From 3c9d232d417cfa3f82519b2363ee90cda7f47b17 Mon Sep 17 00:00:00 2001
From: Martin Raifer <martin@raifer.tech>
Date: Wed, 21 May 2025 16:35:19 +0200
Subject: [PATCH] make sure pannellum viewer is ready to load new photo, fixes
 #11054

while loading a "scene", pannellum cannot load a new panorama scene. This means we have to wait while the viewer is busy loading an existing panorama until we can load a new one.
---
 CHANGELOG.md                        |  2 ++
 modules/services/pannellum_photo.js | 37 ++++++++++++++++++++++-------
 modules/services/panoramax.js       |  7 +++---
 3 files changed, 34 insertions(+), 12 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 593313922..8ee90bffd 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -44,6 +44,7 @@ _Breaking developer changes, which may affect downstream projects or sites that
 #### :scissors: Operations
 #### :camera: Street-Level
 * Fix Mapilio photo markers from showing up on low zoom levels ([#11014], thanks [@keiffer213] and [@haipq07])
+* Fix wrong 360° panorama from being displayed when navigating quickly between photos ([#11054])
 #### :white_check_mark: Validation
 #### :bug: Bugfixes
 * Refresh numeric input fields after leaving focus with the value that is stored in the tag ([#11027])
@@ -58,6 +59,7 @@ _Breaking developer changes, which may affect downstream projects or sites that
 [#10970]: https://github.com/openstreetmap/iD/pull/10970
 [#11014]: https://github.com/openstreetmap/iD/pull/11014
 [#11027]: https://github.com/openstreetmap/iD/pull/11027
+[#11054]: https://github.com/openstreetmap/iD/issues/1104
 [@keiffer213]: https://github.com/keiffer213
 [@haipq07]: https://github.com/haipq07
 
diff --git a/modules/services/pannellum_photo.js b/modules/services/pannellum_photo.js
index 3418c0f8f..1c2c15b18 100644
--- a/modules/services/pannellum_photo.js
+++ b/modules/services/pannellum_photo.js
@@ -9,6 +9,7 @@ const dispatch = d3_dispatch('viewerChanged');
 
 let _currScenes = [];
 let _pannellumViewer;
+let _activeSceneKey;
 
 export default {
 
@@ -29,7 +30,8 @@ export default {
       'default': { firstScene: '' },
       scenes: {},
       minHfov: 20,
-      disableKeyboardCtrl: true
+      disableKeyboardCtrl: true,
+      sceneFadeDuration: 0
     };
 
     _pannellumViewer = window.pannellum.viewer('ideditor-pannellum-viewer', options);
@@ -96,7 +98,7 @@ export default {
    * Shows the photo frame if hidden
    * @param {*} context the HTML wrap of the frame
    */
-  showPhotoFrame: function (context) {
+  showPhotoFrame: function(context) {
     const isHidden = context.selectAll('.photo-frame.pannellum-frame.hide').size();
 
     if (isHidden) {
@@ -116,22 +118,22 @@ export default {
    * Hides the photo frame if shown
    * @param {*} context the HTML wrap of the frame
    */
-  hidePhotoFrame: function (viewerContext) {
+  hidePhotoFrame: function(viewerContext) {
     viewerContext
       .select('photo-frame.pannellum-frame')
       .classed('hide', false);
 
     return this;
-    },
+  },
 
   /**
    * Renders an image inside the frame
    * @param {*} data the image data, it should contain an image_path attribute, a link to the actual image.
    * @param {boolean} keepOrientation if true, HFOV, pitch and yaw will be kept between images
    */
-  selectPhoto: function (data, keepOrientation) {
-    const {key} = data;
-    if ( !(key in _currScenes) ) {
+  selectPhoto: function(data, keepOrientation) {
+    const key = _activeSceneKey = data.image_path;
+    if (!_currScenes.includes(key)) {
       let newSceneOptions = {
         showFullscreenCtrl: false,
         autoLoad: false,
@@ -156,8 +158,25 @@ export default {
       pitch = this.getPitch();
       hfov = this.getHfov();
     }
-    _pannellumViewer.loadScene(key, pitch, yaw, hfov);
-    dispatch.call('viewerChanged');
+    if (_pannellumViewer.isLoaded() !== false) {
+      _pannellumViewer.loadScene(key, pitch, yaw, hfov);
+      dispatch.call('viewerChanged');
+    } else {
+      // pannellum is currently loading another scene: wait for it to finish
+      // loading the previous panorama first
+      const retry = setInterval(() => {
+        if (_pannellumViewer.isLoaded() === false) {
+          // still not done: wait a bit longer
+          return;
+        }
+        if (_activeSceneKey === key) {
+          // only load scene if no other photo has been selected in the meantime
+          _pannellumViewer.loadScene(key, pitch, yaw, hfov);
+          dispatch.call('viewerChanged');
+        }
+        clearInterval(retry);
+      }, 100);
+    }
 
     if (_currScenes.length > 3) {
       const old_key = _currScenes.shift();
diff --git a/modules/services/panoramax.js b/modules/services/panoramax.js
index 5c30e8e7e..c6081c7f9 100644
--- a/modules/services/panoramax.js
+++ b/modules/services/panoramax.js
@@ -483,7 +483,7 @@ export default {
                 _isHD = !_isHD;
                 _definition = _isHD ? highDefinition : standardDefinition;
                 that.selectImage(context, d.id)
-                .showViewer(context);
+                    .showViewer(context);
             });
 
         label
@@ -518,7 +518,7 @@ export default {
             .attr('href', viewerLink)
             .text('panoramax.xyz');
 
-        this.getImageData(d.sequence_id, d.id).then(function(data){
+        this.getImageData(d.sequence_id, d.id).then(function(data) {
             _currentScene = {
                 currentImage: null,
                 nextImage: null,
@@ -589,11 +589,12 @@ export default {
      * @param {*} image_id
      * @returns The fetched image data
      */
-    getImageData: async function(collection_id, image_id){
+    getImageData: async function(collection_id, image_id) {
         const requestUrl = imageDataUrl.replace('{collectionId}', collection_id)
             .replace('{itemId}', image_id);
 
         const response = await fetch(requestUrl, { method: 'GET' });
+
         if (!response.ok) {
             throw new Error(response.status + ' ' + response.statusText);
         }