Properly seperated/cleaned up OpenGL and Vulkan implementations.

private/raid/application.cpp

@@ -5,6 +5,7 @@
 #include <thread>
 #include <fmt/base.h>
 #include <SDL3/SDL.h>
+#include <SDL3/SDL_vulkan.h>
 #include <mijin/detect.hpp>
 #include <mijin/debug/assert.hpp>
 #include <mijin/platform/folders.hpp>
@@ -62,6 +63,12 @@ int stbiEof(void* user)
     mijin::Stream& stream = *static_cast<mijin::Stream*>(user);
     return stream.isAtEnd();
 }
+
+[[nodiscard]]
+constexpr std::uint32_t vkMakeApiVersion(std::uint32_t variant, std::uint32_t major, std::uint32_t minor, std::uint32_t patch) noexcept
+{
+    return ((variant << 29U) | (major << 22U) | (minor << 12U) | patch);
+}
 }
 
 int Application::run(int argc, char** argv)
@@ -114,15 +121,26 @@ int Application::run(int argc, char** argv)
 
         ImGui::Render();
 
-        glClearColor(0.3f, 0.3f, 0.3f, 1.f);
-        glClear(GL_COLOR_BUFFER_BIT);
-        ImGui_ImplOpenGL3_RenderDrawData(ImGui::GetDrawData());
+        switch (mConfig.graphicsApi)
+        {
+        case GraphicsAPI::OPENGL:
+            gl.ClearColor(0.3f, 0.3f, 0.3f, 1.f);
+            gl.Clear(GL_COLOR_BUFFER_BIT);
+            ImGui_ImplOpenGL3_RenderDrawData(ImGui::GetDrawData());
+            break;
+        case GraphicsAPI::VULKAN:
+            MIJIN_TRAP(); // TODO!
+            break;
+        }
 
         if (imguiIO.ConfigFlags & ImGuiConfigFlags_ViewportsEnable)
         {
             ImGui::UpdatePlatformWindows();
             ImGui::RenderPlatformWindowsDefault();
-            SDL_GL_MakeCurrent(mWindow, mGLContext);
+
+            if (mConfig.graphicsApi == GraphicsAPI::OPENGL) {
+                SDL_GL_MakeCurrent(mWindow, gl.context);
+            }
         }
 
         SDL_GL_SwapWindow(mWindow);
@@ -223,23 +241,60 @@ ImTextureID Application::getOrLoadTexture(fs::path path)
     }
 
     // create texture
-    GLuint texture = 0;
-    glGenTextures(1, &texture);
-    glBindTexture(GL_TEXTURE_2D, texture);
+    ImTextureID texture = 0;
+    switch (mConfig.graphicsApi)
+    {
+    case GraphicsAPI::OPENGL:
+    {
+        GLuint glTexture = 0;
+        gl.GenTextures(1, &glTexture);
+        gl.BindTexture(GL_TEXTURE_2D, glTexture);
 
-    // setup texture
-    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
-    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
+        // setup texture
+        gl.TexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
+        gl.TexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
 
-    // upload image
-    glPixelStorei(GL_UNPACK_ROW_LENGTH, 0);
-    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, width, height, 0, GL_RGBA, GL_UNSIGNED_BYTE, imageData);
+        // upload image
+        gl.PixelStorei(GL_UNPACK_ROW_LENGTH, 0);
+        gl.TexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, width, height, 0, GL_RGBA, GL_UNSIGNED_BYTE, imageData);
 
-    mTextures.emplace(std::move(path), texture);
+        texture = glTexture;
+        break;
+    }
+    case GraphicsAPI::VULKAN:
+        MIJIN_TRAP(); // TODO!
+        break;
+    }
+
+    if (texture != 0) {
+        mTextures.emplace(std::move(path), texture);
+    }
 
     return texture;
 }
 
+void Application::destroyTexture(ImTextureID texture)
+{
+    auto it = std::ranges::find_if(mTextures, [texture](const auto& entry) {
+        return entry.second == texture;
+    });
+    MIJIN_ASSERT(it != mTextures.end(), "Invalid texture id.");
+    mTextures.erase(it);
+
+    switch (mConfig.graphicsApi)
+    {
+    case GraphicsAPI::OPENGL:
+    {
+        const GLuint asUint = static_cast<GLuint>(texture);
+        gl.DeleteTextures(1, &asUint);
+        break;
+    }
+    case GraphicsAPI::VULKAN:
+        MIJIN_TRAP(); // TODO
+        break;
+    }
+}
+
 void Application::configureImgui()
 {
     ImGuiIO& imguiIO = ImGui::GetIO();
@@ -379,9 +434,19 @@ bool Application::init()
     {
         return false;
     }
-    if (!initGL())
+    switch (mConfig.graphicsApi)
     {
-        return false;
+    case GraphicsAPI::OPENGL:
+        if (!initOpenGL())
+        {
+            return false;
+        }
+        break;
+    case GraphicsAPI::VULKAN:
+        if (!initVulkan())
+        {
+            return false;
+        }
     }
     if (!initImGui())
     {
@@ -407,14 +472,29 @@ void Application::cleanup()
         }
         ImGui::DestroyContext();
     }
-    for (const auto& [path, texture] : mTextures)
-    {
-        const GLuint asUint = static_cast<GLuint>(texture);
-        glDeleteTextures(1, &asUint);
+    for (const auto& [_, texture] : mTextures) {
+        destroyTexture(texture);
     }
-    if (mGLContext != nullptr)
+    switch (mConfig.graphicsApi)
     {
-        SDL_GL_DestroyContext(mGLContext);
+    case GraphicsAPI::OPENGL:
+        if (gl.context != nullptr)
+        {
+            SDL_GL_DestroyContext(gl.context);
+        }
+        break;
+    case GraphicsAPI::VULKAN:
+        if (vk.device != nullptr)
+        {
+            vk.DeviceWaitIdle(vk.device);
+            vk.DestroyDevice(vk.device, nullptr);
+        }
+        if (vk.instance != nullptr)
+        {
+            vk.DestroyInstance(vk.instance, nullptr);
+        }
+        SDL_Vulkan_UnloadLibrary();
+        break;
     }
     if (mWindow != nullptr)
     {
@@ -426,9 +506,9 @@ void Application::cleanup()
 bool Application::initSDL()
 {
 #if MIJIN_TARGET_OS == MIJIN_OS_LINUX
-    // prefer x11 over wayland, as ImGui viewports don't work with wayland
-    // TODO: this still doesn't work all the time, maybe there will be an update to ImGui in the future?
-    SDL_SetHint(SDL_HINT_VIDEO_DRIVER, "x11,wayland");
+    if (mConfig.flags.x11OnWayland) {
+        SDL_SetHint(SDL_HINT_VIDEO_DRIVER, "x11,wayland");
+    }
 #endif
     if (!SDL_Init(SDL_INIT_VIDEO))
     {
@@ -438,48 +518,146 @@ bool Application::initSDL()
 
     msgInfo("SDL video driver: {}", SDL_GetCurrentVideoDriver());
 
-    // GL attributes must be set before window creation
-    SDL_GL_SetAttribute(SDL_GL_CONTEXT_MAJOR_VERSION, 3);
-    SDL_GL_SetAttribute(SDL_GL_CONTEXT_MINOR_VERSION, 1);
-    SDL_GL_SetAttribute(SDL_GL_CONTEXT_PROFILE_MASK, SDL_GL_CONTEXT_PROFILE_CORE);
-    SDL_GL_SetAttribute(SDL_GL_DOUBLEBUFFER, 1);
+    SDL_WindowFlags windowFlags = SDL_WINDOW_RESIZABLE | SDL_WINDOW_HIGH_PIXEL_DENSITY;
+    switch (mConfig.graphicsApi)
+    {
+    case GraphicsAPI::OPENGL:
+        // GL attributes must be set before window creation
+        SDL_GL_SetAttribute(SDL_GL_CONTEXT_MAJOR_VERSION, 3);
+        SDL_GL_SetAttribute(SDL_GL_CONTEXT_MINOR_VERSION, 1);
+        SDL_GL_SetAttribute(SDL_GL_CONTEXT_PROFILE_MASK, SDL_GL_CONTEXT_PROFILE_CORE);
+        SDL_GL_SetAttribute(SDL_GL_DOUBLEBUFFER, 1);
 
