Use a particle tree for cloth

include/bounce/cloth/cloth.h

@@ -23,6 +23,7 @@
 #include <bounce/common/template/list.h>
 #include <bounce/common/memory/stack_allocator.h>
 #include <bounce/common/memory/block_pool.h>
+#include <bounce/collision/trees/dynamic_tree.h>
 
 class b3World;
 class b3Shape;
@@ -138,12 +139,11 @@ public:
 	// Debug draw the cloth using the associated cloth mesh.
 	void Draw() const;
 private:
+	friend class b3Particle;
+
 	// Compute mass of each particle.
 	void ComputeMass();
 
-	// Update body contacts. 
-	void UpdateBodyContacts();
-
 	// Update contacts
 	void UpdateContacts();
 
@@ -173,7 +173,10 @@ private:
 
 	// List of particles
 	b3List2<b3Particle> m_particleList;
-	
+
+	// Particle tree
+	b3DynamicTree m_particleTree;
+
 	// List of forces
 	b3List2<b3Force> m_forceList;
 };

include/bounce/cloth/particle.h

@@ -152,6 +152,9 @@ private:
 	b3Particle(const b3ParticleDef& def, b3Cloth* cloth);
 	~b3Particle();
 
+	// Synchronize AABB
+	void Synchronize();
+
 	// Type
 	b3ParticleType m_type;
 
@@ -193,12 +196,15 @@ private:
 	// Solution
 	b3Vec3 m_x;
 
-	// 
+	// Parent cloth
 	b3Cloth* m_cloth;
 
 	// Contact
 	b3ParticleBodyContact m_bodyContact;
 
+	// Particle tree identifier
+	u32 m_treeId;
+
 	// 
 	b3Particle* m_prev;
 
@@ -220,6 +226,8 @@ inline void b3Particle::SetPosition(const b3Vec3& position)
 {
 	m_position = position;
 	m_translation.SetZero();
+
+	Synchronize();
 }
 
 inline const b3Vec3& b3Particle::GetPosition() const
@@ -249,6 +257,8 @@ inline float32 b3Particle::GetMass() const
 inline void b3Particle::SetRadius(float32 radius)
 {
 	m_radius = radius;
+	
+	Synchronize();
 }
 
 inline float32 b3Particle::GetRadius() const