It's def an improvement over the trunk generator but I still don't like how it behaves. Yes it may work great on realistic height maps with mountains but on relatively flat land or more varied terrain that the normal terrain generator
Normal terrain generator means tgp. IMHO, tgp does not generate a realistic landscape. It generates a lot of basins (that's were the lakes are located lateron). It mostly fails to generate longer valleys.
So, yes, the river generator relies on a senseful, realistic terrain as input (given that you want realistic rivers). And this, in the current OpenTTD world, to some degree means: Real world heightmap.
creates it just makes stupid things. Too many rivers in the same place,
Increase the flow needed for creating a river. Then you'll get less of them.
too many lakes without outflows
Set the flow consumed per lake tile volume to zero. Then every lake (except maybe for height zero cases, and maps without ocean) will get an outflow.
(the map edge should be considered an outflow if there's no ocean.
Hm, rivers disappearing at the map edge are implemented.
And the city placement... I dunno. I've had it often that I had only acouple of large lakes on the map and nearly ALL cities were places right next to them, sometimes only 1 tile apart.
there should still be a minimum distance between cities or something.
Then you can decrease the weight of the lake city placer. The weights in the detail config indicate, how often which strategy is used.
Obviously, this means some kind of fine-tuning those weights, but this is the price of being able to control where cities and towns are placed, without having to decide on each location oneself.
in general I think it's not right to let the rivers look for outflows.. to some degree the rivers should terraform their way across the map.
This, to be honest, is not the concept of this generator. What you want is river & landscape generation in one.
And, this would damage any heightmap. As I have said some time ago, if I feed it with a heightmap, I expect it to preserve the landscape at least on the large scale.
Also old river arms should dry out if a loop connects up. Rivers with loops in them look stupid too.
Well, at least islands in rivers are realistic.
Also I think the game generates WAY too many lakes to begin with. If you look at the average map and look at towns vs lakes in terms of quantity it's insane how many large lakes there are. I mean look at a normal country.. how many large lakes do they have? Germany has about one large one. That's it.
Depends on which size you require to accept it as lake. But, more important, this is a consequence of the lake basins tgp generates.
What you can do about it is setting the probability for reducing a lake to a high value.
Just some ideas on where to guide this thing.
To be honest, it will not change in the large scale. It is finished except for maybe some fine-tuning and bugfixing.
Rain based is ok but rivers in real life don't just flow down a concrete terrain. They carve themselves into terrain and keep going. The rivers in this should try to do the same. They should carve their way towards other rivers or the map edge.
What you would like is something like an erosion module for OpenTTD. I mean, if they would just carve their way, as you say, you would get a lot of canyons. To do this in a realistic way, you would need to simulate things like glacier movements, different geological conditions, and so on.
Can maybe be done to some extent, but not by me.
In fact, my opinion is that earth presents you so much landscape you can use for heightmaps, that there is no point in spending a lot of time in trying to generate it oneself.
I recently created something like this myself by hand just as an example. See attachment.
If you in particular like the straight lines (I tried to get rid of them), then you can set the number of flow modifications per 1000 tiles to a low value.