wait for camera to be active before rendering (fixes #1733, fixes #1754)

Author: ngokevin

src/core/scene/a-scene.js

@@ -315,17 +315,26 @@ module.exports = registerElement('a-scene', {
         this.addEventListener('loaded', function () {
           if (this.renderStarted) { return; }
 
-          AEntity.prototype.play.call(this);
-          this.resize();
-
-          // Kick off render loop.
-          if (this.renderer) {
-            if (window.performance) {
-              window.performance.mark('render-started');
+          // Wait for camera if necessary.
+          if (this.camera) {
+            startRender(this);
+            return;
+          }
+          this.addEventListener('camera-set-active', function () { startRender(this); });
+
+          function startRender (sceneEl) {
+            AEntity.prototype.play.call(sceneEl);
+            sceneEl.resize();
+
+            // Kick off render loop.
+            if (sceneEl.renderer) {
+              if (window.performance) {
+                window.performance.mark('render-started');
+              }
+              sceneEl.render(0);
+              sceneEl.renderStarted = true;
+              sceneEl.emit('renderstart');
             }
-            this.render(0);
-            this.renderStarted = true;
-            this.emit('renderstart');
           }
         });
 
@@ -388,11 +397,10 @@ module.exports = registerElement('a-scene', {
      */
     render: {
       value: function (time) {
-        var camera = this.camera;
         var timeDelta = time - this.time;
 
         if (this.isPlaying) { this.tick(time, timeDelta); }
-        this.effect.render(this.object3D, camera);
+        this.effect.render(this.object3D, this.camera);
 
         this.time = time;
         this.animationFrameID = window.requestAnimationFrame(this.render.bind(this));

src/systems/camera.js

@@ -1,5 +1,5 @@
-var registerSystem = require('../core/system').registerSystem;
 var constants = require('../constants/');
+var registerSystem = require('../core/system').registerSystem;
 
 var DEFAULT_CAMERA_ATTR = 'data-aframe-default-camera';
 var DEFAULT_USER_HEIGHT = 1.6;
@@ -29,11 +29,13 @@ module.exports.System = registerSystem('camera', {
     // Since entities wait for <a-assets> to load, any cameras attaching to the scene
     // will do so asynchronously.
     sceneEl.addEventListener('loaded', function checkForCamera () {
-      var currentCamera = sceneEl.camera;
-      if (currentCamera) {
-        sceneEl.emit('camera-ready', {cameraEl: currentCamera.el});
+      // Camera already defined.
+      if (sceneEl.camera) {
+        sceneEl.emit('camera-ready', {cameraEl: sceneEl.camera.el});
         return;
       }
+
+      // Set up default camera.
       defaultCameraEl = document.createElement('a-entity');
       defaultCameraEl.setAttribute('position', '0 0 0');
       defaultCameraEl.setAttribute(DEFAULT_CAMERA_ATTR, '');
@@ -69,16 +71,21 @@ module.exports.System = registerSystem('camera', {
    */
   setActiveCamera: function (newCameraEl) {
     var cameraEl;
-    var cameraEls = this.sceneEl.querySelectorAll('[camera]');
+    var cameraEls;
     var i;
-    var sceneEl = this.sceneEl;
-    var newCamera = newCameraEl.getObject3D('camera');
+    var newCamera;
     var previousCamera = this.activeCameraEl;
+    var sceneEl = this.sceneEl;
+
+    // Same camera.
+    newCamera = newCameraEl.getObject3D('camera');
     if (!newCamera || newCameraEl === this.activeCameraEl) { return; }
+
     // Grab the default camera.
     var defaultCameraWrapper = sceneEl.querySelector('[' + DEFAULT_CAMERA_ATTR + ']');
     var defaultCameraEl = defaultCameraWrapper &&
                           defaultCameraWrapper.querySelector('[camera]');
+
     // Remove default camera if new camera is not the default camera.
     if (newCameraEl !== defaultCameraEl) { removeDefaultCamera(sceneEl); }
 
@@ -91,7 +98,9 @@ module.exports.System = registerSystem('camera', {
     if (previousCamera) {
       previousCamera.setAttribute('camera', 'active', false);
     }
+
     // Disable other cameras in the scene
+    cameraEls = sceneEl.querySelectorAll('[camera]');
     for (i = 0; i < cameraEls.length; i++) {
       cameraEl = cameraEls[i];
       if (newCameraEl === cameraEl) { continue; }