feat: Input Method Editor

src/gta_pointers.hpp

@@ -22,6 +22,7 @@ class CGameScriptHandlerMgr;
 class CPedFactory;
 class GtaThread;
 class GameDataHash;
+class InputMethodEditor;
 
 namespace rage
 {
@@ -411,6 +412,9 @@ namespace big
 
 		functions::is_ped_enemies_with m_is_ped_enemies_with;
 		functions::can_do_damage_to_ped m_can_do_damage_to_ped;
+
+		bool* m_allow_keyboard_layout_change;
+		InputMethodEditor* m_ime;
 	};
 #pragma pack(pop)
 	static_assert(sizeof(gta_pointers) % 8 == 0, "Pointers are not properly aligned");

src/gui/components/input_text.cpp

@@ -1,6 +1,7 @@
 #include "fiber_pool.hpp"
 #include "gui/components/components.hpp"
 #include "misc/cpp/imgui_stdlib.h"
+#include "util/input_method_editor.hpp"
 
 namespace big
 {
@@ -15,8 +16,19 @@ namespace big
 		}
 
 		if (ImGui::IsItemActive())
+		{
 			g.self.hud.typing = TYPING_TICKS;
 
+			draw_input_method_editor();
+
+			*g_pointers->m_gta.m_allow_keyboard_layout_change = true;
+		}
+
+		if (ImGui::IsItemDeactivated())
+		{
+			*g_pointers->m_gta.m_allow_keyboard_layout_change = false;
+		}
+
 		return retval;
 	}
 
@@ -31,8 +43,19 @@ namespace big
 		}
 
 		if (ImGui::IsItemActive())
+		{
 			g.self.hud.typing = TYPING_TICKS;
 
+			draw_input_method_editor();
+
+			*g_pointers->m_gta.m_allow_keyboard_layout_change = true;
+		}
+
+		if (ImGui::IsItemDeactivated())
+		{
+			*g_pointers->m_gta.m_allow_keyboard_layout_change = false;
+		}
+
 		return retval;
 	}
 }

src/gui/components/input_text_with_hint.cpp

@@ -1,6 +1,7 @@
 #include "fiber_pool.hpp"
 #include "gui/components/components.hpp"
 #include "misc/cpp/imgui_stdlib.h"
+#include "util/input_method_editor.hpp"
 
 namespace big
 {
@@ -11,7 +12,19 @@ namespace big
 			g_fiber_pool->queue_job(std::move(cb));
 
 		if (ImGui::IsItemActive())
+		{
 			g.self.hud.typing = TYPING_TICKS;
+
+			draw_input_method_editor();
+
+			*g_pointers->m_gta.m_allow_keyboard_layout_change = true;
+		}
+
+		if (ImGui::IsItemDeactivated())
+		{
+			*g_pointers->m_gta.m_allow_keyboard_layout_change = false;
+		}
+
 		return returned;
 	}
 
@@ -22,7 +35,19 @@ namespace big
 			g_fiber_pool->queue_job(std::move(cb));
 
 		if (ImGui::IsItemActive())
+		{
 			g.self.hud.typing = TYPING_TICKS;
+
+			draw_input_method_editor();
+
+			*g_pointers->m_gta.m_allow_keyboard_layout_change = true;
+		}
+
+		if (ImGui::IsItemDeactivated())
+		{
+			*g_pointers->m_gta.m_allow_keyboard_layout_change = false;
+		}
+
 		return returned;
 	}
 }

src/hooks/gui/wndproc.cpp

@@ -1,5 +1,6 @@
 #include "hooking/hooking.hpp"
 #include "renderer/renderer.hpp"
+#include "util/input_method_editor.hpp"
 
 namespace big
 {
@@ -8,6 +9,11 @@ namespace big
 		if (g_running) [[likely]]
 		{
 			g_renderer.wndproc(hwnd, msg, wparam, lparam);
+
+			if (msg == WM_IME_COMPOSITION && lparam & GCS_RESULTSTR) [[unlikely]]
+			{
+				handle_ime_result();
+			}
 		}
 
 		return CallWindowProcW(g_hooking->m_og_wndproc, hwnd, msg, wparam, lparam);

src/pointers.cpp

@@ -1958,6 +1958,16 @@ namespace big
             {
                 g_pointers->m_gta.m_can_do_damage_to_ped = ptr.add(1).rip().as<functions::can_do_damage_to_ped>();
             }
+        },
+        // Input Method Editor
+        {
+            "IME",
+            "75 25 89 44 24 28",
+            [](memory::handle ptr)
+            {
+                g_pointers->m_gta.m_allow_keyboard_layout_change = ptr.sub(4).rip().as<bool*>();
+                g_pointers->m_gta.m_ime = ptr.add(44).rip().sub(0x278 + 0x8).as<InputMethodEditor*>();
+            }
         }
         >(); // don't leave a trailing comma at the end
 

