let cnv;

let dx;

let dy;

let cap;

​

function preload() {

​

}

​

function setup() {

  createCanvas(360, 360);

   background(255);

  cap=createCapture(VIDEO);

  cap.hide();

  x = a = width / 2;

  y = b = height / 2;

  // frameRate(100);

  img=image(cap,0,0,width,height);

  // dx = 0;

  // dy = 0;

}

​

function changeGraay() {

   dx = mouseX - x;

   dy = mouseY - y;

}

​

​

function draw() {

  //笔触跟随鼠标趋势运动 

  // 方法一为什么失灵？

  // if (mouseX > 0 && mouseX < 300  ) {

  // // if(mouseY > 300 || mouseY < 0){

  //   let dx = mouseX - x;

  //   let dy = mouseY - y;

  // // }

  // } 

​

  // 方法二 dist

  // let r2 = dist(mouseX, mouseY, 300, 300);

  // if (r2 > 500) {

  //   let dx = 0;

  //   let dy = 0;

  // }

​

​

  // 鼠标可以增加周围笔触精准度

  //   let r = dist(mouseX, mouseY, x, y);

  //   let value = 1;

  //   if (r < 50) {

  //     let value = 0.6

  //   }else if(r<=50){

  //       let value = 1

  //       }

  dx = mouseX - x;

   dy = mouseY - y;

​

​

​

  strokeWeight(2);

  noFill();

  // line(x, y, newx, newy);

  // bezier(x, y, x + random(-10, 10), y + random(-10, 10), newx + random(-10, 10), newy + random(-10, 10), newx, newy);

  ix=random(0,width);

  iy=random(0,height);

      let col = cap.get(floor(ix), floor(iy));

    stroke(col[1],100);

  line(ix,iy,ix,iy+random(-100,100));

  iix=random(0,width);

  iiy=random(0,height); 

        let col1 = cap.get(floor(iix), floor(iiy));

    stroke(col1[1],100);

  line(iix,iiy,iix,iiy+random(-100,100));

    ix1=random(0,width);

  iy1=random(0,height);

      let col11 = cap.get(floor(ix1), floor(iy1));

    stroke(col11[1],100);

  line(ix1,iy1,ix1,iy1+random(-100,100));

  iix2=random(0,width);

  iiy2=random(0,height); 

        let col12 = cap.get(floor(iix2), floor(iiy2));

    stroke(col12[1],100);

  line(iix2,iiy2,iix2,iiy2+random(-100,100));

​

  // console.log(col);

//   x = newx;

//   y = newy;

}