feat: add sar_dpi_scale

Author: mlugg

src/Modules/Engine.cpp

@@ -5,6 +5,7 @@
 #include "EngineDemoPlayer.hpp"
 #include "EngineDemoRecorder.hpp"
 #include "Event.hpp"
+#include "InputSystem.hpp"
 #include "Features/Camera.hpp"
 #include "Features/Cvars.hpp"
 #include "Features/Demo/DemoParser.hpp"
@@ -57,6 +58,9 @@ Variable sar_cm_rightwarp("sar_cm_rightwarp", "0", "Fix CM wrongwarp.\n");
 REDECL(Engine::Disconnect);
 REDECL(Engine::SetSignonState);
 REDECL(Engine::ChangeLevel);
+#ifndef _WIN32
+REDECL(Engine::GetMouseDelta);
+#endif
 REDECL(Engine::Frame);
 REDECL(Engine::PurgeUnusedModels);
 REDECL(Engine::OnGameOverlayActivated);
@@ -305,6 +309,14 @@ DETOUR(Engine::ChangeLevel, const char *s1, const char *s2) {
 	return Engine::ChangeLevel(thisptr, s1, s2);
 }
 
+#ifndef _WIN32
+// CVEngineClient::GetMouseDelta
+DETOUR_T(void, Engine::GetMouseDelta, int &x, int &y, bool ignore_next) {
+	Engine::GetMouseDelta(thisptr, x, y, ignore_next);
+	inputSystem->DPIScaleDeltas(x, y);
+}
+#endif
+
 void Engine::GetTicks(int &host, int &server, int &client) {
 	auto &et = this->engineTool;
 	using _Fn = int(__rescall *)(void *thisptr);
@@ -773,7 +785,7 @@ DETOUR(Engine::DestroyDebugMesh, int vertCount, Vector *verts) {
 }
 
 bool Engine::Init() {
-	this->engineClient = Interface::Create(this->Name(), "VEngineClient015", false);
+	this->engineClient = Interface::Create(this->Name(), "VEngineClient015");
 	this->s_ServerPlugin = Interface::Create(this->Name(), "ISERVERPLUGINHELPERS001", false);
 
 	if (this->engineClient) {
@@ -792,6 +804,10 @@ bool Engine::Init() {
 		this->GetLevelNameShort = this->engineClient->Original<_GetLevelNameShort>(Offsets::GetLevelNameShort);
 		this->GetLightForPoint = this->engineClient->Original<_GetLightForPoint>(Offsets::GetLightForPoint);
 
+#ifndef _WIN32
+		this->engineClient->Hook(Engine::GetMouseDelta_Hook, Engine::GetMouseDelta, Offsets::GetMouseDelta);
+#endif
+
 		Memory::Read<_Cbuf_AddText>((uintptr_t)this->ClientCmd + Offsets::Cbuf_AddText, &this->Cbuf_AddText);
 #ifndef _WIN32
 		if (sar.game->Is(SourceGame_EIPRelPIC)) {

src/Modules/Engine.hpp

@@ -161,6 +161,11 @@ class Engine : public Module {
 	// CVEngineServer::ChangeLevel
 	DECL_DETOUR(ChangeLevel, const char *s1, const char *s2);
 
+#ifndef _WIN32
+	// CVEngineClient::GetMouseDelta
+	DECL_DETOUR_T(void, GetMouseDelta, int &x, int &y, bool ignore_next);
+#endif
+
 	// CEngine::Frame
 	DECL_DETOUR(Frame);
 

src/Modules/InputSystem.cpp

@@ -9,6 +9,9 @@
 #include "Utils.hpp"
 
 REDECL(InputSystem::SleepUntilInput);
+#ifdef _WIN32
+REDECL(InputSystem::GetRawMouseAccumulators);
+#endif
 
 int InputSystem::GetButton(const char *pString) {
 	return this->StringToButtonCode(this->g_InputSystem->ThisPtr(), pString);
@@ -26,6 +29,24 @@ void InputSystem::SetCursorPos(int x, int y) {
 	return this->SetCursorPosition(this->g_InputSystem->ThisPtr(), x, y);
 }
 
