I've been having issues with rivers. Actually all out door scenery, but I'm at least just trying to come up with a basic terrain with water on it.
So, I want to come up with some procedural way to generate a river on my terrain. Just wiggling a 2D fractal line across the screen isn't going to cut it. I'd like for it to branch sometimes, maybe have two river sometimes (splitting the land mass into thirds), possibly even a circular deal with an island in the middle.
I've played with fractal terrain height maps and setting arbitrary water levels, but it's not really the look I want. Ultimately it all gets mapped to characters and all, but I still end up with bits of land where I don't want them and all.
Ideas? I've seen people talk about using automata to generate terrain, but I can't think how that would be done.
Is there even a procedural way to do this? I'm tempted to cheat and just use some kind of templates, but I know I'll never be happy doing it that way.
> I've been having issues with rivers. Actually all out door scenery, > but I'm at least just trying to come up with a basic terrain with > water on it.
> So, I want to come up with some procedural way to generate a river on > my terrain. Just wiggling a 2D fractal line across the screen isn't > going to cut it. I'd like for it to branch sometimes, maybe have two > river sometimes (splitting the land mass into thirds), possibly even a > circular deal with an island in the middle.
> I've played with fractal terrain height maps and setting arbitrary > water levels, but it's not really the look I want. Ultimately it all > gets mapped to characters and all, but I still end up with bits of > land where I don't want them and all.
> Ideas? I've seen people talk about using automata to generate > terrain, but I can't think how that would be done.
> Is there even a procedural way to do this? I'm tempted to cheat and > just use some kind of templates, but I know I'll never be happy doing > it that way.
Maybe my developer's article will be of some help: http://umbrarumregnum.110mb.com/art5.html You can modify it and use more than one starting point for the river. Since the endpoint is the same, the river will naturally join the main flow. Hope that helps somehow.
Many years ago, when I tried to create remake of 'Master of Magic' and was working on terrain generator, following algorithm worked pretty well:
random point inside continent was choosen as source, as well as random direction - general river flow direction. With each step in flow direction there is chance to turn or branch. Splitting chance is significally lower. If turn rolled, river change direction for 1-3 steps, than return direction to normal. If branch rolled - both childs shouldn't turn to each other side for several turns. There was several cells lookahead, so that when ocean is close enough intensive branching was forced. In my case every continent was surrounded by water, so 'end of algorithm' condition was - another water piece reached.
spag <spagtho...@gmail.com> writes: > I've been having issues with rivers. Actually all out door scenery, > but I'm at least just trying to come up with a basic terrain with > water on it.
> So, I want to come up with some procedural way to generate a river on > my terrain. Just wiggling a 2D fractal line across the screen isn't > going to cut it. I'd like for it to branch sometimes, maybe have two > river sometimes (splitting the land mass into thirds), possibly even a > circular deal with an island in the middle.
I don't think rivers generally branch (although I won't say it never happened). Mostly they do the opposite. How about starting several rivers heading toward roughly the same point, and joining them together when they meet?
On 22 Ago, 08:56, Paul Donnelly <paul-donne...@sbcglobal.net> wrote:
> I don't think rivers generally branch (although I won't say it never > happened). Mostly they do the opposite. How about starting several > rivers heading toward roughly the same point, and joining them > together when they meet?
Start them in the ocean and then branch them as they move uphill :)
> On 22 Ago, 08:56, Paul Donnelly <paul-donne...@sbcglobal.net> wrote:
> > I don't think rivers generally branch (although I won't say it never > > happened). Mostly they do the opposite. How about starting several > > rivers heading toward roughly the same point, and joining them > > together when they meet?
> Start them in the ocean and then branch them as they move uphill :)
> > On 22 Ago, 08:56, Paul Donnelly <paul-donne...@sbcglobal.net> wrote:
> > > I don't think rivers generally branch (although I won't say it never > > > happened). Mostly they do the opposite. How about starting several > > > rivers heading toward roughly the same point, and joining them > > > together when they meet?
