I am trying to generate an ore deposit centred approximately on a specific location with an approximate size and ore values (in the central area of the deposit).

The game is a 2D tile game and id be looking for the deposits to be roughly areas from 20x20 up to 50x50. Each ore tile has its own quantity (say up to 5000, or some patch specific "quality") for more variation and smoother transitions, but I want most of the falloff from around the fields peak to 0 to be around the edge.

void generateOrePatch(World world, int x, int y, int size, int quantity) { ? }

The problem I am having is how to effectively generate these ore tiles without some obvious geometric shape.

For example I tried multiplying some noise (e.g. Simplex) with a linear weight from the edge to the centre of my desired deposit. But of course the result is that while I get some variation within the deposit, the circle itself is obvious.

[attachment=35170:ore-values-simplex.png]

Ideally id like to generate with a lot of variety things like this one I did manually.

[attachment=35171:ore-values-paint.png]

How about laying a few linear 'seams' with weighted vertices and then expanding out from those according to the weights?

Basically for each tile its ore content would be something like:

p = nearest point on nearest seam

d = distance to p

v = ore value of p (interpolated between seam vertices)

ore value for this tile = v/d^2

Just spitballing here.

I spent some time trying to implement this. Ran into a problem with borders between "seams" as you described it, which I partially solved by considering all lines (weighted sum), rather than just the nearest, but the lines still really stand out. Maybe I did fully understand.

[attachment=35243:gd-near.png]

[attachment=35242:gd-segments.png]

Using a sum of multiple lines instead to get a weight. But wondering how to hide the circle and line edge gradients.

[attachment=35244:gd-sum.png]

Still working on the perturb idea to see if I get anything good. But as I understand it, instead of doing something like "cellWeight = f(distanceToCenter(x,y)) * noise(x,y)" you are suggesting to do like "cellWeight = f(distanceToCenter(x + noise(x,y), y + noise(x,y))" where "f" is some simple function to map a weight to an ore value (including cutoffs for full-ore and no-ore cells).

scaled noise with a minimum cutfoff will give you what you want easily

I dont understand how you get the noise peak at a desired location? I did consider using just noise for the entire thing (instead of a specified x,y,size) but had issues avoiding lots of "low yield" patches (I somewhat worked around it by a fairly expensive second pass that eliminated any patches with less than a certain total, or less than a certain cell average) but then had even more trouble making it interact well with other map features (e.g. in a flat desert plenty of ore spawned, but in mountain, water, etc. areas many areas are blocked)