-    // TODO: not sure if these really make sense, but they are in the example
-    SDL_GL_SetAttribute(SDL_GL_DEPTH_SIZE, 24);
-    SDL_GL_SetAttribute(SDL_GL_STENCIL_SIZE, 8);
+        // TODO: not sure if these really make sense, but they are in the example
+        SDL_GL_SetAttribute(SDL_GL_DEPTH_SIZE, 24);
+        SDL_GL_SetAttribute(SDL_GL_STENCIL_SIZE, 8);
+        windowFlags |= SDL_WINDOW_OPENGL;
+        break;
+    case GraphicsAPI::VULKAN:
+        if (!SDL_Vulkan_LoadLibrary(nullptr))
+        {
+            msgError("Error loading Vulkan library: {}.", SDL_GetError());
+            return false;
+        }
+        windowFlags |= SDL_WINDOW_VULKAN;
+        break;
+    }
 
-    const SDL_WindowFlags WINDOW_FLAGS = 0
-            | SDL_WINDOW_OPENGL
-            | SDL_WINDOW_RESIZABLE
-            | SDL_WINDOW_HIGH_PIXEL_DENSITY;
     mWindow = SDL_CreateWindow(
         /* title = */ getWindowTitle().c_str(),
         /* w     = */ 1280,
         /* h     = */ 720,
-        /* flags = */ WINDOW_FLAGS
+        /* flags = */ windowFlags
     );
     return true;
 }
 
-bool Application::initGL()
+bool Application::initOpenGL()
 {
-    mGLContext = SDL_GL_CreateContext(mWindow);
+    gl.context = SDL_GL_CreateContext(mWindow);
     if (mWindow == nullptr)
     {
-        msgError("Error creating SDL window: {}.", SDL_GetError());
+        msgError("Error creating OpenGL context: {}.", SDL_GetError());
         return false;
     }
-    SDL_GL_MakeCurrent(mWindow, mGLContext);
+    SDL_GL_MakeCurrent(mWindow, gl.context);
     SDL_GL_SetSwapInterval(1); // enable vsync, at least for now
 
