Added some documentation cross references for manifold reduction

Jolt/Physics/Body/Body.h

@@ -85,7 +85,8 @@ public:
 	/// Check if this sensor detects static objects entering it.
 	inline bool				SensorDetectsStatic() const										{ return (mFlags.load(memory_order_relaxed) & uint8(EFlags::SensorDetectsStatic)) != 0; }
 
-	/// If PhysicsSettings::mUseManifoldReduction is true, this allows turning off manifold reduction for this specific body. Manifold reduction by default will combine contacts that come from different SubShapeIDs (e.g. different triangles or different compound shapes).
+	/// If PhysicsSettings::mUseManifoldReduction is true, this allows turning off manifold reduction for this specific body.
+	/// Manifold reduction by default will combine contacts with similar normals that come from different SubShapeIDs (e.g. different triangles in a mesh shape or different compound shapes).
 	/// If the application requires tracking exactly which SubShapeIDs are in contact, you can turn off manifold reduction. Note that this comes at a performance cost.
 	inline void				SetUseManifoldReduction(bool inUseReduction)					{ JPH_ASSERT(IsRigidBody()); if (inUseReduction) mFlags.fetch_or(uint8(EFlags::UseManifoldReduction), memory_order_relaxed); else mFlags.fetch_and(uint8(~uint8(EFlags::UseManifoldReduction)), memory_order_relaxed); }
 

Jolt/Physics/Collision/ContactListener.h

@@ -29,7 +29,7 @@ public:
 	RVec3					mBaseOffset;						///< Offset to which all the contact points are relative
 	Vec3					mWorldSpaceNormal;					///< Normal for this manifold, direction along which to move body 2 out of collision along the shortest path
 	float					mPenetrationDepth;					///< Penetration depth (move shape 2 by this distance to resolve the collision)
-	SubShapeID				mSubShapeID1;						///< Sub shapes that formed this manifold (note that when multiple manifolds are combined because they're coplanar, we lose some information here because we only keep track of one sub shape pair that we encounter)
+	SubShapeID				mSubShapeID1;						///< Sub shapes that formed this manifold (note that when multiple manifolds are combined because they're coplanar, we lose some information here because we only keep track of one sub shape pair that we encounter, see description at Body::SetUseManifoldReduction)
 	SubShapeID				mSubShapeID2;
 	ContactPoints			mRelativeContactPointsOn1;			///< Contact points on the surface of shape 1 relative to mBaseOffset.
 	ContactPoints			mRelativeContactPointsOn2;			///< Contact points on the surface of shape 2 relative to mBaseOffset. If there's no penetration, this will be the same as mRelativeContactPointsOn1. If there is penetration they will be different.

Jolt/Physics/PhysicsSettings.h

@@ -101,7 +101,7 @@ struct PhysicsSettings
 	/// Whether or not to use the body pair cache, which removes the need for narrow phase collision detection when orientation between two bodies didn't change
 	bool		mUseBodyPairContactCache = true;
 
-	/// Whether or not to reduce manifolds with similar contact normals into one contact manifold
+	/// Whether or not to reduce manifolds with similar contact normals into one contact manifold (see description at Body::SetUseManifoldReduction)
 	bool		mUseManifoldReduction = true;
 
 	/// If we split up large islands into smaller parallel batches of work (to improve performance)