From 836fbafd4128887633d564d30c1bdeac7738e0bf Mon Sep 17 00:00:00 2001
From: Silent <zdanio95@gmail.com>
Date: Mon, 29 Apr 2024 20:43:25 +0200
Subject: [PATCH] Replaced Rosenberg Audio Fix that was placebo with PS2
 randomness for this audio

Might bring it closer to PS2 odds,
but the feature was never broken in the first place.

Fixes #11
---
 SilentPatchVC/SilentPatchVC.cpp | 46 +++++++++++++++++----------------
 1 file changed, 24 insertions(+), 22 deletions(-)

diff --git a/SilentPatchVC/SilentPatchVC.cpp b/SilentPatchVC/SilentPatchVC.cpp
index c071d4e..381b179 100644
--- a/SilentPatchVC/SilentPatchVC.cpp
+++ b/SilentPatchVC/SilentPatchVC.cpp
@@ -13,6 +13,7 @@
 #include <array>
 #include <memory>
 #include <Shlwapi.h>
+#include <time.h>
 
 #include "Utils/ModuleList.hpp"
 #include "Utils/Patterns.h"
@@ -57,8 +58,6 @@ DebugMenuAPI gDebugMenuAPI;
 
 static HMODULE		hDLLModule;
 
-static const void*		RosieAudioFix_JumpBack;
-
 static RsGlobalType*	RsGlobal;
 static const void*		SubtitlesShadowFix_JumpBack;
 
@@ -78,17 +77,6 @@ inline float GetHeightMult()
 	return ResolutionHeightMult;
 }
 
-
-void __declspec(naked) RosiesAudioFix()
-{
-	_asm
-	{
-		mov     byte ptr [ebx+0CCh], 0
-		mov     byte ptr [ebx+148h], 0
-		jmp		[RosieAudioFix_JumpBack]
-	}
-}
-
 static bool bGameInFocus = true;
 
 static LRESULT (CALLBACK **OldWndProc)(HWND, UINT, WPARAM, LPARAM);
@@ -296,6 +284,21 @@ void __declspec(naked) AutoPilotTimerFix_VC()
 	}
 }
 
+
+// PS2 implementation of rand()
+static uint64_t seed_rand_ps2 = time(nullptr);
+static int rand_ps2()
+{
+	seed_rand_ps2 = 0x5851F42D4C957F2D * seed_rand_ps2 + 1;
+	return ((seed_rand_ps2 >> 32) & 0x7FFFFFFF);
+}
+
+// PS2 rand, but matching PC's RAND_MAX
+static int rand15_ps2()
+{
+	return rand_ps2() & 0x7FFF;
+}
+
 namespace ZeroAmmoFix
 {
 
@@ -875,13 +878,10 @@ void Patch_VC_10(uint32_t width, uint32_t height)
 	using namespace Memory::DynBase;
 
 	RsGlobal = *(RsGlobalType**)DynBaseAddress(0x602D32);
-	RosieAudioFix_JumpBack = (void*)DynBaseAddress(0x42BFFE);
 	SubtitlesShadowFix_JumpBack = (void*)DynBaseAddress(0x551701);
 
 	InjectHook(0x5433BD, FixedRefValue);
 
-	InjectHook(0x42BFF7, RosiesAudioFix, HookType::Jump);
-
 	InjectHook(0x5516FC, SubtitlesShadowFix, HookType::Jump);
 	Patch<BYTE>(0x5517C4, 0xD9);
 	Patch<BYTE>(0x5517DF, 0xD9);
@@ -984,13 +984,10 @@ void Patch_VC_11(uint32_t width, uint32_t height)
 	using namespace Memory::DynBase;
 
 	RsGlobal = *(RsGlobalType**)DynBaseAddress(0x602D12);
-	RosieAudioFix_JumpBack = (void*)DynBaseAddress(0x42BFFE);
 	SubtitlesShadowFix_JumpBack = (void*)DynBaseAddress(0x551721);
 
 	InjectHook(0x5433DD, FixedRefValue);
 
-	InjectHook(0x42BFF7, RosiesAudioFix, HookType::Jump);
-
 	InjectHook(0x55171C, SubtitlesShadowFix, HookType::Jump);
 	Patch<BYTE>(0x5517E4, 0xD9);
 	Patch<BYTE>(0x5517FF, 0xD9);
@@ -1083,13 +1080,10 @@ void Patch_VC_Steam(uint32_t width, uint32_t height)
 	using namespace Memory::DynBase;
 
 	RsGlobal = *(RsGlobalType**)DynBaseAddress(0x602952);
-	RosieAudioFix_JumpBack = (void*)DynBaseAddress(0x42BFCE);
 	SubtitlesShadowFix_JumpBack = (void*)DynBaseAddress(0x5515F1);
 
 	InjectHook(0x5432AD, FixedRefValue);
 
-	InjectHook(0x42BFC7, RosiesAudioFix, HookType::Jump);
-
 	InjectHook(0x5515EC, SubtitlesShadowFix, HookType::Jump);
 	Patch<BYTE>(0x5516B4, 0xD9);
 	Patch<BYTE>(0x5516CF, 0xD9);
@@ -1537,6 +1531,14 @@ void Patch_VC_Common()
 		memmove(isPlayerTargettingChar.get<void>(), isPlayerTargettingChar.get<void>(5), 5);
 		InjectHook(isPlayerTargettingChar.get<void>(5), IsPlayerTargettingChar_ExtraChecks, HookType::Call);
 	}
+
+
+	// Use PS2 randomness for Rosenberg audio to hopefully bring the odds closer to PS2
+	// The functionality was never broken on PC - but the random distribution seemingly made it looks as if it was
+	{
+		auto busted_audio_rand = get_pattern("80 BB 48 01 00 00 00 0F 85 ? ? ? ? E8 ? ? ? ? 25 FF FF 00 00", 13);
+		InjectHook(busted_audio_rand, rand15_ps2);
+	}
 }
 
 BOOL WINAPI DllMain(HINSTANCE hinstDLL, DWORD fdwReason, LPVOID lpvReserved)