/* built with Studio Sketchpad: 
 *   https://sketchpad.cc
 * 
 * observe the evolution of this sketch: 
 *   https://studio.sketchpad.cc/sp/pad/view/ro.MWiBupPH-US/rev.1594
 * 
 * authors: 
 *   Pavel Kostenko (Chrome)
 *   Pavel Kostenko
 *   Pavel Kostenko (Opera)

 * license (unless otherwise specified): 
 *   creative commons attribution-share alike 3.0 license.
 *   https://creativecommons.org/licenses/by-sa/3.0/ 
 */ 



// Pressing Control-R will render this sketch.
// You can use leftMouseButton and RightMouseButton to change vectors

v1 = new PVector(50, 100); // red
v2 = new PVector(100, 50); // blue
vSum = PVector.add(v1, v2);
vSub = PVector.sub(v1, v2);
float dx = dy = 150;
float v1mag = v1.mag();
float v2mag = v2.mag();
float vDist = vSub.mag();
void setup() {  // this is run once.   
    
    // set the background color
    background(255);
    
    // specify canvas size
    size(300, 300); 
      
    // smooth edges
    smooth();
    
    // limit the number of frames per second
    frameRate(30);
    
    // set the width of the line. 
    strokeWeight(2);
    colorMode(HSB, 255);
} 

void draw() {  // this is run repeatedly.
    background(255);
    fill(1, 0, 0);
    
    // Vector#1
    stroke(10, 250, 250);
    line(0 + dx, 0 + dy, v1.x + dx, v1.y + dy);
    circle(v1.x + dx, v1.y + dy, 2);
    
    // Vector#2
    stroke(180, 250, 250);
    line(0 + dx, 0 + dy, v2.x + dx, v2.y + dy);
    circle(v2.x + dx, v2.y + dy, 2);
    
    // draw vector addition
    stroke(110, 250, 250);
    line(0 + dx, 0 + dy, vSum.x + dx, vSum.y + dy);
    circle(vSum.x + dx, vSum.y + dy, 3);
    //
    
    text('v1.mag = ' + v1mag, 0, 10);
    text('v2.mag = ' + v2mag, 0, 20);
    text('vDist = ' + vDist, 0, 30);
}

void mousePressed() {
    //x1 = mouseX;
   // y1 = mouseY;
    //stroke(random(220, 250), 250, 250);
    
}

void mouseDragged() {
    if (mouseButton == LEFT) {
        v1.x = mouseX - dx;
        v1.y = mouseY - dy;
        v1mag = v1.mag();
    } else {
        v2.x = mouseX - dx;
        v2.y = mouseY - dy;
        v2mag = v2.mag();
    }
    vSum = PVector.add(v1, v2);
    vSub = PVector.sub(v1, v2);
    vDist = vSub.mag();
    fill(1, 0, 0);
}

void mouseReleased() {
    if (mouseButton == LEFT) {
        v1.x = mouseX - dx;
        v1.y = mouseY - dy;
    } else if (mouseButton == RIGHT) {
        v2.x = mouseX - dx;
        v2.y = mouseY - dy;
    }
    vSum = PVector.add(v1, v2);
    vSub = PVector.sub(v1, v2);
    //println('angle between vectors is ' + round(getAngleBetweenVectors(v1, v2)));
    //println('distance between vector heads is ' + round(vSub.mag()));
}

void circle(x, y, r) {
    ellipse(x, y, r * 2, r * 2);
}

float getAngleBetweenVectors(v1, v2) {
    float theta = acos(v1.dot(v2) / (v1.mag() * v2.mag()));
    theta = (theta * 180) / PI; // convert radians to degrees
    return theta;
}