From 3bebd54178be8e896200eafe49933c9c0914517e Mon Sep 17 00:00:00 2001
From: Peter Wu <peter@lekensteyn.nl>
Date: Wed, 17 Jun 2015 15:47:44 +0200
Subject: Init turret sequence docs + logical

---
 Venus_Skeleton/Venus_Skeleton.ino | 29 +++++++++++++++--------------
 1 file changed, 15 insertions(+), 14 deletions(-)

diff --git a/Venus_Skeleton/Venus_Skeleton.ino b/Venus_Skeleton/Venus_Skeleton.ino
index 87b8449..f061f0c 100644
--- a/Venus_Skeleton/Venus_Skeleton.ino
+++ b/Venus_Skeleton/Venus_Skeleton.ino
@@ -177,22 +177,23 @@ long microsecondsToCentimeters(long microseconds)
 	return microseconds / 29 / 2;
 }
 
+/**
+ * Given the number of positions $n$, fills the lower half of the array with 0,
+ * 2, 4, ..., $n-1$, then continues filling the upper half with $n-2$, $n-4$,
+ * ..., 5, 3, 1.
+ */
 void initTurretSequence(int array[], int numOfPositions) {
-	int sign = 1;
-	int x = 0;
-
-	for (int i = 0; i < numOfPositions; i++) {
+	// for n=7, fill lower half of array with 0, 2, 4, 6
+	// for n=8, fill lower half of array with 0, 2, 4, 6
+	for (int i = 0; i < numOfPositions / 2; i++) {
+		array[i] = i * 2;
+	}
+	// for n=7, fill upper half of array with 5, 3, 1
+	// for n=8, fill upper half of array with 7, 5, 3, 1
+	int x = numOfPositions / 2 * 2 - 1;
+	for (int i = numOfPositions / 2 + 1; i < numOfPositions; i++) {
 		array[i] = x;
-		x += sign * 2;
-
-		if(x > numOfPositions) {
-			sign = -1;
-			x -= 3;
-		}
-		if(x == numOfPositions) {
-			sign = -1;
-			x -= 1;
-		}
+		x -= 2;
 	}
 }
 
-- 
cgit v1.2.1