centres of the odd numbered rows are offset in the x axis by the radius and in the y axis by .866 of the radius (or do i mean 2 * .866? i can't remember) (.866 is sin(60))

actually, that's wrong. i always do mine the other way around, points upwards and not to the side

anyway, the following will do it, but you'll need to change how you calculate hexcountx and hexcounty

1. ...
   
2.       for (int i = 0; i < hexcountx; i++){
3.         for (int j = 0; j < hexcounty; j++){
4.           if ((j % 2) == 0) {
5.             hexagon[i][j] = new Hexagon((3 * rad * i), (.866 * rad * j), rad);
6.           } else {
7.             hexagon[i][j] = new Hexagon(3 * rad * (i + .5), .866 * rad * j, rad);
8.           }
9.         }
10.       }
11. ...
    

(not sure you noticed, but i've changed my previous comment...)

not sure.

each column is 3 * radius apart, so there are width / (3 * radius) across

each line is .866 * radius apart, so there are height / (.866 * radius) down

but the offset for alternate rows may mean that you're missing half a hex at the start of some lines.

Oh cool good shout.

Below's a bit shorter example using toxiclibs:

Arggh, sorry, that must have been one of the more recent things I've added since the last release (there were dozens & i loose track of when features have been added). You can easily work around it for now by replacing the rotate() line with this one:

Ah, really sorry mister... classic versioning conflict scenario here. Rotating, scaling & translating polygons are only available in the codebase not yet released. But if you're still interested in getting this working it's a similarly easy fix as the rotate above. Translation in terms of vectors simply means addition. So here's the updated HexGrid, which now really should work: