Dear ImGui Implementation (#598)

* added imgui as dependency

* imgui renderer/basic input implementation

* imgui: add layers system

Add video info layer to show fps. Press F10 to toggle it.

* imgui: add custom imgui config

* imgui: gamepad capture, stopping propagation

* imgui: changed config & log file path to use portable dir

* videoout: render blank frame when video output is closed

required to render imgui even when game has no video output

- fixed merge compile-error

.gitmodules

@@ -85,3 +85,8 @@
 [submodule "externals/half"]
 	path = externals/half
 	url = https://github.com/ROCm/half.git
+[submodule "externals/dear_imgui"]
+	path = externals/dear_imgui
+	url = https://github.com/shadps4-emu/ext-imgui.git
+	shallow = true
+	branch = docking

CMakeLists.txt

@@ -561,6 +561,18 @@ set(VIDEO_CORE src/video_core/amdgpu/liverpool.cpp
                src/video_core/renderdoc.h
 )
 
+set(IMGUI src/imgui/imgui_config.h
+          src/imgui/imgui_layer.h
+          src/imgui/layer/video_info.cpp
+          src/imgui/layer/video_info.h
+          src/imgui/renderer/imgui_core.cpp
+          src/imgui/renderer/imgui_core.h
+          src/imgui/renderer/imgui_impl_sdl3.cpp
+          src/imgui/renderer/imgui_impl_sdl3.h
+          src/imgui/renderer/imgui_impl_vulkan.cpp
+          src/imgui/renderer/imgui_impl_vulkan.h
+)
+
 set(INPUT src/input/controller.cpp
           src/input/controller.h
 )
@@ -617,6 +629,7 @@ endif()
 if (ENABLE_QT_GUI)
     qt_add_executable(shadps4
         ${AUDIO_CORE}
+        ${IMGUI}
         ${INPUT}
         ${QT_GUI}
         ${COMMON}
@@ -629,6 +642,7 @@ if (ENABLE_QT_GUI)
 else()
     add_executable(shadps4
         ${AUDIO_CORE}
+        ${IMGUI}
         ${INPUT}
         ${COMMON}
         ${CORE}
@@ -645,9 +659,12 @@ endif()
 
 create_target_directory_groups(shadps4)
 
-target_link_libraries(shadps4 PRIVATE magic_enum::magic_enum fmt::fmt toml11::toml11 tsl::robin_map xbyak::xbyak Tracy::TracyClient RenderDoc::API FFmpeg::ffmpeg)
+target_link_libraries(shadps4 PRIVATE magic_enum::magic_enum fmt::fmt toml11::toml11 tsl::robin_map xbyak::xbyak Tracy::TracyClient RenderDoc::API FFmpeg::ffmpeg Dear_ImGui)
 target_link_libraries(shadps4 PRIVATE Boost::headers GPUOpen::VulkanMemoryAllocator sirit Vulkan::Headers xxHash::xxhash Zydis::Zydis glslang::SPIRV glslang::glslang SDL3::SDL3)
 
+target_compile_definitions(shadps4 PRIVATE IMGUI_USER_CONFIG="imgui/imgui_config.h")
+target_compile_definitions(Dear_ImGui PRIVATE IMGUI_USER_CONFIG="${PROJECT_SOURCE_DIR}/src/imgui/imgui_config.h")
+
 if (APPLE)
   option(USE_SYSTEM_VULKAN_LOADER "Enables using the system Vulkan loader instead of directly linking with MoltenVK. Useful for loading validation layers." OFF)
   if (USE_SYSTEM_VULKAN_LOADER)

externals/CMakeLists.txt

@@ -155,6 +155,17 @@ if (APPLE)
     endif()
 endif()
 
+# Dear ImGui
+add_library(Dear_ImGui
+        dear_imgui/imgui.cpp
+        dear_imgui/imgui_demo.cpp
+        dear_imgui/imgui_draw.cpp
+        dear_imgui/imgui_internal.h
+        dear_imgui/imgui_tables.cpp
+        dear_imgui/imgui_widgets.cpp
+)
+target_include_directories(Dear_ImGui INTERFACE dear_imgui/)
+
 # Tracy
 option(TRACY_ENABLE "" ON)
 option(TRACY_NO_CRASH_HANDLER "" ON) # Otherwise texture cache exceptions will be treaten as a crash

externals/dear_imgui

@@ -0,0 +1 @@
+Subproject commit 636cd4a7d623a2bc9bf59bb3acbb4ca075befba3

src/common/assert.cpp

@@ -18,3 +18,8 @@ void assert_fail_impl() {
     Crash();
     throw std::runtime_error("Unreachable code");
 }
+
+void assert_fail_debug_msg(const char* msg) {
+    LOG_CRITICAL(Debug, "Assertion Failed!\n{}", msg);
+    assert_fail_impl();
+}

src/common/logging/filter.cpp

@@ -117,6 +117,7 @@ bool ParseFilterRule(Filter& instance, Iterator begin, Iterator end) {
     CLS(Render)                                                                                    \
     SUB(Render, Vulkan)                                                                            \
     SUB(Render, Recompiler)                                                                        \
+    CLS(ImGui)                                                                                     \
     CLS(Input)                                                                                     \
     CLS(Tty)                                                                                       \
     CLS(Loader)

src/common/logging/types.h

@@ -84,6 +84,7 @@ enum class Class : u8 {
     Render,             ///< Video Core
     Render_Vulkan,      ///< Vulkan backend
     Render_Recompiler,  ///< Shader recompiler
+    ImGui,              ///< ImGui
     Loader,             ///< ROM loader
     Input,              ///< Input emulation
     Tty,                ///< Debug output from emu

src/core/libraries/videoout/driver.cpp

@@ -161,10 +161,6 @@ int VideoOutDriver::UnregisterBuffers(VideoOutPort* port, s32 attributeIndex) {
 }
 
 std::chrono::microseconds VideoOutDriver::Flip(const Request& req) {
-    if (!req) {
-        return std::chrono::microseconds{0};
-    }
-
     const auto start = std::chrono::high_resolution_clock::now();
 
     // Whatever the game is rendering show splash if it is active
@@ -207,6 +203,11 @@ std::chrono::microseconds VideoOutDriver::Flip(const Request& req) {
     return std::chrono::duration_cast<std::chrono::microseconds>(end - start);
 }
 
+void VideoOutDriver::DrawBlankFrame() {
+    const auto empty_frame = renderer->PrepareBlankFrame(false);
+    renderer->Present(empty_frame);
+}
+
 bool VideoOutDriver::SubmitFlip(VideoOutPort* port, s32 index, s64 flip_arg,
                                 bool is_eop /*= false*/) {
     {
@@ -283,7 +284,14 @@ void VideoOutDriver::PresentThread(std::stop_token token) {
         auto& vblank_status = main_port.vblank_status;
         if (vblank_status.count % (main_port.flip_rate + 1) == 0) {
             const auto request = receive_request();
-            delay = Flip(request);
+            if (!request) {
+                delay = std::chrono::microseconds{0};
+                if (!main_port.is_open) {
+                    DrawBlankFrame();
+                }
+            } else {
+                delay = Flip(request);
+            }
             FRAME_END;
         }
 

src/core/libraries/videoout/driver.h

@@ -102,6 +102,7 @@ private:
     };
 
     std::chrono::microseconds Flip(const Request& req);
+    void DrawBlankFrame(); // Used when there is no flip request to keep ImGui up to date
     void SubmitFlipInternal(VideoOutPort* port, s32 index, s64 flip_arg, bool is_eop = false);
     void PresentThread(std::stop_token token);
 

src/imgui/imgui_config.h

@@ -0,0 +1,29 @@
+// SPDX-FileCopyrightText: Copyright 2024 shadPS4 Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#pragma once
+
+// WARNING: All includes from this file must be relative to allow Dear_ImGui project to compile
+//          without having this project include paths.
+
+#include <cstdint>
+
+extern void assert_fail_debug_msg(const char* msg);
+
+#define ImDrawIdx std::uint32_t
+
+#define IM_STRINGIZE(x) IM_STRINGIZE2(x)
+#define IM_STRINGIZE2(x) #x
+#define IM_ASSERT(_EXPR)                                                                           \
+    ([&]() {                                                                                       \
+        if (!(_EXPR)) [[unlikely]] {                                                               \
+            assert_fail_debug_msg(#_EXPR " at " __FILE__ ":" IM_STRINGIZE(__LINE__));              \
+        }                                                                                          \
+    }())
+
+#define IMGUI_USE_WCHAR32
+#define IMGUI_ENABLE_STB_TRUETYPE
+#define IMGUI_DEFINE_MATH_OPERATORS
+
+#define IM_VEC2_CLASS_EXTRA                                                                        \
+    constexpr ImVec2(float _v) : x(_v), y(_v) {}

src/imgui/imgui_layer.h

@@ -0,0 +1,21 @@
+// SPDX-FileCopyrightText: Copyright 2024 shadPS4 Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#pragma once
+
+namespace ImGui {
+
+class Layer {
+public:
+    virtual ~Layer() = default;
+    static void AddLayer(Layer* layer);
+    static void RemoveLayer(Layer* layer);
+
+    virtual void Draw() = 0;
+
+    virtual bool ShouldGrabGamepad() {
+        return false;
+    }
+};
+
+} // namespace ImGui

src/imgui/layer/video_info.cpp

@@ -0,0 +1,16 @@
+// SPDX-FileCopyrightText: Copyright 2024 shadPS4 Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#include <imgui.h>
+#include "video_info.h"
+
+void ImGui::Layers::VideoInfo::Draw() {
+    const ImGuiIO& io = GetIO();
+
+    m_show = IsKeyPressed(ImGuiKey_F10, false) ^ m_show;
+
+    if (m_show && Begin("Video Info")) {
+        Text("Frame time: %.3f ms (%.1f FPS)", 1000.0f / io.Framerate, io.Framerate);
+        End();
+    }
+}

src/imgui/layer/video_info.h

@@ -0,0 +1,23 @@
+// SPDX-FileCopyrightText: Copyright 2024 shadPS4 Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#pragma once
+
+#include "imgui/imgui_layer.h"
+
+namespace Vulkan {
+class RendererVulkan;
+}
+namespace ImGui::Layers {
+
+class VideoInfo : public Layer {
+    bool m_show = false;
+    ::Vulkan::RendererVulkan* renderer{};
+
+public:
+    explicit VideoInfo(::Vulkan::RendererVulkan* renderer) : renderer(renderer) {}
+
+    void Draw() override;
+};
+
+} // namespace ImGui::Layers

src/imgui/renderer/imgui_core.cpp

@@ -0,0 +1,213 @@
+// SPDX-FileCopyrightText: Copyright 2024 shadPS4 Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#include <SDL3/SDL_events.h>
+#include <imgui.h>
+#include "common/config.h"
+#include "common/path_util.h"
+#include "imgui/imgui_layer.h"
+#include "imgui_core.h"
+#include "imgui_impl_sdl3.h"
+#include "imgui_impl_vulkan.h"
+#include "sdl_window.h"
+#include "video_core/renderer_vulkan/renderer_vulkan.h"
+
+static void CheckVkResult(const vk::Result err) {
+    LOG_ERROR(ImGui, "Vulkan error {}", vk::to_string(err));
+}
+
+static std::vector<ImGui::Layer*> layers;
+
+// Update layers before rendering to allow layer changes to be applied during rendering.
+// Using deque to keep the order of changes in case a Layer is removed then added again between
+// frames.
+static std::deque<std::pair<bool, ImGui::Layer*>> change_layers;
+static std::mutex change_layers_mutex{};
+
+namespace ImGui {
+
+namespace Core {
+
+void Initialize(const ::Vulkan::Instance& instance, const Frontend::WindowSDL& window,
+                const u32 image_count, vk::Format surface_format,
+                const vk::AllocationCallbacks* allocator) {
+
+    const auto config_path = GetUserPath(Common::FS::PathType::UserDir) / "imgui.ini";
+    const auto log_path = GetUserPath(Common::FS::PathType::LogDir) / "imgui_log.txt";
+
+    CreateContext();
+    ImGuiIO& io = GetIO();
+    io.ConfigFlags |= ImGuiConfigFlags_NavEnableKeyboard;
+    io.ConfigFlags |= ImGuiConfigFlags_NavEnableGamepad;
+    io.ConfigFlags |= ImGuiConfigFlags_DockingEnable;
+    io.DisplaySize = ImVec2((float)window.getWidth(), (float)window.getHeight());
+    io.IniFilename = SDL_strdup(config_path.string().c_str());
+    io.LogFilename = SDL_strdup(log_path.string().c_str());
+    StyleColorsDark();
+
+    Sdl::Init(window.GetSdlWindow());
+
+    const Vulkan::InitInfo vk_info{
+        .instance = instance.GetInstance(),
+        .physical_device = instance.GetPhysicalDevice(),
+        .device = instance.GetDevice(),
+        .queue_family = instance.GetPresentQueueFamilyIndex(),
+        .queue = instance.GetPresentQueue(),
+        .image_count = image_count,
+        .min_allocation_size = 1024 * 1024,
+        .pipeline_rendering_create_info{
+            .colorAttachmentCount = 1,
+            .pColorAttachmentFormats = &surface_format,
+        },
+        .allocator = allocator,
+        .check_vk_result_fn = &CheckVkResult,
+    };
+    Vulkan::Init(vk_info);
+}
+
+void OnResize() {
+    Sdl::OnResize();
+}
+
+void Shutdown(const vk::Device& device) {
+    device.waitIdle();
+
+    const ImGuiIO& io = GetIO();
+    const auto ini_filename = (void*)io.IniFilename;
+    const auto log_filename = (void*)io.LogFilename;
+
+    Vulkan::Shutdown();
+    Sdl::Shutdown();
+    DestroyContext();
+
+    SDL_free(ini_filename);
+    SDL_free(log_filename);
+}
+
+bool ProcessEvent(SDL_Event* event) {
+    Sdl::ProcessEvent(event);
+    switch (event->type) {
+    case SDL_EVENT_MOUSE_MOTION:
+    case SDL_EVENT_MOUSE_WHEEL:
+    case SDL_EVENT_MOUSE_BUTTON_DOWN:
+    case SDL_EVENT_MOUSE_BUTTON_UP:
+        return GetIO().WantCaptureMouse;
+    case SDL_EVENT_TEXT_INPUT:
+    case SDL_EVENT_KEY_DOWN:
+    case SDL_EVENT_KEY_UP:
+        return GetIO().WantCaptureKeyboard;
+    case SDL_EVENT_GAMEPAD_BUTTON_DOWN:
+    case SDL_EVENT_GAMEPAD_BUTTON_UP:
+    case SDL_EVENT_GAMEPAD_AXIS_MOTION:
+    case SDL_EVENT_GAMEPAD_ADDED:
+    case SDL_EVENT_GAMEPAD_REMOVED:
+    case SDL_EVENT_GAMEPAD_TOUCHPAD_DOWN:
+    case SDL_EVENT_GAMEPAD_TOUCHPAD_UP:
+    case SDL_EVENT_GAMEPAD_TOUCHPAD_MOTION:
+        return (GetIO().BackendFlags & ImGuiBackendFlags_HasGamepad) != 0;
+    default:
+        return false;
+    }
+}
+
+void NewFrame() {
+    {
+        std::scoped_lock lock{change_layers_mutex};
+        while (!change_layers.empty()) {
+            const auto [to_be_added, layer] = change_layers.front();
+            if (to_be_added) {
+                layers.push_back(layer);
+            } else {
+                const auto [begin, end] = std::ranges::remove(layers, layer);
+                layers.erase(begin, end);
+            }
+            change_layers.pop_front();
+        }
+    }
+
+    Vulkan::NewFrame();
+    Sdl::NewFrame();
+    ImGui::NewFrame();
+
+    bool capture_gamepad = false;
+    for (auto* layer : layers) {
+        layer->Draw();
+        if (layer->ShouldGrabGamepad()) {
+            capture_gamepad = true;
+        }
+    }
+    if (capture_gamepad) {
+        GetIO().BackendFlags |= ImGuiBackendFlags_HasGamepad;
+    } else {
+        GetIO().BackendFlags &= ~ImGuiBackendFlags_HasGamepad;
+    }
+}
+
+void Render(const vk::CommandBuffer& cmdbuf, ::Vulkan::Frame* frame) {
+    ImGui::Render();
+    ImDrawData* draw_data = GetDrawData();
+    if (draw_data->CmdListsCount == 0) {
+        return;
+    }
+
+    if (Config::vkMarkersEnabled()) {
+        cmdbuf.beginDebugUtilsLabelEXT(vk::DebugUtilsLabelEXT{
+            .pLabelName = "ImGui Render",
+        });
+    }
+    cmdbuf.pipelineBarrier(vk::PipelineStageFlagBits::eColorAttachmentOutput,
+                           vk::PipelineStageFlagBits::eColorAttachmentOutput, {}, {}, {},
+                           {vk::ImageMemoryBarrier{
+                               .srcAccessMask = vk::AccessFlagBits::eColorAttachmentWrite,
+                               .dstAccessMask = vk::AccessFlagBits::eColorAttachmentRead,
+                               .oldLayout = vk::ImageLayout::eUndefined,
+                               .newLayout = vk::ImageLayout::eColorAttachmentOptimal,
+                               .srcQueueFamilyIndex = VK_QUEUE_FAMILY_IGNORED,
+                               .dstQueueFamilyIndex = VK_QUEUE_FAMILY_IGNORED,
+                               .image = frame->image,
+                               .subresourceRange{
+                                   .aspectMask = vk::ImageAspectFlagBits::eColor,
+                                   .baseMipLevel = 0,
+                                   .levelCount = 1,
+                                   .baseArrayLayer = 0,
+                                   .layerCount = VK_REMAINING_ARRAY_LAYERS,
+                               },
+                           }});
+
+    vk::RenderingAttachmentInfo color_attachments[1]{
+        {
+            .imageView = frame->image_view,
+            .imageLayout = vk::ImageLayout::eColorAttachmentOptimal,
+            .loadOp = vk::AttachmentLoadOp::eLoad,
+            .storeOp = vk::AttachmentStoreOp::eStore,
+        },
+    };
+    vk::RenderingInfo render_info = {};
+    render_info.renderArea = {
+        .offset = {0, 0},
+        .extent = {frame->width, frame->height},
+    };
+    render_info.layerCount = 1;
+    render_info.colorAttachmentCount = 1;
+    render_info.pColorAttachments = color_attachments;
+    cmdbuf.beginRendering(render_info);
+    Vulkan::RenderDrawData(*draw_data, cmdbuf);
+    cmdbuf.endRendering();
+    if (Config::vkMarkersEnabled()) {
+        cmdbuf.endDebugUtilsLabelEXT();
+    }
+}
+
+} // namespace Core
+
+void Layer::AddLayer(Layer* layer) {
+    std::scoped_lock lock{change_layers_mutex};
+    change_layers.emplace_back(true, layer);
+}
+
+void Layer::RemoveLayer(Layer* layer) {
+    std::scoped_lock lock{change_layers_mutex};
+    change_layers.emplace_back(false, layer);
+}
+
+} // namespace ImGui

