From b6c4f4cf504515631f9b43b41328a2f35f5a24c0 Mon Sep 17 00:00:00 2001
From: yangxiao <yangxiao@cocos2d-x.org>
Date: Tue, 1 Sep 2015 10:39:14 +0800
Subject: [PATCH] add comment

---
 cocos/3d/CCMotionStreak3D.h | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/cocos/3d/CCMotionStreak3D.h b/cocos/3d/CCMotionStreak3D.h
index 168d27c39a..720ca480cd 100644
--- a/cocos/3d/CCMotionStreak3D.h
+++ b/cocos/3d/CCMotionStreak3D.h
@@ -38,7 +38,7 @@ class Texture2D;
  */
 
 /** @class MotionStreak3D.
- * @brief Creates a trailing path.
+ * @brief Creates a trailing path. It is created from a line segment sweeping along the path.
  */
 class MotionStreak3D : public Node, public TextureProtocol
 {
@@ -139,8 +139,15 @@ public:
     virtual void setOpacityModifyRGB(bool value) override;
     virtual bool isOpacityModifyRGB() const override;
     
+    /**
+     * Set the direction of sweeping line segment.
+     * @param sweepAxis Direction of sweeping line segment
+     */
     void setSweepAxis(const Vec3& sweepAxis) { _sweepAxis = sweepAxis.getNormalized(); }
     
+    /**
+     * Get the direction of sweeping line segment
+     */
     const Vec3& getSweepAxis() const { return _sweepAxis; }
     
 CC_CONSTRUCTOR_ACCESS: