added anisotropic friction support for Bullet. Both for static and dynamic objects

8 files changed, 99 insertions, 9 deletions

diff --git a/extern/bullet2/src/BulletCollision/CollisionDispatch/btCollisionObject.cpp b/extern/bullet2/src/BulletCollision/CollisionDispatch/btCollisionObject.cpp
index eebd0c99fcb..846c9b9b989 100644
--- a/extern/bullet2/src/BulletCollision/CollisionDispatch/btCollisionObject.cpp
+++ b/extern/bullet2/src/BulletCollision/CollisionDispatch/btCollisionObject.cpp
@@ -17,7 +17,9 @@ subject to the following restrictions:
 #include "btCollisionObject.h"
 
 btCollisionObject::btCollisionObject()
-	:	m_broadphaseHandle(0),
+	:	m_anisotropicFriction(1.f,1.f,1.f),
+	m_hasAnisotropicFriction(false),
+		m_broadphaseHandle(0),
 		m_collisionShape(0),
 		m_rootCollisionShape(0),
 		m_collisionFlags(btCollisionObject::CF_STATIC_OBJECT),
diff --git a/extern/bullet2/src/BulletCollision/CollisionDispatch/btCollisionObject.h b/extern/bullet2/src/BulletCollision/CollisionDispatch/btCollisionObject.h
index 0961f3e75c9..8442868cf89 100644
--- a/extern/bullet2/src/BulletCollision/CollisionDispatch/btCollisionObject.h
+++ b/extern/bullet2/src/BulletCollision/CollisionDispatch/btCollisionObject.h
@@ -49,6 +49,9 @@ protected:
 	//without destroying the continuous interpolated motion (which uses this interpolation velocities)
 	btVector3	m_interpolationLinearVelocity;
 	btVector3	m_interpolationAngularVelocity;
+	btVector3		m_anisotropicFriction;
+	bool	m_hasAnisotropicFriction;
+
 	btBroadphaseProxy*		m_broadphaseHandle;
 	btCollisionShape*		m_collisionShape;
 	
@@ -119,6 +122,20 @@ public:
 		return  ((m_collisionFlags & (CF_STATIC_OBJECT | CF_KINEMATIC_OBJECT | CF_NO_CONTACT_RESPONSE) )==0);
 	}
 
+	const btVector3& getAnisotropicFriction() const
+	{
+		return m_anisotropicFriction;
+	}
+	void	setAnisotropicFriction(const btVector3& anisotropicFriction)
+	{
+		m_anisotropicFriction = anisotropicFriction;
+		m_hasAnisotropicFriction = (anisotropicFriction[0]!=1.f) || (anisotropicFriction[1]!=1.f) || (anisotropicFriction[2]!=1.f);
+	}
+	bool	hasAnisotropicFriction() const
+	{
+		return m_hasAnisotropicFriction;
+	}
+
 
 	SIMD_FORCE_INLINE bool		isStaticObject() const {
 		return (m_collisionFlags & CF_STATIC_OBJECT) != 0;
diff --git a/extern/bullet2/src/BulletDynamics/ConstraintSolver/btSequentialImpulseConstraintSolver.cpp b/extern/bullet2/src/BulletDynamics/ConstraintSolver/btSequentialImpulseConstraintSolver.cpp
index b8afbd6aac5..2911d52e5ea 100644
--- a/extern/bullet2/src/BulletDynamics/ConstraintSolver/btSequentialImpulseConstraintSolver.cpp
+++ b/extern/bullet2/src/BulletDynamics/ConstraintSolver/btSequentialImpulseConstraintSolver.cpp
@@ -149,6 +149,7 @@ void	initSolverBody(btSolverBody* solverBody, btCollisionObject* collisionObject
 		solverBody->m_originalBody = 0;
 		solverBody->m_angularFactor = 1.f;
 	}
+	
 	solverBody->m_pushVelocity.setValue(0.f,0.f,0.f);
 	solverBody->m_turnVelocity.setValue(0.f,0.f,0.f);
 }
@@ -292,7 +293,7 @@ btScalar resolveSingleCollisionCombinedCacheFriendly(
 	return normalImpulse;
 }
 
