Remove the need to define the imgui function table in add-on projects

Author: crosire

REFERENCE.md

@@ -45,19 +45,15 @@ For more complex examples, see the [examples directory in this repository](../ex
 ## Overlays
 
 It is also supported to add an overlay, which can e.g. be used to display debug information or interact with the user in-application.
-Overlays are created with the use of [Dear ImGui](https://github.com/ocornut/imgui/). Including the `reshade.hpp` header after `imgui.h` will automatically overwrite all Dear ImGui functions to use the instance created and managed by ReShade. This means all you have to do is include these two headers, define the function table variable in one of your source code file and use Dear ImGui as usual (without actually having to build its source code files, only the header files are needed):
+Overlays are created with the use of [Dear ImGui](https://github.com/ocornut/imgui/). Including the `reshade.hpp` header after `imgui.h` will automatically overwrite all Dear ImGui functions to use the instance created and managed by ReShade. This means all you have to do is include these two headers and use Dear ImGui as usual (without having to build its source code files):
 
 ```cpp
 #include <imgui.h>
 #include <reshade.hpp>
 
-// Define this variable in exactly one of your source code files.
-// The function table is automatically populated in the call to 'reshade::register_addon()' and overwrites all Dear ImGui functions.
-imgui_function_table g_imgui_function_table = {};
-
 bool g_popup_window_visible = false;
 
-static void draw_debug_overlay(reshade::api::effect_runtime *runtime, void *imgui_context)
+static void draw_debug_overlay(reshade::api::effect_runtime *runtime)
 {
     ImGui::TextUnformatted("Some text");
 
@@ -72,7 +68,7 @@ static void draw_debug_overlay(reshade::api::effect_runtime *runtime, void *imgu
     }
 }
 
-static void draw_settings_overlay(reshade::api::effect_runtime *runtime, void *imgui_context)
+static void draw_settings_overlay(reshade::api::effect_runtime *runtime)
 {
     ImGui::Checkbox("Popup window is visible", &g_popup_window_visible);
 }

examples/api_trace/api_trace.cpp

@@ -11,8 +11,6 @@
 #include <unordered_map>
 #include <cassert>
 
-imgui_function_table g_imgui_function_table;
-
 namespace
 {
 	bool s_do_capture = false;
@@ -789,7 +787,7 @@ static void on_present(reshade::api::command_queue *, reshade::api::swapchain *)
 	s_do_capture = false;
 }
 
-static void draw_overlay(reshade::api::effect_runtime *, void *)
+static void draw_overlay(reshade::api::effect_runtime *)
 {
 	if (!s_do_capture)
 	{

examples/generic_depth/generic_depth.cpp

@@ -15,8 +15,6 @@ static std::mutex s_mutex;
 
 #ifdef BUILTIN_ADDON
 #include "ini_file.hpp"
-#else
-imgui_function_table g_imgui_function_table;
 #endif
 
 using namespace reshade::api;
@@ -692,7 +690,7 @@ static void on_finish_render_effects(effect_runtime *runtime, command_list *cmd_
 	}
 }
 
-static void draw_settings_overlay(effect_runtime *runtime, void *)
+static void draw_settings_overlay(effect_runtime *runtime)
 {
 	device *const device = runtime->get_device();
 	state_tracking_context &device_state = device->get_private_data<state_tracking_context>(state_tracking_context::GUID);

examples/texturemod_dump/texturemod_overlay.cpp

@@ -11,8 +11,6 @@
 #include <unordered_set>
 #include <malloc.h>
 
-imgui_function_table g_imgui_function_table;
-
 using namespace reshade::api;
 
 struct set_data
@@ -313,7 +311,7 @@ static void on_present(command_queue *queue, swapchain *runtime)
 // See implementation in 'texturemod_dump.cpp'
 extern bool dump_texture(command_queue *queue, resource tex, const resource_desc &desc);
 
-static void draw_overlay(effect_runtime *runtime, void *)
+static void draw_overlay(effect_runtime *runtime)
 {
 	assert(s_is_in_reshade_runtime);
 

include/reshade.hpp

@@ -11,45 +11,62 @@
 #include <Psapi.h>
 
 #define RESHADE_API_VERSION 1
-#define RESHADE_API_VERSION_IMGUI IMGUI_VERSION_NUM
 
 namespace reshade
 {
-	/// <summary>
-	/// Gets the handle to the ReShade module in the current process.