> > Start them in the ocean and then branch them as they move uphill :)
> > Jotaf
> Rivers move uphill?
Of course not, but naive players will never notice!
On Thu, 21 Aug 2008 23:29:54 -0700 (PDT), dominikmarc...@gmail.com wrote:
>Maybe my developer's article will be of some help: >http://umbrarumregnum.110mb.com/art5.html >You can modify it and use more than one starting point for the river. >Since the endpoint is the same, the river will naturally join the main >flow. >Hope that helps somehow.
>Mingos.
I'll probably give something close to that a try. A* through a height map might work, I'll have to play around with it some. Might look better through noise like you talk about, but I don't have any current code for generating that. I tried doing some stuff with Perlin noise a while back, and could never get the combination of variables right so that it gave me the look I was going for.
<konstantin.stup...@gmail.com> wrote: >Many years ago, when I tried to create remake of 'Master of Magic' and >was working >on terrain generator, following algorithm worked pretty well:
>random point inside continent was choosen as source, >as well as random direction - general river flow direction. >With each step in flow direction there >is chance to turn or branch. >Splitting chance is significally lower. >If turn rolled, river change direction for 1-3 steps, >than return direction to normal. >If branch rolled - both childs shouldn't turn to each other side for >several turns. >There was several cells lookahead, so that when ocean is close >enough intensive branching was forced. >In my case every continent was surrounded by water, >so 'end of algorithm' condition was - another water piece reached.
This is kind of what I ended up with, at least picking the starting poing and wandering from there, but the way I did it doesn't look right to me.
Combining that with the path finding might though. Starting in the middle, and working to two (or more) edges from there.
That actually worked. I think my A* routine is a little shakey since I had to convert it over from a hexagon based RL I was playing with, but works reasonably well. I just get a little more hunting than I ever seemed to get with the hexes. Probably won't matter once I make the stream wider.
At first I was having a rough time getting the height map data to be meaningful enough to actually change the course since the values I was using were too large. I used your idea of multiplying the facing value (5 or 7 for diags) with a normalized map (0..1), and it follows the terrain pretty well.
I haven't gotten ambtious with splitting it or anything, but it looks pretty good for single streams. Thanks again.
Could you possibly add these articles to roguebasin? They're certainly interesting new ways of looking at old problems and it would be good to have them there. If its too much trouble, do we have your permission to upload them to roguebasin?
> On 22 Sie, 07:26, spag <spagtho...@gmail.com> wrote:
> > I've been having issues with rivers. Actually all out door scenery, > > but I'm at least just trying to come up with a basic terrain with > > water on it.
> > So, I want to come up with some procedural way to generate a river on > > my terrain. Just wiggling a 2D fractal line across the screen isn't > > going to cut it. I'd like for it to branch sometimes, maybe have two > > river sometimes (splitting the land mass into thirds), possibly even a > > circular deal with an island in the middle.
> > I've played with fractal terrain height maps and setting arbitrary > > water levels, but it's not really the look I want. Ultimately it all > > gets mapped to characters and all, but I still end up with bits of > > land where I don't want them and all.
> > Ideas? I've seen people talk about using automata to generate > > terrain, but I can't think how that would be done.
> > Is there even a procedural way to do this? I'm tempted to cheat and > > just use some kind of templates, but I know I'll never be happy doing > > it that way.
> Maybe my developer's article will be of some help:http://umbrarumregnum.110mb.com/art5.html > You can modify it and use more than one starting point for the river. > Since the endpoint is the same, the river will naturally join the main > flow. > Hope that helps somehow.
> Mingos.
Also, When you talk about 2D fractional brownian motion, is that just a random walk in 2D, or what is it exactly?
On Sun, 24 Aug 2008 01:56:07 -0700 (PDT), Malorzean
<malorz...@gmail.com> wrote: >Also, When you talk about 2D fractional brownian motion, is that just >a random walk in 2D, or what is it exactly?
>Thanks again, >Malorzean
The random walk in 2D of course wouldn't look right for a river, it just meanders all over the place. I've done 2D fractal lines before for a side profile of terrain, and while that simulates a more natural looking line, still wasn't doing it for me.
