/* Bullet Continuous Collision Detection and Physics Library Copyright (c) 2019 Google Inc. http://bulletphysics.org This software is provided 'as-is', without any express or implied warranty. In no event will the authors be held liable for any damages arising from the use of this software. Permission is granted to anyone to use this software for any purpose, including commercial applications, and to alter it and redistribute it freely, subject to the following restrictions: 1. The origin of this software must not be misrepresented; you must not claim that you wrote the original software. If you use this software in a product, an acknowledgment in the product documentation would be appreciated but is not required. 2. Altered source versions must be plainly marked as such, and must not be misrepresented as being the original software. 3. This notice may not be removed or altered from any source distribution. */ #include "BasicTest.h" ///btBulletDynamicsCommon.h is the main Bullet include file, contains most common include files. #include "btBulletDynamicsCommon.h" #include "BulletSoftBody/btDeformableMultiBodyDynamicsWorld.h" #include "BulletSoftBody/btSoftBody.h" #include "BulletSoftBody/btSoftBodyHelpers.h" #include "BulletSoftBody/btDeformableBodySolver.h" #include "BulletSoftBody/btSoftBodyRigidBodyCollisionConfiguration.h" #include "BulletDynamics/Featherstone/btMultiBodyConstraintSolver.h" #include "../CommonInterfaces/CommonParameterInterface.h" #include //printf debugging #include "../CommonInterfaces/CommonDeformableBodyBase.h" #include "../Utils/b3ResourcePath.h" ///The BasicTest shows the contact between volumetric deformable objects and rigid objects. static btScalar E = 50; static btScalar nu = 0.3; // static btScalar damping_alpha = 0.1; // static btScalar damping_beta = 0.01; static btScalar damping_alpha = 0.0; static btScalar damping_beta = 0.0; static btScalar COLLIDING_VELOCITY = 0; class BasicTest : public CommonDeformableBodyBase { // btDeformableLinearElasticityForce* m_linearElasticity; btDeformableMassSpringForce* m_massSpring; btAlignedObjectArray m_eigenvalues, m_Kr, m_Mr; btAlignedObjectArray > m_modes; // each inner array is a mode, outer array size = n_modes unsigned int m_numModes; bool first_step; public: BasicTest(struct GUIHelperInterface* helper) : CommonDeformableBodyBase(helper), m_numModes(0) { // m_linearElasticity = 0; m_massSpring = 0; first_step = true; } virtual ~BasicTest() { } void initPhysics(); void exitPhysics(); // TODO: disable pick force, non-interactive for now. bool pickBody(const btVector3& rayFromWorld, const btVector3& rayToWorld) { return false; } void resetCamera() { float dist = 20; float pitch = 0; float yaw = 90; float targetPos[3] = {0, 3, 0}; m_guiHelper->resetCamera(dist, yaw, pitch, targetPos[0], targetPos[1], targetPos[2]); } void Ctor_RbUpStack() { float mass = 0.5; btCollisionShape* shape = new btBoxShape(btVector3(2, 2, 2)); btTransform startTransform; startTransform.setIdentity(); startTransform.setOrigin(btVector3(0,-2,0)); btRigidBody* rb = createRigidBody(mass, startTransform, shape); rb->setLinearVelocity(btVector3(0,+COLLIDING_VELOCITY, 0)); } void stepSimulation(float deltaTime) { // TODO: remove this. very hacky way of adding initial deformation btSoftBody* psb = static_cast(m_dynamicsWorld)->getSoftBodyArray()[0]; if (first_step && !psb->m_bUpdateRtCst) { // save rest length btAlignedObjectArray rest_length; // assign initial displacement (perturb each nodes by mode 1) for (int i = 0; i < psb->m_nodes.size(); ++i) { for (int k = 0; k < 3; ++k) { psb->m_nodes[i].m_x[k] += m_modes[0][3 * i + k]; } } first_step = false; } float internalTimeStep = 1. / 60.f; m_dynamicsWorld->stepSimulation(deltaTime, 1, internalTimeStep); } virtual void renderScene() { CommonDeformableBodyBase::renderScene(); btDeformableMultiBodyDynamicsWorld* deformableWorld = getDeformableDynamicsWorld(); for (int i = 0; i < deformableWorld->getSoftBodyArray().size(); i++) { btSoftBody* psb = (btSoftBody*)deformableWorld->getSoftBodyArray()[i]; { btSoftBodyHelpers::DrawFrame(psb, deformableWorld->getDebugDrawer()); btSoftBodyHelpers::Draw(psb, deformableWorld->getDebugDrawer(), deformableWorld->getDrawFlags()); } } } }; void BasicTest::initPhysics() { m_guiHelper->setUpAxis(1); ///collision configuration contains default setup for memory, collision setup m_collisionConfiguration = new btSoftBodyRigidBodyCollisionConfiguration(); ///use the default collision dispatcher. For parallel processing you can use a diffent dispatcher (see Extras/BulletMultiThreaded) m_dispatcher = new btCollisionDispatcher(m_collisionConfiguration); m_broadphase = new btDbvtBroadphase(); btDeformableBodySolver* deformableBodySolver = new btDeformableBodySolver(); btDeformableMultiBodyConstraintSolver* sol = new btDeformableMultiBodyConstraintSolver(); sol->setDeformableSolver(deformableBodySolver); m_solver = sol; m_dynamicsWorld = new btDeformableMultiBodyDynamicsWorld(m_dispatcher, m_broadphase, sol, m_collisionConfiguration, deformableBodySolver); btVector3 gravity = btVector3(0, 0, 0); m_dynamicsWorld->setGravity(gravity); m_guiHelper->createPhysicsDebugDrawer(m_dynamicsWorld); // create volumetric soft body { std::string filename("../../../examples/SoftDemo/mesh.vtk"); btSoftBody* psb = btSoftBodyHelpers::CreateFromVtkFile(getDeformableDynamicsWorld()->getWorldInfo(), filename.c_str()); // read in eigenmodes, stiffness and mass matrices unsigned int buffer_n_modes = 0; std::string eigenvalues_file("../../../examples/SoftDemo/eigenvalues.bin"); btSoftBodyHelpers::readBinary(m_eigenvalues, buffer_n_modes, eigenvalues_file.c_str()); m_numModes = buffer_n_modes; std::string Kr_file("../../../examples/SoftDemo/K_r_diag_mat.bin"); btSoftBodyHelpers::readBinary(m_Kr, buffer_n_modes, Kr_file.c_str()); std::string Mr_file("../../../examples/SoftDemo/M_r_diag_mat.bin"); btSoftBodyHelpers::readBinary(m_Mr, buffer_n_modes, Mr_file.c_str()); std::string modes_file("../../../examples/SoftDemo/modes.bin"); btSoftBodyHelpers::readBinaryMat(m_modes, 3 * psb->m_nodes.size(), buffer_n_modes, modes_file.c_str()); // default to 3D getDeformableDynamicsWorld()->addSoftBody(psb); psb->scale(btVector3(2, 2, 2)); psb->translate(btVector3(0, 7, 0)); psb->getCollisionShape()->setMargin(0.1); psb->setTotalMass(0.5); psb->m_cfg.kKHR = 1; // collision hardness with kinematic objects psb->m_cfg.kCHR = 1; // collision hardness with rigid body psb->m_cfg.kDF = 0; psb->m_cfg.collisions = btSoftBody::fCollision::SDF_RD; psb->m_cfg.collisions |= btSoftBody::fCollision::SDF_RDN; psb->m_sleepingThreshold = 0; btSoftBodyHelpers::generateBoundaryFaces(psb); psb->setVelocity(btVector3(0, -COLLIDING_VELOCITY, 0)); // btDeformableLinearElasticityForce* linearElasticity = new btDeformableLinearElasticityForce(100,100,0.01); // m_linearElasticity = linearElasticity; m_massSpring = new btDeformableMassSpringForce(10.0, 0.0); //TODO: this stiffness needs to match the modes getDeformableDynamicsWorld()->addForce(psb, m_massSpring); m_forces.push_back(m_massSpring); } getDeformableDynamicsWorld()->setReducedModelFlag(true); getDeformableDynamicsWorld()->setImplicit(false); getDeformableDynamicsWorld()->setLineSearch(false); getDeformableDynamicsWorld()->setUseProjection(true); getDeformableDynamicsWorld()->getSolverInfo().m_deformable_erp = 0.3; getDeformableDynamicsWorld()->getSolverInfo().m_deformable_maxErrorReduction = btScalar(200); getDeformableDynamicsWorld()->getSolverInfo().m_leastSquaresResidualThreshold = 1e-3; getDeformableDynamicsWorld()->getSolverInfo().m_splitImpulse = true; getDeformableDynamicsWorld()->getSolverInfo().m_numIterations = 100; // add a few rigid bodies // Ctor_RbUpStack(); // TODO: no rigid body for now m_guiHelper->autogenerateGraphicsObjects(m_dynamicsWorld); // { // SliderParams slider("Young's Modulus", &E); // slider.m_minVal = 0; // slider.m_maxVal = 2000; // if (m_guiHelper->getParameterInterface()) // m_guiHelper->getParameterInterface()->registerSliderFloatParameter(slider); // } // { // SliderParams slider("Poisson Ratio", &nu); // slider.m_minVal = 0.05; // slider.m_maxVal = 0.49; // if (m_guiHelper->getParameterInterface()) // m_guiHelper->getParameterInterface()->registerSliderFloatParameter(slider); // } // { // SliderParams slider("Mass Damping", &damping_alpha); // slider.m_minVal = 0; // slider.m_maxVal = 1; // if (m_guiHelper->getParameterInterface()) // m_guiHelper->getParameterInterface()->registerSliderFloatParameter(slider); // } // { // SliderParams slider("Stiffness Damping", &damping_beta); // slider.m_minVal = 0; // slider.m_maxVal = 0.1; // if (m_guiHelper->getParameterInterface()) // m_guiHelper->getParameterInterface()->registerSliderFloatParameter(slider); // } } void BasicTest::exitPhysics() { //cleanup in the reverse order of creation/initialization removePickingConstraint(); //remove the rigidbodies from the dynamics world and delete them int i; for (i = m_dynamicsWorld->getNumCollisionObjects() - 1; i >= 0; i--) { btCollisionObject* obj = m_dynamicsWorld->getCollisionObjectArray()[i]; btRigidBody* body = btRigidBody::upcast(obj); if (body && body->getMotionState()) { delete body->getMotionState(); } m_dynamicsWorld->removeCollisionObject(obj); delete obj; } // delete forces for (int j = 0; j < m_forces.size(); j++) { btDeformableLagrangianForce* force = m_forces[j]; delete force; } m_forces.clear(); //delete collision shapes for (int j = 0; j < m_collisionShapes.size(); j++) { btCollisionShape* shape = m_collisionShapes[j]; delete shape; } m_collisionShapes.clear(); delete m_dynamicsWorld; delete m_solver; delete m_broadphase; delete m_dispatcher; delete m_collisionConfiguration; } class CommonExampleInterface* ReducedBasicTestCreateFunc(struct CommonExampleOptions& options) { return new BasicTest(options.m_guiHelper); }