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Examples: Amend Win32/Winapi + OpenGL example for multi-viewport. (#3218, #5170 and #6086, #2772, #2600, #2359, #2022, #1553)

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ocornut 2023-04-19 16:48:07 +02:00
parent 4bc51c6ff4
commit f498f084d6
2 changed files with 24 additions and 31 deletions
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4
backends/imgui_impl_win32.cpp
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@ -1165,11 +1165,11 @@ static LRESULT CALLBACK ImGui_ImplWin32_WndProcHandler_PlatformWindow(HWND hWnd,
return DefWindowProc(hWnd, msg, wParam, lParam); return DefWindowProc(hWnd, msg, wParam, lParam);
} }
static void ImGui_ImplWin32_InitPlatformInterface(bool platformHasOwnDC) static void ImGui_ImplWin32_InitPlatformInterface(bool platform_has_own_dc)
{ {
WNDCLASSEX wcex; WNDCLASSEX wcex;
wcex.cbSize = sizeof(WNDCLASSEX); wcex.cbSize = sizeof(WNDCLASSEX);
wcex.style = CS_HREDRAW | CS_VREDRAW | (platformHasOwnDC ? CS_OWNDC : 0); wcex.style = CS_HREDRAW | CS_VREDRAW | (platform_has_own_dc ? CS_OWNDC : 0);
wcex.lpfnWndProc = ImGui_ImplWin32_WndProcHandler_PlatformWindow; wcex.lpfnWndProc = ImGui_ImplWin32_WndProcHandler_PlatformWindow;
wcex.cbClsExtra = 0; wcex.cbClsExtra = 0;
wcex.cbWndExtra = 0; wcex.cbWndExtra = 0;

51
examples/example_win32_opengl3/main.cpp
View File

@ -29,8 +29,10 @@ void CleanupDeviceWGL(HWND hWnd, WGL_WindowData* data);
void ResetDeviceWGL(); void ResetDeviceWGL();
LRESULT WINAPI WndProc(HWND hWnd, UINT msg, WPARAM wParam, LPARAM lParam); LRESULT WINAPI WndProc(HWND hWnd, UINT msg, WPARAM wParam, LPARAM lParam);
// Support function for multi-viewports
static void Win32_CreateWindow(ImGuiViewport* viewport) // Unlike most other backend combination, we need specific hooks to combine Win32+OpenGL.
// We could in theory decide to support Win32-specific code in OpenGL backend via e.g. an hypothetical ImGui_ImplOpenGL3_InitForRawWin32().
static void Hook_Renderer_CreateWindow(ImGuiViewport* viewport)
{ {
assert(viewport->RendererUserData == NULL); assert(viewport->RendererUserData == NULL);
@ -39,7 +41,7 @@ static void Win32_CreateWindow(ImGuiViewport* viewport)
viewport->RendererUserData = data; viewport->RendererUserData = data;
} }
static void Win32_DestroyWindow(ImGuiViewport* viewport) static void Hook_Renderer_DestroyWindow(ImGuiViewport* viewport)
{ {
if (viewport->RendererUserData != NULL) if (viewport->RendererUserData != NULL)
{ {
@ -50,25 +52,17 @@ static void Win32_DestroyWindow(ImGuiViewport* viewport)
} }
} }
static void Win32_RenderWindow(ImGuiViewport* viewport, void*) static void Hook_Platform_RenderWindow(ImGuiViewport* viewport, void*)
{ {
WGL_WindowData* data = (WGL_WindowData*)viewport->RendererUserData; // Activate the platform window DC in the OpenGL rendering context
if (WGL_WindowData* data = (WGL_WindowData*)viewport->RendererUserData)
if (data)
{
// Activate the platform window DC in the OpenGL rendering context
wglMakeCurrent(data->hDC, g_hRC); wglMakeCurrent(data->hDC, g_hRC);
}
} }
static void Win32_SwapBuffers(ImGuiViewport* viewport, void*) static void Hook_Renderer_SwapBuffers(ImGuiViewport* viewport, void*)
{ {
WGL_WindowData* data = (WGL_WindowData*)viewport->RendererUserData; if (WGL_WindowData* data = (WGL_WindowData*)viewport->RendererUserData)
::SwapBuffers(data->hDC);
if (data)
{
SwapBuffers(data->hDC);
}
} }
// Main code // Main code
@ -119,22 +113,20 @@ int main(int, char**)
ImGui_ImplWin32_InitForOpenGL(hwnd); ImGui_ImplWin32_InitForOpenGL(hwnd);
ImGui_ImplOpenGL3_Init(); ImGui_ImplOpenGL3_Init();
// Win32+GL needs specific hooks for viewport, as there are specific things needed to tie Win32 and GL api.
if (io.ConfigFlags & ImGuiConfigFlags_ViewportsEnable) if (io.ConfigFlags & ImGuiConfigFlags_ViewportsEnable)
{ {
ImGuiPlatformIO& platform_io = ImGui::GetPlatformIO(); ImGuiPlatformIO& platform_io = ImGui::GetPlatformIO();
IM_ASSERT(platform_io.Renderer_CreateWindow == NULL);
// Store the hdc for this new window IM_ASSERT(platform_io.Renderer_DestroyWindow == NULL);
assert(platform_io.Renderer_CreateWindow == NULL); IM_ASSERT(platform_io.Renderer_SwapBuffers == NULL);
platform_io.Renderer_CreateWindow = Win32_CreateWindow; IM_ASSERT(platform_io.Platform_RenderWindow == NULL);
assert(platform_io.Renderer_DestroyWindow == NULL); platform_io.Renderer_CreateWindow = Hook_Renderer_CreateWindow;
platform_io.Renderer_DestroyWindow = Win32_DestroyWindow; platform_io.Renderer_DestroyWindow = Hook_Renderer_DestroyWindow;
assert(platform_io.Renderer_SwapBuffers == NULL); platform_io.Renderer_SwapBuffers = Hook_Renderer_SwapBuffers;
platform_io.Renderer_SwapBuffers = Win32_SwapBuffers; platform_io.Platform_RenderWindow = Hook_Platform_RenderWindow;
// We need to activate the context before drawing
assert(platform_io.Platform_RenderWindow == NULL);
platform_io.Platform_RenderWindow = Win32_RenderWindow;
} }
// Load Fonts // Load Fonts
// - If no fonts are loaded, dear imgui will use the default font. You can also load multiple fonts and use ImGui::PushFont()/PopFont() to select them. // - If no fonts are loaded, dear imgui will use the default font. You can also load multiple fonts and use ImGui::PushFont()/PopFont() to select them.
// - AddFontFromFileTTF() will return the ImFont* so you can store it if you need to select the font among multiple. // - AddFontFromFileTTF() will return the ImFont* so you can store it if you need to select the font among multiple.
@ -227,6 +219,7 @@ int main(int, char**)
{ {
ImGui::UpdatePlatformWindows(); ImGui::UpdatePlatformWindows();
ImGui::RenderPlatformWindowsDefault(); ImGui::RenderPlatformWindowsDefault();
// Restore the OpenGL rendering context to the main window DC, since platform windows might have changed it. // Restore the OpenGL rendering context to the main window DC, since platform windows might have changed it.
wglMakeCurrent(g_MainWindow.hDC, g_hRC); wglMakeCurrent(g_MainWindow.hDC, g_hRC);
} }