main.cpp

#include <string>
#include <vector>
#include <cmath>
#include <fcntl.h>
#include <termios.h>
#include <unistd.h>

void set_interface_attribs(int fd, int speed) {
    termios tty{};
    if (tcgetattr(fd, &tty) != 0) return; // copying current settings from file descriptor in tty 
    cfsetospeed(&tty, speed); // output speed 
    cfsetispeed(&tty, speed); // input speed
    tty.c_cflag = (tty.c_cflag & ~CSIZE) | CS8; // setting strong format size for frame
    tty.c_iflag &= ~IGNBRK; // turning off ignoring disconnect
    tty.c_lflag = 0; // disable echo and canonical mode
    tty.c_oflag = 0; // turning off output processing 
    tty.c_cc[VMIN] = 0; // read doesn't block (return immediately)
    tty.c_cc[VTIME] = 5; // timeout for reading 0.5s
    tty.c_cflag |= (CLOCAL | CREAD); // ignoring other console lines and accepting for reading from port
    tty.c_cflag &= ~(PARENB | PARODD); // turning off checking errors
    tty.c_cflag &= ~CSTOPB; // using 1 stop bit
    tty.c_cflag &= ~CRTSCTS; // turning off hardware management
    tcsetattr(fd, TCSANOW, &tty); // apply right now
}

int main(int argc, char* argv[]) {
    const char* port = "/dev/ttyUSB0"; // or your any other device which you can see with command 'lsusb'
    int num_leds = 255; // default value ( i guess )
    int speed_baud = B115200; // also default value
    std::string mode = (argc > 1) ? (argv[1]) : "neon"; 
    float speed_step = (argc > 2) ? std::stof(argv[2]) : 0.15f;
    int fd = open(port, O_RDWR | O_NOCTTY | O_SYNC); // read and write access | ignore terminal control signals | sync output 
    set_interface_attribs(fd, speed_baud); // set port speed

    float t = 0;
    std::vector<unsigned char> header = {'A', 'd', 'a', 0x00, 0xFF, 0xAA}; // Adalight protocol frame header for 255 leds

    while (true) {
        std::vector<unsigned char> payload;
        payload.reserve(num_leds * 3);

        for (int i = 0; i < num_leds; ++i) {  // frame generating
            float r = 0, g = 0, b = 0;
            if (mode == "rainbow") {
            	float hue = fmodf(t + i * 0.05f, 6.0f);
            	float x = 255.0f * (1.0f - fabsf(fmodf(hue, 2.0f) - 1.0f));
            		if (hue < 1.0f)  { r = 255; g = x;   b = 0; }
            		else if (hue < 2.0f) { r = x;   g = 255; b = 0; }
            		else if (hue < 3.0f) { r = 0;   g = 255; b = x; }
            		else if (hue < 4.0f) { r = 0;   g = x;   b = 255; }
            		else if (hue < 5.0f) { r = x;   g = 0;   b = 255; }
	           		else { r = 255; g = 0;   b = x; }
   			} else if (mode == "red") r = 255;
        	else if (mode == "blue") b = 255;
        	else if (mode == "green") g = 255;
        	else if (mode == "purple") r = 128, b = 255;
        	else if (mode == "yellow") r = 255, g = 255;
        	else if (mode == "orange") r = 255, g = 140;
        	else if (mode == "turquoise") g = 255, b = 215;
        	else if (mode == "neon") {
        		float wave = (sin(t + i * 0.1f) + 1.0f) / 2.0f;
        		r = 120 + 135 * sin(t * 0.5f + i * 0.05f) / 2.0f;
        		b = 255 * wave;
			} else return 1;
            payload.push_back(static_cast<unsigned char>(r));
            payload.push_back(static_cast<unsigned char>(g));
            payload.push_back(static_cast<unsigned char>(b));
        }
		ssize_t res;
		res = write(fd, header.data(), header.size());
		res = write(fd, payload.data(), payload.size());
		(void)res;
        t += speed_step;
    	if (t > 1000.0) t = 0.0f;

        usleep(20000); // 20ms = 50 FPS
    }

    close(fd);
    return 0;
}