src/imgui/renderer/imgui_core.h

@@ -0,0 +1,31 @@
+// SPDX-FileCopyrightText: Copyright 2024 shadPS4 Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#pragma once
+
+#include "video_core/renderer_vulkan/vk_instance.h"
+#include "vulkan/vulkan_handles.hpp"
+
+union SDL_Event;
+
+namespace Vulkan {
+struct Frame;
+}
+
+namespace ImGui::Core {
+
+void Initialize(const Vulkan::Instance& instance, const Frontend::WindowSDL& window,
+                u32 image_count, vk::Format surface_format,
+                const vk::AllocationCallbacks* allocator = nullptr);
+
+void OnResize();
+
+void Shutdown(const vk::Device& device);
+
+bool ProcessEvent(SDL_Event* event);
+
+void NewFrame();
+
+void Render(const vk::CommandBuffer& cmdbuf, Vulkan::Frame* frame);
+
+} // namespace ImGui::Core

src/imgui/renderer/imgui_impl_sdl3.cpp

@@ -0,0 +1,789 @@
+// SPDX-FileCopyrightText: Copyright 2024 shadPS4 Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+// Based on imgui_impl_sdl3.cpp from Dear ImGui repository
+
+#include <imgui.h>
+#include "imgui_impl_sdl3.h"
+
+// SDL
+#include <SDL3/SDL.h>
+#if defined(__APPLE__)
+#include <TargetConditionals.h>
+#endif
+#ifdef _WIN32
+#ifndef WIN32_LEAN_AND_MEAN
+#define WIN32_LEAN_AND_MEAN
+#endif
+#include <Windows.h>
+#endif
+
+namespace ImGui::Sdl {
+
+// SDL Data
+struct SdlData {
+    SDL_Window* window{};
+    SDL_WindowID window_id{};
+    Uint64 time{};
+    const char* clipboard_text_data{};
+
+    // IME handling
+    SDL_Window* ime_window{};
+
+    // Mouse handling
+    Uint32 mouse_window_id{};
+    int mouse_buttons_down{};
+    SDL_Cursor* mouse_cursors[ImGuiMouseCursor_COUNT]{};
+    SDL_Cursor* mouse_last_cursor{};
+    int mouse_pending_leave_frame{};
+
+    // Gamepad handling
+    ImVector<SDL_Gamepad*> gamepads{};
+    GamepadMode gamepad_mode{};
+    bool want_update_gamepads_list{};
+};
+
+// Backend data stored in io.BackendPlatformUserData to allow support for multiple Dear ImGui
+// contexts It is STRONGLY preferred that you use docking branch with multi-viewports (== single
+// Dear ImGui context + multiple windows) instead of multiple Dear ImGui contexts.
+static SdlData* GetBackendData() {
+    return ImGui::GetCurrentContext() ? (SdlData*)ImGui::GetIO().BackendPlatformUserData : nullptr;
+}
+
+static const char* GetClipboardText(ImGuiContext*) {
+    SdlData* bd = GetBackendData();
+    if (bd->clipboard_text_data)
+        SDL_free((void*)bd->clipboard_text_data);
+    const char* sdl_clipboard_text = SDL_GetClipboardText();
+    bd->clipboard_text_data = sdl_clipboard_text;
+    return bd->clipboard_text_data;
+}
+
+static void SetClipboardText(ImGuiContext*, const char* text) {
+    SDL_SetClipboardText(text);
+}
+
+static void PlatformSetImeData(ImGuiContext*, ImGuiViewport* viewport, ImGuiPlatformImeData* data) {
+    SdlData* bd = GetBackendData();
+    auto window_id = (SDL_WindowID)(intptr_t)viewport->PlatformHandle;
+    SDL_Window* window = SDL_GetWindowFromID(window_id);
+    if ((!data->WantVisible || bd->ime_window != window) && bd->ime_window != nullptr) {
+        SDL_StopTextInput(bd->ime_window);
+        bd->ime_window = nullptr;
+    }
+    if (data->WantVisible) {
+        SDL_Rect r;
+        r.x = (int)data->InputPos.x;
+        r.y = (int)data->InputPos.y;
+        r.w = 1;
+        r.h = (int)data->InputLineHeight;
+        SDL_SetTextInputArea(window, &r, 0);
+        SDL_StartTextInput(window);
+        bd->ime_window = window;
+    }
+}
+
+static ImGuiKey KeyEventToImGuiKey(SDL_Keycode keycode, SDL_Scancode scancode) {
+    // Keypad doesn't have individual key values in SDL3
+    switch (scancode) {
+    case SDL_SCANCODE_KP_0:
+        return ImGuiKey_Keypad0;
+    case SDL_SCANCODE_KP_1:
+        return ImGuiKey_Keypad1;
+    case SDL_SCANCODE_KP_2:
+        return ImGuiKey_Keypad2;
+    case SDL_SCANCODE_KP_3:
+        return ImGuiKey_Keypad3;
+    case SDL_SCANCODE_KP_4:
+        return ImGuiKey_Keypad4;
+    case SDL_SCANCODE_KP_5:
+        return ImGuiKey_Keypad5;
+    case SDL_SCANCODE_KP_6:
+        return ImGuiKey_Keypad6;
+    case SDL_SCANCODE_KP_7:
+        return ImGuiKey_Keypad7;
+    case SDL_SCANCODE_KP_8:
+        return ImGuiKey_Keypad8;
+    case SDL_SCANCODE_KP_9:
+        return ImGuiKey_Keypad9;
+    case SDL_SCANCODE_KP_PERIOD:
+        return ImGuiKey_KeypadDecimal;
+    case SDL_SCANCODE_KP_DIVIDE:
+        return ImGuiKey_KeypadDivide;
+    case SDL_SCANCODE_KP_MULTIPLY:
+        return ImGuiKey_KeypadMultiply;
+    case SDL_SCANCODE_KP_MINUS:
+        return ImGuiKey_KeypadSubtract;
+    case SDL_SCANCODE_KP_PLUS:
+        return ImGuiKey_KeypadAdd;
+    case SDL_SCANCODE_KP_ENTER:
+        return ImGuiKey_KeypadEnter;
+    case SDL_SCANCODE_KP_EQUALS:
+        return ImGuiKey_KeypadEqual;
+    default:
+        break;
+    }
+    switch (keycode) {
+    case SDLK_TAB:
+        return ImGuiKey_Tab;
+    case SDLK_LEFT:
+        return ImGuiKey_LeftArrow;
+    case SDLK_RIGHT:
+        return ImGuiKey_RightArrow;
+    case SDLK_UP:
+        return ImGuiKey_UpArrow;
+    case SDLK_DOWN:
+        return ImGuiKey_DownArrow;
+    case SDLK_PAGEUP:
+        return ImGuiKey_PageUp;
+    case SDLK_PAGEDOWN:
+        return ImGuiKey_PageDown;
+    case SDLK_HOME:
+        return ImGuiKey_Home;
+    case SDLK_END:
+        return ImGuiKey_End;
+    case SDLK_INSERT:
+        return ImGuiKey_Insert;
+    case SDLK_DELETE:
+        return ImGuiKey_Delete;
+    case SDLK_BACKSPACE:
+        return ImGuiKey_Backspace;
+    case SDLK_SPACE:
+        return ImGuiKey_Space;
+    case SDLK_RETURN:
+        return ImGuiKey_Enter;
+    case SDLK_ESCAPE:
+        return ImGuiKey_Escape;
+    case SDLK_APOSTROPHE:
+        return ImGuiKey_Apostrophe;
+    case SDLK_COMMA:
+        return ImGuiKey_Comma;
+    case SDLK_MINUS:
+        return ImGuiKey_Minus;
+    case SDLK_PERIOD:
+        return ImGuiKey_Period;
+    case SDLK_SLASH:
+        return ImGuiKey_Slash;
+    case SDLK_SEMICOLON:
+        return ImGuiKey_Semicolon;
+    case SDLK_EQUALS:
+        return ImGuiKey_Equal;
+    case SDLK_LEFTBRACKET:
+        return ImGuiKey_LeftBracket;
+    case SDLK_BACKSLASH:
+        return ImGuiKey_Backslash;
