From b3c20b40469516389ccd5237a4023eaba98ba686 Mon Sep 17 00:00:00 2001
From: UncraftedName <uncraftedname@gmail.com>
Date: Fri, 5 Aug 2022 20:50:34 -0700
Subject: [PATCH] Add ivp rng seeding

---
 spt/features/rng.cpp | 51 ++++++++++++++++++++++++++++++++++++++++++--
 spt/features/rng.hpp | 18 +++++++++++++---
 2 files changed, 64 insertions(+), 5 deletions(-)

diff --git a/spt/features/rng.cpp b/spt/features/rng.cpp
index 9f6d20351..0c06e0127 100644
--- a/spt/features/rng.cpp
+++ b/spt/features/rng.cpp
@@ -9,16 +9,34 @@
 #include "usercmd.h"
 #endif
 
+ConVar y_spt_set_ivp_seed_on_load(
+    "y_spt_set_ivp_seed_on_load",
+    "",
+    FCVAR_CHEAT,
+    "Sets the ivp seed once during the next load, can prevent some physics rng when running a tas.\n");
+
 RNGStuff spt_rng;
 
 namespace patterns
 {
 	PATTERNS(SetPredictionRandomSeed, "5135", "8B 44 24 ?? 85 C0 75 ?? C7 05 ?? ?? ?? ?? FF FF FF FF");
-}
+	PATTERNS(ivp_srand,
+	         "5135",
+	         "8B 44 24 04 85 C0 75 05 B8 01 00 00 00 A3 ?? ?? ?? ?? C3",
+	         "7122284",
+	         "55 8B EC 8B 45 08 B9 01 00 00 00 85 C0 0F 44 C1 A3 ?? ?? ?? ?? 5D C3");
+	PATTERNS(CBasePlayer__InitVCollision,
+	         "5135",
+	         "57 8B F9 8B 07 8B 90 ?? ?? ?? ?? FF D2 A1 ?? ?? ?? ?? 83 78 30 00",
+	         "7122284",
+	         "55 8B EC 83 EC 34 57 8B F9 8B 07 FF 90 ?? ?? ?? ?? A1 ?? ?? ?? ?? 83 78 30 00");
+} // namespace patterns
 
 void RNGStuff::InitHooks()
 {
 	HOOK_FUNCTION(server, SetPredictionRandomSeed);
+	HOOK_FUNCTION(server, CBasePlayer__InitVCollision);
+	FIND_PATTERN(vphysics, ivp_srand);
 }
 
 int RNGStuff::GetPredictionRandomSeed(int commandOffset)
@@ -32,7 +50,21 @@ bool RNGStuff::ShouldLoadFeature()
 	return true;
 }
 
-void RNGStuff::LoadFeature() {}
+void RNGStuff::PreHook()
+{
+	if (ORIG_ivp_srand)
+	{
+		uint32_t offs[] = {14, 17};
+		int idx = GetPatternIndex((void**)&ORIG_ivp_srand);
+		IVP_RAND_SEED = *(uint32_t**)((uintptr_t)ORIG_ivp_srand + offs[idx]);
+	}
+}
+
+void RNGStuff::LoadFeature()
+{
+	if (ORIG_ivp_srand && ORIG_CBasePlayer__InitVCollision)
+		InitConcommandBase(y_spt_set_ivp_seed_on_load);
+}
 
 void RNGStuff::UnloadFeature() {}
 
@@ -46,3 +78,18 @@ void __cdecl RNGStuff::HOOKED_SetPredictionRandomSeed(void* usercmd)
 
 	spt_rng.ORIG_SetPredictionRandomSeed(usercmd);
 }
+
+void __fastcall RNGStuff::HOOKED_CBasePlayer__InitVCollision(void* thisptr,
+                                                             int edx,
+                                                             const Vector& vecAbsOrigin,
+                                                             const Vector& vecAbsVelocity)
+{
+	spt_rng.ORIG_CBasePlayer__InitVCollision(thisptr, edx, vecAbsOrigin, vecAbsVelocity);
+	// set the seed before any vphys sim happens, don't use GetInt() since that's casted from a float
+	if (y_spt_set_ivp_seed_on_load.GetString()[0] != '\0')
+	{
+		spt_rng.ORIG_ivp_srand((uint32_t)strtoul(y_spt_set_ivp_seed_on_load.GetString(), nullptr, 10));
+		y_spt_set_ivp_seed_on_load.SetValue("");
+	}
+	DevWarning("spt: ivp seed is %u\n", *spt_rng.IVP_RAND_SEED);
+}
diff --git a/spt/features/rng.hpp b/spt/features/rng.hpp
index 2a2cd2b81..0fa09bcdf 100644
--- a/spt/features/rng.hpp
+++ b/spt/features/rng.hpp
@@ -2,6 +2,11 @@
 #include "..\feature.hpp"
 
 typedef void(__cdecl* _SetPredictionRandomSeed)(void* usercmd);
+typedef void(__cdecl* _ivp_srand)(uint32_t seed);
+typedef void(__fastcall* _CBasePlayer__InitVCollision)(void* thisptr,
+                                                       int edx,
+                                                       const Vector& vecAbsOrigin,
+                                                       const Vector& vecAbsVelocity);
 
 // RNG prediction
 class RNGStuff : public FeatureWrapper<RNGStuff>
@@ -10,19 +15,26 @@ class RNGStuff : public FeatureWrapper<RNGStuff>
 	int GetPredictionRandomSeed(int commandOffset);
 	int commandNumber = 0;
 
+	_ivp_srand ORIG_ivp_srand = nullptr;
+
 protected:
 	virtual bool ShouldLoadFeature() override;
-
 	virtual void InitHooks() override;
-
+	virtual void PreHook() override;
 	virtual void LoadFeature() override;
-
 	virtual void UnloadFeature() override;
 
 private:
 	_SetPredictionRandomSeed ORIG_SetPredictionRandomSeed = nullptr;
+	_CBasePlayer__InitVCollision ORIG_CBasePlayer__InitVCollision = nullptr;
 
 	static void __cdecl HOOKED_SetPredictionRandomSeed(void* usercmd);
+	static void __fastcall HOOKED_CBasePlayer__InitVCollision(void* thisptr,
+	                                                          int edx,
+	                                                          const Vector& vecAbsOrigin,
+	                                                          const Vector& vecAbsVelocity);
+
+	uint32_t* IVP_RAND_SEED = nullptr;
 };
 
 extern RNGStuff spt_rng;