#include <TFT_eSPI.h>
#include <Wire.h>

//#define SPI_FREQUENCY  40000000
//#define SPI_READ_FREQUENCY  16000000


#define PIN_IN1 27
#define PIN_IN2 14

#define RED2RED     0
#define GREEN2GREEN 1
#define BLUE2BLUE   2
#define BLUE2RED    3
#define GREEN2RED   4
#define RED2GREEN   5
#define RAINBOW     6

TFT_eSPI tft = TFT_eSPI();

void setup() {

  tft.begin();
  tft.writecommand(0x11);
  tft.setRotation(3);
}

void loop() {
 tft.fillScreen(TFT_BLACK);
 tft.drawCircle(120, 120, 120, TFT_WHITE);
    
 tft.setTextColor(TFT_WHITE, TFT_BLACK);
 tft.setTextDatum(TL_DATUM);

 for (int i=0 ; i<8 ; i++) {
   linearMeter(random(0,34), 30, 40+i*20, 3, 15, 0, 35, GREEN2RED);
   tft.drawString("(A) Extern", 142, 42+i*20); 
 
 }
 delay(5000);
}

void linearMeter(int val, int x, int y, int w, int h, int g, int n, byte s) {
  // Variable to save "value" text colour from scheme and set default
  int colour = TFT_BLUE;
  // Draw n colour blocks
  for (int b = 1; b <= n; b++) {
    if (val > 0 && b <= val) { // Fill in coloured blocks
      switch (s) {
        case 0: colour = TFT_RED; break; // Fixed colour
        case 1: colour = TFT_GREEN; break; // Fixed colour
        case 2: colour = TFT_BLUE; break; // Fixed colour
        case 3: colour = rainbowColor(map(b, 0, n, 127,   0)); break; // Blue to red
        case 4: colour = rainbowColor(map(b, 0, n,  63,   0)); break; // Green to red
        case 5: colour = rainbowColor(map(b, 0, n,   0,  63)); break; // Red to green
        case 6: colour = rainbowColor(map(b, 0, n,   0, 159)); break; // Rainbow (red to violet)
      }
      tft.fillRect(x + b*(w+g), y, w, h, colour);
    }
    else // Fill in blank segments
    {
      tft.fillRect(x + b*(w+g), y, w, h, TFT_DARKGREY);
    }
  }
}

uint16_t rainbowColor(uint8_t spectrum) {
  spectrum = spectrum%192;
  
  uint8_t red   = 0; // Red is the top 5 bits of a 16 bit colour spectrum
  uint8_t green = 0; // Green is the middle 6 bits, but only top 5 bits used here
  uint8_t blue  = 0; // Blue is the bottom 5 bits

  uint8_t sector = spectrum >> 5;
  uint8_t amplit = spectrum & 0x1F;

  switch (sector)
  {
    case 0:
      red   = 0x1F;
      green = amplit; // Green ramps up
      blue  = 0;
      break;
    case 1:
      red   = 0x1F - amplit; // Red ramps down
      green = 0x1F;
      blue  = 0;
      break;
    case 2:
      red   = 0;
      green = 0x1F;
      blue  = amplit; // Blue ramps up
      break;
    case 3:
      red   = 0;
      green = 0x1F - amplit; // Green ramps down
      blue  = 0x1F;
      break;
    case 4:
      red   = amplit; // Red ramps up
      green = 0;
      blue  = 0x1F;
      break;
    case 5:
      red   = 0x1F;
      green = 0;
      blue  = 0x1F - amplit; // Blue ramps down
      break;
  }

  return red << 11 | green << 6 | blue;
}