Vector class for my tutorial on Lua metatables.
Vector = {} | |
Vector.__index = Vector | |
function Vector.__add(a, b) | |
if type(a) == "number" then | |
return Vector.new(b.x + a, b.y + a) | |
elseif type(b) == "number" then | |
return Vector.new(a.x + b, a.y + b) | |
else | |
return Vector.new(a.x + b.x, a.y + b.y) | |
end | |
end | |
function Vector.__sub(a, b) | |
if type(a) == "number" then | |
return Vector.new(b.x - a, b.y - a) | |
elseif type(b) == "number" then | |
return Vector.new(a.x - b, a.y - b) | |
else | |
return Vector.new(a.x - b.x, a.y - b.y) | |
end | |
end | |
function Vector.__mul(a, b) | |
if type(a) == "number" then | |
return Vector.new(b.x * a, b.y * a) | |
elseif type(b) == "number" then | |
return Vector.new(a.x * b, a.y * b) | |
else | |
return Vector.new(a.x * b.x, a.y * b.y) | |
end | |
end | |
function Vector.__div(a, b) | |
if type(a) == "number" then | |
return Vector.new(b.x / a, b.y / a) | |
elseif type(b) == "number" then | |
return Vector.new(a.x / b, a.y / b) | |
else | |
return Vector.new(a.x / b.x, a.y / b.y) | |
end | |
end | |
function Vector.__eq(a, b) | |
return a.x == b.x and a.y == b.y | |
end | |
function Vector.__lt(a, b) | |
return a.x < b.x or (a.x == b.x and a.y < b.y) | |
end | |
function Vector.__le(a, b) | |
return a.x <= b.x and a.y <= b.y | |
end | |
function Vector.__tostring(a) | |
return "(" .. a.x .. ", " .. a.y .. ")" | |
end | |
function Vector.new(x, y) | |
return setmetatable({ x = x or 0, y = y or 0 }, Vector) | |
end | |
function Vector.distance(a, b) | |
return (b - a):len() | |
end | |
function Vector:clone() | |
return Vector.new(self.x, self.y) | |
end | |
function Vector:unpack() | |
return self.x, self.y | |
end | |
function Vector:len() | |
return math.sqrt(self.x * self.x + self.y * self.y) | |
end | |
function Vector:lenSq() | |
return self.x * self.x + self.y * self.y | |
end | |
function Vector:normalize() | |
local len = self:len() | |
self.x = self.x / len | |
self.y = self.y / len | |
return self | |
end | |
function Vector:normalized() | |
return self / self:len() | |
end | |
function Vector:rotate(phi) | |
local c = math.cos(phi) | |
local s = math.sin(phi) | |
self.x = c * self.x - s * self.y | |
self.y = s * self.x + c * self.y | |
return self | |
end | |
function Vector:rotated(phi) | |
return self:clone():rotate(phi) | |
end | |
function Vector:perpendicular() | |
return Vector.new(-self.y, self.x) | |
end | |
function Vector:projectOn(other) | |
return (self * other) * other / other:lenSq() | |
end | |
function Vector:cross(other) | |
return self.x * other.y - self.y * other.x | |
end | |
setmetatable(Vector, { __call = function(_, ...) return Vector.new(...) end }) |
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Can you tell me what's the difference between normalize and normalized? |
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@MarkuBu normalize change the vector itself while normalized don't. |
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@lexnewgate Thanks |
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There's an issue with subtraction and division of a vector with a normal number. The order is wrong when the number is first. E.g.: 1 - Vector(0, 0) will result in Vector(-1, -1). I have a fixed version here: https://gist.github.com/johannesgijsbers/880372fc8800e5d5f3e4