-    glClear = reinterpret_cast<glClear_fn_t>(SDL_GL_GetProcAddress("glClear"));
-    glClearColor = reinterpret_cast<glClearColor_fn_t>(SDL_GL_GetProcAddress("glClearColor"));
-    glGenTextures = reinterpret_cast<glGenTextures_fn_t>(SDL_GL_GetProcAddress("glGenTextures"));
-    glBindTexture = reinterpret_cast<glBindTexture_fn_t>(SDL_GL_GetProcAddress("glBindTexture"));
-    glTexParameteri = reinterpret_cast<glTexParameteri_fn_t>(SDL_GL_GetProcAddress("glTexParameteri"));
-    glPixelStorei = reinterpret_cast<glPixelStorei_fn_t>(SDL_GL_GetProcAddress("glPixelStorei"));
-    glTexImage2D = reinterpret_cast<glTexImage2D_fn_t>(SDL_GL_GetProcAddress("glTexImage2D"));
-    glDeleteTextures = reinterpret_cast<glDeleteTextures_fn_t>(SDL_GL_GetProcAddress("glDeleteTextures"));
+    gl.Clear = reinterpret_cast<glClear_fn_t>(SDL_GL_GetProcAddress("glClear"));
+    gl.ClearColor = reinterpret_cast<glClearColor_fn_t>(SDL_GL_GetProcAddress("glClearColor"));
+    gl.GenTextures = reinterpret_cast<glGenTextures_fn_t>(SDL_GL_GetProcAddress("glGenTextures"));
+    gl.BindTexture = reinterpret_cast<glBindTexture_fn_t>(SDL_GL_GetProcAddress("glBindTexture"));
+    gl.TexParameteri = reinterpret_cast<glTexParameteri_fn_t>(SDL_GL_GetProcAddress("glTexParameteri"));
+    gl.PixelStorei = reinterpret_cast<glPixelStorei_fn_t>(SDL_GL_GetProcAddress("glPixelStorei"));
+    gl.TexImage2D = reinterpret_cast<glTexImage2D_fn_t>(SDL_GL_GetProcAddress("glTexImage2D"));
+    gl.DeleteTextures = reinterpret_cast<glDeleteTextures_fn_t>(SDL_GL_GetProcAddress("glDeleteTextures"));
+
+    return true;
+}
+
+bool Application::initVulkan()
+{
+    vk.GetInstanceProc = reinterpret_cast<vkGetInstanceProcAddr_fn_t>(SDL_Vulkan_GetVkGetInstanceProcAddr());
+    vk.CreateInstance = reinterpret_cast<vkCreateInstance_fn_t>(vk.GetInstanceProc(nullptr, "vkCreateInstance"));
+
+    const VkApplicationInfo applicationInfo = {
+        .apiVersion = vkMakeApiVersion(0, 1, 3, 0) // TODO: probably should let the user specify this?
+    };
+    const VkInstanceCreateInfo instanceCreateInfo = {
+        .pApplicationInfo = &applicationInfo
+    };
+
+    if (const VkResult result = vk.CreateInstance(&instanceCreateInfo, nullptr, &vk.instance); result != VK_SUCCESS)
+    {
+        msgError("Error creating Vulkan instance: {:x}.", static_cast<unsigned>(result));
+        return false;
+    }
+
+    vk.DestroyInstance = reinterpret_cast<vkDestroyInstance_fn_t>(vk.GetInstanceProc(vk.instance, "vkDestroyInstance"));
+    vk.EnumeratePhysicalDevices = reinterpret_cast<vkEnumeratePhysicalDevices_fn_t>(vk.GetInstanceProc(vk.instance, "vkEnumeratePhysicalDevices"));
+    vk.GetPhysicalDeviceQueueFamilyProperties2 = reinterpret_cast<vkGetPhysicalDeviceQueueFamilyProperties2_fn_t>(vk.GetInstanceProc(vk.instance, "vkGetPhysicalDeviceQueueFamilyProperties2"));
+    vk.CreateDevice = reinterpret_cast<vkCreateDevice_fn_t>(vk.GetInstanceProc(vk.instance, "vkCreateDevice"));
+    vk.DestroyDevice = reinterpret_cast<vkDestroyDevice_fn_t>(vk.GetInstanceProc(vk.instance, "vkDestroyDevice"));
+    vk.DeviceWaitIdle = reinterpret_cast<vkDeviceWaitIdle_fn_t>(vk.GetInstanceProc(vk.instance, "vkDeviceWaitIdle"));
+    vk.GetDeviceQueue = reinterpret_cast<vkGetDeviceQueue_fn_t>(vk.GetInstanceProc(vk.instance, "vkGetDeviceQueue"));
+
+    // TODO: this is really cheap... (but should be sufficient in most cases)
+    std::uint32_t physicalDeviceCount = 1;
+    if (const VkResult result = vk.EnumeratePhysicalDevices(vk.instance, &physicalDeviceCount, &vk.physicalDevice); result != VK_SUCCESS)
+    {
+        msgError("Error enumerating Vulkan physical devices: {:x}.", static_cast<unsigned>(result));
+        return false;
+    }
+
+    std::uint32_t queueFamilyPropertyCount = 0;
+    vk.GetPhysicalDeviceQueueFamilyProperties2(vk.physicalDevice, &queueFamilyPropertyCount, nullptr);
+
+    std::vector<VkQueueFamilyProperties2> queueFamilyProperties;
+    queueFamilyProperties.resize(queueFamilyPropertyCount);
+    vk.GetPhysicalDeviceQueueFamilyProperties2(vk.physicalDevice, &queueFamilyPropertyCount, queueFamilyProperties.data());
+
+    // TODO: this should also check for surface support (but who cares?)
+    std::uint32_t queueFamilyIndex = 0;
+    for (; queueFamilyIndex < queueFamilyPropertyCount; ++queueFamilyIndex)
+    {
+        if (queueFamilyProperties[queueFamilyIndex].queueFamilyProperties.queueFlags & VK_QUEUE_GRAPHICS_BIT) {
+            break;
+        }
+    }
+    if (queueFamilyIndex == queueFamilyPropertyCount)
+    {
+        msgError("No suitable Vulkan queue family found.");
+        return false;
+    }
+    vk.queueFamilyIndex = queueFamilyIndex;
+
+    static const float queuePriority = 1.0f;
+    const VkDeviceQueueCreateInfo queueCreateInfo = {
+        .queueFamilyIndex = vk.queueFamilyIndex,
+        .queueCount = 1,
+        .pQueuePriorities = &queuePriority
+    };
+    static const std::array DEVICE_EXTENSIONS = {
+        "VK_KHR_surface"
+    };
+    const VkDeviceCreateInfo deviceCreateInfo = {
+        .queueCreateInfoCount = 1,
+        .pQueueCreateInfos = &queueCreateInfo,
+        .enabledExtensionCount = static_cast<std::uint32_t>(DEVICE_EXTENSIONS.size()),
+        .ppEnabledExtensionNames = DEVICE_EXTENSIONS.data()
+    };
+    if (const VkResult result = vk.CreateDevice(vk.physicalDevice, &deviceCreateInfo, nullptr, &vk.device); result != VK_SUCCESS)
+    {
+        msgError("Error creating Vulkan device: {:x}.", static_cast<unsigned>(result));
+        return false;
+    }
+    vk.GetDeviceQueue(vk.device, /* queueFamilyIndex = */ 0, /* queueIndex = */ 0, &vk.queue);
+
+    if (!SDL_Vulkan_CreateSurface(mWindow, vk.instance, nullptr, &vk.surface))
+    {
+        msgError("Error creating SDL Vulkan surface: {}.", SDL_GetError());
+        return false;
+    }
 
