From b873ecbc96ade9a6e11da5e2e6d7898965dd8236 Mon Sep 17 00:00:00 2001
From: Akash Mozumdar <akashmozumdar@gmail.com>
Date: Sun, 27 Jan 2019 03:04:16 -0500
Subject: [PATCH] add d3dx hooks

---
 vnrhook/engine/match.cc          |  5 ++++
 vnrhook/engine/native/pchooks.cc | 46 ++++++++++++++++++++++++++++++++
 vnrhook/engine/native/pchooks.h  |  1 +
 3 files changed, 52 insertions(+)

diff --git a/vnrhook/engine/match.cc b/vnrhook/engine/match.cc
index 3b154a6..ca4e9f0 100644
--- a/vnrhook/engine/match.cc
+++ b/vnrhook/engine/match.cc
@@ -84,6 +84,11 @@ bool DeterminePCEngine()
   //  return true;
   //}
 
+  for (std::wstring DXVersion : { L"d3dx9", L"d3dx10" })
+	  if (HMODULE module = GetModuleHandleW(DXVersion.c_str())) PcHooks::hookD3DXFunctions(module);
+	  else for (int i = 0; i < 50; ++i)
+		  if (HMODULE module = GetModuleHandleW((DXVersion + L"_" + std::to_wstring(i)).c_str())) PcHooks::hookD3DXFunctions(module);
+
   if (GetProcAddress((HMODULE)processStartAddress, "?Write@String@v8@@QBEHPAGHHH@Z")) 
 	  InsertV8Hook((HMODULE)processStartAddress);
   if (HMODULE module = GetModuleHandleW(L"node.dll"))
diff --git a/vnrhook/engine/native/pchooks.cc b/vnrhook/engine/native/pchooks.cc
index e25d9d2..9665ca4 100644
--- a/vnrhook/engine/native/pchooks.cc
+++ b/vnrhook/engine/native/pchooks.cc
@@ -153,6 +153,52 @@ void PcHooks::hookGDIPlusFunctions()
   NEW_MODULE_HOOK(hModule, GdipMeasureDriverString,     s_arg1, 0,s_arg3,0, USING_UNICODE|USING_STRING, s_arg2 / arg_sz)
 }
 
+
+bool PcHooks::hookD3DXFunctions(HMODULE d3dxModule)
+{
+	ConsoleOutput("Textractor: inserting Direct3D hooks (EXPERIMENTAL)");
+	uintptr_t createFont = (uintptr_t)GetProcAddress(d3dxModule, "D3DXCreateFontIndirectA");
+	if (!createFont) createFont = (uintptr_t)GetProcAddress(d3dxModule, "D3DX10CreateFontIndirectA");
+	if (!createFont)
+	{
+		ConsoleOutput("Textractor: D3DX failed: couldn't find entry function");
+		return false;
+	}
+
+	struct D3DXFont
+	{
+		uintptr_t(*vtable)[20];
+		DWORD data[2000];
+	} font;
+	for (int i = 0, calls = 0; i < 100; ++i)
+	{
+		if (*(BYTE*)(createFont + i) == 0xe8) ++calls;
+		if (calls == 2)
+		{
+			union
+			{
+				void(D3DXFont::*ctor)();
+				uintptr_t addr;
+			} fuckTheTypeSystem;
+			fuckTheTypeSystem.addr = *(uintptr_t*)(createFont + i + 1) + createFont + i + 5;
+			(font.*(fuckTheTypeSystem.ctor))();
+
+			HookParam hp = {};
+			hp.address = (*font.vtable)[14];
+			hp.offset = s_arg3;
+			hp.length_offset = s_arg4 / arg_sz;
+			hp.type = USING_STRING;
+			NewHook(hp, "ID3DXFont::DrawTextA");
+			hp.address = (*font.vtable)[15];
+			hp.type = USING_STRING | USING_UNICODE;
+			NewHook(hp, "ID3DXFont::DrawTextW");
+			return true;
+		}
+	}
+	ConsoleOutput("Textractor: D3DX failed: couldn't find vtable");
+	return false;
+}
+
 // jichi 10/2/2013
 // Note: All functions does not have NO_CONTEXT attribute and will be filtered.
 void PcHooks::hookOtherPcFunctions()
diff --git a/vnrhook/engine/native/pchooks.h b/vnrhook/engine/native/pchooks.h
index 60eac25..2510a7b 100644
--- a/vnrhook/engine/native/pchooks.h
+++ b/vnrhook/engine/native/pchooks.h
@@ -7,6 +7,7 @@ namespace PcHooks {
 
 void hookGDIFunctions();
 void hookGDIPlusFunctions();
+void hookD3DXFunctions(HMODULE d3dxModule);
 void hookOtherPcFunctions();
 
 } // namespace PcHooks