Merge pull request #1919 from erwincoumans/master

btMultiBody: fix indexing issue causing wrong friction to be reported, remove obsolete BT_PYBULLET_GRPC and PYBULLET_EGL

examples/pybullet/examples/contactFriction.py

@@ -0,0 +1,34 @@
+import pybullet as p
+p.connect(p.GUI)
+useMaximalCoordinates = False
+p.loadURDF("plane.urdf", useMaximalCoordinates=useMaximalCoordinates )
+#p.loadURDF("sphere2.urdf",[0,0,1])
+p.loadURDF("cube.urdf",[0,0,1], useMaximalCoordinates=useMaximalCoordinates )
+p.setGravity(0,3,-10)
+while(1):
+	p.stepSimulation()
+	pts = p.getContactPoints()
+	
+	print("num pts=",len(pts))
+	totalNormalForce = 0
+	totalFrictionForce = [0,0,0]
+	totalLateralFrictionForce=[0,0,0]
+	for pt in pts:
+		#print("pt.normal=",pt[7])
+		#print("pt.normalForce=",pt[9])
+		totalNormalForce += pt[9]
+		#print("pt.lateralFrictionA=",pt[10])
+		#print("pt.lateralFrictionADir=",pt[11])
+		#print("pt.lateralFrictionB=",pt[12])
+		#print("pt.lateralFrictionBDir=",pt[13])
+		totalLateralFrictionForce[0]+=pt[11][0]*pt[10]+pt[13][0]*pt[12]
+		totalLateralFrictionForce[1]+=pt[11][1]*pt[10]+pt[13][1]*pt[12]
+		totalLateralFrictionForce[2]+=pt[11][2]*pt[10]+pt[13][2]*pt[12]
+
+	
+	print("totalNormalForce=",totalNormalForce)
+	print("totalLateralFrictionForce=",totalLateralFrictionForce)
+	
+	
+		
+		

examples/pybullet/pybullet.c

@@ -9704,30 +9704,14 @@ PyMODINIT_FUNC
 #if PY_MAJOR_VERSION >= 3
 PyInit_pybullet(void)
 #else
-#ifdef BT_USE_EGL2
-initpybullet_egl(void)
-#else
-#ifdef BT_PYBULLET_GRPC
-initpybullet_grpc(void)
-#else
 initpybullet(void)
-#endif  //BT_USE_EGL2
-#endif  //BT_PYBULLET_GRPC
 #endif
 {
 	PyObject* m;
 #if PY_MAJOR_VERSION >= 3
 	m = PyModule_Create(&moduledef);
-#else
-#ifdef BT_USE_EGL2
-	m = Py_InitModule3("pybullet_egl", SpamMethods, "Python bindings for Bullet");
-#else
-#ifdef BT_PYBULLET_GRPC
-	m = Py_InitModule3("pybullet_grpc", SpamMethods, "Python bindings for Bullet");
 #else
 	m = Py_InitModule3("pybullet", SpamMethods, "Python bindings for Bullet");
-#endif  //BT_USE_EGL2
-#endif  //BT_PYBULLET_GRPC
 #endif
 
 #if PY_MAJOR_VERSION >= 3

src/BulletDynamics/Featherstone/btMultiBodyConstraintSolver.cpp

@@ -1232,7 +1232,7 @@ void btMultiBodyConstraintSolver::convertMultiBodyContact(btPersistentManifold*
 			/////setup the friction constraints
 #define ENABLE_FRICTION
 #ifdef ENABLE_FRICTION
-			solverConstraint.m_frictionIndex = frictionIndex;
+			solverConstraint.m_frictionIndex = m_multiBodyFrictionContactConstraints.size();
 
 			///Bullet has several options to set the friction directions
 			///By default, each contact has only a single friction direction that is recomputed automatically every frame
@@ -1501,9 +1501,13 @@ btScalar btMultiBodyConstraintSolver::solveGroupCacheFriendlyFinish(btCollisionO
 			if ((infoGlobal.m_solverMode & SOLVER_USE_2_FRICTION_DIRECTIONS))
 			{
 				pt->m_appliedImpulseLateral2 = m_multiBodyFrictionContactConstraints[solverConstraint.m_frictionIndex + 1].m_appliedImpulse;
+			} else
+			{
+				pt->m_appliedImpulseLateral2 = 0;
 			}
-			//do a callback here?
 		}
+		
+			//do a callback here?
 	}
 #if 0
 	//multibody joint feedback