-
+//#define NO_FRICTION_TANGENTIALS 1
 #ifndef NO_FRICTION_TANGENTIALS
 
 btScalar resolveSingleFrictionCacheFriendly(
@@ -396,7 +397,7 @@ btScalar resolveSingleFrictionCacheFriendly(
 			return 0.f;
 
 
-		body1.getVelocityInLocalPoint(contactConstraint.m_rel_posA,vel1);
+		body1.getVelocityInLocalPoint(contactConstraint.m_relpos1CrossNormal,vel1);
 		body2.getVelocityInLocalPoint(contactConstraint.m_rel_posB,vel2);
 		btVector3 vel = vel1 - vel2;
 		btScalar rel_vel;
@@ -421,9 +422,9 @@ btScalar resolveSingleFrictionCacheFriendly(
 				(body1.m_invMass + body2.m_invMass + lat_vel.dot(temp1.cross(rel_pos1) + temp2.cross(rel_pos2)));
 			btScalar normal_impulse = contactConstraint.m_appliedImpulse * combinedFriction;
 
-			GEN_set_min(friction_impulse, normal_impulse);
-			GEN_set_max(friction_impulse, -normal_impulse);
-			body1.applyImpulse(lat_vel * -friction_impulse, rel_pos1);
+			btSetMin(friction_impulse, normal_impulse);
+			btSetMin(friction_impulse, -normal_impulse);
+			body1.internalApplyImpulse(lat_vel * -friction_impulse, rel_pos1);
 			body2.applyImpulse(lat_vel * friction_impulse, rel_pos2);
 		}
 	}
@@ -495,6 +496,23 @@ void	btSequentialImpulseConstraintSolver::addFrictionConstraint(const btVector3&
 }
 
 
+void	applyAnisotropicFriction(btCollisionObject* colObj,btVector3& frictionDirection);
+void	applyAnisotropicFriction(btCollisionObject* colObj,btVector3& frictionDirection)
+{
+	if (colObj && colObj->hasAnisotropicFriction())
+	{
+		// transform to local coordinates
+		btVector3 loc_lateral = frictionDirection * colObj->getWorldTransform().getBasis();
+		const btVector3& friction_scaling = colObj->getAnisotropicFriction();
+		//apply anisotropic friction
+		loc_lateral *= friction_scaling;
+		// ... and transform it back to global coordinates
+		frictionDirection = colObj->getWorldTransform().getBasis() * loc_lateral;
+	}
+}
+
+
+
 