+    case SDLK_RIGHTBRACKET:
+        return ImGuiKey_RightBracket;
+    case SDLK_GRAVE:
+        return ImGuiKey_GraveAccent;
+    case SDLK_CAPSLOCK:
+        return ImGuiKey_CapsLock;
+    case SDLK_SCROLLLOCK:
+        return ImGuiKey_ScrollLock;
+    case SDLK_NUMLOCKCLEAR:
+        return ImGuiKey_NumLock;
+    case SDLK_PRINTSCREEN:
+        return ImGuiKey_PrintScreen;
+    case SDLK_PAUSE:
+        return ImGuiKey_Pause;
+    case SDLK_LCTRL:
+        return ImGuiKey_LeftCtrl;
+    case SDLK_LSHIFT:
+        return ImGuiKey_LeftShift;
+    case SDLK_LALT:
+        return ImGuiKey_LeftAlt;
+    case SDLK_LGUI:
+        return ImGuiKey_LeftSuper;
+    case SDLK_RCTRL:
+        return ImGuiKey_RightCtrl;
+    case SDLK_RSHIFT:
+        return ImGuiKey_RightShift;
+    case SDLK_RALT:
+        return ImGuiKey_RightAlt;
+    case SDLK_RGUI:
+        return ImGuiKey_RightSuper;
+    case SDLK_APPLICATION:
+        return ImGuiKey_Menu;
+    case SDLK_0:
+        return ImGuiKey_0;
+    case SDLK_1:
+        return ImGuiKey_1;
+    case SDLK_2:
+        return ImGuiKey_2;
+    case SDLK_3:
+        return ImGuiKey_3;
+    case SDLK_4:
+        return ImGuiKey_4;
+    case SDLK_5:
+        return ImGuiKey_5;
+    case SDLK_6:
+        return ImGuiKey_6;
+    case SDLK_7:
+        return ImGuiKey_7;
+    case SDLK_8:
+        return ImGuiKey_8;
+    case SDLK_9:
+        return ImGuiKey_9;
+    case SDLK_A:
+        return ImGuiKey_A;
+    case SDLK_B:
+        return ImGuiKey_B;
+    case SDLK_C:
+        return ImGuiKey_C;
+    case SDLK_D:
+        return ImGuiKey_D;
+    case SDLK_E:
+        return ImGuiKey_E;
+    case SDLK_F:
+        return ImGuiKey_F;
+    case SDLK_G:
+        return ImGuiKey_G;
+    case SDLK_H:
+        return ImGuiKey_H;
+    case SDLK_I:
+        return ImGuiKey_I;
+    case SDLK_J:
+        return ImGuiKey_J;
+    case SDLK_K:
+        return ImGuiKey_K;
+    case SDLK_L:
+        return ImGuiKey_L;
+    case SDLK_M:
+        return ImGuiKey_M;
+    case SDLK_N:
+        return ImGuiKey_N;
+    case SDLK_O:
+        return ImGuiKey_O;
+    case SDLK_P:
+        return ImGuiKey_P;
+    case SDLK_Q:
+        return ImGuiKey_Q;
+    case SDLK_R:
+        return ImGuiKey_R;
+    case SDLK_S:
+        return ImGuiKey_S;
+    case SDLK_T:
+        return ImGuiKey_T;
+    case SDLK_U:
+        return ImGuiKey_U;
+    case SDLK_V:
+        return ImGuiKey_V;
+    case SDLK_W:
+        return ImGuiKey_W;
+    case SDLK_X:
+        return ImGuiKey_X;
+    case SDLK_Y:
+        return ImGuiKey_Y;
+    case SDLK_Z:
+        return ImGuiKey_Z;
+    case SDLK_F1:
+        return ImGuiKey_F1;
+    case SDLK_F2:
+        return ImGuiKey_F2;
+    case SDLK_F3:
+        return ImGuiKey_F3;
+    case SDLK_F4:
+        return ImGuiKey_F4;
+    case SDLK_F5:
+        return ImGuiKey_F5;
+    case SDLK_F6:
+        return ImGuiKey_F6;
+    case SDLK_F7:
+        return ImGuiKey_F7;
+    case SDLK_F8:
+        return ImGuiKey_F8;
+    case SDLK_F9:
+        return ImGuiKey_F9;
+    case SDLK_F10:
+        return ImGuiKey_F10;
+    case SDLK_F11:
+        return ImGuiKey_F11;
+    case SDLK_F12:
+        return ImGuiKey_F12;
+    case SDLK_F13:
+        return ImGuiKey_F13;
+    case SDLK_F14:
+        return ImGuiKey_F14;
+    case SDLK_F15:
+        return ImGuiKey_F15;
+    case SDLK_F16:
+        return ImGuiKey_F16;
+    case SDLK_F17:
+        return ImGuiKey_F17;
+    case SDLK_F18:
+        return ImGuiKey_F18;
+    case SDLK_F19:
+        return ImGuiKey_F19;
+    case SDLK_F20:
+        return ImGuiKey_F20;
+    case SDLK_F21:
+        return ImGuiKey_F21;
+    case SDLK_F22:
+        return ImGuiKey_F22;
+    case SDLK_F23:
+        return ImGuiKey_F23;
+    case SDLK_F24:
+        return ImGuiKey_F24;
+    case SDLK_AC_BACK:
+        return ImGuiKey_AppBack;
+    case SDLK_AC_FORWARD:
+        return ImGuiKey_AppForward;
+    default:
+        break;
+    }
+    return ImGuiKey_None;
+}
+
+static void UpdateKeyModifiers(SDL_Keymod sdl_key_mods) {
+    ImGuiIO& io = ImGui::GetIO();
+    io.AddKeyEvent(ImGuiMod_Ctrl, (sdl_key_mods & SDL_KMOD_CTRL) != 0);
+    io.AddKeyEvent(ImGuiMod_Shift, (sdl_key_mods & SDL_KMOD_SHIFT) != 0);
+    io.AddKeyEvent(ImGuiMod_Alt, (sdl_key_mods & SDL_KMOD_ALT) != 0);
+    io.AddKeyEvent(ImGuiMod_Super, (sdl_key_mods & SDL_KMOD_GUI) != 0);
+}
+
+static ImGuiViewport* GetViewportForWindowId(SDL_WindowID window_id) {
+    SdlData* bd = GetBackendData();
+    return (window_id == bd->window_id) ? ImGui::GetMainViewport() : nullptr;
+}
+
+// You can read the io.WantCaptureMouse, io.WantCaptureKeyboard flags to tell if dear imgui wants to
+// use your inputs.
+// - When io.WantCaptureMouse is true, do not dispatch mouse input data to your main application, or
+// clear/overwrite your copy of the mouse data.
+// - When io.WantCaptureKeyboard is true, do not dispatch keyboard input data to your main
+// application, or clear/overwrite your copy of the keyboard data. Generally you may always pass all
+// inputs to dear imgui, and hide them from your application based on those two flags. If you have
+// multiple SDL events and some of them are not meant to be used by dear imgui, you may need to
+// filter events based on their windowID field.
+bool ProcessEvent(const SDL_Event* event) {
+    SdlData* bd = GetBackendData();
+    IM_ASSERT(bd != nullptr &&
+              "Context or backend not initialized! Did you call ImGui_ImplSDL3_Init()?");
+    ImGuiIO& io = ImGui::GetIO();
+
+    switch (event->type) {
+    case SDL_EVENT_MOUSE_MOTION: {
+        if (GetViewportForWindowId(event->motion.windowID) == NULL)
+            return false;
+        ImVec2 mouse_pos((float)event->motion.x, (float)event->motion.y);
+        io.AddMouseSourceEvent(event->motion.which == SDL_TOUCH_MOUSEID
+                                   ? ImGuiMouseSource_TouchScreen
+                                   : ImGuiMouseSource_Mouse);
+        io.AddMousePosEvent(mouse_pos.x, mouse_pos.y);
+        return true;
+    }
+    case SDL_EVENT_MOUSE_WHEEL: {
+        if (GetViewportForWindowId(event->wheel.windowID) == NULL)
+            return false;
+        // IMGUI_DEBUG_LOG("wheel %.2f %.2f, precise %.2f %.2f\n", (float)event->wheel.x,
