//F_lying 
//Fastled 16x16 rgb led matrix demo
//Yaroslaw Turbin, 27.10.2020 
//https://vk.com/ldirko
//https://www.reddit.com/user/ldirko/

#include "FastLED.h"

// Matrix size
#define NUM_ROWS 16
#define NUM_COLS 16
// LEDs pin
#define DATA_PIN 3
// LED brightness
#define BRIGHTNESS 255
#define NUM_LEDS NUM_ROWS * NUM_COLS
// Define the array of leds
CRGB leds[NUM_LEDS];


void setup() {
  FastLED.addLeds<NEOPIXEL, DATA_PIN>(leds, NUM_LEDS);
  FastLED.setBrightness(BRIGHTNESS);
}

void loop() {
static byte hue =0;
EVERY_N_MILLISECONDS(30) { hue++; }  //30 - speed of hue change

byte x1 = beatsin8 (18, 0, (NUM_COLS-1));
byte x2 = beatsin8 (23, 0, (NUM_COLS-1)); 
byte x3 = beatsin8 (27, 0, (NUM_COLS-1)); 
byte x4 = beatsin8 (31, 0, (NUM_COLS-1)); 
byte x5 = beatsin8 (33, 0, (NUM_COLS-1)); 

byte y1 = beatsin8 (20, 0, (NUM_ROWS-1)); 
byte y2 = beatsin8 (26, 0, (NUM_ROWS-1));
byte y3 = beatsin8 (15, 0, (NUM_ROWS-1));
byte y4 = beatsin8 (27, 0, (NUM_ROWS-1));
byte y5 = beatsin8 (30, 0, (NUM_ROWS-1));

CRGB color = CHSV (hue,255,BRIGHTNESS);

fadeToBlackBy (leds,NUM_LEDS, 30 );

mydrawLine(x1, y1,  x2, y2, color,1);
mydrawLine(x2, y2,  x3, y3, color,1);
mydrawLine(x2, y2,  x4, y4, color,1);
mydrawLine(x3, y3,  x4, y4, color,1);
mydrawLine(x3, y3,  x1, y1, color,1);
mydrawLine(x4, y4,  x1, y1, color,1);

blur2d (leds,NUM_COLS, NUM_ROWS, 64 );
FastLED.show();

} //loop


uint16_t XY (uint8_t x, uint8_t y) {
  return (y * NUM_COLS + x);
}

void mydrawLine (byte x, byte y, byte x1, byte y1, CRGB color, bool dot){   // my ugly line draw function )))

byte xsteps = abs8(x-x1)+1;  
byte ysteps = abs8(y-y1)+1;
byte steps =  xsteps >= ysteps? xsteps:ysteps;

for (byte i = 1; i <= steps; i++) {
byte dx = lerp8by8 (x, x1, i*255/steps);
byte dy = lerp8by8 (y, y1, i*255/steps);
leds[XY(dx, dy)] += color;    // change to += for brightness look
}

if (dot) {     //add white point at the ends of line 
    leds[XY(x,y)] += CRGB ::White;
    leds[XY(x1,y1)] += CRGB ::White;
         }
}