$ minimalistic 3d game engine in javascript

// minimalistic 3d game engine in javascript

// canvas element
var canvas = document.createElement("canvas");
var ctx = canvas.getContext("2d");
canvas.width = 600;
canvas.height = 600;
document.body.appendChild(canvas);

// camera
var camera = new Camera();

// scene
var scene = new Scene();

// cube
function cube(x, y, z, size, color) {
    var cube = new GameObject();
    cube.model = models.cube;
    cube.position = new Vector3(x, y, z);
    cube.scale = new Vector3(size, size, size);
    cube.color = color;
    scene.add(cube);
}

// sphere
function sphere(x, y, z, size, color) {
    var sphere = new GameObject();
    sphere.model = models.sphere;
    sphere.position = new Vector3(x, y, z);
    sphere.scale = new Vector3(size, size, size);
    sphere.color = color;
    scene.add(sphere);
}

// pyramid
function pyramid(x, y, z, size, color) {
    var pyramid = new GameObject();
    pyramid.model = models.pyramid;
    pyramid.position = new Vector3(x, y, z);
    pyramid.scale = new Vector3(size, size, size);
    pyramid.color = color;
    scene.add(pyramid);
}

// cylinder
function cylinder(x, y, z, size, color) {
    var cylinder = new GameObject();
    cylinder.model = models.cylinder;
    cylinder.position = new Vector3(x, y, z);
    cylinder.scale = new Vector3(size, size, size);
    cylinder.color = color;
    scene.add(cylinder);
}

// cone
function cone(x, y, z, size, color) {
    var cone = new GameObject();
    cone.model = models.cone;
    cone.position = new Vector3(x, y, z);
    cone.scale = new Vector3(size, size, size);
    cone.color = color;
    scene.add(cone);
}

// torus
function torus(x, y, z, size, color) {
    var torus = new GameObject();
    torus.model = models.torus;
    torus.position = new Vector3(x, y, z);
    torus.scale = new Vector3(size, size, size);
    torus.color = color;
    scene.add(torus);
}

// terrain
function terrain(x, y, z, size, color) {
    var terrain = new GameObject();
    terrain.model = models.terrain;
    terrain.position = new Vector3(x, y, z);
    terrain.scale = new Vector3(size, size, size);
    terrain.color = color;
    scene.add(terrain);
}

// light
function light(x, y, z, color) {
    var light = new Light();
    light.position = new Vector3(x, y, z);
    light.color = color;
    scene.add(light);
}

// directional light
function directional_light(x, y, z, color) {
    var directional_light = new DirectionalLight();
    directional_light.position = new Vector3(x, y, z);
    directional_light.color = color;
    scene.add(directional_light);
}

// spot light
function spot_light(x, y, z, color) {
    var spot_light = new SpotLight();
    spot_light.position = new Vector3(x, y, z);
    spot_light.color = color;
    scene.add(spot_light);
}

// point light
function point_light(x, y, z, color) {
    var point_light = new PointLight();
    point_light.position = new Vector3(x, y, z);
    point_light.color = color;
    scene.add(point_light);
}

// ambient light
function ambient_light(color) {
    var ambient_light = new AmbientLight();
    ambient_light.color = color;
    scene.add(ambient_light);
}

// fog
function fog(color, density) {
    var fog = new Fog();
    fog.color = color;
    fog.density = density;
    scene.add(fog);
}

// particle
function particle(x, y, z, size, color) {
    var particle = new Particle();
    particle.position = new Vector3(x, y, z);
    particle.scale = new Vector3(size, size, size);
    particle.color = color;
    scene.add(particle);
}

// image
function image(x, y, width, height, image) {
    var image = new Image();
    image.position = new Vector3(x, y, 0);
    image.scale = new Vector3(width, height, 0);
    image.image = image;
    scene.add(image);
}

// audio
function audio(x, y, z, audio) {
    var audio = new Audio();
    audio.position = new Vector3(x, y, z);
    audio.audio = audio;
    scene.add(audio);
}

