Take Me To The River(s)

This is where I left off last time:

One problem with this map is that borders and rivers are obscured by the forest.  The solution is to draw the forest first and the borders and rivers last, but this turns out to be one of those impossible ordering situations.  I want the mountains after the rivers and borders, and the forests before the rivers and borders, but I also need the mountains after the forests.  (So that I can avoid the mountains when drawing the forests.)  That doesn't work: I can't draw the mountains first *and* last.  The solution in this sort of situation is to draw the mountain on a different layer.  Then I can draw the mountains first, but put its layer on top of the rest of the land so that it is displayed last.

This works, but doesn't look particularly good.  There's a weird refraction effect where the rivers cross the psuedo-3D forests, for one thing.  Looking at sample maps that use forest masses, most of them part the forests around the rivers.

So perhaps it is worthwhile to see if I can do that.  This is much like pushing the forest back from the coast -- but instead of staying a certain distance away from the sea, I stay a certain distance away from river locations.  The only pitfall here is that I don't want my forest edges to overlap -- which can happen if I set this distance too low.

You can see a couple of spots on this map near the ends of rivers where the forest edge is getting drawn back on itself.  As long as it's only small spots like that it looks fine.

Another thing you see quite often in maps with forest masses is some interior texture to indicate trees.  Sometimes this is just a simple repeated line, sometimes the same kind of bumpy line used to define the edge of the forest mass.

So let me see about adding that texture to my forest masses.

The basic shape used in these textures is just a bump.  Sometimes these bumps are peaky (left side of the examples above) and sometimes flatter (right side). These bumps can be fairly widely spaced (upper right) or packed tight (lower left).  So it looks like the basic functionality I need is to fill a forest mass with bumps, with a couple of parameters to control bumpiness and spread.  This is basically the same algorithm I use to place mountain symbols on the map, although this will be simpler.

Here's a first try:

Nailed it!  Although it may benefit from a *few* tweaks.

Okay, that's not too terrible.  The bumps are a little too regular in size and shape, though.  And the color of the bumps needs to be a darkened version of the forest mass color, not black.

You might notice here that I've also implemented some shadowing around the edges of the land to give the land a little 3-D quality.  This implementation is similar to the forest, but in this case I have to avoid this effect on small islands (e.g., in the upper left) or they are too dark.

For fun, I did a side-by-side comparison between my forests and one of my example maps:

The match isn't perfect (not that I'm trying to slavishly copy the sample) but I'm happy that this looks good even alongside a nicely hand-drawn map.