-	/// </summary>
-	inline HMODULE &get_reshade_module_handle()
+	namespace internal
 	{
-		static HMODULE handle = nullptr;
-		if (handle == nullptr)
+		/// <summary>
+		/// Gets the handle to the ReShade module in the current process.
+		/// </summary>
+		inline HMODULE &get_reshade_module_handle()
 		{
-			// Use the kernel32 variant of module enumeration functions so it can be safely called from 'DllMain'
-			HMODULE modules[1024]; DWORD num = 0;
-			if (K32EnumProcessModules(GetCurrentProcess(), modules, sizeof(modules), &num))
+			static HMODULE handle = nullptr;
+			if (handle == nullptr)
 			{
-				if (num > sizeof(modules))
-					num = sizeof(modules);
-
-				for (DWORD i = 0; i < num / sizeof(HMODULE); ++i)
+				// Use the kernel32 variant of module enumeration functions so it can be safely called from 'DllMain'
+				HMODULE modules[1024]; DWORD num = 0;
+				if (K32EnumProcessModules(GetCurrentProcess(), modules, sizeof(modules), &num))
 				{
-					if (GetProcAddress(modules[i], "ReShadeRegisterAddon") &&
-						GetProcAddress(modules[i], "ReShadeUnregisterAddon"))
+					if (num > sizeof(modules))
+						num = sizeof(modules);
+
+					for (DWORD i = 0; i < num / sizeof(HMODULE); ++i)
 					{
-						handle = modules[i];
-						break;
+						if (GetProcAddress(modules[i], "ReShadeRegisterAddon") &&
+							GetProcAddress(modules[i], "ReShadeUnregisterAddon"))
+						{
+							handle = modules[i];
+							break;
+						}
 					}
 				}
 			}
+			return handle;
 		}
-		return handle;
-	}
-	/// <summary>
-	/// Gets the handle to the current add-on module.
-	/// </summary>
-	inline HMODULE &get_current_module_handle()
-	{
-		static HMODULE handle = nullptr;
-		return handle;
+
+		/// <summary>
+		/// Gets the handle to the current add-on module.
+		/// </summary>
+		inline HMODULE &get_current_module_handle()
+		{
+			static HMODULE handle = nullptr;
+			return handle;
+		}
+
+#if defined(IMGUI_VERSION_NUM)
+		/// <summary>
+		/// Gets a pointer to the Dear ImGui function table.
+		/// </summary>
+		inline const imgui_function_table *get_imgui_function_table()
+		{
+			static const auto func = reinterpret_cast<const imgui_function_table *(*)(uint32_t)>(
+				GetProcAddress(get_reshade_module_handle(), "ReShadeGetImGuiFunctionTable"));
+			if (func != nullptr)
+				return func(IMGUI_VERSION_NUM);
+			return nullptr;
+		}
+#endif
 	}
 
 	/// <summary>
@@ -60,8 +77,8 @@ namespace reshade
 	inline void log_message(int level, const char *message)
 	{
 		static const auto func = reinterpret_cast<void(*)(HMODULE, int, const char *)>(
-			GetProcAddress(get_reshade_module_handle(), "ReShadeLogMessage"));
-		func(get_current_module_handle(), level, message);
+			GetProcAddress(internal::get_reshade_module_handle(), "ReShadeLogMessage"));
+		func(internal::get_current_module_handle(), level, message);
 	}
 
 	/// <summary>
@@ -71,9 +88,9 @@ namespace reshade
 	/// <param name="module">Handle of the current add-on module.</param>
 	inline bool register_addon(HMODULE module)
 	{
-		get_current_module_handle() = module;
+		internal::get_current_module_handle() = module;
 
-		const HMODULE reshade_module = get_reshade_module_handle();
+		const HMODULE reshade_module = internal::get_reshade_module_handle();
 		if (reshade_module == nullptr)
 			return false;
 
@@ -83,18 +100,10 @@ namespace reshade
 		if (!func(module, RESHADE_API_VERSION))
 			return false;
 
-#if defined(IMGUI_VERSION)
-		// Check that the ReShade module was built with Dear ImGui support
-		const auto imgui_func = reinterpret_cast<const imgui_function_table *(*)(uint32_t)>(
-			GetProcAddress(reshade_module, "ReShadeGetImGuiFunctionTable"));
-		if (imgui_func == nullptr)
-			return false;