+        // (float)event->wheel.y, event->wheel.preciseX, event->wheel.preciseY);
+        float wheel_x = -event->wheel.x;
+        float wheel_y = event->wheel.y;
+#ifdef __EMSCRIPTEN__
+        wheel_x /= 100.0f;
+#endif
+        io.AddMouseSourceEvent(event->wheel.which == SDL_TOUCH_MOUSEID
+                                   ? ImGuiMouseSource_TouchScreen
+                                   : ImGuiMouseSource_Mouse);
+        io.AddMouseWheelEvent(wheel_x, wheel_y);
+        return true;
+    }
+    case SDL_EVENT_MOUSE_BUTTON_DOWN:
+    case SDL_EVENT_MOUSE_BUTTON_UP: {
+        if (GetViewportForWindowId(event->button.windowID) == NULL)
+            return false;
+        int mouse_button = -1;
+        if (event->button.button == SDL_BUTTON_LEFT) {
+            mouse_button = 0;
+        }
+        if (event->button.button == SDL_BUTTON_RIGHT) {
+            mouse_button = 1;
+        }
+        if (event->button.button == SDL_BUTTON_MIDDLE) {
+            mouse_button = 2;
+        }
+        if (event->button.button == SDL_BUTTON_X1) {
+            mouse_button = 3;
+        }
+        if (event->button.button == SDL_BUTTON_X2) {
+            mouse_button = 4;
+        }
+        if (mouse_button == -1)
+            break;
+        io.AddMouseSourceEvent(event->button.which == SDL_TOUCH_MOUSEID
+                                   ? ImGuiMouseSource_TouchScreen
+                                   : ImGuiMouseSource_Mouse);
+        io.AddMouseButtonEvent(mouse_button, (event->type == SDL_EVENT_MOUSE_BUTTON_DOWN));
+        bd->mouse_buttons_down = (event->type == SDL_EVENT_MOUSE_BUTTON_DOWN)
+                                     ? (bd->mouse_buttons_down | (1 << mouse_button))
+                                     : (bd->mouse_buttons_down & ~(1 << mouse_button));
+        return true;
+    }
+    case SDL_EVENT_TEXT_INPUT: {
+        if (GetViewportForWindowId(event->text.windowID) == NULL)
+            return false;
+        io.AddInputCharactersUTF8(event->text.text);
+        return true;
+    }
+    case SDL_EVENT_KEY_DOWN:
+    case SDL_EVENT_KEY_UP: {
+        if (GetViewportForWindowId(event->key.windowID) == NULL)
+            return false;
+        // IMGUI_DEBUG_LOG("SDL_EVENT_KEY_%d: key=%d, scancode=%d, mod=%X\n", (event->type ==
+        // SDL_EVENT_KEY_DOWN) ? "DOWN" : "UP", event->key.key, event->key.scancode,
+        // event->key.mod);
+        UpdateKeyModifiers((SDL_Keymod)event->key.mod);
+        ImGuiKey key = KeyEventToImGuiKey(event->key.key, event->key.scancode);
+        io.AddKeyEvent(key, (event->type == SDL_EVENT_KEY_DOWN));
+        io.SetKeyEventNativeData(
+            key, event->key.key, event->key.scancode,
+            event->key.scancode); // To support legacy indexing (<1.87 user code). Legacy backend
+                                  // uses SDLK_*** as indices to IsKeyXXX() functions.
+        return true;
+    }
+    case SDL_EVENT_WINDOW_MOUSE_ENTER: {
+        if (GetViewportForWindowId(event->window.windowID) == NULL)
+            return false;
+        bd->mouse_window_id = event->window.windowID;
+        bd->mouse_pending_leave_frame = 0;
+        return true;
+    }
+    // - In some cases, when detaching a window from main viewport SDL may send
+    // SDL_WINDOWEVENT_ENTER one frame too late,
+    //   causing SDL_WINDOWEVENT_LEAVE on previous frame to interrupt drag operation by clear mouse
+    //   position. This is why we delay process the SDL_WINDOWEVENT_LEAVE events by one frame. See
+    //   issue #5012 for details.
+    // FIXME: Unconfirmed whether this is still needed with SDL3.
+    case SDL_EVENT_WINDOW_MOUSE_LEAVE: {
+        if (GetViewportForWindowId(event->window.windowID) == NULL)
+            return false;
+        bd->mouse_pending_leave_frame = ImGui::GetFrameCount() + 1;
+        return true;
+    }
+    case SDL_EVENT_WINDOW_FOCUS_GAINED:
+    case SDL_EVENT_WINDOW_FOCUS_LOST: {
+        if (GetViewportForWindowId(event->window.windowID) == NULL)
+            return false;
+        io.AddFocusEvent(event->type == SDL_EVENT_WINDOW_FOCUS_GAINED);
+        return true;
+    }
+    case SDL_EVENT_GAMEPAD_ADDED:
+    case SDL_EVENT_GAMEPAD_REMOVED: {
+        bd->want_update_gamepads_list = true;
+        return true;
+    }
+    }
+    return false;
+}
+
+static void SetupPlatformHandles(ImGuiViewport* viewport, SDL_Window* window) {
+    viewport->PlatformHandle = (void*)(intptr_t)SDL_GetWindowID(window);
+    viewport->PlatformHandleRaw = nullptr;
+#if defined(_WIN32) && !defined(__WINRT__)
+    viewport->PlatformHandleRaw = (HWND)SDL_GetPointerProperty(
+        SDL_GetWindowProperties(window), SDL_PROP_WINDOW_WIN32_HWND_POINTER, nullptr);
+#elif defined(__APPLE__) && defined(SDL_VIDEO_DRIVER_COCOA)
+    viewport->PlatformHandleRaw = SDL_GetPointerProperty(
+        SDL_GetWindowProperties(window), SDL_PROP_WINDOW_COCOA_WINDOW_POINTER, nullptr);
+#endif
+}
+
+bool Init(SDL_Window* window) {
+    ImGuiIO& io = ImGui::GetIO();
+    IMGUI_CHECKVERSION();
+    IM_ASSERT(io.BackendPlatformUserData == nullptr && "Already initialized a platform backend!");
+
+    // Setup backend capabilities flags
+    SdlData* bd = IM_NEW(SdlData)();
+    io.BackendPlatformUserData = (void*)bd;
+    io.BackendPlatformName = "imgui_impl_sdl3_shadps4";
+    io.BackendFlags |= ImGuiBackendFlags_HasMouseCursors; // We can honor GetMouseCursor() values
+    io.BackendFlags |= ImGuiBackendFlags_HasSetMousePos; // We can honor io.WantSetMousePos requests
+                                                         // (optional, rarely used)
+
+    bd->window = window;
+    bd->window_id = SDL_GetWindowID(window);
+
+    ImGuiPlatformIO& platform_io = ImGui::GetPlatformIO();
+    platform_io.Platform_SetClipboardTextFn = SetClipboardText;
+    platform_io.Platform_GetClipboardTextFn = GetClipboardText;
+    platform_io.Platform_SetImeDataFn = PlatformSetImeData;
+
+    // Gamepad handling
+    bd->gamepad_mode = ImGui_ImplSDL3_GamepadMode_AutoFirst;
+    bd->want_update_gamepads_list = true;
+
+    // Load mouse cursors
+#define CURSOR(left, right)                                                                        \
