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Add vector helpers

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ShadowNinja authored and kwolekr committed Jul 7, 2013
1 parent d22baa8 commit ae8ff4b8e2da35265ebbbe7afe99ed29e61efa7d
Showing with 192 additions and 15 deletions.
  1. +17 −15 builtin/builtin.lua
  2. +10 −0 builtin/misc.lua
  3. +136 −0 builtin/vector.lua
  4. +29 −0 doc/lua_api.txt
@@ -11,18 +11,20 @@ math.randomseed(os.time())
os.setlocale("C", "numeric")

-- Load other files
dofile(minetest.get_modpath("__builtin").."/serialize.lua")
dofile(minetest.get_modpath("__builtin").."/misc_helpers.lua")
dofile(minetest.get_modpath("__builtin").."/item.lua")
dofile(minetest.get_modpath("__builtin").."/misc_register.lua")
dofile(minetest.get_modpath("__builtin").."/item_entity.lua")
dofile(minetest.get_modpath("__builtin").."/deprecated.lua")
dofile(minetest.get_modpath("__builtin").."/misc.lua")
dofile(minetest.get_modpath("__builtin").."/privileges.lua")
dofile(minetest.get_modpath("__builtin").."/auth.lua")
dofile(minetest.get_modpath("__builtin").."/chatcommands.lua")
dofile(minetest.get_modpath("__builtin").."/static_spawn.lua")
dofile(minetest.get_modpath("__builtin").."/detached_inventory.lua")
dofile(minetest.get_modpath("__builtin").."/falling.lua")
dofile(minetest.get_modpath("__builtin").."/features.lua")
dofile(minetest.get_modpath("__builtin").."/voxelarea.lua")
local modpath = minetest.get_modpath("__builtin")
dofile(modpath.."/serialize.lua")
dofile(modpath.."/misc_helpers.lua")
dofile(modpath.."/item.lua")
dofile(modpath.."/misc_register.lua")
dofile(modpath.."/item_entity.lua")
dofile(modpath.."/deprecated.lua")
dofile(modpath.."/misc.lua")
dofile(modpath.."/privileges.lua")
dofile(modpath.."/auth.lua")
dofile(modpath.."/chatcommands.lua")
dofile(modpath.."/static_spawn.lua")
dofile(modpath.."/detached_inventory.lua")
dofile(modpath.."/falling.lua")
dofile(modpath.."/features.lua")
dofile(modpath.."/voxelarea.lua")
dofile(modpath.."/vector.lua")
@@ -106,3 +106,13 @@ function minetest.formspec_escape(str)
return str
end

function math.hypot(x, y)
local t
x = math.abs(x)
y = math.abs(y)
t = math.min(x, y)
x = math.max(x, y)
t = t / x
return x * math.sqrt(1 + t * t)
end

@@ -0,0 +1,136 @@

vector = {}

function vector.new(a, b, c)
v = {x=0, y=0, z=0}
if type(a) == "table" then
v = {x=a.x, y=a.y, z=a.z}
elseif a and b and c then
v = {x=a, y=b, z=c}
end
setmetatable(v, {
__add = vector.add,
__sub = vector.subtract,
__mul = vector.multiply,
__div = vector.divide,
__umn = function(v) return vector.multiply(v, -1) end,
__len = vector.length,
__eq = vector.equals,
})
return v
end

function vector.equals(a, b)
return a.x == b.x and
a.y == b.y and
a.z == b.z
end

function vector.length(v)
return math.hypot(v.x, math.hypot(v.y, v.z))
end

function vector.normalize(v)
return vector.divide(v, vector.length(v))
end

function vector.round(v)
return {
x = math.floor(v.x + 0.5),
y = math.floor(v.y + 0.5),
z = math.floor(v.z + 0.5)
}
end

function vector.distance(a, b)
local x = a.x - b.x
local y = a.y - b.y
local z = a.z - b.z
return math.hypot(x, math.hypot(y, z))
end

function vector.direction(pos1, pos2)
local x_raw = pos2.x - pos1.x
local y_raw = pos2.y - pos1.y
local z_raw = pos2.z - pos1.z
local x_abs = math.abs(x_raw)
local y_abs = math.abs(y_raw)
local z_abs = math.abs(z_raw)
if x_abs >= y_abs and
x_abs >= z_abs then
y_raw = y_raw * (1 / x_abs)
z_raw = z_raw * (1 / x_abs)
x_raw = x_raw / x_abs
end
if y_abs >= x_abs and
y_abs >= z_abs then
x_raw = x_raw * (1 / y_abs)
z_raw = z_raw * (1 / y_abs)
y_raw = y_raw / y_abs
end
if z_abs >= y_abs and
z_abs >= x_abs then
x_raw = x_raw * (1 / z_abs)
y_raw = y_raw * (1 / z_abs)
z_raw = z_raw / z_abs
end
return {x=x_raw, y=y_raw, z=z_raw}
end


function vector.add(a, b)
if type(b) == "table" then
return vector.new(
a.x + b.x,
a.y + b.y,
a.z + b.z)
else
return vector.new(
a.x + b,
a.y + b,
a.z + b)
end
end

function vector.subtract(a, b)
if type(b) == "table" then
return vector.new(
a.x - b.x,
a.y - b.y,
a.z - b.z)
else
return vector.new(
a.x - b,
a.y - b,
a.z - b)
end
end

function vector.multiply(a, b)
if type(b) == "table" then
return vector.new(
a.x * b.x,
a.y * b.y,
a.z * b.z)
else
return vector.new(
a.x * b,
a.y * b,
a.z * b)
end
end

function vector.divide(a, b)
if type(b) == "table" then
return vector.new(
a.x / b.x,
a.y / b.y,
a.z / b.z)
else
return vector.new(
a.x / b,
a.y / b,
a.z / b)
end
end

@@ -988,12 +988,41 @@ Inventory location:
- "nodemeta:<X>,<Y>,<Z>": Any node metadata
- "detached:<name>": A detached inventory

Vector helpers
---------------
vector.new([x[, y, z]]) -> vector
^ x is a table or the x position.
vector.direction(p1, p2) -> vector
vector.distance(p1, p2) -> number
vector.length(v) -> number
vector.normalize(v) -> vector
vector.round(v) -> vector
vector.equal(v1, v2) -> bool
vector.add(v, x) -> vector
^ x can be annother vector or a number
vector.subtract(v, x) -> vector
vector.multiply(v, x) -> vector
vector.divide(v, x) -> vector

You can also use Lua operators on vectors.
For example:
v1 = vector.new()
v1 = v1 + 5
v2 = vector.new(v1)
v1 = v1 * v2
if v1 == v2 then
error("Math broke")
end

Helper functions
-----------------
dump2(obj, name="_", dumped={})
^ Return object serialized as a string, handles reference loops
dump(obj, dumped={})
^ Return object serialized as a string
math.hypot(x, y)
^ Get the hypotenuse of a triangle with legs x and y.
Usefull for distance calculation.
string:split(separator)
^ eg. string:split("a,b", ",") == {"a","b"}
string:trim()

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