Added lume.vector(), updated README and tests

README.md

@@ -52,6 +52,12 @@ used when comparing distances.
 ### lume.angle(x1, y1, x2, y2)
 Returns the angle between the two points.
 
+### lume.vector(angle, magnitude)
+Given an `angle` and `magnitude`, returns a vector.
+```lua
+local x, y = lume.vector(0, 10) -- Returns 10, 0
+```
+
 ### lume.random([a [, b]])
 Returns a random number between `a` and `b`. If only `a` is supplied a number
 between `0` and `a` is returned. If no arguments are supplied a random number

lume.lua

@@ -111,6 +111,11 @@ function lume.angle(x1, y1, x2, y2)
 end
 
 
+function lume.vector(angle, magnitude)
+  return math.cos(angle) * magnitude, math.sin(angle) * magnitude
+end
+
+
 function lume.random(a, b)
   if not a then a, b = 0, 1 end
   if not b then b = 0 end

test/test.lua

@@ -80,6 +80,18 @@ tests["lume.angle"] = function()
   testeq( lume.angle(10, 10, 10, 30), math.rad(90)  )
 end
 
+-- lume.vector
+tests["lume.vector"] = function()
+  local function cmp(a, b) return math.abs(a - b) < 10e-6 end
+  local x, y
+  x, y = lume.vector(0, 10)
+  testeq( cmp(x, 10) and cmp(y, 0), true )
+  x, y = lume.vector(math.pi, 100)
+  testeq( cmp(x, -100) and cmp(y, 0), true )
+  x, y = lume.vector(math.pi * 0.25, 100)
+  testeq( cmp(x, 70.71067811865476) and cmp(y, 70.71067811865476), true )
+end
+
 -- lume.random
 tests["lume.random"] = function()
   testeq( type(lume.random()),      "number" )
@@ -617,4 +629,3 @@ end
 tester.dotests(tests)
 tester.test.global()
 tester.printresults()
-