+    bd->mouse_cursors[ImGuiMouseCursor_##left] = SDL_CreateSystemCursor(SDL_SYSTEM_CURSOR_##right)
+    CURSOR(Arrow, DEFAULT);
+    CURSOR(TextInput, TEXT);
+    CURSOR(ResizeAll, MOVE);
+    CURSOR(ResizeNS, NS_RESIZE);
+    CURSOR(ResizeEW, EW_RESIZE);
+    CURSOR(ResizeNESW, NESW_RESIZE);
+    CURSOR(ResizeNWSE, NWSE_RESIZE);
+    CURSOR(Hand, POINTER);
+    CURSOR(NotAllowed, NOT_ALLOWED);
+#undef CURSOR
+
+    // Set platform dependent data in viewport
+    // Our mouse update function expect PlatformHandle to be filled for the main viewport
+    ImGuiViewport* main_viewport = ImGui::GetMainViewport();
+    SetupPlatformHandles(main_viewport, window);
+
+    // From 2.0.5: Set SDL hint to receive mouse click events on window focus, otherwise SDL doesn't
+    // emit the event. Without this, when clicking to gain focus, our widgets wouldn't activate even
+    // though they showed as hovered. (This is unfortunately a global SDL setting, so enabling it
+    // might have a side-effect on your application. It is unlikely to make a difference, but if
+    // your app absolutely needs to ignore the initial on-focus click: you can ignore
+    // SDL_EVENT_MOUSE_BUTTON_DOWN events coming right after a SDL_WINDOWEVENT_FOCUS_GAINED)
+#ifdef SDL_HINT_MOUSE_FOCUS_CLICKTHROUGH
+    SDL_SetHint(SDL_HINT_MOUSE_FOCUS_CLICKTHROUGH, "1");
+#endif
+
+    // From 2.0.22: Disable auto-capture, this is preventing drag and drop across multiple windows
+    // (see #5710)
+#ifdef SDL_HINT_MOUSE_AUTO_CAPTURE
+    SDL_SetHint(SDL_HINT_MOUSE_AUTO_CAPTURE, "0");
+#endif
+
+    return true;
+}
+
+static void CloseGamepads();
+
+void Shutdown() {
+    SdlData* bd = GetBackendData();
+    IM_ASSERT(bd != nullptr && "No platform backend to shutdown, or already shutdown?");
+    ImGuiIO& io = ImGui::GetIO();
+
+    if (bd->clipboard_text_data) {
+        SDL_free((void*)bd->clipboard_text_data);
+    }
+    for (ImGuiMouseCursor cursor_n = 0; cursor_n < ImGuiMouseCursor_COUNT; cursor_n++)
+        SDL_DestroyCursor(bd->mouse_cursors[cursor_n]);
+    CloseGamepads();
+
+    io.BackendPlatformName = nullptr;
+    io.BackendPlatformUserData = nullptr;
+    io.BackendFlags &= ~(ImGuiBackendFlags_HasMouseCursors | ImGuiBackendFlags_HasSetMousePos |
+                         ImGuiBackendFlags_HasGamepad);
+    IM_DELETE(bd);
+}
+
+static void UpdateMouseData() {
+    SdlData* bd = GetBackendData();
+    ImGuiIO& io = ImGui::GetIO();
+
+    // We forward mouse input when hovered or captured (via SDL_EVENT_MOUSE_MOTION) or when focused
+    // (below)
+    // SDL_CaptureMouse() let the OS know e.g. that our imgui drag outside the SDL window boundaries
+    // shouldn't e.g. trigger other operations outside
+    SDL_CaptureMouse((bd->mouse_buttons_down != 0) ? SDL_TRUE : SDL_FALSE);
+    SDL_Window* focused_window = SDL_GetKeyboardFocus();
+    const bool is_app_focused = (bd->window == focused_window);
+
+    if (is_app_focused) {
+        // (Optional) Set OS mouse position from Dear ImGui if requested (rarely used, only when
+        // ImGuiConfigFlags_NavEnableSetMousePos is enabled by user)
+        if (io.WantSetMousePos)
+            SDL_WarpMouseInWindow(bd->window, io.MousePos.x, io.MousePos.y);
+
+        // (Optional) Fallback to provide mouse position when focused (SDL_EVENT_MOUSE_MOTION
+        // already provides this when hovered or captured)
+        if (bd->mouse_buttons_down == 0) {
+            // Single-viewport mode: mouse position in client window coordinates (io.MousePos is
+            // (0,0) when the mouse is on the upper-left corner of the app window)
+            float mouse_x_global, mouse_y_global;
+            int window_x, window_y;
+            SDL_GetGlobalMouseState(&mouse_x_global, &mouse_y_global);
+            SDL_GetWindowPosition(focused_window, &window_x, &window_y);
+            io.AddMousePosEvent(mouse_x_global - (float)window_x, mouse_y_global - (float)window_y);
+        }
+    }
+}
+
+static void UpdateMouseCursor() {
+    ImGuiIO& io = ImGui::GetIO();
+    if (io.ConfigFlags & ImGuiConfigFlags_NoMouseCursorChange)
+        return;
+    SdlData* bd = GetBackendData();
+
+    ImGuiMouseCursor imgui_cursor = ImGui::GetMouseCursor();
+    if (io.MouseDrawCursor || imgui_cursor == ImGuiMouseCursor_None) {
+        // Hide OS mouse cursor if imgui is drawing it or if it wants no cursor
+        SDL_HideCursor();
+    } else {
+        // Show OS mouse cursor
+        SDL_Cursor* expected_cursor = bd->mouse_cursors[imgui_cursor]
+                                          ? bd->mouse_cursors[imgui_cursor]
+                                          : bd->mouse_cursors[ImGuiMouseCursor_Arrow];
+        if (bd->mouse_last_cursor != expected_cursor) {
+            SDL_SetCursor(expected_cursor); // SDL function doesn't have an early out (see #6113)
+            bd->mouse_last_cursor = expected_cursor;
+        }
+        SDL_ShowCursor();
+    }
+}
+
+static void CloseGamepads() {
+    SdlData* bd = GetBackendData();
+    if (bd->gamepad_mode != ImGui_ImplSDL3_GamepadMode_Manual)
+        for (SDL_Gamepad* gamepad : bd->gamepads)
+            SDL_CloseGamepad(gamepad);
+    bd->gamepads.resize(0);
+}
+
+void SetGamepadMode(GamepadMode mode, SDL_Gamepad** manual_gamepads_array,
+                    int manual_gamepads_count) {
+    SdlData* bd = GetBackendData();
+    CloseGamepads();
+    if (mode == ImGui_ImplSDL3_GamepadMode_Manual) {
+        IM_ASSERT(manual_gamepads_array != nullptr && manual_gamepads_count > 0);
+        for (int n = 0; n < manual_gamepads_count; n++)
+            bd->gamepads.push_back(manual_gamepads_array[n]);
+    } else {
+        IM_ASSERT(manual_gamepads_array == nullptr && manual_gamepads_count <= 0);
+        bd->want_update_gamepads_list = true;
+    }
+    bd->gamepad_mode = mode;
+}
+
+static void UpdateGamepadButton(SdlData* bd, ImGuiIO& io, ImGuiKey key,
+                                SDL_GamepadButton button_no) {
+    bool merged_value = false;
+    for (SDL_Gamepad* gamepad : bd->gamepads)
+        merged_value |= SDL_GetGamepadButton(gamepad, button_no) != 0;
+    io.AddKeyEvent(key, merged_value);
+}
+
+static inline float Saturate(float v) {
