From 548a4328c04ca5f42a04dd7d3dfffdd9a137ed2d Mon Sep 17 00:00:00 2001
From: Human Gamer <39096122+HumanGamer@users.noreply.github.com>
Date: Sun, 24 Mar 2024 17:37:13 -0500
Subject: [PATCH] Made XNA Physics alternative that has the same effect but
 better.

---
 engine/source/game/marble/marble.cpp          | 21 ++++++++------
 engine/source/game/marble/marble.h            |  4 ++-
 engine/source/game/marble/marblephysics.cpp   | 29 ++++++++++---------
 .../Multiplayer/Polysoup/polysoup.mis         |  2 +-
 4 files changed, 32 insertions(+), 24 deletions(-)

diff --git a/engine/source/game/marble/marble.cpp b/engine/source/game/marble/marble.cpp
index 4e8d5848..a02db4d2 100644
--- a/engine/source/game/marble/marble.cpp
+++ b/engine/source/game/marble/marble.cpp
@@ -2262,22 +2262,25 @@ ConsoleMethod(Marble, setMode, void, 3, 3, "(mode)")
 ConsoleMethod(Marble, setPhysics, void, 3, 3, "(physics)")
 {
     const char* physics = argv[2];
-    U32 physicsFlags[3];
-    const char* physicsStrings[3];
+    U32 physicsFlags[Marble::MBPhysics_Count];
+    const char* physicsStrings[Marble::MBPhysics_Count];
 
-    physicsStrings[0] = "MBU";
-    physicsFlags[0] = Marble::MBU;
+    physicsStrings[Marble::MBU] = "MBU";
+    physicsFlags[Marble::MBU] = Marble::MBU;
 
-    physicsStrings[1] = "MBG";
-    physicsFlags[1] = Marble::MBG;
+    physicsStrings[Marble::MBG] = "MBG";
+    physicsFlags[Marble::MBG] = Marble::MBG;
 
-    physicsStrings[2] = "XNA";
-    physicsFlags[2] = Marble::XNA;
+    physicsStrings[Marble::XNA] = "XNA";
+    physicsFlags[Marble::XNA] = Marble::XNA;
+
+    physicsStrings[Marble::XNASlopes] = "XNASlopes";
+    physicsFlags[Marble::XNASlopes] = Marble::XNASlopes;
 
     S32 i = 0;
     while (dStricmp(physicsStrings[i], physics))
     {
-        if (++i >= 3)
+        if (++i >= Marble::MBPhysics_Count)
         {
             Con::errorf("Marble:: Unknown physics mode: %s", physics);
             return;
diff --git a/engine/source/game/marble/marble.h b/engine/source/game/marble/marble.h
index 54588f2e..9324b672 100644
--- a/engine/source/game/marble/marble.h
+++ b/engine/source/game/marble/marble.h
@@ -70,7 +70,9 @@ class Marble : public ShapeBase
     {
         MBU,
         MBG,
-        XNA
+        XNA,
+        XNASlopes,
+        MBPhysics_Count
     };
 
     enum UpdateMaskBits
diff --git a/engine/source/game/marble/marblephysics.cpp b/engine/source/game/marble/marblephysics.cpp
index 99e7ec57..291695c0 100644
--- a/engine/source/game/marble/marblephysics.cpp
+++ b/engine/source/game/marble/marblephysics.cpp
@@ -106,18 +106,21 @@ void Marble::applyContactForces(const Move* move, bool isCentered, Point3D& aCon
         }
     }
 
-    for (S32 i = 0; i < mContacts.size(); i++)
+    if (mPhysics != XNASlopes)
     {
-        Contact* contact = &mContacts[i];
+        for (S32 i = 0; i < mContacts.size(); i++)
+        {
+            Contact *contact = &mContacts[i];
 
-        F64 normalForce = -mDot(contact->normal, A);
+            F64 normalForce = -mDot(contact->normal, A);
 
-        if (normalForce > 0.0 &&
-              (mVelocity.x - contact->surfaceVelocity.x) * contact->normal.x
-            + (mVelocity.y - contact->surfaceVelocity.y) * contact->normal.y
-            + (mVelocity.z - contact->surfaceVelocity.z) * contact->normal.z <= 0.0001)
-        {
-            A += contact->normal * normalForce;
+            if (normalForce > 0.0 &&
+                (mVelocity.x - contact->surfaceVelocity.x) * contact->normal.x
+                + (mVelocity.y - contact->surfaceVelocity.y) * contact->normal.y
+                + (mVelocity.z - contact->surfaceVelocity.z) * contact->normal.z <= 0.0001)
+            {
+                A += contact->normal * normalForce;
+            }
         }
     }
 
@@ -634,10 +637,10 @@ void Marble::advancePhysics(const Move* move, U32 timeDelta)
 
         F64 moveTime = timeStep;
         computeFirstPlatformIntersect(moveTime, smPathItrVec);
-        //if (mPhysics == XNA)
-        //    mPosition += mVelocity * moveTime; // XNA
-        //else
-        testMove(mVelocity, mPosition, moveTime, mRadius, sCollisionMask, false); // MBU
+        if (mPhysics == XNA)
+            mPosition += mVelocity * moveTime; // XNA
+        else
+            testMove(mVelocity, mPosition, moveTime, mRadius, sCollisionMask, false); // MBU
 
         if (!mMovePathSize && timeStep * 0.99 > moveTime && moveTime > 0.001000000047497451)
         {
diff --git a/game/marble/data/missions/Multiplayer/Polysoup/polysoup.mis b/game/marble/data/missions/Multiplayer/Polysoup/polysoup.mis
index df7d4e39..54745431 100644
--- a/game/marble/data/missions/Multiplayer/Polysoup/polysoup.mis
+++ b/game/marble/data/missions/Multiplayer/Polysoup/polysoup.mis
@@ -11,7 +11,7 @@ name = $Text::LevelNameMP26;
          difficulty = "4";
          gameType = "MultiPlayer";
          gameMode = "Scrum";
-         physics = "XNA";
+         physics = "XNASlopes";
          time = "300000";
          maxGemsPerGroup = "9";
          desc = "A preview mission";