/
distance.lua
120 lines (110 loc) · 1.86 KB
/
distance.lua
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planetoids.geometry = {}
local geo = planetoids.geometry
local abs = math.abs
local floor = math.floor
local hash_pos = minetest.hash_node_position
local function greatest(x,y,z)
if x>y then
if x>z then
return x
else
return z
end
else
if y>z then
return y
else
return z
end
end
end
geo.manhattan = {
_2d = function(a,b)
local x=abs(a.x-b.x)
local z=abs(a.z-b.z)
return x+z
end,
_3d = function(a,b)
local x=abs(a.x-b.x)
local y=abs(a.y-b.y)
local z=abs(a.z-b.z)
return x+y+z
end,
}
geo.chebyshev = {
_2d = function(a,b)
local x=abs(a.x-b.x)
local z=abs(a.z-b.z)
return greatest(x,0,z)
end,
_3d = function(a,b)
local x=abs(a.x-b.x)
local y=abs(a.y-b.y)
local z=abs(a.z-b.z)
return greatest(x,y,z)
end,
}
geo.euclidean = {
_2d = function(a,b)
local x=abs(a.x-b.x)
local z=abs(a.z-b.z)
return math.sqrt((x*x)+(z*z))
end,
_2d_fast = function(a,b)
local x=abs(a.x-b.x)
local z=abs(a.z-b.z)
return (x*x)+(z*z)
end,
_3d = function(a,b)
local x=abs(a.x-b.x)
local y=abs(a.y-b.y)
local z=abs(a.z-b.z)
return math.sqrt((x*x)+(y*y)+(z*z))
end,
_3d_fast = function(a,b)
local x=abs(a.x-b.x)
local y=abs(a.y-b.y)
local z=abs(a.z-b.z)
return (x*x)+(y*y)+(z*z)
end,
}
geo.oddprod = {
_2d = function(a,b)
local x=abs(a.x-b.x)
local z=abs(a.z-b.z)
if x <= 1 then
x=1
end
if z <= 1 then
z=1
end
return abs(x*z)
end,
_3d = function(a,b)
local x=abs(a.x-b.x)
local y=abs(a.y-b.y)
local z=abs(a.z-b.z)
if x <= 1 then
x=1
end
if y <= 1 then
y=1
end
if z <= 1 then
z=1
end
return abs(x*y*z)
end,
}
local get_distance_function = function (geometry, dimensions)
if geo[geometry] then
if dimensions == 3 then
return geo[geometry]._3d
else
return geo[geometry]._2d
end
else
return nil
end
end
planetoids.get_distance_function = get_distance_function