+    return v < 0.0f ? 0.0f : v > 1.0f ? 1.0f : v;
+}
+static void UpdateGamepadAnalog(SdlData* bd, ImGuiIO& io, ImGuiKey key, SDL_GamepadAxis axis_no,
+                                float v0, float v1) {
+    float merged_value = 0.0f;
+    for (SDL_Gamepad* gamepad : bd->gamepads) {
+        float vn = Saturate((float)(SDL_GetGamepadAxis(gamepad, axis_no) - v0) / (float)(v1 - v0));
+        if (merged_value < vn)
+            merged_value = vn;
+    }
+    io.AddKeyAnalogEvent(key, merged_value > 0.1f, merged_value);
+}
+
+static void UpdateGamepads() {
+    ImGuiIO& io = ImGui::GetIO();
+    SdlData* bd = GetBackendData();
+
+    // Update list of gamepads to use
+    if (bd->want_update_gamepads_list && bd->gamepad_mode != ImGui_ImplSDL3_GamepadMode_Manual) {
+        CloseGamepads();
+        int sdl_gamepads_count = 0;
+        const SDL_JoystickID* sdl_gamepads = SDL_GetGamepads(&sdl_gamepads_count);
+        for (int n = 0; n < sdl_gamepads_count; n++)
+            if (SDL_Gamepad* gamepad = SDL_OpenGamepad(sdl_gamepads[n])) {
+                bd->gamepads.push_back(gamepad);
+                if (bd->gamepad_mode == ImGui_ImplSDL3_GamepadMode_AutoFirst)
+                    break;
+            }
+        bd->want_update_gamepads_list = false;
+    }
+
+    // FIXME: Technically feeding gamepad shouldn't depend on this now that they are regular inputs.
+    if ((io.ConfigFlags & ImGuiConfigFlags_NavEnableGamepad) == 0)
+        return;
+    io.BackendFlags &= ~ImGuiBackendFlags_HasGamepad;
+    if (bd->gamepads.Size == 0)
+        return;
+    io.BackendFlags |= ImGuiBackendFlags_HasGamepad;
+
+    // Update gamepad inputs
+    const int thumb_dead_zone = 8000; // SDL_gamepad.h suggests using this value.
+    UpdateGamepadButton(bd, io, ImGuiKey_GamepadStart, SDL_GAMEPAD_BUTTON_START);
+    UpdateGamepadButton(bd, io, ImGuiKey_GamepadBack, SDL_GAMEPAD_BUTTON_BACK);
+    UpdateGamepadButton(bd, io, ImGuiKey_GamepadFaceLeft,
+                        SDL_GAMEPAD_BUTTON_WEST); // Xbox X, PS Square
+    UpdateGamepadButton(bd, io, ImGuiKey_GamepadFaceRight,
+                        SDL_GAMEPAD_BUTTON_EAST); // Xbox B, PS Circle
+    UpdateGamepadButton(bd, io, ImGuiKey_GamepadFaceUp,
+                        SDL_GAMEPAD_BUTTON_NORTH); // Xbox Y, PS Triangle
+    UpdateGamepadButton(bd, io, ImGuiKey_GamepadFaceDown,
+                        SDL_GAMEPAD_BUTTON_SOUTH); // Xbox A, PS Cross
+    UpdateGamepadButton(bd, io, ImGuiKey_GamepadDpadLeft, SDL_GAMEPAD_BUTTON_DPAD_LEFT);
+    UpdateGamepadButton(bd, io, ImGuiKey_GamepadDpadRight, SDL_GAMEPAD_BUTTON_DPAD_RIGHT);
+    UpdateGamepadButton(bd, io, ImGuiKey_GamepadDpadUp, SDL_GAMEPAD_BUTTON_DPAD_UP);
+    UpdateGamepadButton(bd, io, ImGuiKey_GamepadDpadDown, SDL_GAMEPAD_BUTTON_DPAD_DOWN);
+    UpdateGamepadButton(bd, io, ImGuiKey_GamepadL1, SDL_GAMEPAD_BUTTON_LEFT_SHOULDER);
+    UpdateGamepadButton(bd, io, ImGuiKey_GamepadR1, SDL_GAMEPAD_BUTTON_RIGHT_SHOULDER);
+    UpdateGamepadAnalog(bd, io, ImGuiKey_GamepadL2, SDL_GAMEPAD_AXIS_LEFT_TRIGGER, 0.0f, 32767);
+    UpdateGamepadAnalog(bd, io, ImGuiKey_GamepadR2, SDL_GAMEPAD_AXIS_RIGHT_TRIGGER, 0.0f, 32767);
+    UpdateGamepadButton(bd, io, ImGuiKey_GamepadL3, SDL_GAMEPAD_BUTTON_LEFT_STICK);
+    UpdateGamepadButton(bd, io, ImGuiKey_GamepadR3, SDL_GAMEPAD_BUTTON_RIGHT_STICK);
+    UpdateGamepadAnalog(bd, io, ImGuiKey_GamepadLStickLeft, SDL_GAMEPAD_AXIS_LEFTX,
+                        -thumb_dead_zone, -32768);
+    UpdateGamepadAnalog(bd, io, ImGuiKey_GamepadLStickRight, SDL_GAMEPAD_AXIS_LEFTX,
+                        +thumb_dead_zone, +32767);
+    UpdateGamepadAnalog(bd, io, ImGuiKey_GamepadLStickUp, SDL_GAMEPAD_AXIS_LEFTY, -thumb_dead_zone,
+                        -32768);
+    UpdateGamepadAnalog(bd, io, ImGuiKey_GamepadLStickDown, SDL_GAMEPAD_AXIS_LEFTY,
+                        +thumb_dead_zone, +32767);
+    UpdateGamepadAnalog(bd, io, ImGuiKey_GamepadRStickLeft, SDL_GAMEPAD_AXIS_RIGHTX,
+                        -thumb_dead_zone, -32768);
+    UpdateGamepadAnalog(bd, io, ImGuiKey_GamepadRStickRight, SDL_GAMEPAD_AXIS_RIGHTX,
+                        +thumb_dead_zone, +32767);
+    UpdateGamepadAnalog(bd, io, ImGuiKey_GamepadRStickUp, SDL_GAMEPAD_AXIS_RIGHTY, -thumb_dead_zone,
+                        -32768);
+    UpdateGamepadAnalog(bd, io, ImGuiKey_GamepadRStickDown, SDL_GAMEPAD_AXIS_RIGHTY,
+                        +thumb_dead_zone, +32767);
+}
+
+void NewFrame() {
+    SdlData* bd = GetBackendData();
+    IM_ASSERT(bd != nullptr && "No platform backend to shutdown, or already shutdown?");
+    ImGuiIO& io = ImGui::GetIO();
+
+    // Setup time step (we don't use SDL_GetTicks() because it is using millisecond resolution)
+    // (Accept SDL_GetPerformanceCounter() not returning a monotonically increasing value. Happens
+    // in VMs and Emscripten, see #6189, #6114, #3644)
+    static Uint64 frequency = SDL_GetPerformanceFrequency();
+    Uint64 current_time = SDL_GetPerformanceCounter();
+    if (current_time <= bd->time)
+        current_time = bd->time + 1;
+    io.DeltaTime = bd->time > 0 ? (float)((double)(current_time - bd->time) / (double)frequency)
+                                : (float)(1.0f / 60.0f);
+    bd->time = current_time;
+
+    if (bd->mouse_pending_leave_frame && bd->mouse_pending_leave_frame >= ImGui::GetFrameCount() &&
+        bd->mouse_buttons_down == 0) {
+        bd->mouse_window_id = 0;
+        bd->mouse_pending_leave_frame = 0;
+        io.AddMousePosEvent(-FLT_MAX, -FLT_MAX);
+    }
+
+    UpdateMouseData();
+    UpdateMouseCursor();
+
+    // Update game controllers (if enabled and available)
+    UpdateGamepads();
+}
+
+void OnResize() {
+    SdlData* bd = GetBackendData();
+    ImGuiIO& io = ImGui::GetIO();
+
+    int w, h;
+    int display_w, display_h;
+    SDL_GetWindowSize(bd->window, &w, &h);
+    if (SDL_GetWindowFlags(bd->window) & SDL_WINDOW_MINIMIZED) {
+        w = h = 0;
+    }
+    SDL_GetWindowSizeInPixels(bd->window, &display_w, &display_h);
+    io.DisplaySize = ImVec2((float)w, (float)h);
+    if (w > 0 && h > 0) {
+        io.DisplayFramebufferScale = {(float)display_w / (float)w, (float)display_h / (float)h};
+    }
+}
+
+} // namespace ImGui::Sdl

