From ceb91064d5409afdc43ef0ad45a57d8123fedffb Mon Sep 17 00:00:00 2001
From: Jose Luis Blanco-Claraco <joseluisblancoc@gmail.com>
Date: Thu, 18 Jan 2024 23:35:11 +0100
Subject: [PATCH] viz API: add enqueue_custom_nanogui_code()

---
 .../include/mola_kernel/interfaces/VizInterface.h   |  5 ++++-
 mola_viz/include/mola_viz/MolaViz.h                 |  8 +++++++-
 mola_viz/src/MolaViz.cpp                            | 13 +++++++++++++
 3 files changed, 24 insertions(+), 2 deletions(-)

diff --git a/mola_kernel/include/mola_kernel/interfaces/VizInterface.h b/mola_kernel/include/mola_kernel/interfaces/VizInterface.h
index 2d473c52..0f6d9f83 100644
--- a/mola_kernel/include/mola_kernel/interfaces/VizInterface.h
+++ b/mola_kernel/include/mola_kernel/interfaces/VizInterface.h
@@ -1,4 +1,4 @@
-/* -------------------------------------------------------------------------
+/* -------------------------------------------------------------------------
  *   A Modular Optimization framework for Localization and mApping  (MOLA)
  * Copyright (C) 2018-2024 Jose Luis Blanco, University of Almeria
  * See LICENSE for license information.
@@ -52,6 +52,9 @@ class VizInterface
         const std::string&           viewportName = "main",
         const std::string&           parentWindow = "main") = 0;
 
+    virtual std::future<void> enqueue_custom_nanogui_code(
+        const std::function<void(void)>& userCode) = 0;
+
     virtual std::future<bool> output_console_message(
         const std::string& msg, const std::string& parentWindow = "main") = 0;
 };
diff --git a/mola_viz/include/mola_viz/MolaViz.h b/mola_viz/include/mola_viz/MolaViz.h
index 218edb04..48896a17 100644
--- a/mola_viz/include/mola_viz/MolaViz.h
+++ b/mola_viz/include/mola_viz/MolaViz.h
@@ -62,7 +62,8 @@ class MolaViz : public ExecutableBase, public VizInterface
     static bool     IsRunning();
     static MolaViz* Instance();
 
-    /** Returned object is owned by the VizInterface, do NOT delete it. */
+    /** Returned object is owned by the VizInterface, do NOT delete it. Updates
+     * to it must be done via enqueue_custom_nanogui_code()*/
     std::future<nanogui::Window*> create_subwindow(
         const std::string& subWindowTitle,
         const std::string& parentWindow = DEFAULT_WINDOW_NAME) override;
@@ -98,6 +99,11 @@ class MolaViz : public ExecutableBase, public VizInterface
         const std::string& msg,
         const std::string& parentWindow = "main") override;
 
+    /// Updates to nanogui window controls must happen via this method to ensure
+    /// it is run by the correct thread, in the next available time slot.
+    std::future<void> enqueue_custom_nanogui_code(
+        const std::function<void(void)>& userCode) override;
+
     /** @} */
 
     /** @name mola-viz GUI update handlers registry
diff --git a/mola_viz/src/MolaViz.cpp b/mola_viz/src/MolaViz.cpp
index b9345474..3ab050fb 100644
--- a/mola_viz/src/MolaViz.cpp
+++ b/mola_viz/src/MolaViz.cpp
@@ -792,6 +792,19 @@ std::future<bool> MolaViz::output_console_message(
     return task->get_future();
 }
 
+std::future<void> MolaViz::enqueue_custom_nanogui_code(
+    const std::function<void(void)>& userCode)
+{
+    using return_type = void;
+
+    auto task = std::make_shared<std::packaged_task<return_type()>>(
+        [=]() { userCode(); });
+
+    auto lck = mrpt::lockHelper(guiThreadPendingTasksMtx_);
+    guiThreadPendingTasks_.emplace_back([=]() { (*task)(); });
+    return task->get_future();
+}
+
 #if 0
 // Visualize GT:
 if (1)