cube.js

class Vector3{
  constructor(x,y,z){
    this.x = x;
    this.y = y;
    this.z = z;
  }
}

class Vector2{
  constructor(x,y){
    this.x = x;
    this.y = y;
  }
}

function transformation(point, cam_pos, cam_angle, display){
  x = point.x - cam_pos.x;
  y = point.y - cam_pos.y;
  z = point.z - cam_pos.z;
  dx = Math.cos(cam_angle.y) * (Math.sin(cam_angle.z) * y + Math.cos(cam_angle.z) * x) - Math.sin(cam_angle.y) * z;
  dy = Math.sin(cam_angle.x) * (Math.cos(cam_angle.y) * z + Math.sin(cam_angle.y) * (Math.sin(cam_angle.z) * y + Math.cos(cam_angle.z) * x)) + Math.cos(cam_angle.x) * (Math.cos(cam_angle.z) * y - Math.sin(cam_angle.z) * x);
  dz = Math.cos(cam_angle.x) * (Math.cos(cam_angle.y) * z + Math.sin(cam_angle.y) * (Math.sin(cam_angle.z) * y + Math.cos(cam_angle.z) * x)) - Math.sin(cam_angle.x) * (Math.cos(cam_angle.z) * y - Math.sin(cam_angle.z) * x);

  bx = (display.z/dz) * dx + display.x;
  by = (display.z/dz) * dy + display.y;
  point2D = new Vector2(bx,by);
  return point2D;
}

function multiply(a, b) {
  var aNumRows = a.length, aNumCols = a[0].length,
      bNumRows = b.length, bNumCols = b[0].length,
      m = new Array(aNumRows);  // initialize array of rows
  for (var r = 0; r < aNumRows; ++r) {
    m[r] = new Array(bNumCols); // initialize the current row
    for (var c = 0; c < bNumCols; ++c) {
      m[r][c] = 0;             // initialize the current cell
      for (var i = 0; i < aNumCols; ++i) {
        m[r][c] += a[r][i] * b[i][c];
      }
    }
  }
  return m;
}

function transformation1(point, cam_pos, cam_angle, res, sensor, f, s){
  var sinX = Math.sin(cam_angle.x);
  var sinY = Math.sin(cam_angle.y);
  var sinZ = Math.sin(cam_angle.z);

  var cosX = Math.cos(cam_angle.x);
  var cosY = Math.cos(cam_angle.y);
  var cosZ = Math.cos(cam_angle.z);

  let mat1 = [[(f * res.x)/(2 * sensor.x), s, 0, 0],[0, (f * res.y)/(2 * sensor.y), 0, 0], [0, -1, 1, 0], [0, 0, 0, 1]];
  let mat2 = [[1, 0, 0, 0], [0, cosX, -sinX, 0], [0, sinX, cosX, 0], [0, 0, 0, 1]];
  let mat3 = [[cosY, sinY, 0, 0], [0, 1, 0, 0], [-sinY, cosY, 1, 0], [0, 0, 0, 1]];
  let mat4 = [[cosZ, -sinZ, 0, 0], [sinZ, cosZ, 0, 0], [0, 0, 1, 0], [0, 0, 0, 1]];
  let mat5 = [[1, 0, 0, -cam_pos.x], [0, 1, 0, -cam_pos.y], [0, 0, 1, -cam_pos.z], [0, 0, 0, 1]];
  let mat6 = [[point.x], [point.y], [point.z], [1]];

  let tmp1 = multiply(mat1, mat2);
  let tmp2 = multiply(tmp1, mat3);
  let tmp3 = multiply(tmp2, mat4);
  let tmp4 = multiply(tmp3, mat5);
  let result = multiply(tmp4, mat6);
  let z = result[2][0];
  let mat7 = [[1/z, 0, 0, 0], [0, 1/z, 0, 0], [0, 0, 1, 0], [0, 0, 0, 1]];

  let result1 = multiply(mat7, result);
  //console.log(z);
  point2D = new Vector2(result[0][0] / z, result[1][0] / z);
  //point2D = new Vector2(result1[0][0], result1[1][0])
  //console.log(point2D);
  return point2D;
}


function rotatex(point, angle){
  xn = point.x;
  yn = point.y * Math.cos(angle) - point.z * Math.sin(angle);
  zn = point.y * Math.sin(angle) + point.z * Math.cos(angle);
  return new Vector3(xn,yn,zn);
}

function rotatey(point, angle){
  xn = point.x * Math.cos(angle) - point.z * Math.sin(angle);
  yn = point.y;
  zn = point.z * Math.cos(angle) + point.x * Math.sin(angle);
  return new Vector3(xn,yn,zn);
}

