Examples: GLFW, Vulkan: GLFW binding viewport tweaks to supports Vulkan better (do not call SwapBuffer, share context etc.). Added DUMMY (empty) platform/viewport interface in the viewport code.

examples/imgui_impl_glfw.cpp

@@ -36,10 +36,17 @@
 #endif
 
 // Data
-static GLFWwindow*  g_Window = NULL;
-static double       g_Time = 0.0f;
-static bool         g_MouseJustPressed[5] = { false, false, false, false, false };
-static GLFWcursor*  g_MouseCursors[ImGuiMouseCursor_Count_] = { 0 };
+enum GlfwClientApi
+{
+    GlfwClientApi_Unknown,
+    GlfwClientApi_OpenGL,
+    GlfwClientApi_Vulkan
+};
+static GLFWwindow*      g_Window = NULL;
+static GlfwClientApi    g_ClientApi = GlfwClientApi_Unknown;
+static double           g_Time = 0.0f;
+static bool             g_MouseJustPressed[5] = { false, false, false, false, false };
+static GLFWcursor*      g_MouseCursors[ImGuiMouseCursor_Count_] = { 0 };
 
 // Forward Declarations
 static void ImGui_ImplGlfw_InitPlatformInterface();
@@ -98,7 +105,7 @@ void ImGui_ImplGlfw_InstallCallbacks(GLFWwindow* window)
     glfwSetCharCallback(window, ImGui_ImplGlfw_CharCallback);
 }
 
-bool    ImGui_ImplGlfw_Init(GLFWwindow* window, bool install_callbacks)
+bool ImGui_ImplGlfw_Init(GLFWwindow* window, bool install_callbacks)
 {
     g_Window = window;
 
@@ -149,6 +156,15 @@ bool    ImGui_ImplGlfw_Init(GLFWwindow* window, bool install_callbacks)
     if (io.ConfigFlags & ImGuiConfigFlags_MultiViewports)
         ImGui_ImplGlfw_InitPlatformInterface();
 
+    g_ClientApi = GlfwClientApi_OpenGL;
+    return true;
+}
+
+bool ImGui_ImplGlfw_InitForVulkan(GLFWwindow* window, bool install_callbacks)
+{
+    if (!ImGui_ImplGlfw_Init(window, install_callbacks))
+        return false;
+    g_ClientApi = GlfwClientApi_Vulkan;
     return true;
 }
 
@@ -161,6 +177,7 @@ void ImGui_ImplGlfw_Shutdown()
         glfwDestroyCursor(g_MouseCursors[cursor_n]);
         g_MouseCursors[cursor_n] = NULL;
     }
+    g_ClientApi = GlfwClientApi_Unknown;
 }
 
 static void ImGui_ImplGlfw_UpdateMouse()
@@ -176,7 +193,6 @@ static void ImGui_ImplGlfw_UpdateMouse()
     io.MouseHoveredViewport = 0;
 
     // Update buttons
-    ImGuiIO& io = ImGui::GetIO();
     for (int i = 0; i < IM_ARRAYSIZE(io.MouseDown); i++)
     {
         // If a mouse press event came, always pass it as "mouse held this frame", so we don't miss click-release events that are shorter than 1 frame.
@@ -296,7 +312,8 @@ static void ImGui_ImplGlfw_CreateViewport(ImGuiViewport* viewport)
     glfwWindowHint(GLFW_VISIBLE, false);
     glfwWindowHint(GLFW_FOCUSED, false);
     glfwWindowHint(GLFW_DECORATED, (viewport->Flags & ImGuiViewportFlags_NoDecoration) ? false : true);
-    data->Window = glfwCreateWindow((int)viewport->Size.x, (int)viewport->Size.y, "No Title Yet", NULL, g_Window);
+    GLFWwindow* share_window = (g_ClientApi == GlfwClientApi_OpenGL) ? g_Window : NULL;
+    data->Window = glfwCreateWindow((int)viewport->Size.x, (int)viewport->Size.y, "No Title Yet", NULL, share_window);
     data->WindowOwned = true;
     viewport->PlatformHandle = (void*)data->Window;
     viewport->Name = NULL;
@@ -405,7 +422,8 @@ static void ImGui_ImplGlfw_SetWindowTitle(ImGuiViewport* viewport, const char* t
 static void ImGui_ImplGlfw_RenderViewport(ImGuiViewport* viewport)
 {
     ImGuiPlatformDataGlfw* data = (ImGuiPlatformDataGlfw*)viewport->PlatformUserData;
-    glfwMakeContextCurrent(data->Window);
+    if (g_ClientApi == GlfwClientApi_OpenGL)
+        glfwMakeContextCurrent(data->Window);
 
