From a6e15b2f577b5d00bce2d8db624d95838e19609d Mon Sep 17 00:00:00 2001
From: Alexander Alekhin <alexander.a.alekhin@gmail.com>
Date: Thu, 29 Oct 2020 23:38:30 +0000
Subject: [PATCH] cmake: prefer using Eigen configuration files

- for better compatibility with Ceres 2.0.0 CMake scripts
---
 cmake/OpenCVFindLibsPerf.cmake | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/cmake/OpenCVFindLibsPerf.cmake b/cmake/OpenCVFindLibsPerf.cmake
index b9b1a95799..7b3874ff0e 100644
--- a/cmake/OpenCVFindLibsPerf.cmake
+++ b/cmake/OpenCVFindLibsPerf.cmake
@@ -51,7 +51,12 @@ endif(WITH_CUDA)
 
 # --- Eigen ---
 if(WITH_EIGEN AND NOT HAVE_EIGEN)
-  find_package(Eigen3 QUIET)
+  if(NOT OPENCV_SKIP_EIGEN_FIND_PACKAGE_CONFIG)
+    find_package(Eigen3 CONFIG QUIET)  # Ceres 2.0.0 CMake scripts doesn't work with CMake's FindEigen3.cmake module (due to missing EIGEN3_VERSION_STRING)
+  endif()
+  if(NOT Eigen3_FOUND)
+    find_package(Eigen3 QUIET)
+  endif()
 
   if(Eigen3_FOUND)
     if(TARGET Eigen3::Eigen)