Add IAT based hooking to allow hooking 64bit opengl32.dll

* Needs vigorous testing in as many situations as I can think of, not least
  32bit, 64bit, D3D11, D3D9, OpenGL, managed apps, different windows SDKs,
  delay loading dlls (not sure if these will work), statically linked libs,
  LoadLibrary + GetProcAddress
* Credit goes to jslutter for originally bringing it to my attention &
  suggesting it.
* References:
  http://msdn.microsoft.com/en-us/magazine/bb985992.aspx
  http://msdn.microsoft.com/en-us/magazine/cc301808.aspx
  http://www.codeproject.com/Articles/6265/Process-wide-API-spying-an-ultimate-hack

renderdoc/hooks/d3d11_hooks.cpp

@@ -39,12 +39,14 @@ public:
 	{
 		bool success = true;
 
+#if USE_MHOOK
 		// require dxgi.dll hooked as well for proper operation
 		if(GetModuleHandleA("dxgi.dll") == NULL)
 		{
 			RDCWARN("Failed to load dxgi.dll - not inserting D3D11 hooks.");
 			return false;
 		}
+#endif
 
 		// also require d3dcompiler_??.dll
 		if(GetD3DCompiler() == NULL)
@@ -58,6 +60,7 @@ public:
 
 		if(!success) return false;
 		
+#if USE_MHOOK
 		// FRAPS compatibility. Save out the first 16 bytes (arbitrary number) of the 'real' function code.
 		// this should be
 		// jmp D3D11CreateDeviceAndSwapChain_hook
@@ -68,6 +71,7 @@ public:
 		void *hooked_func_ptr = GetProcAddress(GetModuleHandleA("d3d11.dll"), "D3D11CreateDeviceAndSwapChain");
 		if(hooked_func_ptr == NULL) return false;
 		memcpy(CreateDeviceAndSwapChain_ident, hooked_func_ptr, 16);
+#endif
 
 		m_HasHooks = true;
 		m_EnabledHooks = true;
@@ -188,6 +192,7 @@ private:
 
 		PFN_D3D11_CREATE_DEVICE_AND_SWAP_CHAIN createFunc = (PFN_D3D11_CREATE_DEVICE_AND_SWAP_CHAIN)GetProcAddress(GetModuleHandleA("d3d11.dll"), "D3D11CreateDeviceAndSwapChain");
 		
+#if USE_MHOOK
 		if(createFunc)
 		{
 			byte ident[16];
@@ -211,6 +216,7 @@ private:
 			if(!memcmp(ident, CreateDeviceAndSwapChain_ident, 16) && m_HasHooks)
 				createFunc = CreateDeviceAndSwapChain();
 		}
+#endif
 
 		// shouldn't ever get here, we should either have it from procaddress or the trampoline, but let's be
 		// safe.

renderdoc/hooks/dxgi_hooks.cpp

@@ -40,8 +40,10 @@ public:
 	{
 		bool success = true;
 
+#if USE_MHOOK
 		// require d3d11.dll hooked as well for proper operation
 		if(GetModuleHandleA("d3d11.dll") == NULL) return false;
+#endif
 
 		success &= CreateDXGIFactory.Initialize("CreateDXGIFactory", DLL_NAME, CreateDXGIFactory_hook);
 		success &= CreateDXGIFactory1.Initialize("CreateDXGIFactory1", DLL_NAME, CreateDXGIFactory1_hook);

renderdoc/hooks/gl_win32_hooks.cpp

@@ -228,11 +228,13 @@ class OpenGLHook : LibraryHook
 			if(!m_EnabledHooks)
 				return false;
 			
+#if USE_MHOOK
 			if(GetModuleHandleA(DLL_NAME) == NULL)
 			{
 				RDCWARN("Failed to load %s - not inserting OpenGL hooks.", DLL_NAME);
 				return false;
 			}
+#endif
 
 			bool success = SetupHooks(GL);
 

renderdoc/hooks/hooks.h

@@ -35,36 +35,64 @@ using std::map;
 
 #if defined(WIN32)
 
-#include "3rdparty/mhook/mhook-lib/mhook.h"
+#define USE_MHOOK 0
+#define USE_IAT_HOOK 1
+
+#if USE_MHOOK
+	#include "3rdparty/mhook/mhook-lib/mhook.h"
+#elif USE_IAT_HOOK
+	#include "os/win32/win32_hook.h"
+#else
+	#error "No hook method enabled"
+#endif
 
 template<typename FuncType>
 class Hook
 {
 	public:
-		Hook() { trampoline = NULL; }
-		~Hook() { Mhook_Unhook(&trampoline); }
+		Hook()
+		{
+			orig_funcptr = NULL;
+		}
+		~Hook()
+		{
+#if USE_MHOOK
+			Mhook_Unhook(&orig_funcptr);
+#endif
+		}
 		
 		FuncType operator()()
 		{
-			return (FuncType)trampoline;
+			return (FuncType)orig_funcptr;
 		}
 
 		bool Initialize(const char *function, const char *module_name, void *destination_function_ptr)
 		{
-			trampoline = Process::GetFunctionAddress(module_name, function);
+			orig_funcptr = Process::GetFunctionAddress(module_name, function);
 
-			if(trampoline == NULL)
+#if USE_MHOOK
+			if(orig_funcptr == NULL)
 				return false;
-
-			return Mhook_SetHook(&trampoline, destination_function_ptr);
+			
+			return Mhook_SetHook(&orig_funcptr, destination_function_ptr);
+#elif USE_IAT_HOOK
+			return Win32_IAT_Hook(&orig_funcptr, module_name, function, destination_function_ptr);
+#else
+			#error "No hook method enabled"
+#endif
 		}
 
 	private:
-		void* trampoline;
+		void *orig_funcptr;
 };
 
-#define HOOKS_BEGIN() Mhook_SuspendOtherThreads()
-#define HOOKS_END() Mhook_ResumeOtherThreads()
+#if USE_MHOOK
+	#define HOOKS_BEGIN() Mhook_SuspendOtherThreads()
+	#define HOOKS_END() Mhook_ResumeOtherThreads()
+#else
+	#define HOOKS_BEGIN() Win32_IAT_BeginHooks()
+	#define HOOKS_END() Win32_IAT_EndHooks()
+#endif
 
 #elif defined(LINUX)