Add initial DDP UDP output

wled00/DDP.cpp

@@ -0,0 +1,123 @@
+
+/*
+** Expected interface:
+** 
+**     realtimeBrodacast(IPAddress client, uint16_t busLength, byte rgbwData[busLength][4]);
+**
+*/
+
+#include <Arduino.h>
+#include <WiFiUdp.h>
+#include "DDP.h"
+
+#define DDP_HEADER_LEN 10
+#define DDP_SYNCPACKET_LEN 10
+
+#define DDP_FLAGS1_VER 0xc0  // version mask
+#define DDP_FLAGS1_VER1 0x40 // version=1
+#define DDP_FLAGS1_PUSH 0x01
+#define DDP_FLAGS1_QUERY 0x02
+#define DDP_FLAGS1_REPLY 0x04
+#define DDP_FLAGS1_STORAGE 0x08
+#define DDP_FLAGS1_TIME 0x10
+
+#define DDP_ID_DISPLAY 1
+#define DDP_ID_CONFIG 250
+#define DDP_ID_STATUS 251
+
+//1440 channels per packet
+#define DDP_CHANNELS_PER_PACKET 1440 // 480 leds
+
+
+// 
+// copies a 4 byte rgbw buffer to a 3 byte rgb buffer (skipping the w channel)
+// 
+// destination - the buffer to write to
+// source - the buffer to read from
+// length - the number of 4 byte channels in the source buffer
+// 
+void copyRgbwToRgb(byte *destination, byte *source, uint16_t length) {
+
+    uint16_t destinationOffset = 0;
+    uint16_t sourceOffset = 0;
+    
+    for (uint16_t offset = 0; offset < length; offset++)
+    {
+        destination[destinationOffset+0] = source[sourceOffset+0];
+        destination[destinationOffset+1] = source[sourceOffset+1];
+        destination[destinationOffset+2] = source[sourceOffset+2];
+
+        destinationOffset += 3;
+        sourceOffset += 4;
+    }
+}
+
+//
+// Send real time DDP UDP updates to the specified client
+//
+// client - the IP address to send to
+// busLength - the number of pixels
+// rgbwData - a buffer of at least busLength*4 bytes long
+//
+uint8_t realtimeBrodacast(IPAddress client, uint16_t busLength, byte *rgbwData) {
+
+    WiFiUDP ddpUdp;
+    
+    // calclate the number of UDP packets we need to send
+    uint16_t channelCount = busLength * 3;
+    uint16_t packetCount = channelCount / DDP_CHANNELS_PER_PACKET;
+    if (channelCount % DDP_CHANNELS_PER_PACKET) {
+        packetCount++;
+    }
+
+    // allocate a buffer for the UDP packet
+    size_t bufferSize = DDP_HEADER_LEN + DDP_CHANNELS_PER_PACKET ;
+    byte* buffer = (byte*)malloc(bufferSize);
+    if (!buffer) {
+        return 1;
+    }
+
+    memset(buffer, 0, bufferSize);
+
+    // set common header values
+    buffer[0] = DDP_FLAGS1_VER1;
+    buffer[2] = 1;
+    buffer[3] = DDP_ID_DISPLAY;
+
+    // there are 3 channels per RGB pixel
+    int channel = 0; // TODO: allow specifying the start channel
+
+    for (int packetIndex = 0; packetIndex < packetCount; packetIndex++) {
+
+        // how much data is after the header
+        uint16_t packetSize = DDP_CHANNELS_PER_PACKET;
+
+        if (packetIndex == (packetCount -1)) {
+            // last packet, set the push flag
+            buffer[0] = DDP_FLAGS1_VER1 | DDP_FLAGS1_PUSH;
+
+            if (channelCount % DDP_CHANNELS_PER_PACKET) {
+                packetSize = channelCount % DDP_CHANNELS_PER_PACKET;
+            }
+        }
+
+        //offset
+        buffer[4] = (channel & 0xFF000000) >> 24;
+        buffer[5] = (channel & 0xFF0000) >> 16;
+        buffer[6] = (channel & 0xFF00) >> 8;
+        buffer[7] = (channel & 0xFF);
+
+        //size
+        buffer[8] = (packetSize & 0xFF00) >> 8;
+        buffer[9] = packetSize & 0xFF;
+
+        // copy the data into our buffer
+        copyRgbwToRgb(&buffer[DDP_HEADER_LEN], rgbwData, busLength);
+
+        ddpUdp.beginPacket(client, DDP_PORT);
+        ddpUdp.write(buffer, packetSize);
+        ddpUdp.endPacket();
+
+        channel += packetSize;
+    }
+}

wled00/DDP.h

@@ -0,0 +1,4 @@
+#define DDP_PORT 4048
+
+#define DDP_PUSH_FLAG 0x01
+#define DDP_TIMECODE_FLAG 0x10