From 58c557188422169b0ac170a4e1443ee3b4898681 Mon Sep 17 00:00:00 2001
From: fed <58637860+fedddddd@users.noreply.github.com>
Date: Fri, 15 Dec 2023 19:04:30 +0100
Subject: [PATCH] Patch r_preloadShaders crash

---
 src/client/component/renderer.cpp | 19 ++++++++++
 src/common/utils/hook.cpp         |  7 ++++
 src/common/utils/hook.hpp         | 58 +++++++++++++++++++++++++++++++
 src/common/utils/memory.cpp       | 27 ++++++++++++++
 src/common/utils/memory.hpp       |  2 ++
 5 files changed, 113 insertions(+)

diff --git a/src/client/component/renderer.cpp b/src/client/component/renderer.cpp
index f2758790..3c0e8b0e 100644
--- a/src/client/component/renderer.cpp
+++ b/src/client/component/renderer.cpp
@@ -132,6 +132,21 @@ namespace renderer
 				a.jmp(0x1C4136_b);
 			});
 		}
+
+		void r_preload_shaders_stub(utils::hook::assembler& a)
+		{
+			const auto is_zero = a.newLabel();
+
+			a.mov(rax, qword_ptr(SELECT_VALUE(0x123FFF30_b, 0x111DC230_b)));
+			a.test(rax, rax);
+			a.jz(is_zero);
+
+			a.mov(rcx, qword_ptr(rax, 0x540C68));
+			a.jmp(SELECT_VALUE(0x5CF1FF_b, 0x6E76FF_b));
+
+			a.bind(is_zero);
+			a.jmp(SELECT_VALUE(0x5CF20A_b, 0x6E7722_b));
+		}
 	}
 	
 	class component final : public component_interface
@@ -166,6 +181,10 @@ namespace renderer
 				r_use_custom_red_dot_brightness = dvars::register_bool("r_useCustomRedDotBrightness",
 					true, game::DVAR_FLAG_SAVED, "Use custom red-dot brightness values");
 			}
+
+			// patch r_preloadShaders crash at init
+			utils::hook::jump(SELECT_VALUE(0x5CF1F1_b, 0x6E76F1_b), utils::hook::assemble(r_preload_shaders_stub), true);
+			dvars::override::register_bool("r_preloadShaders", false, game::DVAR_FLAG_SAVED);
 		}
 	};
 }
diff --git a/src/common/utils/hook.cpp b/src/common/utils/hook.cpp
index 3c6c9df3..5e6bc9bb 100644
--- a/src/common/utils/hook.cpp
+++ b/src/common/utils/hook.cpp
@@ -3,6 +3,13 @@
 
 #include <MinHook.h>
 
+Mem seg_ptr(const SReg& segment, const uint64_t off)
+{
+	auto mem = ptr_abs(off);
+	mem.setSegment(segment);
+	return mem;
+}
+
 namespace utils::hook
 {
 	namespace
diff --git a/src/common/utils/hook.hpp b/src/common/utils/hook.hpp
index e7899d73..911b183d 100644
--- a/src/common/utils/hook.hpp
+++ b/src/common/utils/hook.hpp
@@ -1,11 +1,14 @@
 #pragma once
 #include "signature.hpp"
+#include "memory.hpp"
 
 #include <asmjit/core/jitruntime.h>
 #include <asmjit/x86/x86assembler.h>
 
 using namespace asmjit::x86;
 
+Mem seg_ptr(const SReg& segment, const uint64_t off);
+
 namespace utils::hook
 {
 	namespace detail
@@ -204,4 +207,59 @@ namespace utils::hook
 	}
 
 	uint8_t* allocate_somewhere_near(const void* base_address, const size_t size);
+
+	template <size_t Base>
+	void* allocate_far_jump()
+	{
+		constexpr auto alloc_size = 0x1000;
+		constexpr auto far_jmp_size = 0xC;
+
+		const auto alloc_jump_table = []
+		{
+			return reinterpret_cast<char*>(
+				memory::allocate_near(Base, alloc_size, PAGE_EXECUTE_READWRITE));
+		};
+
+		static auto jump_table = alloc_jump_table();
+		static auto current_pos = jump_table;
+
+		if (current_pos + far_jmp_size >= jump_table + alloc_size)
+		{
+			jump_table = alloc_jump_table();
+			current_pos = jump_table;
+		}
+
+		const auto ptr = current_pos;
+		current_pos += far_jmp_size;
+		return ptr;
+	}
+
+	template <size_t Base, typename T>
+	void* create_far_jump(const T dest)
+	{
+		static std::unordered_map<void*, void*> allocated_jumps;
+		if (const auto iter = allocated_jumps.find(reinterpret_cast<void*>(dest)); iter != allocated_jumps.end())
+		{
+			return iter->second;
+		}
+
+		const auto pos = allocate_far_jump<Base>();
+		jump(pos, dest, true);
+		allocated_jumps.insert(std::make_pair(dest, pos));
+		return pos;
+	}
+
+	template <size_t Base, typename T>
+	void far_jump(const size_t address, const T dest)
+	{
+		const auto pos = create_far_jump<Base>(dest);
+		jump(address, pos, false);
+	}
+
+	template <size_t Base, typename T>
+	void far_call(const size_t address, const T dest)
+	{
+		const auto pos = create_far_jump<Base>(dest);
+		call(address, pos);
+	}
 }
diff --git a/src/common/utils/memory.cpp b/src/common/utils/memory.cpp
index bc93d644..9f079814 100644
--- a/src/common/utils/memory.cpp
+++ b/src/common/utils/memory.cpp
@@ -166,6 +166,33 @@ namespace utils
 		return false;
 	}
 
+	void* memory::allocate_near(const size_t address, const size_t size, const std::uint32_t protect)
+	{
+		SYSTEM_INFO system_info{};
+		GetSystemInfo(&system_info);
+
+		const auto page_size = system_info.dwPageSize;
+		const auto aligned_size = size + (~size & (page_size - 1));
+		auto current_address = address;
+
+		while (true)
+		{
+			current_address -= page_size;
+
+			if (current_address <= reinterpret_cast<size_t>(system_info.lpMinimumApplicationAddress))
+			{
+				return nullptr;
+			}
+
+			const auto result = VirtualAlloc(reinterpret_cast<void*>(current_address), aligned_size, MEM_RESERVE | MEM_COMMIT, protect);
+			if (result != nullptr)
+			{
+				std::memset(result, 0, aligned_size);
+				return result;
+			}
+		}
+	}
+
 	memory::allocator* memory::get_allocator()
 	{
 		return &memory::mem_allocator_;
diff --git a/src/common/utils/memory.hpp b/src/common/utils/memory.hpp
index 01f9554f..9887e308 100644
--- a/src/common/utils/memory.hpp
+++ b/src/common/utils/memory.hpp
@@ -69,6 +69,8 @@ namespace utils
 		static bool is_bad_code_ptr(const void* ptr);
 		static bool is_rdata_ptr(void* ptr);
 
+		static void* allocate_near(const size_t address, const size_t size, const std::uint32_t protect);
+
 		static allocator* get_allocator();
 
 	private: