From ca6b42e20eb3b8931ab36765595b56633c8719b0 Mon Sep 17 00:00:00 2001
From: "Skyth (Asilkan)"
 <19259897+blueskythlikesclouds@users.noreply.github.com>
Date: Thu, 23 Jan 2025 19:41:15 +0300
Subject: [PATCH] Interpolate barrels in Spagonia Night to fix softlock at high
 frame rates. (#153)

---
 UnleashedRecomp/api/Hedgehog/Math/Vector.h    |  1 +
 UnleashedRecomp/api/SWA.h                     |  1 +
 .../api/SWA/CharacterUtility/CharacterProxy.h | 14 +++++
 UnleashedRecomp/patches/object_patches.cpp    | 59 +++++++++++++++++++
 UnleashedRecompLib/config/SWA.toml            | 10 ++++
 5 files changed, 85 insertions(+)
 create mode 100644 UnleashedRecomp/api/SWA/CharacterUtility/CharacterProxy.h

diff --git a/UnleashedRecomp/api/Hedgehog/Math/Vector.h b/UnleashedRecomp/api/Hedgehog/Math/Vector.h
index b1c0f3d..7ea0e38 100644
--- a/UnleashedRecomp/api/Hedgehog/Math/Vector.h
+++ b/UnleashedRecomp/api/Hedgehog/Math/Vector.h
@@ -17,6 +17,7 @@ namespace Hedgehog::Math
         be<float> X;
         be<float> Y;
         be<float> Z;
+        be<float> W;
     };
 
     class CVector4
diff --git a/UnleashedRecomp/api/SWA.h b/UnleashedRecomp/api/SWA.h
index e2a846e..1478fe2 100644
--- a/UnleashedRecomp/api/SWA.h
+++ b/UnleashedRecomp/api/SWA.h
@@ -59,6 +59,7 @@
 #include "SWA/CSD/CsdTexListMirage.h"
 #include "SWA/CSD/GameObjectCSD.h"
 #include "SWA/Camera/Camera.h"
+#include "SWA/CharacterUtility/CharacterProxy.h"
 #include "SWA/HUD/GeneralWindow/GeneralWindow.h"
 #include "SWA/HUD/Loading/Loading.h"
 #include "SWA/HUD/Pause/HudPause.h"
diff --git a/UnleashedRecomp/api/SWA/CharacterUtility/CharacterProxy.h b/UnleashedRecomp/api/SWA/CharacterUtility/CharacterProxy.h
new file mode 100644
index 0000000..4032727
--- /dev/null
+++ b/UnleashedRecomp/api/SWA/CharacterUtility/CharacterProxy.h
@@ -0,0 +1,14 @@
+#pragma once
+
+#include <Hedgehog/Math/Vector.h>
+
+namespace SWA
+{
+    class CCharacterProxy
+    {
+    public:
+        SWA_INSERT_PADDING(0x120);
+        Hedgehog::Math::CVector m_Position;
+        Hedgehog::Math::CVector m_Velocity;
+    };
+}
diff --git a/UnleashedRecomp/patches/object_patches.cpp b/UnleashedRecomp/patches/object_patches.cpp
index b7ebe36..54c391b 100644
--- a/UnleashedRecomp/patches/object_patches.cpp
+++ b/UnleashedRecomp/patches/object_patches.cpp
@@ -1,3 +1,6 @@
+#include <user/config.h>
+#include <SWA/CharacterUtility/CharacterProxy.h>
+
 // CObjFlame::CObjFlame
 // A field is not zero initialized,
 // causing collisions to constantly get created
@@ -8,3 +11,59 @@ PPC_FUNC(sub_82608E60)
     memset(base + ctx.r3.u32, 0, 0x154);
     __imp__sub_82608E60(ctx, base);
 }
+
+// The barrel gets stuck at a slope at high frame rates and softlocks the player.
+// We can update the character proxy at 30 FPS, and interpolate the visuals to work around this issue.
+static constexpr size_t OBJ_BIG_BARREL_SIZE = 0x1A0;
+
+struct ObjBigBarrelEx
+{
+    float elapsedTime{};
+    bool interpolate{};
+};
+
+void ObjBigBarrelAllocMidAsmHook(PPCRegister& r3)
+{
+    r3.u32 += sizeof(ObjBigBarrelEx);
+}
+
+// CObjBigBarrel::CObjBigBarrel
+PPC_FUNC_IMPL(__imp__sub_8271AC08);
+PPC_FUNC(sub_8271AC08)
+{
+    new (base + ctx.r3.u32 + OBJ_BIG_BARREL_SIZE) ObjBigBarrelEx();
+    __imp__sub_8271AC08(ctx, base);
+}
+
+// CObjBigBarrel::Integrate
+PPC_FUNC_IMPL(__imp__sub_8271AA30);
+PPC_FUNC(sub_8271AA30)
+{
+    auto objBigBarrelEx = reinterpret_cast<ObjBigBarrelEx*>(base + ctx.r3.u32 + OBJ_BIG_BARREL_SIZE);
+    objBigBarrelEx->interpolate = ctx.f1.f64 < (1.0 / 30.0);
+    objBigBarrelEx->elapsedTime += ctx.f1.f64;
+
+    if (!objBigBarrelEx->interpolate || objBigBarrelEx->elapsedTime >= (1.0f / 30.0f))
+    {
+        ctx.f1.f64 = objBigBarrelEx->elapsedTime;
+        __imp__sub_8271AA30(ctx, base);
+        objBigBarrelEx->elapsedTime = 0.0f;
+    }
+}
+
+void ObjBigBarrelSetPositionMidAsmHook(PPCRegister& r3, PPCRegister& r4)
+{
+    uint8_t* base = g_memory.base;
+    auto objBigBarrelEx = reinterpret_cast<ObjBigBarrelEx*>(base + r3.u32 + OBJ_BIG_BARREL_SIZE);
+
+    if (objBigBarrelEx->interpolate)
+    {
+        auto characterProxy = reinterpret_cast<SWA::CCharacterProxy*>(base + PPC_LOAD_U32(r3.u32 + 0x100));
+        auto position = reinterpret_cast<Hedgehog::Math::CVector*>(base + r4.u32);
+
+        float factor = (1.0f / 30.0f) - objBigBarrelEx->elapsedTime;
+        position->X = position->X - characterProxy->m_Velocity.X * factor;
+        position->Y = position->Y - characterProxy->m_Velocity.Y * factor;
+        position->Z = position->Z - characterProxy->m_Velocity.Z * factor;
+    }
+}
diff --git a/UnleashedRecompLib/config/SWA.toml b/UnleashedRecompLib/config/SWA.toml
index cbb8971..70a9b67 100644
--- a/UnleashedRecompLib/config/SWA.toml
+++ b/UnleashedRecompLib/config/SWA.toml
@@ -680,3 +680,13 @@ registers = ["r3"]
 name = "TitleMenuRemoveContinueOnCorruptSaveMidAsmHook"
 address = 0x82585470
 registers = ["r3"]
+
+[[midasm_hook]]
+name = "ObjBigBarrelAllocMidAsmHook"
+address = 0x8271B778
+registers = ["r3"]
+
+[[midasm_hook]]
+name = "ObjBigBarrelSetPositionMidAsmHook"
+address = 0x8271B5C8
+registers = ["r3", "r4"]