     return true;
 }
@@ -511,14 +689,22 @@ bool Application::initImGui()
     ImGui::StyleColorsDark();
 
     // init the backends
-    if (!ImGui_ImplSDL3_InitForOpenGL(mWindow, mGLContext))
+    switch (mConfig.graphicsApi)
     {
-        msgError("Error initializing ImGui SDL3 backend.");
-        return false;
-    }
-    if (!ImGui_ImplOpenGL3_Init(IMGUI_GLSL_VERSION))
-    {
-        msgError("Error initializing ImGui OpenGL3 backend.");
+    case GraphicsAPI::OPENGL:
+        if (!ImGui_ImplSDL3_InitForOpenGL(mWindow, gl.context))
+        {
+            msgError("Error initializing ImGui SDL3 backend.");
+            return false;
+        }
+        if (!ImGui_ImplOpenGL3_Init(IMGUI_GLSL_VERSION))
+        {
+            msgError("Error initializing ImGui OpenGL3 backend.");
+            return false;
+        }
+        break;
+    case GraphicsAPI::VULKAN:
+        MIJIN_TRAP(); // TODO!
         return false;
     }
 

public/raid/internal/opengl.hpp

@@ -0,0 +1,45 @@
+
+#pragma once
+
+#if !defined(RAID_INTERNAL_OPENGL_HPP_INCLUDED)
+#define RAID_INTERNAL_OPENGL_HPP_INCLUDED 1
+
+#include <cstdint>
+
+namespace raid
+{
+struct MixinOpenGLApplication
+{
+    using GLbitfield = std::uint32_t;
+    using GLint = std::int32_t;
+    using GLuint = std::uint32_t;
+    using GLsizei = std::int32_t;
+    using GLenum = std::uint32_t;
+    using GLfloat = float;
+
+    using glClear_fn_t = void (*)(GLbitfield);
+    using glClearColor_fn_t = void (*)(GLfloat, GLfloat, GLfloat, GLfloat);
+    using glGenTextures_fn_t = void (*)(GLsizei, GLuint*);
+    using glBindTexture_fn_t = void (*)(GLenum, GLuint);
+    using glTexParameteri_fn_t = void (*)(GLenum, GLenum, GLint);
+    using glPixelStorei_fn_t = void (*)(GLenum, GLint);
+    using glTexImage2D_fn_t = void (*)(GLenum, GLint, GLint, GLsizei, GLsizei, GLint, GLenum, GLenum, const void*);
+    using glDeleteTextures_fn_t = void (*)(GLsizei, const GLuint*);
+
+    struct OpenGLData
+    {
+        SDL_GLContext context;
+
+        glClear_fn_t Clear;
+        glClearColor_fn_t ClearColor;
+        glGenTextures_fn_t GenTextures;
+        glBindTexture_fn_t BindTexture;
+        glTexParameteri_fn_t TexParameteri;
+        glPixelStorei_fn_t PixelStorei;
+        glTexImage2D_fn_t TexImage2D;
+        glDeleteTextures_fn_t DeleteTextures;
+    };
+};
+} // namespace raid
+
+#endif // !defined(RAID_INTERNAL_OPENGL_HPP_INCLUDED)

