From b81a947eb0d6195729031a2e692abcb68f8029c8 Mon Sep 17 00:00:00 2001
From: Hanno Braun <hanno@habraun.net>
Date: Mon, 23 Mar 2009 12:44:29 +0100
Subject: [PATCH] Body: Store the previous position every time the position is
 set.

---
 src/net/habraun/sd/Body.scala      | 12 ++++++++++++
 test/net/habraun/sd/BodyTest.scala | 22 ++++++++++++++++++++++
 2 files changed, 34 insertions(+)

diff --git a/src/net/habraun/sd/Body.scala b/src/net/habraun/sd/Body.scala
index b217c1c..c6e79e0 100644
--- a/src/net/habraun/sd/Body.scala
+++ b/src/net/habraun/sd/Body.scala
@@ -45,12 +45,24 @@ class Body {
 
 	def position_=(p: Vec2D) {
 		if (p == null) throw new NullPointerException
+		_previousPosition = _position
 		_position = p
 	}
 
 
 
 	/**
+	 * The previous position of the body, before the position was set.
+	 * This attribute is initialized with the value Vec2D(0, 0).
+	 */
+
+	private[this] var _previousPosition = Vec2D(0, 0)
+
+	def previousPosition = _previousPosition
+
+
+
+	/**
 	 * The body's shape.
 	 * The shape is needed for collision detection.
 	 * Must not be null.
diff --git a/test/net/habraun/sd/BodyTest.scala b/test/net/habraun/sd/BodyTest.scala
index 4105e40..3d50d57 100644
--- a/test/net/habraun/sd/BodyTest.scala
+++ b/test/net/habraun/sd/BodyTest.scala
@@ -57,6 +57,28 @@ class BodyTest {
 
 
 	@Test
+	def setPositionCheckPreviousPosition {
+		val previousPosition = Vec2D(5, 0)
+
+		val body = new Body
+		body.position = previousPosition
+		body.position = Vec2D(0, 5)
+
+		assertEquals(previousPosition, body.previousPosition)
+	}
+
+
+
+	@Test
+	def checkInitialPreviousPosition {
+		val body = new Body
+
+		assertEquals(body.position, body.previousPosition)
+	}
+
+
+
+	@Test
 	def checkInitialVelocity {
 		val body = new Body
 		assertEquals(Vec2D(0, 0), body.velocity)
-- 
2.11.4.GIT