From 469ce857249dd9c38226ea73e114ec567fdfd038 Mon Sep 17 00:00:00 2001
From: "Stephan T. Lavavej" <stl@microsoft.com>
Date: Fri, 22 Nov 2024 16:16:52 -0800
Subject: [PATCH] Patch librealsense v2.44.0 to include `<chrono>` for
 `system_clock`

Fixes:
C:\gitP\isl-org\Open3D\build_amd64\librealsense\src\ext_librealsense\src\backend.h(108,79): error C2039: 'system_clock': is not a member of 'std::chrono'

And cascaded:
C:\gitP\isl-org\Open3D\build_amd64\librealsense\src\ext_librealsense\src\backend.cpp(28,88): error C2039: 'system_clock': is not a member of 'std::chrono'
C:\gitP\isl-org\Open3D\build_amd64\librealsense\src\ext_librealsense\src\mf\mf-backend.h(31,26): error C2039: 'high_resolution_clock': is not a member of 'std::chrono'
C:\gitP\isl-org\Open3D\build_amd64\librealsense\src\ext_librealsense\src\mf\mf-backend.cpp(26,9): error C2512: 'std::chrono::time_point': no appropriate default constructor available
---
 3rdparty/librealsense/fix-include-chrono.patch | 12 ++++++++++++
 3rdparty/librealsense/librealsense.cmake       |  3 +++
 2 files changed, 15 insertions(+)
 create mode 100644 3rdparty/librealsense/fix-include-chrono.patch

diff --git a/3rdparty/librealsense/fix-include-chrono.patch b/3rdparty/librealsense/fix-include-chrono.patch
new file mode 100644
index 00000000000..fe3ea80b784
--- /dev/null
+++ b/3rdparty/librealsense/fix-include-chrono.patch
@@ -0,0 +1,12 @@
+diff --git a/src/backend.h b/src/backend.h
+index a402e3dfb..0acd299c0 100644
+--- a/src/backend.h
++++ b/src/backend.h
+@@ -14,6 +14,7 @@
+ 
+ #include <memory>       // For shared_ptr
+ #include <functional>   // For function
++#include <chrono>
+ #include <thread>       // For this_thread::sleep_for
+ #include <vector>
+ #include <algorithm>
diff --git a/3rdparty/librealsense/librealsense.cmake b/3rdparty/librealsense/librealsense.cmake
index e5caa700df7..8c4e98b57e6 100644
--- a/3rdparty/librealsense/librealsense.cmake
+++ b/3rdparty/librealsense/librealsense.cmake
@@ -20,6 +20,9 @@ ExternalProject_Add(
     # Patch for macOS ARM64 support for versions < 2.50.0
     COMMAND ${GIT_EXECUTABLE} apply --ignore-space-change --ignore-whitespace
         ${CMAKE_CURRENT_LIST_DIR}/fix-macos-arm64.patch
+    # Patch to include the <chrono> header for the system_clock type
+    COMMAND ${GIT_EXECUTABLE} apply --ignore-space-change --ignore-whitespace
+        ${CMAKE_CURRENT_LIST_DIR}/fix-include-chrono.patch
     CMAKE_ARGS
         -DCMAKE_INSTALL_PREFIX=<INSTALL_DIR>
         -DBUILD_SHARED_LIBS=OFF