add normalize_to and normalize_self_to methods

src/vec.rs

@@ -246,6 +246,11 @@ pub trait EuclideanVector<T>: NumericVector<T> {
      */
     pure fn normalize(&self) -> self;
     
+    /**
+     * Set the length of the vector whilst preserving the direction
+     */
+    pure fn normalize_to(&self, length: T) -> self;
+    
     /**
      * Linearly intoperlate between the vector and `other`
      *
@@ -270,6 +275,11 @@ pub trait MutableEuclideanVector<T>: MutableNumericVector<&self/T>
      */
     fn normalize_self(&mut self);
     
+    /**
+     * Set the vector to a specified length whilst preserving the direction
+     */
+    fn normalize_self_to(&mut self, length: T);
+    
     /**
      * Linearly intoperlate the vector towards `other`
      */
@@ -453,6 +463,12 @@ pub impl<T:Copy Number Exp> Vec2<T>: EuclideanVector<T> {
         return self.mul_t(n);
     }
     
+    #[inline(always)]
+    pure fn normalize_to(&self, length: T) -> Vec2<T> {
+        let mut n: T = length / self.length();
+        return self.mul_t(n);
+    }
+    
     #[inline(always)]
     pure fn lerp(&self, other: &Vec2<T>, amount: T) -> Vec2<T> {
         self.add_v(&other.sub_v(self).mul_t(amount))
@@ -467,6 +483,12 @@ pub impl<T:Copy Number Exp> Vec2<T>: MutableEuclideanVector<&self/T> {
         self.mul_self_t(&n);
     }
     
+    #[inline(always)]
+    fn normalize_self_to(&mut self, length: &T) {
+        let mut n: T = length / self.length();
+        self.mul_self_t(&n);
+    }
+    
     fn lerp_self(&mut self, other: &Vec2<T>, amount: &T) {
         self.add_self_v(&other.sub_v(&*self).mul_t(*amount));
     }
@@ -701,6 +723,12 @@ pub impl<T:Copy Number Exp> Vec3<T>: EuclideanVector<T> {
         return self.mul_t(n);
     }
     
+    #[inline(always)]
+    pure fn normalize_to(&self, length: T) -> Vec3<T> {
+        let mut n: T = length / self.length();
+        return self.mul_t(n);
+    }
+    
     #[inline(always)]
     pure fn lerp(&self, other: &Vec3<T>, amount: T) -> Vec3<T> {
         self.add_v(&other.sub_v(self).mul_t(amount))
@@ -715,6 +743,12 @@ pub impl<T:Copy Number Exp> Vec3<T>: MutableEuclideanVector<&self/T> {
         self.mul_self_t(&n);
     }
     
+    #[inline(always)]
+    fn normalize_self_to(&mut self, length: &T) {
+        let mut n: T = length / self.length();
+        self.mul_self_t(&n);
+    }
+    
     fn lerp_self(&mut self, other: &Vec3<T>, amount: &T) {
         self.add_self_v(&other.sub_v(&*self).mul_t(*amount));
     }
@@ -949,6 +983,12 @@ pub impl<T:Copy Number Exp> Vec4<T>: EuclideanVector<T> {
         return self.mul_t(n);
     }
     
+    #[inline(always)]
+    pure fn normalize_to(&self, length: T) -> Vec4<T> {
+        let mut n: T = length / self.length();
+        return self.mul_t(n);
+    }
+    
     #[inline(always)]
     pure fn lerp(&self, other: &Vec4<T>, amount: T) -> Vec4<T> {
         self.add_v(&other.sub_v(self).mul_t(amount))
@@ -963,6 +1003,12 @@ pub impl<T:Copy Number Exp> Vec4<T>: MutableEuclideanVector<&self/T> {
         self.mul_self_t(&n);
     }
     
+    #[inline(always)]
+    fn normalize_self_to(&mut self, length: &T) {
+        let mut n: T = length / self.length();
+        self.mul_self_t(&n);
+    }
+    
     fn lerp_self(&mut self, other: &Vec4<T>, amount: &T) {
         self.add_self_v(&other.sub_v(&*self).mul_t(*amount));
     }