// load 3d models
var models = {};
var model_names = ["cube", "sphere", "pyramid", "cylinder", "cone", "torus", "terrain", "particle"];
var model_count = 0;
for (var i = 0; i < model_names.length; i++) {
    var model = new Model();
    model.load(model_names[i], function() {
        model_count++;
        if (model_count == model_names.length) {
            init();
        }
    });
    models[model_names[i]] = model;
}

// button
function button(x, y, width, height, color, text, onclick) {
    var button = new Button();
    button.position = new Vector3(x, y, 0);
    button.scale = new Vector3(width, height, 0);
    button.color = color;
    button.text = text;
    button.onclick = onclick;
    scene.add(button);
}

// text
function text(x, y, size, color, text) {
    var text = new Text();
    text.position = new Vector3(x, y, 0);
    text.scale = new Vector3(size, size, 0);
    text.color = color;
    text.text = text;
    scene.add(text);
}

// input
function input(x, y, width, height, color, text, onchange) {
    var input = new Input();
    input.position = new Vector3(x, y, 0);
    input.scale = new Vector3(width, height, 0);
    input.text = text;
    input.onchange = onchange;
    scene.add(input);
}

// slider
function slider(x, y, width, height, color, min, max, value, onchange) {
    var slider = new Slider();
    slider.position = new Vector3(x, y, 0);
    slider.scale = new Vector3(width, height, 0);
    slider.color = color;
    slider.min = min;
    slider.max = max;
    slider.value = value;
    slider.onchange = onchange;
    scene.add(slider);
}

// checkbox
function checkbox(x, y, width, height, color, checked, onchange) {
    var checkbox = new Checkbox();
    checkbox.position = new Vector3(x, y, 0);
    checkbox.scale = new Vector3(width, height, 0);
    checkbox.checked = checked;
    checkbox.onchange = onchange;
    scene.add(checkbox);
}

// radio
function radio(x, y, width, height, color, checked, onchange) {
    var radio = new Radio();
    radio.position = new Vector3(x, y, 0);
    radio.scale = new Vector3(width, height, 0);
    radio.checked = checked;
    radio.onchange = onchange;
    scene.add(radio);
}

// dropdown
function dropdown(x, y, width, height, color, options, onchange) {
    var dropdown = new Dropdown();
    dropdown.position = new Vector3(x, y, 0);
    dropdown.scale = new Vector3(width, height, 0);
    dropdown.options = options;
    dropdown.onchange = onchange;
    scene.add(dropdown);
}

// progressbar
function progressbar(x, y, width, height, color, value) {
    var progressbar = new Progressbar();
    progressbar.position = new Vector3(x, y, 0);
    progressbar.scale = new Vector3(width, height, 0);
    progressbar.color = color;
    progressbar.value = value;
    scene.add(progressbar);
}

// canvas
function canvas(x, y, width, height, color) {
    var canvas = new Canvas();
    canvas.position = new Vector3(x, y, 0);
    canvas.scale = new Vector3(width, height, 0);
    canvas.color = color;
    scene.add(canvas);
}

// window
function window(x, y, width, height, color, text) {
    var window = new Window();
    window.position = new Vector3(x, y, 0);
    window.scale = new Vector3(width, height, 0);
    window.color = color;
    window.text = text;
    scene.add(window);
}

// panel
function panel(x, y, width, height, color) {
    var panel = new Panel();
    panel.position = new Vector3(x, y, 0);
    panel.scale = new Vector3(width, height, 0);
    panel.color = color;
    scene.add(panel);
}

// scrollbar
function scrollbar(x, y, width, height, color, vertical, value, onchange) {
    var scrollbar = new Scrollbar();
    scrollbar.position = new Vector3(x, y, 0);
    scrollbar.scale = new Vector3(width, height, 0);
    scrollbar.color = color;
    scrollbar.vertical = vertical;
    scrollbar.value = value;
    scrollbar.onchange = onchange;
    scene.add(scrollbar);
}

