Update index.html

public/index.html

@@ -20,6 +20,73 @@ async function activateXR() {
   const canvas = document.createElement("canvas");
   document.body.appendChild(canvas);
   const gl = canvas.getContext("webgl", {xrCompatible: true});
+const scene = new THREE.Scene();
+
+// The cube will have a different color on each side.
+const materials = [
+  new THREE.MeshBasicMaterial({color: 0xff0000}),
+  new THREE.MeshBasicMaterial({color: 0x0000ff}),
+  new THREE.MeshBasicMaterial({color: 0x00ff00}),
+  new THREE.MeshBasicMaterial({color: 0xff00ff}),
+  new THREE.MeshBasicMaterial({color: 0x00ffff}),
+  new THREE.MeshBasicMaterial({color: 0xffff00})
+];
+
+// Create the cube and add it to the demo scene.
+const cube = new THREE.Mesh(new THREE.BoxBufferGeometry(0.2, 0.2, 0.2), materials);
+cube.position.set(1, 1, 1);
+scene.add(cube);
+// Set up the WebGLRenderer, which handles rendering to the session's base layer.
+const renderer = new THREE.WebGLRenderer({
+  alpha: true,
+  preserveDrawingBuffer: true,
+  canvas: canvas,
+  context: gl
+});
+renderer.autoClear = false;
+
+// The API directly updates the camera matrices.
+// Disable matrix auto updates so three.js doesn't attempt
+// to handle the matrices independently.
+const camera = new THREE.PerspectiveCamera();
+camera.matrixAutoUpdate = false;
+// Initialize a WebXR session using "immersive-ar".
+const session = await navigator.xr.requestSession("immersive-ar");
+session.updateRenderState({
+  baseLayer: new XRWebGLLayer(session, gl)
+});
+
+// A 'local' reference space has a native origin that is located
+// near the viewer's position at the time the session was created.
+const referenceSpace = await session.requestReferenceSpace('local');
+// Create a render loop that allows us to draw on the AR view.
+const onXRFrame = (time, frame) => {
+  // Queue up the next draw request.
+  session.requestAnimationFrame(onXRFrame);
+
+  // Bind the graphics framebuffer to the baseLayer's framebuffer
+  gl.bindFramebuffer(gl.FRAMEBUFFER, session.renderState.baseLayer.framebuffer)
+
+  // Retrieve the pose of the device.
+  // XRFrame.getViewerPose can return null while the session attempts to establish tracking.
+  const pose = frame.getViewerPose(referenceSpace);
+  if (pose) {
+    // In mobile AR, we only have one view.
+    const view = pose.views[0];
+
+    const viewport = session.renderState.baseLayer.getViewport(view);
+    renderer.setSize(viewport.width, viewport.height)
+
+    // Use the view's transform matrix and projection matrix to configure the THREE.camera.
+    camera.matrix.fromArray(view.transform.matrix)
+    camera.projectionMatrix.fromArray(view.projectionMatrix);
+    camera.updateMatrixWorld(true);
+
+    // Render the scene with THREE.WebGLRenderer.
+    renderer.render(scene, camera)
+  }
+}
+session.requestAnimationFrame(onXRFrame);
 
   // To be continued in upcoming steps.
 }