From f5e93a3ea54338b8a4a20f020168940d8314103f Mon Sep 17 00:00:00 2001 From: Landon Manning Date: Sun, 21 Dec 2014 00:51:14 -0500 Subject: [PATCH] Snagged vec2 from @vrld's HUMP library This was the original basis of vec3, so why not add it in, too? --- modules/vec2.lua | 191 +++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 191 insertions(+) create mode 100644 modules/vec2.lua diff --git a/modules/vec2.lua b/modules/vec2.lua new file mode 100644 index 0000000..9abdf34 --- /dev/null +++ b/modules/vec2.lua @@ -0,0 +1,191 @@ +--[[ +Copyright (c) 2010-2013 Matthias Richter + +Permission is hereby granted, free of charge, to any person obtaining a copy +of this software and associated documentation files (the "Software"), to deal +in the Software without restriction, including without limitation the rights +to use, copy, modify, merge, publish, distribute, sublicense, and/or sell +copies of the Software, and to permit persons to whom the Software is +furnished to do so, subject to the following conditions: + +The above copyright notice and this permission notice shall be included in +all copies or substantial portions of the Software. + +Except as contained in this notice, the name(s) of the above copyright holders +shall not be used in advertising or otherwise to promote the sale, use or +other dealings in this Software without prior written authorization. + +THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR +IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, +FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE +AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER +LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, +OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN +THE SOFTWARE. +]]-- + +local assert = assert +local sqrt, cos, sin, atan2 = math.sqrt, math.cos, math.sin, math.atan2 + +local vector = {} +vector.__index = vector + +local function new(x,y) + return setmetatable({x = x or 0, y = y or 0}, vector) +end +local zero = new(0,0) + +local function isvector(v) + return type(v) == 'table' and type(v.x) == 'number' and type(v.y) == 'number' +end + +function vector:clone() + return new(self.x, self.y) +end + +function vector:unpack() + return self.x, self.y +end + +function vector:__tostring() + return "("..tonumber(self.x)..","..tonumber(self.y)..")" +end + +function vector.__unm(a) + return new(-a.x, -a.y) +end + +function vector.__add(a,b) + assert(isvector(a) and isvector(b), "Add: wrong argument types ( expected)") + return new(a.x+b.x, a.y+b.y) +end + +function vector.__sub(a,b) + assert(isvector(a) and isvector(b), "Sub: wrong argument types ( expected)") + return new(a.x-b.x, a.y-b.y) +end + +function vector.__mul(a,b) + if type(a) == "number" then + return new(a*b.x, a*b.y) + elseif type(b) == "number" then + return new(b*a.x, b*a.y) + else + assert(isvector(a) and isvector(b), "Mul: wrong argument types ( or expected)") + return a.x*b.x + a.y*b.y + end +end + +function vector.__div(a,b) + assert(isvector(a) and type(b) == "number", "wrong argument types (expected / )") + return new(a.x / b, a.y / b) +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.permul(a,b) + assert(isvector(a) and isvector(b), "permul: wrong argument types ( expected)") + return new(a.x*b.x, a.y*b.y) +end + +function vector:len2() + return self.x * self.x + self.y * self.y +end + +function vector:len() + return sqrt(self.x * self.x + self.y * self.y) +end + +function vector.dist(a, b) + assert(isvector(a) and isvector(b), "dist: wrong argument types ( expected)") + local dx = a.x - b.x + local dy = a.y - b.y + return sqrt(dx * dx + dy * dy) +end + +function vector.dist2(a, b) + assert(isvector(a) and isvector(b), "dist: wrong argument types ( expected)") + local dx = a.x - b.x + local dy = a.y - b.y + return (dx * dx + dy * dy) +end + +function vector:normalize_inplace() + local l = self:len() + if l > 0 then + self.x, self.y = self.x / l, self.y / l + end + return self +end + +function vector:normalized() + return self:clone():normalize_inplace() +end + +function vector:rotate_inplace(phi) + local c, s = cos(phi), sin(phi) + self.x, self.y = c * self.x - s * self.y, s * self.x + c * self.y + return self +end + +function vector:rotated(phi) + local c, s = cos(phi), sin(phi) + return new(c * self.x - s * self.y, s * self.x + c * self.y) +end + +function vector:perpendicular() + return new(-self.y, self.x) +end + +function vector:projectOn(v) + assert(isvector(v), "invalid argument: cannot project vector on " .. type(v)) + -- (self * v) * v / v:len2() + local s = (self.x * v.x + self.y * v.y) / (v.x * v.x + v.y * v.y) + return new(s * v.x, s * v.y) +end + +function vector:mirrorOn(v) + assert(isvector(v), "invalid argument: cannot mirror vector on " .. type(v)) + -- 2 * self:projectOn(v) - self + local s = 2 * (self.x * v.x + self.y * v.y) / (v.x * v.x + v.y * v.y) + return new(s * v.x - self.x, s * v.y - self.y) +end + +function vector:cross(v) + assert(isvector(v), "cross: wrong argument types ( expected)") + return self.x * v.y - self.y * v.x +end + +-- ref.: http://blog.signalsondisplay.com/?p=336 +function vector:trim_inplace(maxLen) + local s = maxLen * maxLen / self:len2() + s = (s > 1 and 1) or math.sqrt(s) + self.x, self.y = self.x * s, self.y * s + return self +end + +function vector:angleTo(other) + if other then + return atan2(self.y, self.x) - atan2(other.y, other.x) + end + return atan2(self.y, self.x) +end + +function vector:trimmed(maxLen) + return self:clone():trim_inplace(maxLen) +end + + +-- the module +return setmetatable({new = new, isvector = isvector, zero = zero}, +{__call = function(_, ...) return new(...) end})