I have a grid of tiles each with coordinates such as (-3, 5) or (1, 540) I want to generate a unique seed for each tile but I haven't found a way to do such
You need some kind of "pairing function" - Wiki describes such functions for natural numbers while you need integers including negative ones.
You can enumerate all integer points at coordinate plane in spiral manner
^ OY
|
16 15 14 13 12
17 4 3 2 11
18 5 0 1 10 ==> OX
19 6 7 8 9
20 21 22 23 24
So, for example, point -2,-2 has index 20
To calculate such index from coordinates, you can use simple algorithm (details here)
if y * y >= x * x then begin
p := 4 * y * y - y - x;
if y < x then
p := p - 2 * (y - x)
end
else begin
p := 4 * x * x - y - x;
if y < x then
p := p + 2 *(y - x)
end;
You don't ask for reverse mapping, but it is definitely possible (layer number is (1 + floor(sqrt(p))) / 2 and so on)
To complete: Python function for reverse mapping
def ptoxy(p):
layer = (int(math.sqrt(p)) + 1) // 2 # integer division
topleft = 4*layer*layer
if p <= topleft:
if p <= topleft - 2 * layer:
return [layer, 3*layer + p - topleft]
else:
return [-layer + topleft - p, layer]
else:
if p >= topleft + 2 * layer:
return [p-topleft - 3*layer, -layer]
else:
return [-layer, layer-p + topleft]