added pointcoud2 example (ros#111)

rospy_tutorials/010_publish_pointcloud2/publish_pointcloud2.launch

@@ -0,0 +1,4 @@
+<launch>
+  <node name="publish_pointcloud2" pkg="rospy_tutorials" type="publish_pointcloud2.py" output="screen"/>
+</launch>
+

rospy_tutorials/010_publish_pointcloud2/publish_pointcloud2.py

@@ -0,0 +1,40 @@
+#!/usr/bin/env python
+from __future__ import print_function
+
+import rospy
+import numpy as np
+from sensor_msgs import point_cloud2
+from sensor_msgs.msg import PointCloud2
+from sensor_msgs.msg import PointField
+from std_msgs.msg import Header
+
+width = 100
+height = 100
+
+def publishPC2(count):
+    fields = [PointField('x', 0, PointField.FLOAT32, 1),
+              PointField('y', 4, PointField.FLOAT32, 1),
+              PointField('z', 8, PointField.FLOAT32, 1),
+              PointField('intensity', 12, PointField.FLOAT32, 1)]
+
+    header = Header()
+    header.frame_id = "map"
+    header.stamp = rospy.Time.now()
+
+    x, y = np.meshgrid(np.linspace(-2,2,width), np.linspace(-2,2,height))
+    z = 0.5 * np.sin(2*x - count/10.0) * np.sin(2*y)
+    points = np.array([x,y,z,z]).reshape(4,-1).T
+
+    pc2 = point_cloud2.create_cloud(header, fields, points)
+    pub.publish(pc2)
+
+if __name__ == '__main__':
+    rospy.init_node('pc2_publisher')
+    pub = rospy.Publisher('points2', PointCloud2, queue_size=100)
+    rate = rospy.Rate(10)
+
+    count = 0
+    while not rospy.is_shutdown():
+        publishPC2(count)
+        count += 1
+        rate.sleep()

rospy_tutorials/CMakeLists.txt

@@ -98,6 +98,15 @@ install(FILES
   DESTINATION ${CATKIN_PACKAGE_SHARE_DESTINATION}/009_advanced_publish
 )
 
+catkin_install_python(PROGRAMS
+  010_publish_pointcloud2/publish_pointcloud2.py
+  DESTINATION ${CATKIN_PACKAGE_SHARE_DESTINATION}/010_publish_pointcloud2
+)
+install(FILES
+  010_publish_pointcloud2/publish_pointcloud2.launch
+  DESTINATION ${CATKIN_PACKAGE_SHARE_DESTINATION}/010_publish_pointcloud2
+)
+
 if(CATKIN_ENABLE_TESTING)
   find_package(rostest)
   foreach(T