src/imgui/renderer/imgui_impl_sdl3.h

@@ -0,0 +1,31 @@
+// SPDX-FileCopyrightText: Copyright 2024 shadPS4 Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+// Based on imgui_impl_sdl3.h from Dear ImGui repository
+
+#pragma once
+
+struct SDL_Window;
+struct SDL_Renderer;
+struct SDL_Gamepad;
+typedef union SDL_Event SDL_Event;
+
+namespace ImGui::Sdl {
+
+bool Init(SDL_Window* window);
+void Shutdown();
+void NewFrame();
+bool ProcessEvent(const SDL_Event* event);
+void OnResize();
+
+// Gamepad selection automatically starts in AutoFirst mode, picking first available SDL_Gamepad.
+// You may override this. When using manual mode, caller is responsible for opening/closing gamepad.
+enum GamepadMode {
+    ImGui_ImplSDL3_GamepadMode_AutoFirst,
+    ImGui_ImplSDL3_GamepadMode_AutoAll,
+    ImGui_ImplSDL3_GamepadMode_Manual
+};
+void SetGamepadMode(GamepadMode mode, SDL_Gamepad** manual_gamepads_array = NULL,
+                    int manual_gamepads_count = -1);
+
+}; // namespace ImGui::Sdl

src/imgui/renderer/imgui_impl_vulkan.h

@@ -0,0 +1,43 @@
+// SPDX-FileCopyrightText: Copyright 2024 shadPS4 Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+// Based on imgui_impl_vulkan.h from Dear ImGui repository
+
+#pragma once
+
+#define VULKAN_HPP_NO_EXCEPTIONS
+#include "video_core/renderer_vulkan/vk_common.h"
+
+struct ImDrawData;
+
+namespace ImGui::Vulkan {
+
+struct InitInfo {
+    vk::Instance instance;
+    vk::PhysicalDevice physical_device;
+    vk::Device device;
+    uint32_t queue_family;
+    vk::Queue queue;
+    uint32_t image_count;               // >= 2
+    vk::DeviceSize min_allocation_size; // Minimum allocation size
+    vk::PipelineCache pipeline_cache;
+    uint32_t subpass;
+    vk::PipelineRenderingCreateInfoKHR pipeline_rendering_create_info;
+
+    // (Optional) Allocation, Logging
+    const vk::AllocationCallbacks* allocator{};
+    void (*check_vk_result_fn)(vk::Result err);
+};
+
+vk::DescriptorSet AddTexture(vk::Sampler sampler, vk::ImageView image_view,
+                             vk::ImageLayout image_layout);
+
+void RemoveTexture(vk::DescriptorSet descriptor_set);
+
+bool Init(InitInfo info);
+void Shutdown();
+void NewFrame();
+void RenderDrawData(ImDrawData& draw_data, vk::CommandBuffer command_buffer,
+                    vk::Pipeline pipeline = VK_NULL_HANDLE);
+
+} // namespace ImGui::Vulkan

src/sdl_window.cpp

@@ -9,6 +9,7 @@
 #include "common/config.h"
 #include "common/version.h"
 #include "core/libraries/pad/pad.h"
+#include "imgui/renderer/imgui_core.h"
 #include "input/controller.h"
 #include "sdl_window.h"
 #include "video_core/renderdoc.h"
@@ -80,6 +81,10 @@ void WindowSDL::waitEvent() {
         return;
     }
 
+    if (ImGui::Core::ProcessEvent(&event)) {
+        return;
+    }
+
     switch (event.type) {
     case SDL_EVENT_WINDOW_RESIZED:
     case SDL_EVENT_WINDOW_MAXIMIZED:
@@ -115,6 +120,7 @@ void WindowSDL::waitEvent() {
 
 void WindowSDL::onResize() {
     SDL_GetWindowSizeInPixels(window, &width, &height);
+    ImGui::Core::OnResize();
 }
 
 void WindowSDL::onKeyPress(const SDL_Event* event) {

src/sdl_window.h

@@ -58,6 +58,10 @@ public:
         return is_open;
     }
 
+    [[nodiscard]] SDL_Window* GetSdlWindow() const {
+        return window;
+    }
+
     WindowSystemInfo getWindowInfo() const {
         return window_info;
     }

src/video_core/renderer_vulkan/renderer_vulkan.cpp

@@ -6,6 +6,7 @@
 #include "common/singleton.h"
 #include "core/file_format/splash.h"
 #include "core/libraries/system/systemservice.h"
+#include "imgui/renderer/imgui_core.h"
 #include "sdl_window.h"
 #include "video_core/renderer_vulkan/renderer_vulkan.h"
 #include "video_core/renderer_vulkan/vk_rasterizer.h"
@@ -73,7 +74,7 @@ RendererVulkan::RendererVulkan(Frontend::WindowSDL& window_, AmdGpu::Liverpool*
       draw_scheduler{instance}, present_scheduler{instance}, flip_scheduler{instance},
       swapchain{instance, window},
       rasterizer{std::make_unique<Rasterizer>(instance, draw_scheduler, liverpool)},
-      texture_cache{rasterizer->GetTextureCache()} {
+      texture_cache{rasterizer->GetTextureCache()}, video_info_ui{this} {
     const u32 num_images = swapchain.GetImageCount();
     const vk::Device device = instance.GetDevice();
 
@@ -84,9 +85,14 @@ RendererVulkan::RendererVulkan(Frontend::WindowSDL& window_, AmdGpu::Liverpool*
         frame.present_done = device.createFence({.flags = vk::FenceCreateFlagBits::eSignaled});
         free_queue.push(&frame);
     }
+
+    // Setup ImGui
+    ImGui::Core::Initialize(instance, window, num_images, swapchain.GetSurfaceFormat().format);
+    ImGui::Layer::AddLayer(&video_info_ui);
 }
 
 RendererVulkan::~RendererVulkan() {
+    ImGui::Layer::RemoveLayer(&video_info_ui);
     draw_scheduler.Finish();
     const vk::Device device = instance.GetDevice();
     for (auto& frame : present_frames) {
@@ -94,6 +100,7 @@ RendererVulkan::~RendererVulkan() {
         device.destroyImageView(frame.image_view);
         device.destroyFence(frame.present_done);
     }
+    ImGui::Core::Shutdown(device);
 }
 
 void RendererVulkan::RecreateFrame(Frame* frame, u32 width, u32 height) {
@@ -254,6 +261,8 @@ Frame* RendererVulkan::PrepareFrameInternal(VideoCore::Image& image, bool is_eop
 }
 
 void RendererVulkan::Present(Frame* frame) {
+    ImGui::Core::NewFrame();
+
     swapchain.AcquireNextImage();
 
     const vk::Image swapchain_image = swapchain.Image();
@@ -286,7 +295,7 @@ void RendererVulkan::Present(Frame* frame) {
             vk::ImageMemoryBarrier{
                 .srcAccessMask = vk::AccessFlagBits::eColorAttachmentWrite,
                 .dstAccessMask = vk::AccessFlagBits::eTransferRead,
-                .oldLayout = vk::ImageLayout::eGeneral,
+                .oldLayout = vk::ImageLayout::eUndefined,
                 .newLayout = vk::ImageLayout::eTransferSrcOptimal,
                 .srcQueueFamilyIndex = VK_QUEUE_FAMILY_IGNORED,
                 .dstQueueFamilyIndex = VK_QUEUE_FAMILY_IGNORED,
@@ -317,6 +326,8 @@ void RendererVulkan::Present(Frame* frame) {
             },
         };
 
+        ImGui::Core::Render(cmdbuf, frame);
+
         cmdbuf.pipelineBarrier(vk::PipelineStageFlagBits::eColorAttachmentOutput,
                                vk::PipelineStageFlagBits::eTransfer,
                                vk::DependencyFlagBits::eByRegion, {}, {}, pre_barriers);

src/video_core/renderer_vulkan/renderer_vulkan.h

@@ -4,6 +4,8 @@
 #pragma once
 
 #include <condition_variable>
+
+#include "imgui/layer/video_info.h"
 #include "video_core/amdgpu/liverpool.h"
 #include "video_core/renderer_vulkan/vk_instance.h"
 #include "video_core/renderer_vulkan/vk_scheduler.h"
@@ -103,6 +105,8 @@ private:
     std::condition_variable_any frame_cv;
     std::optional<VideoCore::Image> splash_img;
     std::vector<VAddr> vo_buffers_addr;
+
+    ImGui::Layers::VideoInfo video_info_ui;
 };
 
 } // namespace Vulkan