Crashing when dragging imgui window out of the main window #8713
Description
Version/Branch of Dear ImGui:
Version v1.91.9b, Branch: docking
Back-ends:
imgui_impl_opengl3.cpp + imgui_impl_glfw.cpp
Compiler, OS:
Windows 11 + GCC 14.2.0
Full config/build information:
Dear ImGui 1.92.0 WIP (19199)
--------------------------------
sizeof(size_t): 8, sizeof(ImDrawIdx): 2, sizeof(ImDrawVert): 20
define: __cplusplus=202302
define: _WIN32
define: _WIN64
define: __MINGW32__
define: __MINGW64__
define: __GNUC__=14
define: IMGUI_HAS_VIEWPORT
define: IMGUI_HAS_DOCK
--------------------------------
io.BackendPlatformName: imgui_impl_glfw (3310)
io.BackendRendererName: imgui_impl_opengl3
io.ConfigFlags: 0x00000483
NavEnableKeyboard
NavEnableGamepad
DockingEnable
ViewportsEnable
io.ConfigDpiScaleFonts
io.ConfigDpiScaleViewports
io.ConfigViewportsNoDecoration
io.ConfigNavCaptureKeyboard
io.ConfigInputTextCursorBlink
io.ConfigWindowsResizeFromEdges
io.ConfigMemoryCompactTimer = 60.0
io.BackendFlags: 0x00001C1E
HasMouseCursors
HasSetMousePos
PlatformHasViewports
HasMouseHoveredViewport
RendererHasVtxOffset
RendererHasTextures
RendererHasViewports
--------------------------------
io.Fonts: 1 fonts, Flags: 0x00000000, TexSize: 512,128
io.Fonts->FontLoaderName: stb_truetype
io.DisplaySize: 1280.00,800.00
io.DisplayFramebufferScale: 1.00,1.00
--------------------------------
style.WindowPadding: 8.00,8.00
style.WindowBorderSize: 1.00
style.FramePadding: 4.00,3.00
style.FrameRounding: 0.00
style.FrameBorderSize: 0.00
style.ItemSpacing: 8.00,4.00
style.ItemInnerSpacing: 4.00,4.00Details:
Crashing when dragging imgui window outside the main window.
I started working on my project after a break and i thought viewports had worked, but it kept crashing. I tried to look for fix for quite some time and it ended up being glfw version. Switching from glfw 3.3.9 to glfw 3.4 fixed it. Making this issue post to find what's causing the crash with glfw older version, since from going trough posts about imgui it seems like it has been working with 3.x.x. also i couldn't find any other issues refering to imgui_impl_glfw.cpp:1501.
imgui_impl_glfw.cpp at line 1501 ( ImGuiIO& io = ImGui::GetIO(bd->Context); ) is where the program is crashing. It appears that the GetPropA.
static LRESULT CALLBACK ImGui_ImplGlfw_WndProc(HWND hWnd, UINT msg, WPARAM wParam, LPARAM lParam)
{
ImGui_ImplGlfw_Data* bd = (ImGui_ImplGlfw_Data*)::GetPropA(hWnd, "IMGUI_BACKEND_DATA");
ImGuiIO& io = ImGui::GetIO(bd->Context);
...
Rest of the implementation
...Callstack
ImGui_ImplGlfw_WndProc(HWND hWnd, UINT msg, WPARAM wParam, LPARAM lParam) (c:\Users\35850\Desktop\testing\build\_deps\imgui-src\backends\imgui_impl_glfw.cpp:1501)
user32.dll!USER32!DispatchMessageW (Unknown Source:0)
user32.dll!USER32!DispatchMessageW (Unknown Source:0)
user32.dll!USER32!GetClassLongW (Unknown Source:0)
ntdll.dll!ntdll!KiUserCallbackDispatcher (Unknown Source:0)
win32u.dll!win32u!NtUserShowWindow (Unknown Source:0)
_glfwPlatformShowWindow(_GLFWwindow * window) (c:\Users\35850\Desktop\testing\build\_deps\glfw-src\src\win32_window.c:1777)
glfwShowWindow(GLFWwindow * handle) (c:\Users\35850\Desktop\testing\build\_deps\glfw-src\src\window.c:761)
ImGui_ImplGlfw_ShowWindow(ImGuiViewport * viewport) (c:\Users\35850\Desktop\testing\build\_deps\imgui-src\backends\imgui_impl_glfw.cpp:1307)
ImGui::UpdatePlatformWindows() (c:\Users\35850\Desktop\testing\build\_deps\imgui-src\imgui.cpp:16985)
main() (c:\Users\35850\Desktop\testing\example.cpp:220)
thanks for help in advance!
Screenshots/Video:
Variables at the time of the crash
Minimal, Complete and Verifiable Example code:
Building original example with the cmakelists.txt below:
// Original examples/example_glfw_opengl3/main.cppcmake_minimum_required(VERSION 3.10)
project(testing VERSION 0.1.0 LANGUAGES C CXX)
set(CMAKE_CXX_STANDARD 23)
set(CMAKE_CXX_STANDARD_REQUIRED ON)
set(CMAKE_RUNTIME_OUTPUT_DIRECTORY ${CMAKE_BINARY_DIR}/bin)
set(CMAKE_LIBRARY_OUTPUT_DIRECTORY ${CMAKE_BINARY_DIR}/lib)
set(CMAKE_ARCHIVE_OUTPUT_DIRECTORY ${CMAKE_BINARY_DIR}/lib)
include(FetchContent)
FetchContent_Declare(
glfw
GIT_REPOSITORY https://github.com/glfw/glfw.git
GIT_TAG 3.3.10
)
set(GLFW_BUILD_DOCS OFF CACHE BOOL "" FORCE)
set(GLFW_BUILD_TESTS OFF CACHE BOOL "" FORCE)
set(GLFW_BUILD_EXAMPLES OFF CACHE BOOL "" FORCE)
set(GLFW_INSTALL OFF CACHE BOOL "" FORCE)
FetchContent_MakeAvailable(glfw)
FetchContent_Declare(
imgui
GIT_REPOSITORY https://github.com/ocornut/imgui.git
GIT_TAG docking
)
FetchContent_MakeAvailable(imgui)
add_library(imgui STATIC
${imgui_SOURCE_DIR}/imgui.cpp
${imgui_SOURCE_DIR}/imgui_draw.cpp
${imgui_SOURCE_DIR}/imgui_widgets.cpp
${imgui_SOURCE_DIR}/imgui_tables.cpp
${imgui_SOURCE_DIR}/imgui_demo.cpp
${imgui_SOURCE_DIR}/misc/cpp/imgui_stdlib.cpp
${imgui_SOURCE_DIR}/backends/imgui_impl_opengl3.cpp
${imgui_SOURCE_DIR}/backends/imgui_impl_glfw.cpp
)
target_include_directories(imgui PUBLIC
${imgui_SOURCE_DIR}
${imgui_SOURCE_DIR}/backends
${imgui_SOURCE_DIR}/misc/cpp
)
find_package(OpenGL REQUIRED)
target_link_libraries(imgui PUBLIC glfw OpenGL::GL)
add_executable(example example.cpp)
target_link_libraries(example PRIVATE imgui glfw OpenGL::GL)
target_include_directories(example PRIVATE
${CMAKE_CURRENT_SOURCE_DIR}/include
)