 btScalar btSequentialImpulseConstraintSolver::solveGroupCacheFriendlySetup(btCollisionObject** /*bodies */,int /*numBodies */,btPersistentManifold** manifoldPtr, int numManifolds,btTypedConstraint** constraints,int numConstraints,const btContactSolverInfo& infoGlobal,btIDebugDraw* debugDrawer,btStackAlloc* stackAlloc)
 {
@@ -755,19 +773,31 @@ btScalar btSequentialImpulseConstraintSolver::solveGroupCacheFriendlySetup(btCol
 							if (!cp.m_lateralFrictionInitialized)
 							{
 								cp.m_lateralFrictionDir1 = vel - cp.m_normalWorldOnB * rel_vel;
+								
+								//scale anisotropic friction
+								
+								applyAnisotropicFriction(colObj0,cp.m_lateralFrictionDir1);
+								applyAnisotropicFriction(colObj1,cp.m_lateralFrictionDir1);
+
 								btScalar lat_rel_vel = cp.m_lateralFrictionDir1.length2();
+
+
 								if (lat_rel_vel > SIMD_EPSILON)//0.0f)
 								{
 									cp.m_lateralFrictionDir1 /= btSqrt(lat_rel_vel);
 									addFrictionConstraint(cp.m_lateralFrictionDir1,solverBodyIdA,solverBodyIdB,frictionIndex,cp,rel_pos1,rel_pos2,colObj0,colObj1, relaxation);
 									cp.m_lateralFrictionDir2 = cp.m_lateralFrictionDir1.cross(cp.m_normalWorldOnB);
-									cp.m_lateralFrictionDir2.normalize();//??
+									cp.m_lateralFrictionDir2.normalize();
+									applyAnisotropicFriction(colObj0,cp.m_lateralFrictionDir2);
+									applyAnisotropicFriction(colObj1,cp.m_lateralFrictionDir2);
+
 									addFrictionConstraint(cp.m_lateralFrictionDir2,solverBodyIdA,solverBodyIdB,frictionIndex,cp,rel_pos1,rel_pos2,colObj0,colObj1, relaxation);
 								} else
 								{
 									//re-calculate friction direction every frame, todo: check if this is really needed
-									
 									btPlaneSpace1(cp.m_normalWorldOnB,cp.m_lateralFrictionDir1,cp.m_lateralFrictionDir2);
+									applyAnisotropicFriction(colObj0,cp.m_lateralFrictionDir2);
+									applyAnisotropicFriction(colObj1,cp.m_lateralFrictionDir2);
 									addFrictionConstraint(cp.m_lateralFrictionDir1,solverBodyIdA,solverBodyIdB,frictionIndex,cp,rel_pos1,rel_pos2,colObj0,colObj1, relaxation);
 									addFrictionConstraint(cp.m_lateralFrictionDir2,solverBodyIdA,solverBodyIdB,frictionIndex,cp,rel_pos1,rel_pos2,colObj0,colObj1, relaxation);
 								}
diff --git a/extern/bullet2/src/BulletDynamics/Dynamics/btRigidBody.cpp b/extern/bullet2/src/BulletDynamics/Dynamics/btRigidBody.cpp
index e2afb687ac6..93d70de39d8 100644
--- a/extern/bullet2/src/BulletDynamics/Dynamics/btRigidBody.cpp
+++ b/extern/bullet2/src/BulletDynamics/Dynamics/btRigidBody.cpp
@@ -45,6 +45,7 @@ void	btRigidBody::setupRigidBody(const btRigidBody::btRigidBodyConstructionInfo&
 	m_linearVelocity.setValue(btScalar(0.0), btScalar(0.0), btScalar(0.0));
 	m_angularVelocity.setValue(btScalar(0.),btScalar(0.),btScalar(0.));
 	m_angularFactor = btScalar(1.);
+	m_anisotropicFriction.setValue(1.f,1.f,1.f);
 	m_gravity.setValue(btScalar(0.0), btScalar(0.0), btScalar(0.0));
 	m_totalForce.setValue(btScalar(0.0), btScalar(0.0), btScalar(0.0));
 	m_totalTorque.setValue(btScalar(0.0), btScalar(0.0), btScalar(0.0)),
diff --git a/source/blender/src/buttons_logic.c b/source/blender/src/buttons_logic.c
index 58fb2d456b9..3d6a82aef57 100644
--- a/source/blender/src/buttons_logic.c
+++ b/source/blender/src/buttons_logic.c
@@ -3072,6 +3072,25 @@ static uiBlock *advanced_bullet_menu(void *arg_ob)
 					xco, yco, 118, 19, &ob->margin, 0.0, 1.0, 1, 0, 
 					"Collision margin");
 		}
+		uiDefButBitI(block, TOG, OB_ANISOTROPIC_FRICTION, B_REDR, "Anisotropic", 
+						xco+120, yco, 120, 19,
+						&ob->gameflag, 0.0, 1.0, 10, 0,
+						"Enable anisotropic friction");			
+
+		yco-=25;
+
+		if (ob->gameflag & OB_ANISOTROPIC_FRICTION) {
+			uiDefButF(block, NUM, 0, "X:", 
+				xco, yco, 80, 19,&ob->anisotropicFriction[0], 0.0, 1.0, 10, 0,
+					"Relative friction coefficient in the x-direction.");
+			uiDefButF(block, NUM, 0, "Y:", 
+				xco+80, yco, 80, 19,&ob->anisotropicFriction[1], 0.0, 1.0, 10, 0,
+					"Relative friction coefficient in the y-direction.");
+			uiDefButF(block, NUM, 0, "Z:", 
+				xco+160, yco, 80, 19,&ob->anisotropicFriction[2], 0.0, 1.0, 10, 0,
+					"Relative friction coefficient in the z-direction.");
+		}
+
 	}
 			
