Error in CImGui GlfwOpenGL3 renderloop!

[moe93]

Hello,

I am trying to get started with CImGui.jl and seem to have trouble getting anything to work properly. I am running on a Windows 10 machine, with Julia 1.10.5.

I started a project and have the following installed

(MyProject) pkg> status
Project MyProject v0.1.0
Status `path\to\MyProject.jl\Project.toml`
  [5d785b6c] CImGui v3.0.0
  [f7f18e0c] GLFW v3.4.3
  [66fc600b] ModernGL v1.1.7

(MyProject) pkg>

I initially attempted to run the demo and examples and had trouble running either. So I decided to attempt something simpler and easier to trace. I copied the example 'Your First Gui \o/' and tried to run it. For the sake of completeness, here is the code used.

import CImGui as ig, ModernGL, GLFW
ig.set_backend(:GlfwOpenGL3)
ctx = ig.CreateContext()
ig.render(ctx; window_size=(360, 480), window_title="ImGui Window") do
    ig.Begin("Hello ImGui")
    if ig.Button("My Button")
        @info "Triggered"
    end
    ig.End()
end

The window opens up just fine, but about 10 seconds later, it crashes on its own giving the following error message

┌ Error: Error in CImGui GlfwOpenGL3 renderloop!
│   exception =
│    GLFWError (PLATFORM_ERROR): WGL: Failed to make context current: The requested transformation operation is not supported.
│    Stacktrace:
│     [1] _ErrorCallbackWrapper(code::Int32, description::Cstring)
│       @ GLFW path\to\.julia\packages\GLFW\wmoTL\src\callback.jl:43
│     [2] MakeContextCurrent
│       @ path\to\.julia\packages\GLFW\wmoTL\src\glfw3.jl:776 [inlined]
│     [3] renderloop(ui::var"#19#20", ctx::Ptr{CImGui.lib.ImGuiContext}, ::Val{:GlfwOpenGL3}; hotloading::Bool, on_exit::Nothing, clear_color::Vector{Float32}, window_size::Tuple{Int64, Int64}, window_title::String, engine::Nothing, opengl_version::VersionNumber)
│       @ GlfwOpenGLBackend path\to\.julia\packages\CImGui\nVW4u\ext\GlfwOpenGLBackend.jl:125
│     [4] renderloop
│       @ path\to\.julia\packages\CImGui\nVW4u\ext\GlfwOpenGLBackend.jl:54 [inlined]
│     [5] (::GlfwOpenGLBackend.var"#5#6"{@Kwargs{window_size::Tuple{Int64, Int64}, window_title::String}, Tuple{var"#19#20", Ptr{CImGui.lib.ImGuiContext}, Val{:GlfwOpenGL3}}})()
│       @ GlfwOpenGLBackend path\to\.julia\packages\CImGui\nVW4u\ext\GlfwOpenGLBackend.jl:176
└ @ GlfwOpenGLBackend path\to\.julia\packages\CImGui\nVW4u\ext\GlfwOpenGLBackend.jl:147

Any ideas?

[JamesWrigley]

What happens if you pin GLFW_jll to 3.3?

[moe93]

Pining GLFW v3.3.0 doesn't resolve the issue.

I seem to have figured out the issue though; the OpenGL version. Changing it in the renderer to opengl_version=v"3.0" fixes the problem, did not realize the default was set to v"3.2" in the renderer.

I double checked with my C++ imgui code and I do use 3.0 there as well. However, if I specify version 3.2 in the C++ imgui program, everything runs fine with no issues. I am not so sure why that is an issue when it comes to the Julia one.

[JamesWrigley]

Pining GLFW v3.3.0 doesn't resolve the issue.

I meant GLFW_jll though :) GLFW.jl's version numbering doesn't match the version of the GLFW library that's used. I'm wondering about this because GLFW 3.4 was quite a large release.

I seem to have figured out the issue though; the OpenGL version. Changing it in the renderer to opengl_version=v"3.0" fixes the problem, did not realize the default was set to v"3.2" in the renderer.

I double checked with my C++ imgui code and I do use 3.0 there as well. However, if I specify version 3.2 in the C++ imgui program, everything runs fine with no issues. I am not so sure why that is an issue when it comes to the Julia one.

Oh interesting, I would've thought an OpenGL version problem would manifest sooner 🤔 I believe there are some differences between the renderloop we implement and the official example with GLFW/OpenGL3 but I never looked into the differences. Perhaps that's causing it.