134 lines
3.7 KiB
C++
134 lines
3.7 KiB
C++
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/*
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** Expected interface:
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**
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** realtimeBrodacast(IPAddress client, uint16_t busLength, byte rgbwData[busLength][4]);
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**
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** http://www.3waylabs.com/ddp/
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*/
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#include <Arduino.h>
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#include <WiFiUdp.h>
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#include "DDP.h"
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#define DDP_HEADER_LEN 10
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#define DDP_SYNCPACKET_LEN 10
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#define DDP_FLAGS1_VER 0xc0 // version mask
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#define DDP_FLAGS1_VER1 0x40 // version=1
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#define DDP_FLAGS1_PUSH 0x01
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#define DDP_FLAGS1_QUERY 0x02
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#define DDP_FLAGS1_REPLY 0x04
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#define DDP_FLAGS1_STORAGE 0x08
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#define DDP_FLAGS1_TIME 0x10
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#define DDP_ID_DISPLAY 1
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#define DDP_ID_CONFIG 250
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#define DDP_ID_STATUS 251
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//1440 channels per packet
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#define DDP_CHANNELS_PER_PACKET 1440 // 480 leds
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//
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// copies a 4 byte rgbw buffer to a 3 byte rgb buffer (skipping the w channel)
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//
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// Parameters:
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// destination - the buffer to write to must be able to hold length*3 bytes
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// source - the buffer to read from
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// length - the number of 4 byte channels in the source buffer
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// Returns:
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// the pointer in the source where we have copied up to
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//
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uint8_t* copyRgbwToRgb(uint8_t *destination, uint8_t *source, uint16_t length) {
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while (length--)
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{
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*(destination++) = *(source++); // R
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*(destination++) = *(source++); // G
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*(destination++) = *(source++); // B
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source++; // W
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}
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return source;
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}
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//
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// Send real time DDP UDP updates to the specified client
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//
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// client - the IP address to send to
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// busLength - the number of pixels
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// rgbwData - a buffer of at least busLength*4 bytes long
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//
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uint8_t realtimeBrodacast(IPAddress client, uint16_t busLength, uint8_t *rgbwData) {
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WiFiUDP ddpUdp;
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// calclate the number of UDP packets we need to send
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uint16_t channelCount = busLength * 3;
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uint16_t packetCount = channelCount / DDP_CHANNELS_PER_PACKET;
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if (channelCount % DDP_CHANNELS_PER_PACKET) {
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packetCount++;
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}
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// allocate a buffer for the UDP packet
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size_t bufferSize = (DDP_HEADER_LEN + DDP_CHANNELS_PER_PACKET) * sizeof(uint8_t);
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uint8_t* buffer = (byte*)malloc(bufferSize);
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if (!buffer) {
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return 1;
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}
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memset(buffer, 0, bufferSize);
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// set common header values
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buffer[0] = DDP_FLAGS1_VER1;
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buffer[2] = 1;
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buffer[3] = DDP_ID_DISPLAY;
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// there are 3 channels per RGB pixel
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int channel = 0; // TODO: allow specifying the start channel
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// if we need to split
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//
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//
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for (uint16_t currentPacket = 0; currentPacket < packetCount; currentPacket++) {
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// how much data is after the header
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uint16_t packetSize = DDP_CHANNELS_PER_PACKET;
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if (currentPacket == (packetCount - 1)) {
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// last packet, set the push flag
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// TODO: determine if we want to send an empty push packet to each destination after sending the pixel data
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buffer[0] = DDP_FLAGS1_VER1 | DDP_FLAGS1_PUSH;
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if (channelCount % DDP_CHANNELS_PER_PACKET) {
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packetSize = channelCount % DDP_CHANNELS_PER_PACKET;
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}
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}
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// data offset in bytes, 32-bit number, MSB first
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buffer[4] = (channel & 0xFF000000) >> 24;
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buffer[5] = (channel & 0xFF0000) >> 16;
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buffer[6] = (channel & 0xFF00) >> 8;
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buffer[7] = (channel & 0xFF);
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// data length in bytes, 16-bit number, MSB first
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buffer[8] = (packetSize & 0xFF00) >> 8;
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buffer[9] = packetSize & 0xFF;
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// copy the data from the source buffer into our pack
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rgbwData = copyRgbwToRgb(&buffer[DDP_HEADER_LEN], rgbwData, packetSize);
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ddpUdp.beginPacket(client, DDP_PORT);
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ddpUdp.write(buffer, packetSize);
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ddpUdp.endPacket();
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channel += packetSize;
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}
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free(buffer);
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return 0;
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}
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