-
-		// Check that the ReShade module supports the used Dear ImGui version
-		const imgui_function_table *const imgui_table = imgui_func(RESHADE_API_VERSION_IMGUI);
-		if (imgui_table == nullptr)
+#if defined(IMGUI_VERSION_NUM)
+		// Check that the ReShade module was built with Dear ImGui support and supports the used Dear ImGui version
+		if (!internal::get_imgui_function_table())
 			return false;
-		g_imgui_function_table = *imgui_table;
 #endif
 
 		return true;
@@ -105,7 +114,7 @@ namespace reshade
 	/// <param name="module">Handle of the current add-on module.</param>
 	inline void unregister_addon(HMODULE module)
 	{
-		const HMODULE reshade_module = get_reshade_module_handle();
+		const HMODULE reshade_module = internal::get_reshade_module_handle();
 		if (reshade_module == nullptr)
 			return;
 
@@ -123,7 +132,7 @@ namespace reshade
 	inline void register_event(typename reshade::addon_event_traits<ev>::decl callback)
 	{
 		static const auto func = reinterpret_cast<void(*)(reshade::addon_event, void *)>(
-			GetProcAddress(get_reshade_module_handle(), "ReShadeRegisterEvent"));
+			GetProcAddress(internal::get_reshade_module_handle(), "ReShadeRegisterEvent"));
 		func(ev, static_cast<void *>(callback));
 	}
 	/// <summary>
@@ -134,7 +143,7 @@ namespace reshade
 	inline void unregister_event(typename reshade::addon_event_traits<ev>::decl callback)
 	{
 		static const auto func = reinterpret_cast<void(*)(reshade::addon_event, void *)>(
-			GetProcAddress(get_reshade_module_handle(), "ReShadeUnregisterEvent"));
+			GetProcAddress(internal::get_reshade_module_handle(), "ReShadeUnregisterEvent"));
 		func(ev, static_cast<void *>(callback));
 	}
 
@@ -144,23 +153,21 @@ namespace reshade
 	/// </summary>
 	/// <param name="title">A null-terminated title string, or <see langword="nullptr"/> to register a settings overlay for this add-on.</param>
 	/// <param name="callback">Pointer to the callback function.</param>
-	inline void register_overlay(const char *title, void(*callback)(reshade::api::effect_runtime *runtime, void *imgui_context))
+	inline void register_overlay(const char *title, void(*callback)(reshade::api::effect_runtime *runtime))
 	{
-		static const auto func = reinterpret_cast<void(*)(const char *, void(*)(reshade::api::effect_runtime *, void *))>(
-			GetProcAddress(get_reshade_module_handle(), "ReShadeRegisterOverlay"));
-		if (func != nullptr) // May not exist if ReShade was built without "RESHADE_GUI" defined
-			func(title, callback);
+		static const auto func = reinterpret_cast<void(*)(const char *, void(*)(reshade::api::effect_runtime *))>(
+			GetProcAddress(internal::get_reshade_module_handle(), "ReShadeRegisterOverlay"));
+		func(title, callback);
 	}
 	/// <summary>
 	/// Unregisters an overlay that was previously registered via <see cref="register_overlay"/>.
 	/// </summary>
 	/// <param name="title">A null-terminated title string.</param>
 	/// <param name="callback">Pointer to the callback function.</param>
-	inline void unregister_overlay(const char *title, void(*callback)(reshade::api::effect_runtime *runtime, void *imgui_context))
+	inline void unregister_overlay(const char *title, void(*callback)(reshade::api::effect_runtime *runtime))
 	{
-		static const auto func = reinterpret_cast<void(*)(const char *, void(*)(reshade::api::effect_runtime *, void *))>(
-			GetProcAddress(get_reshade_module_handle(), "ReShadeUnregisterOverlay"));
-		if (func != nullptr)
-			func(title, callback);
+		static const auto func = reinterpret_cast<void(*)(const char *, void(*)(reshade::api::effect_runtime *))>(
+			GetProcAddress(internal::get_reshade_module_handle(), "ReShadeUnregisterOverlay"));
+		func(title, callback);
 	}
 }