function rotatez(point, angle){
  xn = point.x * Math.cos(angle) - point.y * Math.sin(angle);
  yn = point.x * Math.sin(angle) + point.y * Math.cos(angle);
  zn = point.z;
  return new Vector3(xn,yn,zn);
}

function translateXYZ(point, x, y, z){
  xn = point.x + x;
  yn = point.y + y;
  zn = point.z + z;
  return new Vector3(xn,yn,zn);
}

function translateObject(vertices, x, y, z){
  for (i = 0; i < vertices.length; i++){
    vertices[i] = translateXYZ(vertices[i], x, y, z);
  }
  return vertices;
}

function rotateObjectX(vertices, angleX){
  for (i = 0; i < vertices.length; i++){
    vertices[i] = rotatex(vertices[i], angleX);
  }
  return vertices;
}

function rotateObjectY(vertices, angleY){
  for (i = 0; i < vertices.length; i++){
    vertices[i] = rotatey(vertices[i], angleY);
  }
  return vertices;
}


let a = 64;
let vertices  = [new Vector3(a,a,a), new Vector3(a,-a,a), new Vector3(-a, -a, a), new Vector3(-a,a,a), new Vector3(a,a,-a), new Vector3(a,-a,-a), new Vector3(-a,-a,-a), new Vector3(-a,a,-a) ];
let edges  = [new Vector2(1,2), new Vector2(2,3), new Vector2(3,4), new Vector2(4,1), new Vector2(5,6), new Vector2(6,7), new Vector2(7,8), new Vector2(8,5), new Vector2(1,5), new Vector2(2,6), new Vector2(3,7), new Vector2(4,8)];

let axes = [new Vector3(0,0,0), new Vector3(-600,0,0), new Vector3(0,-600,0), new Vector3(0,0,-600)];
let axes_conn = [new Vector2(1,2), new Vector2(1,3), new Vector2(1,4)];

let cam_angle = new Vector3(0,0,0);
let display   = new Vector3(550, 375, 256);
var cam_pos   = new Vector3(256, 256, 2048);

function setup(){
  createCanvas(1100,750);
  frameRate(60);
}


function mouseDragged(){
  vertices = rotateObjectX(vertices, (mouseY - pmouseY)*0.005);
  vertices = rotateObjectY(vertices, (mouseX - pmouseX)*0.005);
}

let key  = false;
let xdir = 0;
let ydir = 0;
let zdir = 0;
let rotate = 0;

function keyPressed(){
  if (keyCode === ENTER){
    key = !key;
  }
  if (keyCode === 82){
    rotate++;
  }
  if (keyCode === 38){
    ydir -= 1;
  }
  if (keyCode === 40){
    ydir += 1;
  }
  if (keyCode === 37){
    xdir -= 1;
  }
  if (keyCode === 39){
    xdir += 1;
  }
  if (keyCode === 187){
    zdir -= 1;
  }
  if (keyCode === 189){
    zdir += 1;
  }
  if (keyCode === 8){
    ydir = 0;
    xdir = 0;
    zidr = 0;
  }
}

function draw(){
  if (key){
    background(0);
    if (rotate%3 == 1){
      rotateObjectX(vertices, 0.01);
    }
    if (rotate%3 == 2){
      rotateObjectY(vertices, 0.01);
    }
    //translateObject(vertices, xdir, ydir, 0);
    cam_pos.x += xdir;
    cam_pos.y += ydir;
    cam_pos.z += zdir;
    //cam_angle.y += 0.01;
    for (i = 0; i < edges.length; i++){
        var cur_edge = edges[i];
        //var pixel1 = transformation(vertices[cur_edge.x - 1], cam_pos, cam_angle, display);
        //var pixel2 = transformation(vertices[cur_edge.y - 1], cam_pos, cam_angle, display);
        var pixel1 = transformation1(vertices[cur_edge.x - 1], cam_pos, cam_angle, new Vector2(700,700), new Vector2(0.1,0.1), 1, 1);
        var pixel2 = transformation1(vertices[cur_edge.y - 1], cam_pos, cam_angle, new Vector2(700,700), new Vector2(0.1,0.1), 1, 1);
        stroke('green');
        line(pixel1.x | 0, pixel1.y | 0, pixel2.x | 0, pixel2.y | 0);
    }
    /*
    for (i = 0; i < axes_conn.length; i++){
        var cur_edge = axes_conn[i];
        var pixel1 = transformation(axes[cur_edge.x - 1], cam_pos, cam_angle, display);
        var pixel2 = transformation(axes[cur_edge.y - 1], cam_pos, cam_angle, display);
        stroke('green');
        line(pixel1.x | 0, pixel1.y | 0, pixel2.x | 0, pixel2.y | 0);
        //console.log(pixel1.x | 0, pixel1.y | 0, pixel2.x | 0, pixel2.y | 0);
    }
    */

  }
}