You can use brownian motion to create 2D height maps, which you can use to create cool 3D terrain models, planet surfaces, etc. Not a really in depth article, but a good starting point here:
Once you have a height map, letting the river "flow" using a shortest route algorithm between two points works pretty well. It's not going to be technically accurate, as it's possible that the shortest route could end up having to take the water up hill to make it happen, but it looks good.
I suppose to be technically accurate, you could do a two pass thing over the height map. Generate it first, get the path of the river, and then go through an lower the map along the path over the river below some threashold. I don't think it would matter much if converting it all to ascii, but I don't know, someone might want to make movement costs associated with moving through terrain like that cost more, and moving along the shores of a river would tend to cost the least because they are often flat.
> Could you possibly add these articles to roguebasin? They're certainly > interesting new ways of looking at old problems and it would be good > to have them there. If its too much trouble, do we have your > permission to upload them to roguebasin?
> Thanks > Malorzean
I can't recall whether I actually gave my permission on Roguebasin or not to wikify my articles... If not, I'll add myself to the permission list tonight. You can wikify my articles if you feel they're useful, of course, I have no problem with that.
When I speak of any kind of noise, be it Perlin noise or fBm, I mean the algorithms included in Jice's tcodlib, since they're exactly what I use. They're usually just 2d noises, not random walk, Brownian island generation nor anything similar.
On 24 ago, 10:56, Malorzean <malorz...@gmail.com> wrote:
> Also, When you talk about 2D fractional brownian motion, is that just > a random walk in 2D, or what is it exactly?
Like I said in the above post, noise, not random walk. I don't really know how it works, since the algorithm isn't mine. fBm, from what I understand, is a sum or interpolation of several Perlin noises with different zoom values or something like that. You'd need to ask Jice about how he implemented it and what information sources he used...
Gamedev.net has an article about rivers: http://www.gamedev.net/reference/programming/features/randomriver/ It is quite similar to what have been discussed here already, but features some code too. I remember that there was an other one too, that was more tile orientated, but I can't find right now.
On the topic of Perlin noise and fBm, wikipedia is always helpful: http://en.wikipedia.org/wiki/Perlin_noise (looka ta the images for example) The article has links you can follow further and google finds more. :)
On 27 août, 08:30, dominikmarc...@gmail.com wrote:
> On 24 ago, 10:56, Malorzean <malorz...@gmail.com> wrote:
> > Also, When you talk about 2D fractional brownian motion, is that just > > a random walk in 2D, or what is it exactly?
> Like I said in the above post, noise, not random walk. I don't really > know how it works, since the algorithm isn't mine. fBm, from what I > understand, is a sum or interpolation of several Perlin noises with > different zoom values or something like that. You'd need to ask Jice > about how he implemented it and what information sources he used...
> Mingos.
Indeed, libtcod's fbm is a fractal sum of 2D perlin noises. You take a perlin noise, it gives you big flat hills. You add a scaled down version, it results in smaller hills on top of the big hills. You repeat the process until the details are small enough. The number of steps is called octave.
On 27 ago, 10:02, aave <tapiovier...@gmail.com> wrote:
> Gamedev.net has an article about rivers:http://www.gamedev.net/reference/programming/features/randomriver/ > It is quite similar to what have been discussed here already, but > features some code too. I remember that there was an other one too, > that was more tile orientated, but I can't find right now.
> On the topic of Perlin noise and fBm, wikipedia is always helpful:http://en.wikipedia.org/wiki/Perlin_noise(looka ta the images for > example) > The article has links you can follow further and google finds more. :)
Thank you for the link, aave. This is exactly what I mean when talking about noises, either Perlin or fBm.
By the way, the idea about making rivers sprung to my mind after reading one of the pages the wiki links to: the one about creating a random universe, which uses the noise's absolute values as well :). It might be interesting to read even if one's not interested in creating rivers since it might be potentially useful for many things, not only in procedural random world generation.
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