src/util/input_method_editor.hpp

@@ -0,0 +1,125 @@
+#pragma once
+#include "common.hpp"
+#include "pointers.hpp"
+
+#include <imgui_internal.h>
+
+#pragma pack(push, 8)
+class InputMethodEditor
+{
+public:
+	uint32_t m_count; //0x0000
+	uint32_t m_selected_index; //0x0004
+	wchar_t m_composition_string[31]; //0x0008
+	wchar_t m_candidate_list[9][31]; //0x0046
+	bool m_active; //0x0274
+	char pad_0275[3]; //0x0275
+}; //Size: 0x0278
+static_assert(sizeof(InputMethodEditor) == 0x278);
+#pragma pack(pop)
+
+namespace
+{
+	// https://github.com/ocornut/imgui/blob/864a2bf6b824f9c1329d8493386208d4b0fd311c/imgui_widgets.cpp#L3948
+	static bool STB_TEXTEDIT_INSERTCHARS(ImGuiInputTextState* obj, int pos, const ImWchar* new_text, int new_text_len)
+	{
+		const bool is_resizable = (obj->Flags & ImGuiInputTextFlags_CallbackResize) != 0;
+		const int text_len      = obj->CurLenW;
+		IM_ASSERT(pos <= text_len);
+
+		const int new_text_len_utf8 = ImTextCountUtf8BytesFromStr(new_text, new_text + new_text_len);
+		if (!is_resizable && (new_text_len_utf8 + obj->CurLenA + 1 > obj->BufCapacityA))
+			return false;
+
+		// Grow internal buffer if needed
+		if (new_text_len + text_len + 1 > obj->TextW.Size)
+		{
+			if (!is_resizable)
+				return false;
+			IM_ASSERT(text_len < obj->TextW.Size);
+			obj->TextW.resize(text_len + ImClamp(new_text_len * 4, 32, ImMax(256, new_text_len)) + 1);
+		}
+
+		ImWchar* text = obj->TextW.Data;
+		if (pos != text_len)
+			memmove(text + pos + new_text_len, text + pos, (size_t)(text_len - pos) * sizeof(ImWchar));
+		memcpy(text + pos, new_text, (size_t)new_text_len * sizeof(ImWchar));
+
+		obj->Edited = true;
+		obj->CurLenW += new_text_len;
+		obj->CurLenA += new_text_len_utf8;
+		obj->TextW[obj->CurLenW] = '\0';
+
+		return true;
+	}
+}
+
+namespace big
+{
+	inline void handle_ime_result()
+	{
+		auto state = ImGui::GetInputTextState(ImGui::GetActiveID());
+
+		if (!state)
+			return;
+
+		auto context = ImmGetContext(g_pointers->m_hwnd);
+
+		wchar_t buf[31]{};
+		int len = ImmGetCompositionStringW(context, GCS_RESULTSTR, buf, sizeof(buf) - 1) / 2;
+
+		if (STB_TEXTEDIT_INSERTCHARS(state, state->Stb.cursor, (ImWchar*)buf, len))
+		{
+			state->Stb.cursor += len;
+			state->Stb.has_preferred_x = 0;
+
+			state->CursorFollow = true;
+		}
+
+		ImmReleaseContext(g_pointers->m_hwnd, context);
+	}
+
+	inline void draw_input_method_editor()
+	{
+		if (!g_pointers->m_gta.m_ime->m_active)
+			return;
+
+		std::string text;
+
+		char buf[62];
+		ImTextStrToUtf8(buf, sizeof(buf), (ImWchar*)g_pointers->m_gta.m_ime->m_composition_string, nullptr);
+
+		text += buf;
+
+		for (uint32_t i = 0; i < g_pointers->m_gta.m_ime->m_count; ++i)
+		{
+			ImTextStrToUtf8(buf, sizeof(buf), (ImWchar*)g_pointers->m_gta.m_ime->m_candidate_list[i], nullptr);
+
+			text += '\n';
+			text += (i == g_pointers->m_gta.m_ime->m_selected_index ? '>' : ' ');
+			text += std::to_string(i + 1);
+			text += '\t';
+			text += buf;
+		}
+
+		constexpr float pd = 7.5f; // padding
+		constexpr float lt = 1.f;  // line thickness
+
+		ImVec2 ts = ImGui::CalcTextSize(text.c_str());
+
+		ImVec2 bl = ImGui::GetItemRectMin();      // bottom-left
+		ImVec2 br = {bl.x + ts.x + 2 * pd, bl.y}; // bottom-right
+		ImVec2 tl = {bl.x, bl.y - ts.y - 2 * pd}; // top-left
+		ImVec2 tr = {br.x, tl.y};                 // top-right
+
+		auto dl = ImGui::GetForegroundDrawList();
+
+		dl->AddRectFilled(tl, br, g.window.background_color | IM_COL32_A_MASK);
+		dl->AddText({tl.x + pd, tl.y + pd}, g.window.text_color, text.c_str());
+
+		dl->AddLine(tl, tr, IM_COL32_BLACK);                               // top
+		dl->AddLine({bl.x, bl.y - lt}, {br.x, br.y - lt}, IM_COL32_BLACK); // bottom
+		dl->AddLine(tl, bl, IM_COL32_BLACK);                               // left
+		dl->AddLine({tr.x - lt, tr.y}, {br.x - lt, br.y}, IM_COL32_BLACK); // right
+	}
+}