From 6f050bd1c8f8689f2f33683b46a258264c3f30c4 Mon Sep 17 00:00:00 2001
From: Colby Klein <shakesoda@gmail.com>
Date: Mon, 10 Aug 2015 18:59:43 -0700
Subject: [PATCH] Add utils.smoothstep (smooth hermite interpolation)

---
 modules/utils.lua | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/modules/utils.lua b/modules/utils.lua
index 939e819..68494a3 100644
--- a/modules/utils.lua
+++ b/modules/utils.lua
@@ -12,6 +12,11 @@ function utils.lerp(v, l, h)
 	return v * (h - l) + l
 end
 
+function utils.smoothstep(v, l, h)
+	local t = utils.clamp((v - l) / (h - l), 0.0, 1.0)
+	return t * t * (3.0 - 2.0 * t)
+end
+
 function utils.round(v, precision)
 	if precision then return utils.round(v / precision) * precision end
 	return v >= 0 and math.floor(v+0.5) or math.ceil(v-0.5)