/*  GT911_ESP32v2
 *    05/04/2024
 Bug fixed effecting certain boards
     Basic sketch to see if I ca get ESP32 to work with GT911 touch screen
     working for multiple touch

     Debounce needs to be removed for multiple touches but is included
     to make the output easier to read

  Screen > Pins Used ESP32 Dev Module

     RST > GPIO 15
     VCC > 3.3v
     GND > GND
     INT > GPIO 2
     SDA > SDA (GPIO 21)
     SCL > SCL (GPIO 22)
*/
//Used for GT911
#include "Wire.h"

uint8_t addr  = 0x5d;  //CTP IIC ADDRESS
const int GT911_RESET = 15;   //CTP RESET
const int GT911_INT =   2;   //CTP  INT



unsigned long captouchbounce = 0;//like button bounce for touch
int captouched = 0;//1 means there has been a touch
int captouchx = 0;
int captouchy = 0;
int lastpixeltouched = 1000;//keeps track of the last touched pixel to prevent excess bounce

unsigned char  GTP_CFG_DATA[] =
{
  0x5A, 0x20, 0x03, 0xE0, 0x01, 0x05, 0x0D, 0x00,
  0x01, 0x08, 0x28, 0x08, 0x50, 0x32, 0x03, 0x05,
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  0x00, 0x00, 0x00, 0x88, 0x29, 0x0A, 0x35, 0x37,
  0xD3, 0x07, 0x00, 0x00, 0x01, 0x81, 0x02, 0x1D,
  0x00, 0x01, 0x00, 0x00, 0x00, 0x03, 0x64, 0x32,
  0x00, 0x00, 0x00, 0x28, 0x5A, 0x94, 0xC5, 0x02,
  0x00, 0x00, 0x00, 0x00, 0x98, 0x2B, 0x00, 0x84,
  0x33, 0x00, 0x74, 0x3C, 0x00, 0x67, 0x46, 0x00,
  0x5C, 0x53, 0x00, 0x5C, 0x00, 0x00, 0x00, 0x00,
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  0x02, 0x04, 0x06, 0x08, 0x0A, 0x0C, 0x0E, 0x10,
  0x12, 0x14, 0xFF, 0xFF, 0xFF, 0xFF, 0x00, 0x00,
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x02,
  0x04, 0x06, 0x08, 0x0F, 0x10, 0x12, 0x16, 0x18,
  0x1C, 0x1D, 0x1E, 0x1F, 0x20, 0x21, 0x22, 0xFF,
  0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  0x25, 0x01
};

struct TouchLocation
{
  uint16_t x;
  uint16_t y;
};



TouchLocation touchLocations[5];

void inttostr(uint16_t value, uint8_t *str);
uint8_t GT911_Send_Cfg(uint8_t * buf, uint16_t cfg_len);
void writeGT911TouchRegister( uint16_t regAddr, uint8_t *val, uint16_t cnt);
uint8_t readGT911TouchAddr( uint16_t regAddr, uint8_t * pBuf, uint8_t len );
uint8_t readGT911TouchLocation( TouchLocation * pLoc, uint8_t num );
uint32_t dist(const TouchLocation & loc);
uint32_t dist(const TouchLocation & loc1, const TouchLocation & loc2);
bool sameLoc( const TouchLocation & loc, const TouchLocation & loc2 );

uint8_t buf[80];

void gt911setup() {

  delay(300);
  pinMode(GT911_RESET, OUTPUT);
  pinMode     (GT911_INT, OUTPUT);
  digitalWrite(GT911_RESET, LOW);
  delay(20);
  digitalWrite(GT911_INT, LOW);
  delay(50);
  digitalWrite(GT911_RESET, HIGH);
  delay(100);
  pinMode     (GT911_RESET, INPUT);
  delay(100);
  uint8_t re = GT911_Send_Cfg((uint8_t*)GTP_CFG_DATA, sizeof(GTP_CFG_DATA));
  pinMode(GT911_RESET, OUTPUT);
  pinMode     (GT911_INT, OUTPUT);
  digitalWrite(GT911_RESET, LOW);
  delay(20);
  digitalWrite(GT911_INT, LOW);
  delay(50);
  digitalWrite(GT911_RESET, HIGH);
  delay(100);
  pinMode     (GT911_INT, INPUT);
  delay(100);
  re = GT911_Send_Cfg((uint8_t*)GTP_CFG_DATA, sizeof(GTP_CFG_DATA));
  uint8_t bb[2];
  readGT911TouchAddr(0x8047, bb, 2);
  while (bb[1] != 32) {
    Serial.println("Capacitive touch screen initialized failure");
    pinMode(GT911_RESET, OUTPUT);
    pinMode     (GT911_INT, OUTPUT);
    digitalWrite(GT911_RESET, LOW);
    delay(20);
    digitalWrite(GT911_INT, LOW);
    delay(50);
    digitalWrite(GT911_RESET, HIGH);
    delay(100);
    pinMode     (GT911_INT, INPUT);
    delay(100);
    uint8_t re = GT911_Send_Cfg((uint8_t*)GTP_CFG_DATA, sizeof(GTP_CFG_DATA));
  }
  Serial.println("Capacitive touch screen  initialized success");

