How to Integrate Dear ImGui with Vulkan: Complete Backend Setup Guide

Integrate Dear ImGui with Vulkan by initializing the imgui_impl_vulkan backend using an ImGui_ImplVulkan_InitInfo structure containing your device, queue, and render pass, then call ImGui_ImplVulkan_RenderDrawData() each frame inside your command buffer to render the UI.

Dear ImGui ships with an official Vulkan renderer backend in the ocornut/imgui repository that manages vertex buffers, descriptor pools, and pipeline state automatically. To integrate Dear ImGui with Vulkan, you include backends/imgui_impl_vulkan.h, populate the initialization structure with your existing Vulkan context handles, and execute the per-frame functions within your rendering loop. This backend supports both traditional render passes and the VK_KHR_dynamic_rendering extension.

Required Vulkan Context

Before initializing ImGui, your application must create and own a functional Vulkan context. The backend does not create these objects for you—it only consumes them.

You must provide:

• VkInstance – Created with necessary surface extensions.
• VkPhysicalDevice – Selected GPU supporting required queue families.
• VkDevice – Logical device with graphics queue capabilities.
• VkQueue – Graphics queue for command submission.
• VkRenderPass – Render pass used for your swap chain, or dynamic rendering configuration.
• VkDescriptorPool (optional) – Either create one yourself or set DescriptorPoolSize > 0 to let ImGui create it internally.
• VkPipelineCache (optional) – For pipeline creation caching.

These handles populate the ImGui_ImplVulkan_InitInfo structure defined in backends/imgui_impl_vulkan.h.

Initializing the Vulkan Backend

Include Headers

Add the ImGui core header and the Vulkan backend files. You also need a platform backend (GLFW, SDL, Win32) initialized before the renderer.

#include "imgui.h"
#include "imgui_impl_vulkan.h"
#include "imgui_impl_glfw.h"   // Replace with your platform backend

Configure ImGui_ImplVulkan_InitInfo

Fill the initialization structure with your Vulkan handles. Since version 2025-09-26, render pass parameters moved into the PipelineInfoMain sub-structure.

ImGui_ImplVulkan_InitInfo init_info = {};
init_info.Instance       = g_Instance;          // Your VkInstance
init_info.PhysicalDevice = g_PhysicalDevice;    // Your VkPhysicalDevice
init_info.Device         = g_Device;            // Your VkDevice
init_info.QueueFamily    = g_QueueFamily;       // Graphics queue family index
init_info.Queue          = g_Queue;             // Your VkQueue
init_info.PipelineCache  = g_PipelineCache;     // Optional: VK_NULL_HANDLE allowed
init_info.DescriptorPool = g_DescriptorPool;    // Optional: set 0 to auto-create
init_info.MinImageCount  = g_MinImageCount;     // >= 2 (match your swap chain)
init_info.ImageCount     = wd->ImageCount;      // Swap chain image count
init_info.Allocator      = g_Allocator;         // Optional: custom VkAllocationCallbacks

// Render pass configuration (required)
init_info.PipelineInfoMain.RenderPass    = wd->RenderPass;
init_info.PipelineInfoMain.Subpass       = 0;
init_info.PipelineInfoMain.MSAASamples   = VK_SAMPLE_COUNT_1_BIT;

// Optional: custom shader modules (leave zeroed for built-in shaders)
init_info.CustomShaderVertCreateInfo = {};
init_info.CustomShaderFragCreateInfo = {};

// Optional: error callback
init_info.CheckVkResultFn = [](VkResult err){ /* handle error */ };

Initialize Backends

Initialize your platform backend first, then the Vulkan renderer. The font texture uploads automatically during the first ImGui_ImplVulkan_NewFrame() call.

// Platform backend must come first
ImGui_ImplGlfw_InitForVulkan(window, true);

// Initialize Vulkan backend
ImGui_ImplVulkan_Init(&init_info);

Per-Frame Rendering Loop

Each frame, synchronize ImGui with your Vulkan command buffer recording.

// 1. Start frame
ImGui_ImplVulkan_NewFrame();
ImGui_ImplGlfw_NewFrame();   // Your platform backend
ImGui::NewFrame();

// 2. Build UI
ImGui::Begin("Vulkan Example");
ImGui::Text("Hello from Vulkan!");
ImGui::End();

// 3. Render
ImGui::Render();
ImDrawData* draw_data = ImGui::GetDrawData();

// Skip if minimized
if (draw_data->DisplaySize.x > 0.0f && draw_data->DisplaySize.y > 0.0f)
{
    VkCommandBuffer cmd = ...;  // Your acquired command buffer
    
    // Render to command buffer (pipeline arg optional)
    ImGui_ImplVulkan_RenderDrawData(draw_data, cmd, VK_NULL_HANDLE);
    
    // ... submit command buffer and present
}

Managing Custom Textures

The backend identifies textures via VkDescriptorSet cast to ImTextureID. Register your images using the provided helper functions in backends/imgui_impl_vulkan.cpp.

