NvOptimusEnablement build error

[prlw1]

Just tried to build with today's git head of imgui/implot/implot_demos with gcc 10.3.0 and see:

[ 92%] Building CXX object CMakeFiles/app.dir/common/Fonts/RobotoItalic.cpp.o
/usr/src/local/implot_demos/common/App.cpp: In constructor ‘App::App(std::string, int, int, int, const char**)’:
/usr/src/local/implot_demos/common/App.cpp:152:5: error: ‘NvOptimusEnablement’ was not declared in this scope
  152 |     NvOptimusEnablement = AmdPowerXpressRequestHighPerformance = result["gpu"].as<bool>();
      |     ^~~~~~~~~~~~~~~~~~~
/usr/src/local/implot_demos/common/App.cpp:152:27: error: ‘AmdPowerXpressRequestHighPerformance’ was not declared in this scope
  152 |     NvOptimusEnablement = AmdPowerXpressRequestHighPerformance = result["gpu"].as<bool>();
      |                           ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

[prlw1]

It seems there's a missing #if defined (_WIN32) (I'm not on windows)

[tatolevicz]

Have you solved this issue?

[prlw1]

Better is the enemy of good... This was all I needed to get over the above problem:

diff --git a/common/App.cpp b/common/App.cpp
index 15670b9..e659512 100644
--- a/common/App.cpp
+++ b/common/App.cpp
@@ -149,7 +149,9 @@ App::App(std::string title, int w, int h, int argc, char const *argv[])
     const bool no_vsync = result["vsync"].as<bool>();
     const bool use_msaa = result["msaa"].as<bool>();
     const bool im_style = result["imgui"].as<bool>();
+#if defined(_WIN32)
     NvOptimusEnablement = AmdPowerXpressRequestHighPerformance = result["gpu"].as<bool>();
+#endif

 #ifdef _DEBUG
     title += " - OpenGL - Debug";
@@ -317,4 +319,4 @@ ImVec2 App::GetWindowSize() const
     int w, h;
     glfwGetWindowSize(Window, &w, &h);
     return ImVec2(w, h);
-}
\ No newline at end of file
+}

I then hit further issues I hoped to make a patch for, but those are probably local to my build environment...

[tatolevicz]

I was abble to build the project on macos without issues.. if you want some help let me know.

[rmaia3d]

Can confirm adding #if defined(_WIN32) just before line 152 (where NvOptimusEnablement variable is used), and the #endif right after it, fixed the compilation error.

But then I get stuck with ld: cannot find -limm32 error at the linking stage for the spectogram app. I'm on Ubuntu 20.04.

Tried some google searches and couldn't find how I can get imm32 lib added to Ubuntu...

[tatolevicz]

Hey @rmaia3d, just change the CmakeLists:

from this:

target_link_libraries(imgui PUBLIC glfw glad OpenGL::GL imm32)

to this:

if (WIN32)
  target_link_libraries(imgui PUBLIC glfw glad OpenGL::GL imm32)
else()
  target_link_libraries(imgui PUBLIC glfw glad OpenGL::GL)
endif()

and at the beginning of the file from this:

cmake_minimum_required(VERSION 3.0.0)
project(implot_demos VERSION 0.1.0)

to this:

cmake_minimum_required(VERSION 3.0.0)
project(implot_demos VERSION 0.1.0)

set(CMAKE_CXX_STANDARD 17)
add_compile_options(-O3 -march=native)

this way I was able to build for mac and windows as well.

I don't know if the architecture flag is needed for you but, as I'm on a macOS, it was needed.

[rmaia3d]

Thanks a lot @tatolevicz !!

Making the changes you suggested to the CMakeLists.txt file did it! I was able to compile succesfully all the demos, albeit with some deprecated warnings. But no errors.

I also tested not including the -march flag, and in Ubuntu it also threw compilation errors. So seems like that flag is indeed needed for non-Win32 platforms...

[tatolevicz]

I'm glad to help you @rmaia3d ! Have a nice new year = ).

[rmaia3d]

@tatolevicz Thank you very much!! Happy 2022 to you too! :-)

[icyveins7]

Can confirm that as of today, this build error (and the imm32 error) still exist on Lubuntu 20.04. But the fixes above to App.cpp and the CMakeLists also still work.

[fmvin]

Confirm that @rmaia3d fix resolves this still existing build issue on ubuntu 2210.

[mithgil]

Thanks for the response! I'm also a ubuntu 22 user. 5 binary files (demo, graph, mandel, maps and perlin) are successfully built in the demos, but filter got a problem:

mplot/implot_demos/demos/filter.cpp: In member function ‘virtual void ImFilter::Update()’:
/home/tim/c/implot/implot_demos/demos/filter.cpp:73:51: error: ‘GetWindowContentRegionWidth’ is not a member of ‘ImGui’; did you mean ‘GetWindowContentRegionMin’?
   73 |         ImGui::BeginChild("ChildL", ImVec2(ImGui::GetWindowContentRegionWidth() * 0.5f, -1));
      |                                                   ^~~~~~~~~~~~~~~~~~~~~~~~~~~
      |                                                   GetWindowContentRegionMin
make[2]: *** [CMakeFiles/filter.dir/build.make:76: CMakeFiles/filter.dir/demos/filter.cpp.o] Error 1
make[1]: *** [CMakeFiles/Makefile2:878: CMakeFiles/filter.dir/all] Error 2
make: *** [Makefile:136: all] Error 2

Does anyone have an idea on how to fix it?

[RobertAlbus]

@mithgil ImGui::GetWindowContentRegionWidth was deprecated and needs to be replaced with GetWindowContentRegionMax().x - GetWindowContentRegionMin().x.

You need to update demos/filter.cpp:73

        ImGui::BeginChild("ChildL", ImVec2(ImGui::GetWindowContentRegionWidth() * 0.5f, -1));

becomes

        ImGui::BeginChild("ChildL", ImVec2(ImGui::GetWindowContentRegionMax().x - ImGui::GetWindowContentRegionMin().x * 0.5f, -1));

https://github.com/ocornut/imgui/blob/master/docs/CHANGELOG.txt#L882-L883 I find it strange that such a handy utility method would be deprecated :thinking: but here we are