Added function to query the world bounds of a physics system (#816)

Jolt/Physics/Collision/BroadPhase/BroadPhase.h

@@ -95,6 +95,9 @@ public:
 	/// Same as BroadPhaseQuery::CastAABox but can be implemented in a way to take no broad phase locks.
 	virtual void		CastAABoxNoLock(const AABoxCast &inBox, CastShapeBodyCollector &ioCollector, const BroadPhaseLayerFilter &inBroadPhaseLayerFilter, const ObjectLayerFilter &inObjectLayerFilter) const = 0;
 
+	/// Get the bounding box of all objects in the broadphase
+	virtual AABox		GetBounds() const = 0;
+
 #ifdef JPH_TRACK_BROADPHASE_STATS
 	/// Trace the collected broadphase stats in CSV form.
 	/// This report can be used to judge and tweak the efficiency of the broadphase.

Jolt/Physics/Collision/BroadPhase/BroadPhaseBruteForce.cpp

@@ -300,4 +300,14 @@ void BroadPhaseBruteForce::FindCollidingPairs(BodyID *ioActiveBodies, int inNumA
 	}
 }
 
+AABox BroadPhaseBruteForce::GetBounds() const
+{
+	shared_lock lock(mMutex);
+
+	AABox bounds;
+	for (BodyID b : mBodyIDs)
+		bounds.Encapsulate(mBodyManager->GetBody(b).GetWorldSpaceBounds());
+	return bounds;
+}
+
 JPH_NAMESPACE_END

Jolt/Physics/Collision/BroadPhase/BroadPhaseBruteForce.h

@@ -28,6 +28,7 @@ public:
 	virtual void		CastAABoxNoLock(const AABoxCast &inBox, CastShapeBodyCollector &ioCollector, const BroadPhaseLayerFilter &inBroadPhaseLayerFilter, const ObjectLayerFilter &inObjectLayerFilter) const override;
 	virtual void		CastAABox(const AABoxCast &inBox, CastShapeBodyCollector &ioCollector, const BroadPhaseLayerFilter &inBroadPhaseLayerFilter, const ObjectLayerFilter &inObjectLayerFilter) const override;
 	virtual void		FindCollidingPairs(BodyID *ioActiveBodies, int inNumActiveBodies, float inSpeculativeContactDistance, const ObjectVsBroadPhaseLayerFilter &inObjectVsBroadPhaseLayerFilter, const ObjectLayerPairFilter &inObjectLayerPairFilter, BodyPairCollector &ioPairCollector) const override;
+	virtual AABox		GetBounds() const override;
 
 private:
 	Array<BodyID>		mBodyIDs;

Jolt/Physics/Collision/BroadPhase/BroadPhaseQuadTree.cpp

@@ -579,6 +579,17 @@ void BroadPhaseQuadTree::FindCollidingPairs(BodyID *ioActiveBodies, int inNumAct
 	}
 }
 
+AABox BroadPhaseQuadTree::GetBounds() const
+{
+	// Prevent this from running in parallel with node deletion in FrameSync(), see notes there
+	shared_lock lock(mQueryLocks[mQueryLockIdx]);
+
+	AABox bounds;
+	for (BroadPhaseLayer::Type l = 0; l < mNumLayers; ++l)
+		bounds.Encapsulate(mLayers[l].GetBounds());
+	return bounds;
+}
+
 #ifdef JPH_TRACK_BROADPHASE_STATS
 
 void BroadPhaseQuadTree::ReportStats()

Jolt/Physics/Collision/BroadPhase/BroadPhaseQuadTree.h

@@ -41,6 +41,7 @@ public:
 	virtual void			CastAABoxNoLock(const AABoxCast &inBox, CastShapeBodyCollector &ioCollector, const BroadPhaseLayerFilter &inBroadPhaseLayerFilter, const ObjectLayerFilter &inObjectLayerFilter) const override;
 	virtual void			CastAABox(const AABoxCast &inBox, CastShapeBodyCollector &ioCollector, const BroadPhaseLayerFilter &inBroadPhaseLayerFilter, const ObjectLayerFilter &inObjectLayerFilter) const override;
 	virtual void			FindCollidingPairs(BodyID *ioActiveBodies, int inNumActiveBodies, float inSpeculativeContactDistance, const ObjectVsBroadPhaseLayerFilter &inObjectVsBroadPhaseLayerFilter, const ObjectLayerPairFilter &inObjectLayerPairFilter, BodyPairCollector &ioPairCollector) const override;
+	virtual AABox			GetBounds() const override;
 #ifdef JPH_TRACK_BROADPHASE_STATS
 	virtual void			ReportStats() override;
 #endif // JPH_TRACK_BROADPHASE_STATS

Jolt/Physics/Collision/BroadPhase/QuadTree.cpp

@@ -221,6 +221,17 @@ void QuadTree::DiscardOldTree()
 	}
 }
 
+AABox QuadTree::GetBounds() const
+{
+	uint32 node_idx = GetCurrentRoot().mIndex;
+	JPH_ASSERT(node_idx != cInvalidNodeIndex);
+	const Node &node = mAllocator->Get(node_idx);
+
+	AABox bounds;
+	node.GetNodeBounds(bounds);
+	return bounds;
+}
+
 void QuadTree::UpdatePrepare(const BodyVector &inBodies, TrackingVector &ioTracking, UpdateState &outUpdateState, bool inFullRebuild)
 {
 #ifdef JPH_ENABLE_ASSERTS