// tab
function tab(x, y, width, height, color, tabs) {
    var tab = new Tab();
    tab.position = new Vector3(x, y, 0);
    tab.scale = new Vector3(width, height, 0);
    tab.color = color;
    tab.tabs = tabs;
    scene.add(tab);
}

// file load 3D models
function load_model(name, callback) {
    var model = new Model();
    model.load(name, callback);
    models[name] = model;
}

// file load image
function load_image(name, callback) {
    var image = new Image();
    image.load(name, callback);
    images[name] = image;
}

// file load audio
function load_audio(name, callback) {
    var audio = new Audio();
    audio.load(name, callback);
    audios[name] = audio;
}

// file load font
function load_font(name, callback) {
    var font = new Font();
    font.load(name, callback);
    fonts[name] = font;
}

// file load images
var images = {};
var image_names = [];
var image_count = 0;
for (var i = 0; i < image_names.length; i++) {
    var image = new Image();
    image.load(image_names[i], function() {
        image_count++;
        if (image_count == image_names.length) {
            init();
        }
    });
    images[image_names[i]] = image;
}

// bind arrow keys to move player (and camera)
function bind_arrow_keys() {
    document.addEventListener("keydown", function(e) {
        if (e.keyCode == 37) {
            player.position.x -= 1;
        }
        if (e.keyCode == 38) {
            player.position.y -= 1;
        }
        if (e.keyCode == 39) {
            player.position.x += 1;
        }
        if (e.keyCode == 40) {
            player.position.y += 1;
        }
    });
}

// bind mouse click to shoot
function bind_mouse_click() {
    document.addEventListener("click", function(e) {
        var bullet = new GameObject();
        bullet.model = models.cube;
        bullet.position = new Vector3(player.position.x, player.position.y, player.position.z);
        bullet.velocity = new Vector3(e.clientX - canvas.width / 2, e.clientY - canvas.height / 2, 0);
        scene.add(bullet);
    });
}

// bind mouse move to look around
function bind_mouse_move() {
    document.addEventListener("mousemove", function(e) {
        camera.rotation.x = e.clientY / canvas.height * Math.PI;
        camera.rotation.y = e.clientX / canvas.width * Math.PI;
    });
}

// bind mouse wheel to zoom
function bind_mouse_wheel() {
    document.addEventListener("wheel", function(e) {
        camera.position.z += e.deltaY / 100;
    });
}

// bind spacebar to jump (or swim)
function bind_spacebar() {
    document.addEventListener("keydown", function(e) {
        if (e.keyCode == 32) {
            player.velocity.y = 1;
        }
    });
}

// bind escape to pause
function bind_escape() {
    document.addEventListener("keydown", function(e) {
        if (e.keyCode == 27) {
            paused = !paused;
        }
    });
}

// bind enter for action (or start)
function bind_enter() {
    document.addEventListener("keydown", function(e) {
        if (e.keyCode == 13) {
            started = true;
        }
    });
}

// bind right mouse click for secondary action
function bind_right_mouse_click() {
    document.addEventListener("contextmenu", function(e) {
        e.preventDefault();
    });
    document.addEventListener("mousedown", function(e) {
        if (e.button == 2) {
            secondary_action = true;
        }
    });
    document.addEventListener("mouseup", function(e) {
        if (e.button == 2) {
            secondary_action = false;
        }
    });
}

// display current score
function display_score() {
    var score = new Text();
    score.position = new Vector3(0, 0, 0);
    score.scale = new Vector3(0.1, 0.1, 0.1);
    score.color = new Color(1, 1, 1);
    score.text = "Score: " + player.score;
    scene.add(score);
}

// display health
function display_health() {
    var health = new Text();
    health.position = new Vector3(0, 0.1, 0);
    health.scale = new Vector3(0.1, 0.1, 0.1);
    health.color = new Color(1, 1, 1);
    health.text = "Health: " + player.health;
    scene.add(health);
}