     if (glfwWindowShouldClose(data->Window))
         viewport->PlatformRequestClose = true;
@@ -414,7 +432,8 @@ static void ImGui_ImplGlfw_RenderViewport(ImGuiViewport* viewport)
 static void ImGui_ImplGlfw_SwapBuffers(ImGuiViewport* viewport)
 {
     ImGuiPlatformDataGlfw* data = (ImGuiPlatformDataGlfw*)viewport->PlatformUserData;
-    glfwSwapBuffers(data->Window);
+    if (g_ClientApi == GlfwClientApi_OpenGL)
+        glfwSwapBuffers(data->Window);
 }
 
 static void ImGui_ImplGlfw_InitPlatformInterface()

examples/imgui_impl_glfw.h

@@ -13,6 +13,7 @@
 struct GLFWwindow;
 
 IMGUI_API bool        ImGui_ImplGlfw_Init(GLFWwindow* window, bool install_callbacks);
+IMGUI_API bool        ImGui_ImplGlfw_InitForVulkan(GLFWwindow* window, bool install_callbacks);
 IMGUI_API void        ImGui_ImplGlfw_Shutdown();
 IMGUI_API void        ImGui_ImplGlfw_NewFrame();
 

examples/imgui_impl_vulkan.cpp

@@ -57,6 +57,10 @@ static VkBuffer               g_IndexBuffer[IMGUI_VK_QUEUED_FRAMES] = {};
 static VkDeviceMemory         g_UploadBufferMemory = VK_NULL_HANDLE;
 static VkBuffer               g_UploadBuffer = VK_NULL_HANDLE;
 
+// Forward Declarations
+static void ImGui_ImplVulkan_InitPlatformInterface();
+static void ImGui_ImplVulkan_ShutdownPlatformInterface();
+
 static uint32_t __glsl_shader_vert_spv[] =
 {
     0x07230203,0x00010000,0x00080001,0x0000002e,0x00000000,0x00020011,0x00000001,0x0006000b,
@@ -699,12 +703,17 @@ bool    ImGui_ImplVulkan_Init(ImGui_ImplVulkan_InitInfo *init_data)
     g_DescriptorPool = init_data->DescriptorPool;
     g_CheckVkResult = init_data->CheckVkResultFn;
 
+    ImGuiIO& io = ImGui::GetIO();
     ImGui_ImplVulkan_CreateDeviceObjects();
+    if (io.ConfigFlags & ImGuiConfigFlags_MultiViewports)
+        ImGui_ImplVulkan_InitPlatformInterface();
+
     return true;
 }
 
 void ImGui_ImplVulkan_Shutdown()
 {
+    ImGui_ImplVulkan_ShutdownPlatformInterface();
     ImGui_ImplVulkan_InvalidateDeviceObjects();
 }
 
