quackscape/assets/js/scene.js

import { getScene } from "./api";

require("aframe");

// Detect iOS devices
// There is probably a better way to handle issues there, but...
var iOS = /iPad|iPhone|iPod/.test(navigator.userAgent);

// Define the <quackscape-scene> element

class QuackscapeScene extends HTMLElement {
  connectedCallback() {
    // When one is created, automatically load the scene
    this.scene = this.getAttribute("scene");
    this.embedded = this.getAttribute("embedded") != undefined;
    this.x = this.getAttribute("x") | 0;
    this.y = this.getAttribute("y") | 0;
    this.z = this.getAttribute("z") | 0;

    loadScene(this.scene, this.x, this.y, this.z, this, this.embedded);
  }
}

document.addEventListener("contextmenu", function (event) {
  event.preventDefault();
});

customElements.define("quackscape-scene", QuackscapeScene);

// Function to load a scene into a destination object
// x and y signify the initial looking direction, -1 for the scene's default

async function loadScene(
  scene_id,
  x = -1,
  y = -1,
  z = -1,
  destination = null,
  embedded = false
) {
  // Get WebGL maximum texture size
  var canvas = document.createElement("canvas");
  var gl =
    canvas.getContext("webgl") || canvas.getContext("experimental-webgl");

  if (!gl) {
    alert("Unable to initialize WebGL. Your browser may not support it.");
    return;
  }

  var maxTextureSize = gl.getParameter(gl.MAX_TEXTURE_SIZE);

  if (iOS) {
    maxTextureSize = Math.min(8192, maxTextureSize);
  }

  // Get scene information from API
  getScene(scene_id).then((response) => {
    var scene = response.obj;

    // Get largest image that will fit in the texture size from scene.resolutions
    // First, order the resolutions by width
    var resolutions = scene.base_content.resolutions.sort(
      (a, b) => b.width - a.width
    );

    // Then, find the first resolution that is less than or equal to the max texture size
    var content = resolutions.find(
      (resolution) => resolution.width <= maxTextureSize
    );

    // Select a destination element if not specified
    if (!destination) {
      destination = document.getElementsByTagName("quackscape-scene")[0];
    }

    destination.setAttribute("id", scene_id);

    // Start by removing any existing scenes
    var scenes = document.getElementsByTagName("a-scene");
    if (scenes.length > 0) {
      scenes[0].remove();
    }

    // Now, build the scene element
    var a_scene = document.createElement("a-scene");
    a_scene.setAttribute("cursor", "rayOrigin: mouse");

    if (embedded) {
      a_scene.setAttribute("embedded", "embedded");
    }

    // Create a-camera element
    var rig = document.createElement("a-entity");
    rig.setAttribute("id", "rig");

    // Rotate camera if requested
    if (x != -1 && y != -1 && z != -1) {
      rig.setAttribute("rotation", x + " " + y + " " + z);
    }

    var camera = document.createElement("a-camera");
    camera.setAttribute("wasd-controls-enabled", "false"); // TODO: Find a more elegant way to disable z axis movement
    rig.appendChild(camera);
    a_scene.appendChild(rig);

    // Create a-assets element
    var assets = document.createElement("a-assets");
    a_scene.appendChild(assets);

    // Add background image as sky
    var sky = document.createElement("a-sky");
    sky.setAttribute("src", "#" + content.id);
    a_scene.appendChild(sky);

    // Add img element to assets
    var background = document.createElement("img");
    background.setAttribute("id", content.id);
    background.setAttribute("src", content.file);
    assets.appendChild(background);

    // Add elements to scene
    scene.elements.forEach((element) => {
      var node = document.createElement(element.data.tag);
      node.setAttribute("id", element.data.id);

      for (const [key, value] of Object.entries(element.data.attributes)) {
        node.setAttribute(key, value);
      }

      // Add node to scene
      a_scene.appendChild(node);
    });

    destination.appendChild(a_scene);

    // Dispatch a signal for the editor to pick up
    const loaded_event = new CustomEvent("loadedQuackscapeScene");
    document.dispatchEvent(loaded_event);
  });
}

window.loadScene = loadScene;

export { loadScene };