// Register texture
VkDescriptorSet tex_desc = ImGui_ImplVulkan_AddTexture(
    myImageView, 
    VK_IMAGE_LAYOUT_SHADER_READ_ONLY_OPTIMAL
);
ImTextureID my_tex = (ImTextureID)tex_desc;

// Use in UI
ImGui::Image(my_tex, ImVec2(100, 100));

// Cleanup when done
ImGui_ImplVulkan_RemoveTexture(tex_desc);

The backend automatically creates linear and nearest samplers (SamplerLinearDS and SamplerNearestDS) accessible through draw callbacks around lines 340-350 in imgui_impl_vulkan.cpp.

Cleanup and Shutdown

Ensure device idle before destroying ImGui objects to prevent in-flight resource deletion.

vkDeviceWaitIdle(g_Device);
ImGui_ImplVulkan_Shutdown();   // Destroys internal Vulkan objects
ImGui_ImplGlfw_Shutdown();     // Platform shutdown
ImGui::DestroyContext();

Key Source Files

Reference these files in the ocornut/imgui repository for implementation details:

• backends/imgui_impl_vulkan.h – Public API declarations and ImGui_ImplVulkan_InitInfo structure.
• backends/imgui_impl_vulkan.cpp – Backend implementation handling buffer uploads, descriptor management, and pipeline creation.
• examples/example_glfw_vulkan/main.cpp – Complete working example with swap chain management.
• examples/example_sdl2_vulkan/main.cpp – SDL2 variant for cross-platform applications.
• examples/example_win32_vulkan/main.cpp – Native Win32 platform backend without third-party libraries.

Summary

• Prepare Vulkan context before initialization: instance, device, queue, and render pass.
• Fill ImGui_ImplVulkan_InitInfo carefully, noting that RenderPass, Subpass, and MSAASamples reside in the PipelineInfoMain sub-structure.
• Initialize platform backend first, then call ImGui_ImplVulkan_Init().
• Each frame: call ImGui_ImplVulkan_NewFrame(), build UI, ImGui::Render(), then ImGui_ImplVulkan_RenderDrawData() with your command buffer.
• Manage textures via ImGui_ImplVulkan_AddTexture() and ImGui_ImplVulkan_RemoveTexture().
• Shutdown with ImGui_ImplVulkan_Shutdown() after ensuring vkDeviceWaitIdle().

Frequently Asked Questions

Do I need to create a descriptor pool for ImGui?

No. While you can provide your own VkDescriptorPool via ImGui_ImplVulkan_InitInfo::DescriptorPool, you may instead set DescriptorPoolSize to a value greater than zero and leave DescriptorPool as VK_NULL_HANDLE. The backend will create and manage an internal descriptor pool automatically, sized according to your specified DescriptorPoolSize.

How do I use Dear ImGui with Vulkan dynamic rendering?

The backend supports VK_KHR_dynamic_rendering. Instead of providing a VkRenderPass in PipelineInfoMain.RenderPass, configure the dynamic rendering parameters in the initialization structure. Check the comments in imgui_impl_vulkan.h for the specific fields related to dynamic rendering attachments and pipeline flags.

Can I use custom shaders with the Vulkan backend?

Yes. Populate ImGui_ImplVulkan_InitInfo::CustomShaderVertCreateInfo and CustomShaderFragCreateInfo with your VkShaderModuleCreateInfo structures before calling ImGui_ImplVulkan_Init(). If you leave these fields zeroed, the backend uses its built-in vertex and fragment shaders compiled from imgui_impl_vulkan.cpp.

How do I display my own images in ImGui with Vulkan?

Call ImGui_ImplVulkan_AddTexture() with your VkImageView and desired image layout (typically VK_IMAGE_LAYOUT_SHADER_READ_ONLY_OPTIMAL). This returns a VkDescriptorSet that you cast to ImTextureID and pass to ImGui::Image(). Call ImGui_ImplVulkan_RemoveTexture() before destroying the underlying image view to prevent descriptor set leaks.

{
  "mcpServers": {
    "instagit": {
      "command": "npx",
      "args": ["-y", "instagit@latest"]
    }
  }
}