From 9012afc534a4e8735fc7ea799c9442eb4addb250 Mon Sep 17 00:00:00 2001
From: Connor McLaughlin <stenzek@gmail.com>
Date: Sat, 20 Aug 2022 22:08:15 +1000
Subject: [PATCH] Qt: Forward text input to ImGui

---
 pcsx2-qt/DisplayWidget.cpp      | 11 +++++++++++
 pcsx2/Frontend/ImGuiManager.cpp | 21 +++++++++++++++++++++
 pcsx2/Frontend/ImGuiManager.h   |  6 ++++++
 3 files changed, 38 insertions(+)

diff --git a/pcsx2-qt/DisplayWidget.cpp b/pcsx2-qt/DisplayWidget.cpp
index 3b2ae0739f..cfd820eaff 100644
--- a/pcsx2-qt/DisplayWidget.cpp
+++ b/pcsx2-qt/DisplayWidget.cpp
@@ -17,6 +17,8 @@
 
 #include "common/Assertions.h"
 
+#include "pcsx2/Frontend/ImGuiManager.h"
+
 #include "DisplayWidget.h"
 #include "EmuThread.h"
 #include "MainWindow.h"
@@ -224,6 +226,15 @@ bool DisplayWidget::event(QEvent* event)
 		case QEvent::KeyRelease:
 		{
 			const QKeyEvent* key_event = static_cast<QKeyEvent*>(event);
+			
+			// Forward text input to imgui.
+			if (ImGuiManager::WantsTextInput() && key_event->type() == QEvent::KeyPress)
+			{
+				const QString text(key_event->text());
+				if (!text.isEmpty())
+					ImGuiManager::AddTextInput(text.toStdString());
+			}
+
 			if (key_event->isAutoRepeat())
 				return true;
 
diff --git a/pcsx2/Frontend/ImGuiManager.cpp b/pcsx2/Frontend/ImGuiManager.cpp
index 1b7fe09599..d0aa12b345 100644
--- a/pcsx2/Frontend/ImGuiManager.cpp
+++ b/pcsx2/Frontend/ImGuiManager.cpp
@@ -778,6 +778,27 @@ ImFont* ImGuiManager::GetFixedFont()
 
 #ifdef PCSX2_CORE
 
+bool ImGuiManager::WantsTextInput()
+{
+	return s_imgui_wants_keyboard.load(std::memory_order_acquire);
+}
+
+void ImGuiManager::AddTextInput(std::string str)
+{
+	if (!s_imgui_wants_keyboard.load(std::memory_order_acquire))
+		return;
+
+	// Has to go through the CPU -> GS thread :(
+	Host::RunOnCPUThread([str = std::move(str)]() {
+		GetMTGS().RunOnGSThread([str = std::move(str)]() {
+			if (!ImGui::GetCurrentContext())
+				return;
+
+			ImGui::GetIO().AddInputCharactersUTF8(str.c_str());
+		});
+	});
+}
+
 void ImGuiManager::UpdateMousePosition(float x, float y)
 {
 	if (!ImGui::GetCurrentContext())
diff --git a/pcsx2/Frontend/ImGuiManager.h b/pcsx2/Frontend/ImGuiManager.h
index 10d931cf8c..54473083e8 100644
--- a/pcsx2/Frontend/ImGuiManager.h
+++ b/pcsx2/Frontend/ImGuiManager.h
@@ -50,6 +50,12 @@ namespace ImGuiManager
 	ImFont* GetFixedFont();
 
 #ifdef PCSX2_CORE
+	/// Returns true if imgui wants to intercept text input.
+	bool WantsTextInput();
+
+	/// Called on the UI or CPU thread in response to a key press. String is UTF-8.
+	void AddTextInput(std::string str);
+
 	/// Called on the UI or CPU thread in response to mouse movement.
 	void UpdateMousePosition(float x, float y);