}

void scani2c() {
  byte error, address;
  int nDevices;
  Serial.println("Scanning...");
  nDevices = 0;
  for (address = 1; address < 127; address++ )
  {
    // The i2c_scanner uses the return value of
    // the Write.endTransmisstion to see if
    // a device did acknowledge to the address.
    Wire.beginTransmission(address);
    error = Wire.endTransmission();

    if (error == 0)
    {
      Serial.print("I2C device found at address 0x");
      if (address < 16)
        Serial.print("0");
      Serial.print(address, HEX);
      Serial.println("  !");

      nDevices++;
    }
    else if (error == 4)
    {
      Serial.print("Unknown error at address 0x");
      if (address < 16)
        Serial.print("0");
      Serial.println(address, HEX);
    }
  }
  if (nDevices == 0)
    Serial.println("No I2C devices found\n");
  else
    Serial.println("done\n");
}



uint8_t GT911_Send_Cfg(uint8_t * buf, uint16_t cfg_len)
{
  uint8_t retry = 0;
  for (retry = 0; retry < 5; retry++)
  {
    writeGT911TouchRegister(0x8047, buf, cfg_len);
    //if(ret==0)break;
    delay(10);
  }
  return retry;
}

void writeGT911TouchRegister( uint16_t regAddr, uint8_t *val, uint16_t cnt)
{
  uint16_t i = 0;

  Wire.beginTransmission(addr);
  Wire.write( regAddr >> 8 ); // register 0
  Wire.write( regAddr);  // register 0
  for (i = 0; i < cnt; i++, val++) //data
  {
    Wire.write( *val );  // value
  }
  uint8_t retVal = Wire.endTransmission();

}

uint8_t readGT911TouchAddr( uint16_t regAddr, uint8_t * pBuf, uint8_t len )
{
  uint8_t i;
  uint8_t returned;
  uint8_t retVal;
  Wire.beginTransmission(addr);
  Wire.write( regAddr >> 8 ); // register 0
  Wire.write( regAddr);  // register 0
  retVal = Wire.endTransmission();
  
  returned = Wire.requestFrom(addr, len);    // request 1 bytes from slave device #2
  for (i = 0; (i < len) && Wire.available(); i++)

  {
    pBuf[i] = Wire.read();
  }
   return i;
}




uint8_t readGT911TouchLocation( TouchLocation * pLoc, uint8_t num )
{
  uint8_t retVal;
  uint8_t i;
  uint8_t k;
  uint8_t  ss[1];

  do
  {
    
    if (!pLoc) break; // must have a buffer
    if (!num)  break; // must be able to take at least one
    ss[0] = 0;
    
    readGT911TouchAddr( 0x814e, ss, 1);
    uint8_t status = ss[0];
    
    
    if ((status & 0x0f) == 0) break; // no points detected
    uint8_t hitPoints = status & 0x0f;
      //Serial.print("number of hit points = ");
     //  Serial.println( hitPoints );
    //uint8_t tbuf[32];//original code, buffer is too small
    uint8_t tbuf[40];//changed to 40 as that is number called for in  readGT911TouchAddrTest( 0x8150, tbuf, 40); 
    uint8_t tbuf1[8];
    readGT911TouchAddr( 0x8150, tbuf, 40);
    readGT911TouchAddr( 0x8150 + 32, tbuf1, 8);

    for (k = 0, i = 0; (i <  4 * 8) && (k < num); k++, i += 8)
    {
      pLoc[k].x = tbuf[i + 1] << 8 | tbuf[i + 0];
      pLoc[k].y = tbuf[i + 3] << 8 | tbuf[i + 2];
    }
    pLoc[k].x = tbuf1[1] << 8 | tbuf1[0];
    pLoc[k].y = tbuf1[3] << 8 | tbuf1[2];
    
    retVal = hitPoints;
    
  } while (0);

  ss[0] = 0;
  writeGT911TouchRegister( 0x814e, ss, 1);
  
  delay(2);
  return retVal;
}

void checkfortouchscreen() {
  int q;
  captouched = 0;
  pinMode     (GT911_INT, INPUT);
  uint8_t st = digitalRead(GT911_INT);
  if (!st)  //Hardware touch interrupt
  {
    //Serial.println("Touch: ");
    
    uint8_t count = readGT911TouchLocation( touchLocations, 5 );
    
       
    
    if (count > 0) {
      
      static TouchLocation caplastTouch = touchLocations[0];// only take single touch, not dealing with multitouch
      caplastTouch = touchLocations[0];
      if (millis() > captouchbounce) { //cuts out multitouch
        captouchbounce = millis() + 250;//debounce value, probably best to remove when trying to capture multi touches
        //as two fingers may touch at sligtly different timings.
        //left in to make the output easier to read.
        Serial.print("Touches: ");
        Serial.println(count);
        //works through the aray of x/y locations
        //If touch gestures are being worked out you would need to store these values and compare with the next set.
        //for gestures you will probably need to remove the debounce
        for(q=0;q < count;q++){
          captouched = 1;
          captouchx = touchLocations[q].x;
          captouchy = touchLocations[q].y;
          Serial.print(captouchx);
          Serial.print(" : ");
          Serial.println(captouchy);  
        }
        //only using first touch for now
        /*
        if (touchLocations[0].x > 0 && touchLocations[0].y > 0) { //only do somethng if there is an x and Y value
          captouched = 1;
          captouchx = touchLocations[0].x;
          captouchy = touchLocations[0].y;
          Serial.print(captouchx);
          Serial.print(" : ");
          Serial.println(captouchy);
         
        }
        */
      }
    }
    
  }
}


void setup() {
  Serial.begin(115200);
  Serial.println("GT911_ESP32v2 Multi Touch");

  Wire.begin();
  scani2c();

  gt911setup();

}

void loop() {
  checkfortouchscreen();

}