Art-Net transmit support for network LEDs

Like DDP, this allows WLED to address network systems using the Art-Net protocol.

Universe starts at zero, because that's the first universe in Art-Net.

Works with RGB. It's coded to also work with RGBW, but I couldn't find a great place to enable it without mucking with things I don't understand.

wled00/bus_manager.cpp

@@ -383,24 +383,24 @@ uint8_t BusOnOff::getPins(uint8_t* pinArray) {
 
 BusNetwork::BusNetwork(BusConfig &bc) : Bus(bc.type, bc.start, bc.autoWhite) {
   _valid = false;
-//      switch (bc.type) {
-//        case TYPE_NET_ARTNET_RGB:
-//          _rgbw = false;
-//          _UDPtype = 2;
-//          break;
-//        case TYPE_NET_E131_RGB:
-//          _rgbw = false;
-//          _UDPtype = 1;
-//          break;
-//        case TYPE_NET_DDP_RGB:
-//          _rgbw = false;
-//          _UDPtype = 0;
-//          break;
-//        default: // TYPE_NET_DDP_RGB / TYPE_NET_DDP_RGBW
+     switch (bc.type) {
+       case TYPE_NET_ARTNET_RGB:
+         _rgbw = false;
+         _UDPtype = 2;
+         break;
+       case TYPE_NET_E131_RGB:
+         _rgbw = false;
+         _UDPtype = 1;
+         break;
+       case TYPE_NET_DDP_RGB:
+         _rgbw = false;
+         _UDPtype = 0;
+         break;
+       default: // TYPE_NET_DDP_RGB / TYPE_NET_DDP_RGBW
       _rgbw = bc.type == TYPE_NET_DDP_RGBW;
       _UDPtype = 0;
-//          break;
-//      }
+         break;
+     }
   _UDPchannels = _rgbw ? 4 : 3;
   _data = (byte *)malloc(bc.count * _UDPchannels);
   if (_data == nullptr) return;

wled00/data/settings_leds.htm

@@ -345,7 +345,7 @@ ${i+1}:
 <!--option value="46">PWM RGB+DCCT</option-->'}
 <option value="80">DDP RGB (network)</option>
 <!--option value="81">E1.31 RGB (network)</option-->
-<!--option value="82">ArtNet RGB (network)</option-->
+<option value="82">Art-Net RGB (network)</option>
 <option value="88">DDP RGBW (network)</option>
 </select><br>
 <div id="co${i}" style="display:inline">Color Order:

wled00/udp.cpp

@@ -791,6 +791,57 @@ uint8_t realtimeBroadcast(uint8_t type, IPAddress client, uint16_t length, uint8
 
     case 2: //ArtNet
     {
+      // calculate the number of UDP packets we need to send
+      size_t channelCount = length * (isRGBW?4:3); // 1 channel for every R,G,B,(W?) value
+      size_t ARTNET_CHANNELS_PER_PACKET = isRGBW?512:510; // 512/4=128 RGBW LEDs, 510/3=170 RGB LEDs
+      size_t packetCount = ((channelCount-1)/ARTNET_CHANNELS_PER_PACKET)+1;
+
+      uint32_t channel = 0; 
+      size_t bufferOffset = 0;
+
+      sequenceNumber++;
+
+      for (size_t currentPacket = 0; currentPacket < packetCount; currentPacket++) {
+
+        if (sequenceNumber > 255) sequenceNumber = 0;
+
+        if (!ddpUdp.beginPacket(client, ARTNET_DEFAULT_PORT)) {
+          DEBUG_PRINTLN(F("Art-Net WiFiUDP.beginPacket returned an error"));
+          return 1; // borked
+        }
+
+        size_t packetSize = ARTNET_CHANNELS_PER_PACKET;
+
+        if (currentPacket == (packetCount - 1U)) {
+          // last packet
+          if (channelCount % ARTNET_CHANNELS_PER_PACKET) {
+            packetSize = channelCount % ARTNET_CHANNELS_PER_PACKET;
+          }
+        }
+
+        const byte ART_NET_HEADER[12] = {0x41,0x72,0x74,0x2d,0x4e,0x65,0x74,0x00,0x00,0x50,0x00,0x0e};
+
+        ddpUdp.write(ART_NET_HEADER,12); // This doesn't change. Hard coded ID, OpCode, and protocol version.
+        ddpUdp.write(sequenceNumber & 0xFF); // sequence number. 1..255
+        ddpUdp.write(0x00); // physical - more an FYI, not really used for anything. 0..3
+        ddpUdp.write((currentPacket) & 0xFF); // Universe LSB. 1 full packet == 1 full universe, so just use current packet number.
+        ddpUdp.write(0x00); // Universe MSB, unused.
+        ddpUdp.write(0xFF & (packetSize >> 8)); // 16-bit length of channel data, MSB
+        ddpUdp.write(0xFF & (packetSize     )); // 16-bit length of channel data, LSB
+
+        for (size_t i = 0; i < packetSize; i += (isRGBW?4:3)) {
+          ddpUdp.write(scale8(buffer[bufferOffset++], bri)); // R
+          ddpUdp.write(scale8(buffer[bufferOffset++], bri)); // G
+          ddpUdp.write(scale8(buffer[bufferOffset++], bri)); // B
+          if (isRGBW) ddpUdp.write(scale8(buffer[bufferOffset++], bri)); // W
+        }
+
+        if (!ddpUdp.endPacket()) {
+          DEBUG_PRINTLN(F("Art-Net WiFiUDP.endPacket returned an error"));
+          return 1; // borked
+        }
+        channel += packetSize;
+      }
     } break;
   }
   return 0;