// display ammo
function display_ammo() {
    var ammo = new Text();
    ammo.position = new Vector3(0, 0.2, 0);
    ammo.scale = new Vector3(0.1, 0.1, 0.1);
    ammo.text = "Ammo: " + player.ammo;
    scene.add(ammo);
}

// display time
function display_time() {
    var time = new Text();
    time.position = new Vector3(0, 0.3, 0);
    time.scale = new Vector3(0.1, 0.1, 0.1);
    time.color = new Color(1, 1, 1);
    time.text = "Time: " + player.time;
    scene.add(time);
}

// display money
function display_money() {
    var money = new Text();
    money.position = new Vector3(0, 0.5, 0);
    money.text = "Money: " + player.money;
    scene.add(money);
}

// display fps
function display_fps() {
    var fps = new Text();
    fps.position = new Vector3(0, 0.4, 0);
    fps.scale = new Vector3(0.1, 0.1, 0.1);
    fps.color = new Color(1, 1, 1);
    fps.text = "FPS: " + player.fps;
    scene.add(fps);
}

// display (mini) map
function display_map() {
    var map = new Image();
    map.position = new Vector3(0, 0, 0);
    map.scale = new Vector3(1, 1, 0);
    map.image = images.map;
    scene.add(map);
}

// display inventory
function display_inventory() {
    var inventory = new Image();
    inventory.position = new Vector3(0, 0, 0);
    inventory.scale = new Vector3(1, 1, 0);
    inventory.image = images.inventory;
    scene.add(inventory);
}

// display pause menu
function display_pause_menu() {
    var pause_menu = new Image();
    pause_menu.position = new Vector3(0, 0, 0);
    pause_menu.scale = new Vector3(1, 1, 0);
    pause_menu.image = images.pause_menu;
    scene.add(pause_menu);
}

// display settings menu
function display_settings_menu() {
    var settings_menu = new Image();
    settings_menu.position = new Vector3(0, 0, 0);
    settings_menu.scale = new Vector3(1, 1, 0);
    settings_menu.image = images.settings_menu;
    scene.add(settings_menu);
}

// throw weapon
function throw_weapon() {
    var weapon = new GameObject();
    weapon.model = models.cube;
    weapon.position = new Vector3(player.position.x, player.position.y, player.position.z);
    weapon.velocity = velocity.set
    scene.add(weapon);
}

// shoot weapon
function shoot_weapon() {
    var bullet = new GameObject();
    bullet.model = models.cube;
    bullet.position = new Vector3(player.position.x, player.position.y, player.position.z);
    weapon.velocity = velocity.set
    scene.add(bullet);
}

// explosion
function explosion(x, y, z) {
    var explosion = new Particle();
    explosion.position = new Vector3(x, y, z);
    explosion.scale = new Vector3(0.1, 0.1, 0.1);
    explosion.velocity = new Vector3(Math.random() * 2 - 1, Math.random() * 2 - 1, 0);
    scene.add(explosion);
}

// spawn enemy
function spawn_enemy() {
    var enemy = new GameObject();
    enemy.model = models.cube;
    enemy.position = new Vector3(Math.random() * 10 - 5, Math.random() * 10 - 5, 0);
    scene.add(enemy);
}

// spawn item
function spawn_item() {
    var item = new GameObject();
    item.model = models.cube;
    item.position = new Vector3(Math.random() * 10 - 5, Math.random() * 10 - 5, 0);
    scene.add(item);
}

// spawn powerup
function spawn_powerup() {
    var powerup = new GameObject();
    powerup.model = models.cube;
    powerup.position = new Vector3(Math.random() * 10 - 5, Math.random() * 10 - 5, 0);
    scene.add(powerup);
}

// display level
function display_level() {
    var level = new Text();
    level.position = new Vector3(0, 0.6, 0);
    level.text = "Level: " + player.level;
    scene.add(level);
}