/*Processing.js
Snake
A snake that follows your cursor.

RIP: moving as in snake
Snake

Sebas E. first steps in processing
*/
float positionX =250;
float positionY =250;
float px=100;
float py=200;

float[] x = new float[20];
float[] y = new float[20];
float segLength = 10;

void setup() {
  size(500, 500);
  smooth();
   background(20,20);
}

void draw() {
 
  //image( loadImage("dirt.jpg"), 0, 0 );
  dragSegment(0, positionX ,positionY);
  for(int i=0; i < x.length-1; i++) {
    dragSegment(i+1, x[i], y[i]);
  }
  //set new position
  positionX = (positionX + 0.1*px);
  positionY= (positionY + 0.1*py);
 
 
 if((positionX<=0 && px<0) || (positionX>=width && px>0)){px *=-1;}
 if(positionY>=height && py>0){py *=-1.001; background(random
(255),random(255),random(255),20);} // AE: transp adapted 
 if(positionY<=0 && py <0){py *=-1;}
 
 py +=7;
 
 constrain(positionX,0,width);
 constrain(positionY,0,height);
}

//push and pause
void keyPressed(){
  if(key == 'd'){ px += 5;}
  if(key == 'a'){  px += -5;}
  if(key == 's'){  py=1;}
  if(key == 'w'){  py=-1;}
  if(key == 'p'){px = 0; py=0;}
}



void dragSegment(int i, float xin, float yin) {
  float dx = xin - x[i];
  float dy = yin - y[i];
  float angle = atan2(dy, dx);  
  x[i] = xin - cos(angle) * segLength;
  y[i] = yin - sin(angle) * segLength;
  //stroke(23, 79, 4, 220);
  

  pushMatrix();
  translate(x[i], y[i]);
  rotate(angle);
  
  color c;
  
  if ( i % 3 == 1 )
    c = color(0, 0, 0, 255);
  else if ( i % 3 == 2 )
    c = color(255, 255, 0, 255);
  else
    c = color(255, 0, 0, 255);

  stroke( c );
  strokeWeight(10);
  line(0, 0, segLength, 0);
  
  if ( i == x.length - 1 )
  {
    fill( c );
    noStroke();
    beginShape(TRIANGLES);
    vertex(0, 5);
    vertex(-2 * segLength, 0);
    vertex(0, -5);
    endShape();
  }
  
  if ( i == 0 )
  {
   // stroke(0, 255);
   noStroke();
   fill(0, 255);
   ellipse(segLength, -2, 3, 3);
   ellipse(segLength, 2, 3, 3);
    //point(segLength, -2);
    //point(segLength, 2);
  }
  
  popMatrix();
}