennan Rusnell
> > <bre...@gm...> wrote:
> > > I'd recommend using Ridged Multifractals:
> > >
> > https://www.internal.pandromeda.com/engineering/musgrave/unsecure/S01_Course_Notes.html
> > > http://www.ypoart.com/downloads/Musgrave.htm
> > > http://vterrain.org/Elevation/Artificial/
> > > This is a great book on the topic:
> > >
> > http://books.google.com/books/about/Texturing_modeling.html?id=bDlSJd8GfMcC
> > > Hope this helps.
> > > --
> > > Brennan Rusnell
> > >
> > > On Mon, Aug 8, 2011 at 7:22 PM, Joel B <one...@ea...> wrote:
> > >>
> > >> Hello, I'm looking for algorithms for generating 2d terrain from a side
> > >> view, like the old Defender game from the 80's, except with mountains
> > grass,
> > >> rocks, lakes etc instead of just lines.
> > >>
> > >> Here is an example of what I have done in Photoshop:
> > >>
> > >> http://img855.imageshack.us/img855/8125/examplelp.png
> > >>
> > >> Anyone on this list have some suggestions? It doesn't have to be real
> > >> time, although that would be interesting too.
> > >>
> > >>  - Joel
> > >>
> > >>
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> 
> 
> -- 
> Megan Fox
> http://www.glassbottomgames.com/


-- 
Andy Farnell <pad...@ob...>