Jolt/Physics/Collision/BroadPhase/QuadTree.h

@@ -197,6 +197,9 @@ public:
 	/// Will throw away the previous frame's nodes so that we can start building a new tree in the background
 	void						DiscardOldTree();
 
+	/// Get the bounding box for this tree
+	AABox						GetBounds() const;
+
 	/// Update the broadphase, needs to be called regularly to achieve a tight fit of the tree when bodies have been modified.
 	/// UpdatePrepare() will build the tree, UpdateFinalize() will lock the root of the tree shortly and swap the trees and afterwards clean up temporary data structures.
 	void						UpdatePrepare(const BodyVector &inBodies, TrackingVector &ioTracking, UpdateState &outUpdateState, bool inFullRebuild);

Jolt/Physics/PhysicsSystem.h

@@ -188,6 +188,9 @@ public:
 	/// - During the ContactListener::OnContactRemoved callback this function can be used to determine if this is the last contact pair between the bodies (function returns false) or if there are other contacts still present (function returns true).
 	bool						WereBodiesInContact(const BodyID &inBody1ID, const BodyID &inBody2ID) const { return mContactManager.WereBodiesInContact(inBody1ID, inBody2ID); }
 
+	/// Get the bounding box of all bodies in the physics system
+	AABox						GetBounds() const											{ return mBroadPhase->GetBounds(); }
+
 #ifdef JPH_TRACK_BROADPHASE_STATS
 	/// Trace the accumulated broadphase stats to the TTY
 	void						ReportBroadphaseStats()										{ mBroadPhase->ReportStats(); }

Samples/SamplesApp.cpp

@@ -480,6 +480,7 @@ SamplesApp::SamplesApp()
 			mDebugUI->CreateCheckBox(drawing_options, "Draw Contact Manifolds (M)", ContactConstraintManager::sDrawContactManifolds, [](UICheckBox::EState inState) { ContactConstraintManager::sDrawContactManifolds = inState == UICheckBox::STATE_CHECKED; });
 			mDebugUI->CreateCheckBox(drawing_options, "Draw Motion Quality Linear Cast", PhysicsSystem::sDrawMotionQualityLinearCast, [](UICheckBox::EState inState) { PhysicsSystem::sDrawMotionQualityLinearCast = inState == UICheckBox::STATE_CHECKED; });
 			mDebugUI->CreateCheckBox(drawing_options, "Draw Bounding Boxes", mBodyDrawSettings.mDrawBoundingBox, [this](UICheckBox::EState inState) { mBodyDrawSettings.mDrawBoundingBox = inState == UICheckBox::STATE_CHECKED; });
+			mDebugUI->CreateCheckBox(drawing_options, "Draw Physics System Bounds", mDrawPhysicsSystemBounds, [this](UICheckBox::EState inState) { mDrawPhysicsSystemBounds = inState == UICheckBox::STATE_CHECKED; });
 			mDebugUI->CreateCheckBox(drawing_options, "Draw Center of Mass Transforms", mBodyDrawSettings.mDrawCenterOfMassTransform, [this](UICheckBox::EState inState) { mBodyDrawSettings.mDrawCenterOfMassTransform = inState == UICheckBox::STATE_CHECKED; });
 			mDebugUI->CreateCheckBox(drawing_options, "Draw World Transforms", mBodyDrawSettings.mDrawWorldTransform, [this](UICheckBox::EState inState) { mBodyDrawSettings.mDrawWorldTransform = inState == UICheckBox::STATE_CHECKED; });
 			mDebugUI->CreateCheckBox(drawing_options, "Draw Velocity", mBodyDrawSettings.mDrawVelocity, [this](UICheckBox::EState inState) { mBodyDrawSettings.mDrawVelocity = inState == UICheckBox::STATE_CHECKED; });
@@ -2223,6 +2224,9 @@ void SamplesApp::DrawPhysics()
 
 	if (mDrawConstraintReferenceFrame)
 		mPhysicsSystem->DrawConstraintReferenceFrame(mDebugRenderer);
+
+	if (mDrawPhysicsSystemBounds)
+		mDebugRenderer->DrawWireBox(mPhysicsSystem->GetBounds(), Color::sGreen);
 #endif // JPH_DEBUG_RENDERER
 
 	// This map collects the shapes that we used this frame

Samples/SamplesApp.h

@@ -105,6 +105,7 @@ private:
 	bool					mDrawConstraints = false;									// If the constraints should be drawn
 	bool					mDrawConstraintLimits = false;								// If the constraint limits should be drawn
 	bool					mDrawConstraintReferenceFrame = false;						// If the constraint reference frames should be drawn
+	bool					mDrawPhysicsSystemBounds = false;							// If the bounds of the physics system should be drawn
 	BodyManager::DrawSettings mBodyDrawSettings;										// Settings for how to draw bodies from the body manager
 	SkeletonPose::DrawSettings mPoseDrawSettings;										// Settings for drawing skeletal poses
 #endif // JPH_DEBUG_RENDERER