/*EtchaSketch
 * 2 pots, X,Y, increment, and plot lines. might require error checks, and corrections
 * increment accordingly
 * 
 * This program communicates on the serial port, to a seprate program that handles the drawing of recieved cordinates.  
 *
 */
/**Fucntion Defs**/
void svgHeader();
void svgFooter();
void polyLineBegin();
void polyLineEnd();

int Reset = 4;     //programticaly reset the arduino  
int potX = A0;    
int potY = A1;    

int sensorValX = 0;  
int sensorValY = 0;  

int oldX = 0;
int oldY = 0;

int del = 2;       //a button on pin 2 for deleting drawn content 
int delbutton = 0;

void setup() {
    Serial.begin(9600);
    pinMode(del, INPUT);
    delay(1000);
}

void loop() {
  // close the svg and start over
  if(digitalRead(del) == LOW ){
	   delbutton=1;
     polyLineEnd();
     svgFooter();
     digitalWrite(Reset, LOW);
     digitalWrite(Reset, HIGH);
     svgHeader();
     polyLineBegin();
	  }else{
			  delbutton=0;
		  }	  

  sensorValX = analogRead(potX);
  sensorValY = analogRead(potY);
/*dont draw if pots not changing    
  Ah but the sensors are noisy, so thresholding
*/
int threshold =3;
int xVariance = abs(sensorValX-oldX);
int yVariance = abs(sensorValY-oldY);
if (xVariance >=threshold && yVariance >= threshold ||xVariance >=threshold || yVariance >=threshold){
    Serial.print(sensorValX);
    Serial.print(",");
    Serial.print(sensorValY);
    Serial.print(",");
    delay(100);
    oldX=sensorValX;
    oldY=sensorValY; 
    }else{
       ; //dont do shi.
    }
} //end loop

 /**Functions**/

void polyLineBegin(){
  Serial.println ("<polyline points=\""); //x,y points go here
  
  }
  
void polyLineEnd(){
   Serial.println ("0, 0\" stroke=\"red\" fill=\"transparent\" stroke-width=\"5\"/>");  //a dirty hack to avoid dealing with 1 last trailing comma.
  }

void svgHeader(){
Serial.println("<svg width=\"1023\" height=\"1023\" version=\"1.1\" xmlns=\"http://www.w3.org/2000/svg\">"); 
  };  
  
void svgFooter(){
Serial.println ("</svg>");
  };