diff --git a/README.md b/README.md
index 26a8af4..2aec81a 100644
--- a/README.md
+++ b/README.md
@@ -38,7 +38,7 @@ lume.lerp(100, 200, .5) -- Returns 150
 ```
 
 ### lume.smooth(a, b, amount)
-Similar to `lume.lerp()` but uses cosine interpolation instead of linear
+Similar to `lume.lerp()` but uses cubic interpolation instead of linear
 interpolation.
 
 ### lume.pingpong(x)
diff --git a/lume.lua b/lume.lua
index 1d2f3a2..83e6c5d 100644
--- a/lume.lua
+++ b/lume.lua
@@ -59,7 +59,8 @@ end
 
 
 function lume.smooth(a, b, amount)
-  local m = (1 - math_cos(lume.clamp(amount, 0, 1) * math_pi)) / 2
+  local t = lume.clamp(amount, 0, 1)
+  local m = t*t*(3-2*t)
   return a + (b - a) * m
 end
 
@@ -136,7 +137,7 @@ end
 
 
 function lume.map(t, fn)
-  local rtn = {} 
+  local rtn = {}
   for k, v in pairs(t) do rtn[k] = fn(v) end
   return rtn
 end
@@ -170,7 +171,7 @@ end
 
 function lume.set(t, retainkeys)
   local rtn = {}
-  for k, v in pairs(lume.invert(t)) do 
+  for k, v in pairs(lume.invert(t)) do
     rtn[retainkeys and v or (#rtn + 1)] = k
   end
   return rtn
@@ -253,7 +254,7 @@ function lume.fn(fn, ...)
   local args = {...}
   return function(...)
     local a = lume.merge(lume.clone(args), {...})
-    return fn(unpack(a)) 
+    return fn(unpack(a))
   end
 end
 
@@ -363,8 +364,8 @@ end
 
 function lume.format(str, vars)
   if not vars then return str end
-  local f = function(x) 
-    return tostring(vars[x] or vars[tonumber(x)] or "{" .. x .. "}") 
+  local f = function(x)
+    return tostring(vars[x] or vars[tonumber(x)] or "{" .. x .. "}")
   end
   return (str:gsub("{(.-)}", f))
 end
@@ -401,7 +402,7 @@ function lume.hotswap(modname)
   local oldglobal = lume.clone(_G)
   local updated = {}
   local function update(old, new)
-    if updated[old] then return end 
+    if updated[old] then return end
     updated[old] = true
     local oldmt, newmt = getmetatable(old), getmetatable(new)
     if oldmt and newmt then update(oldmt, newmt) end
@@ -421,7 +422,7 @@ function lume.hotswap(modname)
     local newmod = require(modname)
     if type(oldmod) == "table" then update(oldmod, newmod) end
     for k, v in pairs(oldglobal) do
-      if v ~= _G[k] and type(v) == "table" then 
+      if v ~= _G[k] and type(v) == "table" then
         update(v, _G[k])
         _G[k] = v
       end
@@ -434,9 +435,9 @@ end
 
 
 function lume.rgba(color)
-  local a = math_floor((color / 2 ^ 24) % 256)
-  local r = math_floor((color / 2 ^ 16) % 256)
-  local g = math_floor((color / 2 ^ 08) % 256)
+  local a = math_floor((color / 16777216) % 256)
+  local r = math_floor((color /    65536) % 256)
+  local g = math_floor((color /      256) % 256)
   local b = math_floor((color) % 256)
   return r, g, b, a
 end
@@ -457,4 +458,4 @@ function lume.chain(value)
 end
 
 
-return lume
+return lume
\ No newline at end of file