const h = 400;

const d = 100;

let v = 5;

var t = 0;

var v1;

var v2;

var v3;

var v4;

var V;

var VR = [];

var Vt;

var PV;

var PC;

const E = [

  [0, 1],

  [1, 3],

  [3, 2],

  [2, 0],

];

function matmul(a,b){

  var res=[]

  var sum=0

  for(i=0;i<a.length;i++){

    for(j=0;j<b.length;j++){

      res.push([])

      for(k=0;k<b.length;k++){

        sum+=a[j][k]+b[k][i]

      }

      res[i].push(sum)

      console.log(res[i])

    }

  }

  return res

}

console.log(matmul([[0,1],[1,0]],[[1,2],[3,4]]))

function setup() {

  createCanvas(w, h, WEBGL);

  v1 = createVector(-10, -10, d);

  v2 = createVector(10, -10, d);

  v3 = createVector(-10, 10, d);

  v4 = createVector(10, 10, d);

  V = [v1, v2, v3, v4];

  //console.log(Vf[i].x);

  //console.log(v1)

}

function forward() {

  for (i = 0; i < V.length; i++) {

    V[i].add(0, 0, -v);

  }

  //console.log(Vf)

}

function back() {

  for (i = 0; i < V.length; i++) {

    V[i].add(0, 0, v);

  }

}

function sleft() {

  for (i = 0; i < V.length; i++) {

    V[i].add(v / 10);

  }

}

function sright() {

  for (i = 0; i < V.length; i++) {

    V[i].add(-v / 10);

    //console.log(Vf[i])

  }

}

function lleft() {

  t += PI / 180;

}

function lright() {

  t -= PI / 180;

}

function draw() {

  //translate(w / 2, h / 2);

  var Rx = [

    [1, 0, 0],

    [0, cos(t), -sin(t)],

    [0, sin(t), cos(t)],

  ];

  var Ry = [

    [cos(t), 0, -sin(t)],

    [0, 1, 0],

    [sin(t), 0, cos(t)],

  ];

  background(220);

  if (keyIsDown(188) || keyIsDown(87)) {

    forward();

    //console.log(Vf)

  }

  if (keyIsDown(79) || keyIsDown(83)) {

    back();

  }

  if (keyIsDown(222) || keyIsDown(81)) {

    sleft();

  }

  if (keyIsDown(190)) {

    sright();

  }

  if (keyIsDown(65)) {

    lleft();

    //print(t)

  }

  if (keyIsDown(69)) {

    lright();

  }

  PV = [];

  PC = [];

  //console.log(v1)

  VR = [];

  for (i = 0; i < V.length; i++) {

    //print(cos(t))

    //print(sin(t))

    //print(V[i])

    VR.push([

      cos(t) * V[i].x + sin(t) * V[i].z,

      V[i].y,

      -sin(t) * V[i].x + cos(t) * V[i].z,

    ]);

    //print(VR[i])

    per0 = atan(VR[i][0] / VR[i][2]);

    //console.log(per0)

    //console.log((Vf[i]-p))

    //console.log(Vf[i][0]+','+Vf[i].z)

    per1 = atan(VR[i][1] / mag(VR[i][0], VR[i][2]));

    //print(per1)

    //console.log(Vt[i])

    //PC.append([d*sw*per1,d*sh*per0])

    PC.push([VR[i][2] * w * per0, VR[i][2] * h * per1]);

    PV.push([

      (abs(per0) * w * VR[i][0]) / abs(VR[i][0]),

      (abs(per1) * h * VR[i][1]) / abs(VR[i][1]),

    ]);

    //print(PV)

  }

  for (i = 0; i < E.length; i++) {

    //console.log(PV[0][0])

    //console.log(PV[0][1])

    //console.log(PV[1])

    //console.log(PV[1][1])

    line(PV[E[i][0]][0], PV[E[i][0]][1], PV[E[i][1]][0], PV[E[i][1]][1]);

    line(PV[E[i][0]][0], PV[E[i][0]][1], PC[E[i][0]][0], PC[E[i][0]][1]);

  }

}

​