@@ -790,3 +799,83 @@ VkPresentModeKHR ImGui_ImplVulkan_SelectPresentMode(VkPhysicalDevice physical_de
 
     return VK_PRESENT_MODE_FIFO_KHR; // Always available
 }
+
+// --------------------------------------------------------------------------------------------------------
+// Platform Windows (OPTIONAL/EXPERIMENTAL)
+// --------------------------------------------------------------------------------------------------------
+
+#include "imgui_internal.h"     // ImGuiViewport
+
+struct ImGuiPlatformDataVulkan
+{
+    // store swap chain, render target/frame buffer, etc.
+
+    ImGuiPlatformDataVulkan() { }
+    ~ImGuiPlatformDataVulkan() { }
+};
+
+static void ImGui_ImplVulkan_CreateViewport(ImGuiViewport* viewport)
+{
+    ImGuiPlatformDataVulkan* data = IM_NEW(ImGuiPlatformDataVulkan)();
+    viewport->RendererUserData = data;
+
+    // FIXME-PLATFORM
+    //HWND hwnd = (HWND)viewport->PlatformHandle;
+    //IM_ASSERT(hwnd != 0);
+
+    //...
+}
+
+static void ImGui_ImplVulkan_DestroyViewport(ImGuiViewport* viewport)
+{
+    if (ImGuiPlatformDataVulkan* data = (ImGuiPlatformDataVulkan*)viewport->RendererUserData)
+    {
+        //...
+        IM_DELETE(data);
+    }
+    viewport->RendererUserData = NULL;
+}
+
+static void ImGui_ImplVulkan_ResizeViewport(ImGuiViewport* viewport, int w, int h)
+{
+    ImGuiPlatformDataVulkan* data = (ImGuiPlatformDataVulkan*)viewport->RendererUserData;
+    //...
+    (void)data;
+    (void)w;
+    (void)h;
+}
+
+static void ImGui_ImplVulkan_RenderViewport(ImGuiViewport* viewport)
+{
+    ImGuiPlatformDataVulkan* data = (ImGuiPlatformDataVulkan*)viewport->RendererUserData;
+    ImVec4 clear_color = ImGui::GetStyle().Colors[ImGuiCol_WindowBg]; // FIXME-PLATFORM
+    clear_color.w = 1.0f;
+
+    (void)data;
+    // clear
+    // call ImGui_ImplVulkan_RenderDrawData(&viewport->DrawData)
+}
+
+static void ImGui_ImplVulkan_SwapBuffers(ImGuiViewport* viewport)
+{
+    ImGuiPlatformDataVulkan* data = (ImGuiPlatformDataVulkan*)viewport->RendererUserData;
+    (void)data;
+    //...
+}
+
+void ImGui_ImplVulkan_InitPlatformInterface()
+{
+    ImGuiIO& io = ImGui::GetIO();
+    io.RendererInterface.CreateViewport = ImGui_ImplVulkan_CreateViewport;
+    io.RendererInterface.DestroyViewport = ImGui_ImplVulkan_DestroyViewport;
+    io.RendererInterface.ResizeViewport = ImGui_ImplVulkan_ResizeViewport;
+    io.RendererInterface.RenderViewport = ImGui_ImplVulkan_RenderViewport;
+    io.RendererInterface.SwapBuffers = ImGui_ImplVulkan_SwapBuffers;
+}
+
+void ImGui_ImplVulkan_ShutdownPlatformInterface()
+{
+    ImGuiIO& io = ImGui::GetIO();
+    memset(&io.RendererInterface, 0, sizeof(io.RendererInterface));
+}
+

examples/vulkan_example/main.cpp

@@ -568,10 +568,11 @@ int main(int, char**)
     init_info.CheckVkResultFn = check_vk_result;
 
     ImGuiIO& io = ImGui::GetIO(); (void)io;
+    //io.ConfigFlags |= ImGuiConfigFlags_MultiViewports;
     //io.ConfigFlags |= ImGuiConfigFlags_NavEnableKeyboard;  // Enable Keyboard Controls
 
     ImGui_ImplVulkan_Init(&init_info);
-    ImGui_ImplGlfw_Init(window, true);
+    ImGui_ImplGlfw_InitForVulkan(window, true);
 
     // Setup style
     ImGui::StyleColorsDark();
@@ -689,6 +690,9 @@ int main(int, char**)
         ImGui_ImplVulkan_Render(g_CommandBuffer[g_FrameIndex]);
         frame_end();
         frame_present();
+
+        ImGui::UpdatePlatformWindows();
+        ImGui::RenderPlatformWindows();
     }
 
     // Cleanup