good but wrong teardown order; device wait idle

src/nu/ImGui.zig

@@ -2,11 +2,105 @@
 
 const std = @import("std");
 
+const vk = @import("vk");
+const nu = @import("../nu.zig");
+const au = @import("Render/au.zig");
 const Render = @import("Render.zig");
+const Window = @import("Window.zig");
 
-pub fn init(alloc: std.mem.Allocator) !void {
-    _ = alloc;
+const im = @import("cimgui");
+
+pub fn loader_wrapper(procname: [*c]const u8, _: ?*anyopaque) callconv(.C) vk.PfnVoidFunction {
+    return au.glfwGetInstanceProcAddress(au.I.handle, procname);
+}
+
+var ctx: *im.c.ImGuiContext = undefined;
+var descriptor_pool: vk.DescriptorPool = undefined;
+
+pub fn init() !void {
+    ctx = im.c.igCreateContext(null) orelse {
+        return error.igCreateContextFailed;
+    };
+    errdefer im.c.igDestroyContext(ctx);
+
+    if (!im.c.ImGui_ImplVulkan_LoadFunctions(loader_wrapper, null)) {
+        return error.igVulkanLoadFunctionsFailed;
+    }
+
+    if (!im.c.ImGui_ImplGlfw_InitForVulkan(@ptrCast(Window.handle), true)) {
+        return error.igGlfwInitFailed;
+    }
+    errdefer im.c.ImGui_ImplGlfw_Shutdown();
+
+    descriptor_pool = try au.D.createDescriptorPool(&vk.DescriptorPoolCreateInfo{
+        .flags = .{ .free_descriptor_set_bit = true },
+        .pool_size_count = 1,
+        .p_pool_sizes = &.{vk.DescriptorPoolSize{
+            .descriptor_count = 32,
+            .type = .combined_image_sampler,
+        }},
+        .max_sets = 32,
+    }, null);
+    errdefer au.D.destroyDescriptorPool(descriptor_pool, null);
+
+    if (im.c.ImGui_ImplVulkan_Init(@constCast(&im.c.ImGui_ImplVulkan_InitInfo{
+        .Instance = @ptrFromInt(@intFromEnum(au.I.handle)),
+        .PhysicalDevice = @ptrFromInt(@intFromEnum(au.device_config.pdev)),
+        .Device = @ptrFromInt(@intFromEnum(au.D.handle)),
+        .QueueFamily = au.device_config.family,
+        .Queue = @ptrFromInt(@intFromEnum(au.Q.handle)),
+        .DescriptorPool = @ptrFromInt(@intFromEnum(descriptor_pool)),
+        .RenderPass = null,
+        .MinImageCount = 2,
+        .ImageCount = @intCast(nu.options.render.frames_in_flight),
+        .PipelineRenderingCreateInfo = @bitCast(vk.PipelineRenderingCreateInfo{
+            .view_mask = 0,
+            .depth_attachment_format = .undefined,
+            .stencil_attachment_format = .undefined,
+            .color_attachment_count = 1,
+            .p_color_attachment_formats = &.{au.device_config.format.format},
+        }),
+        .MSAASamples = 0,
+        .PipelineCache = null,
+        .Subpass = 0,
+        .UseDynamicRendering = true,
+        .Allocator = null,
+    })) != true) {
+        return error.igVulkanInitFailed;
+    }
+    errdefer im.c.ImGui_ImplVulkan_Shutdown();
+
+    if (!im.c.ImGui_ImplVulkan_CreateFontsTexture()) {
+        return error.igVulkanFontTextureFailed;
+    }
+
+    try Render.add_present_callback(present);
+    errdefer Render.remove_present_callback(present);
+}
+
+pub fn frame() void {
+    im.c.ImGui_ImplGlfw_NewFrame();
+    im.c.ImGui_ImplVulkan_NewFrame();
+    im.c.igNewFrame();
+
+    im.c.igShowDemoWindow(null);
+
+    im.c.igEndFrame();
+    im.c.igRender();
 }
 
 pub fn deinit() void {
+    Render.remove_present_callback(present);
+    im.c.ImGui_ImplVulkan_Shutdown();
+    au.D.destroyDescriptorPool(descriptor_pool, null);
+    im.c.ImGui_ImplGlfw_Shutdown();
+    im.c.igDestroyContext(ctx);
+}
+
+pub fn present(cmd: au.CommandBufferProxy) void {
+    im.c.ImGui_ImplVulkan_RenderDrawData(
+        im.c.igGetDrawData(),
+        @ptrFromInt(@intFromEnum(cmd.handle)),
+        null,
+    );
 }