From 0b438cc8d121e5fc9d306a18f41ae206acfce95f Mon Sep 17 00:00:00 2001
From: schneefux <schneefux+commit@schneefux.xyz>
Date: Sat, 18 Jun 2016 16:46:25 +0200
Subject: udp server: listen on multicast, handle faster

---
 esp-ledstrip.ino | 34 +++++++++++++++++++++-------------
 1 file changed, 21 insertions(+), 13 deletions(-)

diff --git a/esp-ledstrip.ino b/esp-ledstrip.ino
index 3404f85..914cdf5 100644
--- a/esp-ledstrip.ino
+++ b/esp-ledstrip.ino
@@ -25,21 +25,23 @@
 
 const char* ssid = "";
 const char* password = "";
-#define ME "esplamp1"
+#define ME "esplamp-1"
 #ifdef WITH_MQTT
-const char* mqtt_server = "mqtt.example.net";
+const char* mqtt_server = "";
 #endif
 #ifdef WITH_UDP
 const int udpPort = 2391;
+IPAddress multicastAddr(239, 1, 0, 0);
 #endif
 #ifdef WITH_MQTT
 const char* connectTopic = "api/" ME "/connected";
 const char* outTopic = "api/" ME "/status/rgb";
 const char* inTopic = "api/" ME "/set/rgb";
+const char* updateTopic = "api/" ME "/get/rgb";
 #endif
 
 //                      R  G  B
-const int leds[]     = {2, 0, 3}; // !TX is inverted, not used here
+const int leds[]     = {2, 0, 3}; // remember: TX is inverted, not used here
 unsigned int state[] = {0, 0, 0};
 unsigned char cstate[] = {0, 0, 0};
 
@@ -66,13 +68,15 @@ void writeJson() {
   root.printTo(cJson, sizeof(cJson));
 }
 
-void updateLeds() {
+void updateLeds(bool fast) {
   for(int i=0; i<3; i++)
     analogWrite(leds[i], state[i]);
-  writeJson();
+  if (!fast) {
+    writeJson();
 #ifdef WITH_MQTT
-  if (mqtt.connected()) mqtt.publish(outTopic, cJson, true);
+    if (mqtt.connected()) mqtt.publish(outTopic, cJson, true);
 #endif
+  }
 }
 
 #ifdef WITH_HTTP
@@ -85,7 +89,7 @@ void handleRoot() {
   if(server.hasArg("blue"))
     state[2] = server.arg("blue").toInt();
     
-  updateLeds();
+  updateLeds(false);
   server.send(200, "application/json", cJson);
 }
 #endif
@@ -99,7 +103,10 @@ void handleMqtt(char* topic, byte* payload, unsigned int length) {
     state[0] = root["red"];
     state[1] = root["green"];
     state[2] = root["blue"];
-    updateLeds();
+    updateLeds(false);
+  }
+  if (strcmp(topic, updateTopic) == 0) {
+    updateLeds(false); // force update /rgb information
   }
 }
 
@@ -109,24 +116,25 @@ void connectMqtt() {
     // topic, msg, retain
     mqtt.publish(connectTopic, "online", true);
     mqtt.subscribe(inTopic);
+    mqtt.subscribe(updateTopic);
   }
 }
 #endif
 
 #ifdef WITH_UDP
 /* UDP API */
+// expected to be most time critical
 void handleUdp() {
   if (!RAWudp)
-    RAWudp.begin(udpPort);
+    RAWudp.beginMulticast(WiFi.localIP(), multicastAddr, udpPort);
   if (!RAWudp)
     return;
-    
-  int cb = RAWudp.parsePacket();
-  if (cb) {
+
+  if (RAWudp.parsePacket()) {
     RAWudp.read(cstate, 3);
     for(int i=0; i<3; i++)
       state[i] = cstate[i] << 2;
-    updateLeds();
+    updateLeds(true); // skip publishing
   }
 }
 #endif
-- 
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