public/raid/internal/vulkan.hpp

@@ -0,0 +1,176 @@
+
+#pragma once
+
+#if !defined(RAID_INTERNAL_VULKAN_HPP_INCLUDED)
+#define RAID_INTERNAL_VULKAN_HPP_INCLUDED 1
+
+#include <cstdint>
+
+#if !defined(RAID_USE_VULKAN_H)
+#define RAID_USE_VULKAN_H 0
+#endif
+
+#if RAID_USE_VULKAN_H
+#include <vulkan/vulkan.h>
+#endif
+
+namespace raid
+{
+struct MixinVulkanApplication
+{
+#if !RAID_USE_VULKAN_H
+    // flags
+    using VkFlags = std::uint32_t;
+    using VkInstanceCreateFlags = VkFlags;
+    using VkQueueFlags = VkFlags;
+    using VkDeviceCreateFlags = VkFlags;
+    using VkDeviceQueueCreateFlags = VkFlags;
+
+    // enums
+    enum VkResult
+    {
+        VK_SUCCESS = 0
+    };
+    enum VkStructureType
+    {
+        VK_STRUCTURE_TYPE_APPLICATION_INFO = 0,
+        VK_STRUCTURE_TYPE_INSTANCE_CREATE_INFO = 1,
+        VK_STRUCTURE_TYPE_DEVICE_QUEUE_CREATE_INFO = 2,
+        VK_STRUCTURE_TYPE_DEVICE_CREATE_INFO = 3,
+        VK_STRUCTURE_TYPE_QUEUE_FAMILY_PROPERTIES_2 = 1000059005
+    };
+    enum VkSystemAllocationScope {};
+    enum VkInternalAllocationType {};
+    enum VkQueueFlagBits : VkFlags
+    {
+        VK_QUEUE_GRAPHICS_BIT = 0x00000001
+    };
+
+    // handles
+    using VkDevice = struct VkDevice_*;
+    using VkQueue = struct VkQueue_*;
+
+    // structs
+    struct VkExtent3D
+    {
+        std::uint32_t width = 0;
+        std::uint32_t height = 0;
+        std::uint32_t depth = 0;
+    };
+
+    struct VkApplicationInfo
+    {
+        VkStructureType sType = VK_STRUCTURE_TYPE_APPLICATION_INFO;
+        const void* pNext = nullptr;
+        const char* pApplicationNane = nullptr;
+        std::uint32_t applicationVersion = 0;
+        const char* pEngineName = nullptr;
+        std::uint32_t engineVersion = 0;
+        std::uint32_t apiVersion = 0;
+    };
+    struct VkInstanceCreateInfo
+    {
+        VkStructureType sType = VK_STRUCTURE_TYPE_INSTANCE_CREATE_INFO;
+        const void* pNext = nullptr;
+        VkInstanceCreateFlags flags = 0;
+        const VkApplicationInfo* pApplicationInfo = nullptr;
+        std::uint32_t enabledLayerCount = 0;
+        const char* const* ppEnabledLayerNames = nullptr;
+        std::uint32_t enabledExtensionCount = 0;
+        const char* const* ppEnabledExtensionNames = nullptr;
+    };
+
+    struct VkQueueFamilyProperties
+    {
+        VkQueueFlags queueFlags = 0;
+        std::uint32_t queueCount = 0;
+        std::uint32_t timestampValidBits = 0;
+        VkExtent3D minImageTransferGranularity = {};
+    };
+
+    struct VkQueueFamilyProperties2
+    {
+        VkStructureType sType = VK_STRUCTURE_TYPE_QUEUE_FAMILY_PROPERTIES_2;
+        void* pNext = nullptr;
+        VkQueueFamilyProperties queueFamilyProperties = {};
+    };
+
+    struct VkDeviceQueueCreateInfo
+    {
+        VkStructureType sType = VK_STRUCTURE_TYPE_DEVICE_QUEUE_CREATE_INFO;
+        const void* pNext = nullptr;
+        VkDeviceQueueCreateFlags flags = 0;
+        std::uint32_t queueFamilyIndex = 0;
+        std::uint32_t queueCount = 0;
+        const float* pQueuePriorities = nullptr;
+    };
+
+    struct VkPhysicalDeviceFeatures;
+    struct VkDeviceCreateInfo
+    {
+        VkStructureType sType = VK_STRUCTURE_TYPE_DEVICE_CREATE_INFO;
+        const void* pNext = nullptr;
+        VkDeviceCreateFlags flags;
+        std::uint32_t queueCreateInfoCount = 0;
+        const VkDeviceQueueCreateInfo* pQueueCreateInfos = nullptr;
+        std::uint32_t enabledLayerCount = 0;
+        const char* const* ppEnabledLayerNames = nullptr;
