Use ImGui functions directly in renderer vtables

Remove small per-backend wrapper functions and wire the vtables to the real ImGui functions and existing helpers. Added renderer_noop_wait_idle and a renderer_call_backend_new_frame template in the header to avoid duplicated no-op/new-frame wrappers. Updated Metal, OpenGL and Vulkan backends to use ImGui_Impl* Shutdown/NewFrame directly and to reference existing functions (e.g. platform_glfw_supports_vulkan, imiv_vulkan_screen_capture). This reduces boilerplate and keeps behavior unchanged.

Signed-off-by: Vlad <shaamaan@gmail.com>

Author: ssh4net

src/imiv/imiv_renderer.h

@@ -131,12 +131,29 @@ renderer_noop_quiesce_texture_preview_submission(RendererState& renderer_state,
     return true;
 }
 
+inline bool
+renderer_noop_wait_idle(RendererState& renderer_state,
+                        std::string& error_message)
+{
+    (void)renderer_state;
+    error_message.clear();
+    return true;
+}
+
 inline void
 renderer_noop_platform_windows(RendererState& renderer_state)
 {
     (void)renderer_state;
 }
 
+template<void (*Fn)()>
+inline void
+renderer_call_backend_new_frame(RendererState& renderer_state)
+{
+    (void)renderer_state;
+    Fn();
+}
+
 void
 renderer_select_backend(RendererState& renderer_state, BackendKind backend);
 BackendKind

src/imiv/imiv_renderer_metal.mm

@@ -2036,8 +2036,6 @@ bool metal_imgui_init(RendererState& renderer_state,
         return true;
     }
 
-    void metal_imgui_shutdown() { ImGui_ImplMetal_Shutdown(); }
-
     void metal_imgui_new_frame(RendererState& renderer_state)
     {
         RendererBackendState* state = backend_state<RendererBackendState>(
@@ -2279,7 +2277,7 @@ bool metal_probe_runtime_support(std::string& error_message)
     metal_cleanup,
     metal_wait_idle,
     metal_imgui_init,
-    metal_imgui_shutdown,
+    ImGui_ImplMetal_Shutdown,
     metal_imgui_new_frame,
     renderer_framebuffer_size_changed,
     metal_resize_main_window,

src/imiv/imiv_renderer_opengl.cpp

@@ -1634,14 +1634,6 @@ void main()
         renderer_state.backend = nullptr;
     }
 
-    bool opengl_wait_idle(RendererState& renderer_state,
-                          std::string& error_message)
-    {
-        (void)renderer_state;
-        error_message.clear();
-        return true;
-    }
-
     bool opengl_imgui_init(RendererState& renderer_state,
                            std::string& error_message)
     {
@@ -1661,14 +1653,6 @@ void main()
         return false;
     }
 
-    void opengl_imgui_shutdown() { ImGui_ImplOpenGL3_Shutdown(); }
-
-    void opengl_imgui_new_frame(RendererState& renderer_state)
-    {
-        (void)renderer_state;
-        ImGui_ImplOpenGL3_NewFrame();
-    }
-
     void opengl_prepare_platform_windows(RendererState& renderer_state)
     {
         RendererBackendState* state = backend_state<RendererBackendState>(
@@ -1891,10 +1875,10 @@ void main()
         renderer_clear_backend_window<RendererBackendState>,
         renderer_noop_platform_windows,
         opengl_cleanup,
-        opengl_wait_idle,
+        renderer_noop_wait_idle,
         opengl_imgui_init,
-        opengl_imgui_shutdown,
-        opengl_imgui_new_frame,
+        ImGui_ImplOpenGL3_Shutdown,
+        renderer_call_backend_new_frame<ImGui_ImplOpenGL3_NewFrame>,
         renderer_framebuffer_size_changed,
         renderer_set_framebuffer_size,
         renderer_set_clear_color,

src/imiv/imiv_renderer_vulkan.cpp

@@ -285,14 +285,6 @@ namespace {
         return false;
     }
 
-    void vulkan_imgui_shutdown() { ImGui_ImplVulkan_Shutdown(); }
-
-    void vulkan_imgui_new_frame(RendererState& renderer_state)
-    {
-        (void)renderer_state;
-        ImGui_ImplVulkan_NewFrame();
-    }
-
     bool vulkan_needs_main_window_resize(RendererState& renderer_state,
                                          int width, int height)
     {
@@ -351,21 +343,9 @@ namespace {
             frame_present(*vk_state);
     }
 
-    bool vulkan_screen_capture(ImGuiID viewport_id, int x, int y, int w, int h,
-                               unsigned int* pixels, void* user_data)
-    {
-        return imiv_vulkan_screen_capture(viewport_id, x, y, w, h, pixels,
-                                          user_data);
-    }
-
-    bool vulkan_probe_runtime_support(std::string& error_message)
-    {
-        return platform_glfw_supports_vulkan(error_message);
-    }
-
     const RendererBackendVTable k_vulkan_vtable = {
         BackendKind::Vulkan,
-        vulkan_probe_runtime_support,
+        platform_glfw_supports_vulkan,
         vulkan_get_viewer_texture_refs,
         vulkan_texture_is_loading,
         vulkan_create_texture,
@@ -381,16 +361,16 @@ namespace {
         vulkan_cleanup,
         vulkan_wait_idle,
         vulkan_imgui_init,
-        vulkan_imgui_shutdown,
-        vulkan_imgui_new_frame,
+        ImGui_ImplVulkan_Shutdown,
+        renderer_call_backend_new_frame<ImGui_ImplVulkan_NewFrame>,
         vulkan_needs_main_window_resize,
         vulkan_resize_main_window,
         vulkan_set_main_clear_color,
         renderer_noop_platform_windows,
         renderer_noop_platform_windows,
         vulkan_frame_render,
         vulkan_frame_present,
-        vulkan_screen_capture,
+        imiv_vulkan_screen_capture,
     };
 
 }  // namespace