+Variable sar_dpi_scale("sar_dpi_scale", "1", 1, "Fraction to scale mouse DPI down by.\n");
+void InputSystem::DPIScaleDeltas(int &x, int &y) {
+	static int saved_x = 0;
+	static int saved_y = 0;
+
+	int scale = sar_dpi_scale.GetInt();
+	if (scale < 1) scale = 1;
+
+	saved_x += x;
+	saved_y += y;
+
+	x = saved_x / scale;
+	y = saved_y / scale;
+
+	saved_x %= scale;
+	saved_y %= scale;
+}
+
 // CInputSystem::SleepUntilInput
 DETOUR(InputSystem::SleepUntilInput, int nMaxSleepTimeMS) {
 	if (sar_disable_no_focus_sleep.GetBool()) {
@@ -35,12 +56,23 @@ DETOUR(InputSystem::SleepUntilInput, int nMaxSleepTimeMS) {
 	return InputSystem::SleepUntilInput(thisptr, nMaxSleepTimeMS);
 }
 
+#ifdef _WIN32
+// CInputSystem::GetRawMouseAccumulators
+DETOUR_T(void, InputSystem::GetRawMouseAccumulators, int &x, int &y) {
+	InputSystem::GetRawMouseAccumulators(thisptr, x, y);
+	inputSystem->DPIScaleDeltas(x, y);
+}
+#endif
+
 bool InputSystem::Init() {
 	this->g_InputSystem = Interface::Create(this->Name(), "InputSystemVersion001");
 	if (this->g_InputSystem) {
 		this->StringToButtonCode = this->g_InputSystem->Original<_StringToButtonCode>(Offsets::StringToButtonCode);
 
 		this->g_InputSystem->Hook(InputSystem::SleepUntilInput_Hook, InputSystem::SleepUntilInput, Offsets::SleepUntilInput);
+#ifdef _WIN32
+		this->g_InputSystem->Hook(InputSystem::GetRawMouseAccumulators_Hook, InputSystem::GetRawMouseAccumulators, Offsets::GetRawMouseAccumulators);
+#endif
 		this->IsButtonDown = this->g_InputSystem->Original<_IsButtonDown>(Offsets::IsButtonDown);
 		this->GetCursorPosition = this->g_InputSystem->Original<_GetCursorPosition>(Offsets::GetCursorPosition);
 		this->SetCursorPosition = this->g_InputSystem->Original<_SetCursorPosition>(Offsets::SetCursorPosition);

src/Modules/InputSystem.hpp

@@ -235,9 +235,16 @@ class InputSystem : public Module {
 	void GetCursorPos(int &x, int &y);
 	void SetCursorPos(int x, int y);
 
+	void DPIScaleDeltas(int &x, int &y);
+
 	// CInputSystem::SleepUntilInput
 	DECL_DETOUR(SleepUntilInput, int nMaxSleepTimeMS);
 
+#ifdef _WIN32
+	// CInputSystem::GetRawMouseAccumulators
+	DECL_DETOUR_T(void, GetRawMouseAccumulators, int &x, int &y);
+#endif
+
 	bool Init() override;
 	void Shutdown() override;
 	const char *Name() override { return MODULE("inputsystem"); }

src/OffsetsData.hpp

@@ -24,6 +24,7 @@ OFFSET_DEFAULT(GetSaveDirName, 124, 124)
 OFFSET_DEFAULT(ExecuteClientCmd, 104, 104)
 OFFSET_DEFAULT(GetActiveSplitScreenPlayerSlot, 127, 127)
 OFFSET_DEFAULT(GetSteamAPIContext, 177, 178)
+OFFSET_DEFAULT(GetMouseDelta, -1, 161) // This method only exists on Linux
 OFFSET_DEFAULT(IsPaused, 86, 86)
 OFFSET_DEFAULT(DebugDrawPhysCollide, 75, 75)
 OFFSET_DEFAULT(Con_IsVisible, 11, 11)
@@ -75,6 +76,7 @@ OFFSET_DEFAULT(CreateNewTextureID, 41, 41)
 // CInputSystem
 OFFSET_DEFAULT(StringToButtonCode, 31, 31)
 OFFSET_DEFAULT(SleepUntilInput, 33, 33)
+OFFSET_DEFAULT(GetRawMouseAccumulators, 50, 52)
 OFFSET_DEFAULT(IsButtonDown, 14, 14)
 OFFSET_DEFAULT(GetCursorPosition, 45, 45)
 OFFSET_DEFAULT(SetCursorPosition, 38, 38)