+        uint32_t enabledExtensionCount = 0;
+        const char* const* ppEnabledExtensionNames = nullptr;
+        const VkPhysicalDeviceFeatures* pEnabledFeatures = nullptr;
+    };
+
+    // Vulkan function pointer types
+    using PFN_vkVoidFunction = void (*)();
+    // TODO: VKAPI_PTR?
+    using PFN_vkAllocationFunction = void* (*)(void* pUserData, std::size_t size, std::size_t alignment, VkSystemAllocationScope allocationScope);
+    using PFN_vkReallocationFunction = void* (*)(void* pUserData, void* pOriginal, std::size_t size, std::size_t alignment, VkSystemAllocationScope allocationScope);
+    using PFN_vkFreeFunction = void (*)(void* pUserData, void* pMemory);
+    using PFN_vkInternalAllocationNotification = void (*)(void* pUserData, std::size_t size, VkInternalAllocationType allocationType, VkSystemAllocationScope allocationScope);
+    using PFN_vkInternalFreeNotification = void (*)(void* pUserData, std::size_t size, VkInternalAllocationType allocationType, VkSystemAllocationScope allocationScope);
+    struct VkAllocationCallbacks
+    {
+        void* pUserData = nullptr;
+        PFN_vkAllocationFunction pfnAllocation = nullptr;
+        PFN_vkReallocationFunction pfnReallocation = nullptr;
+        PFN_vkFreeFunction pfnFree = nullptr;
+        PFN_vkInternalAllocationNotification pfnInternalAllocation = nullptr;
+        PFN_vkInternalFreeNotification pfnInternalFree = nullptr;
+    };
+
+    // function pointers
+    using vkGetInstanceProcAddr_fn_t = PFN_vkVoidFunction (*)(VkInstance instance, const char* pName);
+    using vkCreateInstance_fn_t = VkResult (*)(const VkInstanceCreateInfo* pCreateInfo, const VkAllocationCallbacks* pAllocator, VkInstance* pInstance);
+    using vkDestroyInstance_fn_t = void (*)(VkInstance instance, const VkAllocationCallbacks* pAllocator);
+    using vkEnumeratePhysicalDevices_fn_t = VkResult (*)(VkInstance instance, std::uint32_t* pPhysicalDeviceCount, VkPhysicalDevice* pPhysicalDevices);
+    using vkGetPhysicalDeviceQueueFamilyProperties2_fn_t = void (*)(VkPhysicalDevice physicalDevice, std::uint32_t* pQueueFamilyPropertyCount, VkQueueFamilyProperties2* pQueueFamilyProperties);
+    using vkCreateDevice_fn_t = VkResult (*)(VkPhysicalDevice physicalDevice, const VkDeviceCreateInfo* pCreateInfo, const VkAllocationCallbacks* pAllocator, VkDevice* pDevice);
+    using vkDestroyDevice_fn_t = void (*)(VkDevice device, const VkAllocationCallbacks* pAllocator);
+    using vkDeviceWaitIdle_fn_t = VkResult (*)(VkDevice device);
+    using vkGetDeviceQueue_fn_t = void (*)(VkDevice device, std::uint32_t queueFamilyIndex, std::uint32_t queueIndex, VkQueue* pQueue);
+#endif // !RAID_USE_VULKAN_H
+
+    struct VulkanData
+    {
+        VkInstance instance;
+        VkPhysicalDevice physicalDevice;
+        VkDevice device;
+        VkQueue queue;
+        VkSurfaceKHR surface;
+
+        vkGetInstanceProcAddr_fn_t GetInstanceProc;
+        vkCreateInstance_fn_t CreateInstance;
+        vkDestroyInstance_fn_t DestroyInstance;
+        vkEnumeratePhysicalDevices_fn_t EnumeratePhysicalDevices;
+        vkGetPhysicalDeviceQueueFamilyProperties2_fn_t GetPhysicalDeviceQueueFamilyProperties2;
+        vkCreateDevice_fn_t CreateDevice;
+        vkDestroyDevice_fn_t DestroyDevice;
+        vkDeviceWaitIdle_fn_t DeviceWaitIdle;
+        vkGetDeviceQueue_fn_t GetDeviceQueue;
+
+        std::uint32_t queueFamilyIndex;
+    };
+};
+} // namespace raid
+
+#endif // !defined(RAID_INTERNAL_VULKAN_HPP_INCLUDED)

