use grpc port -1 by default in PyBullet. add grpcClient.py and grpcServer.py

examples/pybullet/examples/grpcClient.py

@@ -0,0 +1,19 @@
+
+import pybullet as p
+
+usePort = True
+
+if (usePort):
+	id = p.connect(p.GRPC,"localhost:12345")
+else:
+	id = p.connect(p.GRPC,"localhost") 
+print("id=",id)
+
+if (id<0):
+	print("Cannot connect to GRPC server")
+	exit(0)
+	
+print ("Connected to GRPC")
+r2d2 = p.loadURDF("r2d2.urdf")
+print("numJoints = ", p.getNumJoints(r2d2))
+

examples/pybullet/examples/grpcServer.py

@@ -0,0 +1,29 @@
+import pybullet as p
+import time
+
+useDirect = False
+usePort = True
+
+p.connect(p.GUI)
+id = p.loadPlugin("grpcPlugin")
+#dynamically loading the plugin
+#id = p.loadPlugin("E:/develop/bullet3/bin/pybullet_grpcPlugin_vs2010_x64_debug.dll", postFix="_grpcPlugin")
+
+#start the GRPC server at hostname, port
+if (id<0):
+	print("Cannot load grpcPlugin")
+	exit(0)
+	
+if usePort:
+	p.executePluginCommand(id, "localhost:12345")
+else:
+	p.executePluginCommand(id, "localhost")
+
+while p.isConnected():
+	if (useDirect):
+		#Only in DIRECT mode, since there is no 'ping' you need to manually call to handle RCPs:
+		numRPC = 10
+		p.executePluginCommand(id, intArgs=[numRPC])
+	else:
+		dt = 1./240.
+		time.sleep(dt)