 	uiBlockSetDirection(block, UI_TOP);
@@ -3110,6 +3129,9 @@ void buttons_bullet(uiBlock *block, Object *ob)
 		uiBlockSetCol(block, TH_BUT_SETTING2);
 
 		uiBlockBeginAlign(block);
+		
+		
+
 		uiDefButBitI(block, TOG, OB_GHOST, 0, "Ghost", 10, 182, 60, 19, 
 				&ob->gameflag, 0, 0, 0, 0, 
 				"Objects that don't restitute collisions (like a ghost)");
diff --git a/source/gameengine/Ketsji/KX_ConvertPhysicsObjects.cpp b/source/gameengine/Ketsji/KX_ConvertPhysicsObjects.cpp
index e4c7e7f9317..68e0997aec0 100644
--- a/source/gameengine/Ketsji/KX_ConvertPhysicsObjects.cpp
+++ b/source/gameengine/Ketsji/KX_ConvertPhysicsObjects.cpp
@@ -1025,6 +1025,14 @@ void	KX_ConvertBulletObject(	class	KX_GameObject* gameobj,
 	//need a bit of damping, else system doesn't behave well
 	ci.m_inertiaFactor = shapeprops->m_inertia/0.4f;//defaults to 0.4, don't want to change behaviour
 	
+	ci.m_do_anisotropic = shapeprops->m_do_anisotropic;
+	ci.m_anisotropicFriction.setValue(shapeprops->m_friction_scaling[0],shapeprops->m_friction_scaling[1],shapeprops->m_friction_scaling[2]);
+
+	//smprop->m_do_fh = kxshapeprops->m_do_fh;
+	//smprop->m_do_rot_fh = kxshapeprops->m_do_rot_fh ;
+
+	
+	
 	
 	///////////////////
 	ci.m_gamesoftFlag = objprop->m_gamesoftFlag;
diff --git a/source/gameengine/Physics/Bullet/CcdPhysicsController.cpp b/source/gameengine/Physics/Bullet/CcdPhysicsController.cpp
index 166731459e7..8ec040e89ee 100644
--- a/source/gameengine/Physics/Bullet/CcdPhysicsController.cpp
+++ b/source/gameengine/Physics/Bullet/CcdPhysicsController.cpp
@@ -500,6 +500,11 @@ void CcdPhysicsController::CreateRigidbody()
 			body->setAngularFactor(0.f);
 		}
 	}
+	if (m_object && m_cci.m_do_anisotropic)
+	{
+		m_object->setAnisotropicFriction(m_cci.m_anisotropicFriction);
+	}
+		
 }
 
 static void DeleteBulletShape(btCollisionShape* shape)
diff --git a/source/gameengine/Physics/Bullet/CcdPhysicsController.h b/source/gameengine/Physics/Bullet/CcdPhysicsController.h
index 1366764eb63..f001d6043cb 100644
--- a/source/gameengine/Physics/Bullet/CcdPhysicsController.h
+++ b/source/gameengine/Physics/Bullet/CcdPhysicsController.h
@@ -186,7 +186,9 @@ struct CcdConstructionInfo
 		m_MotionState(0),
 		m_shapeInfo(0),
 		m_physicsEnv(0),
-		m_inertiaFactor(1.f)
+		m_inertiaFactor(1.f),
+		m_do_anisotropic(false),
+		m_anisotropicFriction(1.f,1.f,1.f)
 	{
 	}
 
@@ -259,6 +261,9 @@ struct CcdConstructionInfo
 	
 	CcdPhysicsEnvironment*	m_physicsEnv; //needed for self-replication
 	float	m_inertiaFactor;//tweak the inertia (hooked up to Blender 'formfactor'
+	bool	m_do_anisotropic;
+	btVector3 m_anisotropicFriction;
+
 };