public/raid/raid.hpp

@@ -14,6 +14,9 @@
 #include <mijin/virtual_filesystem/memory.hpp>
 #include <mijin/virtual_filesystem/stacked.hpp>
 #include <SDL3/SDL.h>
+#include <SDL3/SDL_vulkan.h>
+#include "./internal/opengl.hpp"
+#include "./internal/vulkan.hpp"
 
 namespace raid
 {
@@ -51,11 +54,32 @@ struct FontConfig
     FontFlags flags;
 };
 
-class Application
+struct ApplicationFlags : mijin::BitFlags<ApplicationFlags>
+{
+    /**
+     * (Linux only) prefer X11 even when on Wayland. Required for multi-viewport support, but currently really buggy.
+     * \see https://github.com/ocornut/imgui/issues/8609
+     * \see https://github.com/ocornut/imgui/issues/8587
+     */
+    bool x11OnWayland : 1 = false;
+};
+
+enum class GraphicsAPI : std::uint8_t
+{
+    OPENGL,
+    VULKAN
+};
+
+struct ApplicationConfig
+{
+    ApplicationFlags flags = {};
+    GraphicsAPI graphicsApi = GraphicsAPI::OPENGL;
+};
+
+class Application : private MixinOpenGLApplication, MixinVulkanApplication
 {
 private:
     SDL_Window* mWindow = nullptr;
-    SDL_GLContext mGLContext = nullptr;
 
     mijin::StackedFileSystemAdapter mFS;
     mijin::MemoryFileSystemAdapter* mMemoryFS = nullptr;
@@ -65,34 +89,20 @@ private:
     bool mRunning = true;
     ImGuiWindowFlags mMainWindowFlags = DEFAULT_MAIN_WINDOW_FLAGS;
     std::unordered_map<ImGuiStyleVar, std::variant<float, ImVec2>> mMainWindowStyles;
+    const ApplicationConfig mConfig;
 
-    using GLbitfield = std::uint32_t;
-    using GLint = std::int32_t;
-    using GLuint = std::uint32_t;
-    using GLsizei = std::int32_t;
-    using GLenum = std::uint32_t;
-    using GLfloat = float;
-
-    using glClear_fn_t = void (*)(GLbitfield);
-    using glClearColor_fn_t = void (*)(GLfloat, GLfloat, GLfloat, GLfloat);
-    using glGenTextures_fn_t = void (*)(GLsizei, GLuint*);
-    using glBindTexture_fn_t = void (*)(GLenum, GLuint);
-    using glTexParameteri_fn_t = void (*)(GLenum, GLenum, GLint);
-    using glPixelStorei_fn_t = void (*)(GLenum, GLint);
-    using glTexImage2D_fn_t = void (*)(GLenum, GLint, GLint, GLsizei, GLsizei, GLint, GLenum, GLenum, const void*);
-    using glDeleteTextures_fn_t = void (*)(GLsizei, const GLuint*);
-
-    glClear_fn_t glClear;
-    glClearColor_fn_t glClearColor;
-    glGenTextures_fn_t glGenTextures;
-    glBindTexture_fn_t glBindTexture;
-    glTexParameteri_fn_t glTexParameteri;
-    glPixelStorei_fn_t glPixelStorei;
-    glTexImage2D_fn_t glTexImage2D;
-    glDeleteTextures_fn_t glDeleteTextures;
+    union
+    {
+        OpenGLData gl;
+        VulkanData vk;
+    };
 public:
+    explicit Application(ApplicationConfig config = {}) noexcept : mConfig(config) {}
     virtual ~Application() = default;
 
+    [[nodiscard]]
+    const ApplicationConfig& getConfig() const noexcept { return mConfig; }
+
     [[nodiscard]]
     mijin::StackedFileSystemAdapter& getFS() { return mFS; }
 
@@ -129,6 +139,8 @@ public:
     [[nodiscard]]
     ImTextureID getOrLoadTexture(fs::path path);
 
+    void destroyTexture(ImTextureID texture);
+
 protected:
     virtual void render() = 0;
     virtual std::string getFolderName() = 0;
@@ -195,7 +207,8 @@ protected:
     virtual void cleanup();
 private:
     bool initSDL();
-    bool initGL();
+    bool initOpenGL();
+    bool initVulkan();
     bool initImGui();
     void handleSDLEvents();
     void loadImGuiConfig();
@@ -221,6 +234,8 @@ private:
     std::string mFolderName;
     std::string mWindowTitle;
 public:
+    explicit QuickApp(ApplicationConfig config = {}) noexcept : Application(config) {}
+
     void preInit(QuickAppOptions options);
     void render() override;
     std::string getFolderName() override;