diff --git a/src/funs/mix.rs b/src/funs/mix.rs
index 6af376e..fa59ece 100644
--- a/src/funs/mix.rs
+++ b/src/funs/mix.rs
@@ -1,56 +1,137 @@
 use num::cast::*;
 use vec::{Vec2, Vec3, Vec4};
 
+use extent::{Clamp, clamp};
+
 pub trait Mix {
     pure fn mix(other: &self, value: &self) -> self;
+    pure fn smooth_step(edge0: &self, edge1: &self) -> self;
+    pure fn step(edge: &self) -> self;
 }
 
 #[inline(always)] pub pure fn mix<T:Mix>(a: &T, b: &T, value: &T) -> T { a.mix(b, value) }
+#[inline(always)] pub pure fn smooth_step<T:Mix>(x: &T, edge0: &T, edge1: &T) -> T { x.smooth_step(edge0, edge1) }
+#[inline(always)] pub pure fn step<T:Mix>(x: &T, edge: &T) -> T { x.step(edge) }
 
 pub impl f32: Mix {
     #[inline(always)]
     pure fn mix(other: &f32, value: &f32) -> f32 {
-        self * (1f32 - (*value)) + (*other) * (*value)
+        self * (1.0 - (*value)) + (*other) * (*value)
+    }
+    
+    #[inline(always)]
+    pure fn smooth_step(edge0: &f32, edge1: &f32) -> f32 {
+        let t = clamp(&((self - *edge0) / (*edge1 - *edge0)), &0.0, &1.0);
+        return t * t * (3.0 - 2.0 * t);
+    }
+    
+    #[inline(always)]
+    pure fn step(edge: &f32) -> f32 {
+        if self < *edge { 0.0 } else { 1.0 }
     }
 }
 
 pub impl f64: Mix {
     #[inline(always)]
     pure fn mix(other: &f64, value: &f64) -> f64 {
-        self * (1f64 - (*value)) + (*other) * (*value)
+        self * (1.0 - (*value)) + (*other) * (*value)
+    }
+    
+    #[inline(always)]
+    pure fn smooth_step(edge0: &f64, edge1: &f64) -> f64 {
+        let t = clamp(&((self - *edge0) / (*edge1 - *edge0)), &0.0, &1.0);
+        return t * t * (3.0 - 2.0 * t);
+    }
+    
+    #[inline(always)]
+    pure fn step(edge: &f64) -> f64 {
+        if self < *edge { 0.0 } else { 1.0 }
     }
 }
 
 pub impl float: Mix {
     #[inline(always)]
     pure fn mix(other: &float, value: &float) -> float {
-        self * (1f - (*value)) + (*other) * (*value)
+        self * (1.0 - (*value)) + (*other) * (*value)
+    }
+    
+    #[inline(always)]
+    pure fn smooth_step(edge0: &float, edge1: &float) -> float {
+        let t = clamp(&((self - *edge0) / (*edge1 - *edge0)), &0.0, &1.0);
+        return t * t * (3.0 - 2.0 * t);
+    }
+    
+    #[inline(always)]
+    pure fn step(edge: &float) -> float {
+        if self < *edge { 0.0 } else { 1.0 }
     }
 }
 
 pub impl<T:Copy Mix> Vec2<T>: Mix {
     #[inline(always)]
-    pure fn mix(other: &Vec2<T>, values: &Vec2<T>) -> Vec2<T> {
-        Vec2::new(self[0].mix(&other[0], &values[0]),
-                  self[1].mix(&other[1], &values[1]))
+    pure fn mix(other: &Vec2<T>, value: &Vec2<T>) -> Vec2<T> {
+        Vec2::new(self[0].mix(&other[0], &value[0]),
+                  self[1].mix(&other[1], &value[1]))
+    }
+    
+    #[inline(always)]
+    pure fn smooth_step(edge0: &Vec2<T>, edge1: &Vec2<T>) -> Vec2<T> {
+        Vec2::new(self[0].smooth_step(&edge0[0], &edge1[0]),
+                  self[1].smooth_step(&edge0[1], &edge1[1]))
+    }
+    
+    #[inline(always)]
+    pure fn step(edge: &Vec2<T>) -> Vec2<T> {
+        Vec2::new(self[0].step(&edge[0]),
+                  self[1].step(&edge[1]))
     }
 }
 
 pub impl<T:Copy Mix> Vec3<T>: Mix {
     #[inline(always)]
-    pure fn mix(other: &Vec3<T>, values: &Vec3<T>) -> Vec3<T> {
-        Vec3::new(self[0].mix(&other[0], &values[0]),
-                  self[1].mix(&other[1], &values[1]),
-                  self[2].mix(&other[2], &values[2]))
+    pure fn mix(other: &Vec3<T>, value: &Vec3<T>) -> Vec3<T> {
+        Vec3::new(self[0].mix(&other[0], &value[0]),
+                  self[1].mix(&other[1], &value[1]),
+                  self[2].mix(&other[2], &value[2]))
+    }
+    
+    #[inline(always)]
+    pure fn smooth_step(edge0: &Vec3<T>, edge1: &Vec3<T>) -> Vec3<T> {
+        Vec3::new(self[0].smooth_step(&edge0[0], &edge1[0]),
+                  self[1].smooth_step(&edge0[1], &edge1[1]),
+                  self[2].smooth_step(&edge0[2], &edge1[2]))
+    }
+    
+    #[inline(always)]
+    pure fn step(edge: &Vec3<T>) -> Vec3<T> {
+        Vec3::new(self[0].step(&edge[0]),
+                  self[1].step(&edge[1]),
+                  self[2].step(&edge[2]))
     }
 }
 
 pub impl<T:Copy Mix> Vec4<T>: Mix {
     #[inline(always)]
-    pure fn mix(other: &Vec4<T>, values: &Vec4<T>) -> Vec4<T> {
-        Vec4::new(self[0].mix(&other[0], &values[0]),
-                  self[1].mix(&other[1], &values[1]),
-                  self[2].mix(&other[2], &values[2]),
-                  self[3].mix(&other[3], &values[3]))
+    pure fn mix(other: &Vec4<T>, value: &Vec4<T>) -> Vec4<T> {
+        Vec4::new(self[0].mix(&other[0], &value[0]),
+                  self[1].mix(&other[1], &value[1]),
+                  self[2].mix(&other[2], &value[2]),
+                  self[3].mix(&other[3], &value[3]))
+    }
+    
+    #[inline(always)]
+    pure fn smooth_step(edge0: &Vec4<T>, edge1: &Vec4<T>) -> Vec4<T> {
+        Vec4::new(self[0].smooth_step(&edge0[0], &edge1[0]),
+                  self[1].smooth_step(&edge0[1], &edge1[1]),
+                  self[2].smooth_step(&edge0[2], &edge1[2]),
+                  self[3].smooth_step(&edge0[3], &edge1[3]))
+    }
+    
+    #[inline(always)]
+    pure fn step(edge: &Vec4<T>) -> Vec4<T> {
+        Vec4::new(self[0].step(&edge[0]),
+                  self[1].step(&edge[1]),
+                  self[2].step(&edge[2]),
+                  self[3].step(&edge[3]))
     }
 }
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