1 /* 2 Written by Xuchen Han <xuchenhan2015@u.northwestern.edu> 3 4 Bullet Continuous Collision Detection and Physics Library 5 Copyright (c) 2019 Google Inc. http://bulletphysics.org 6 This software is provided 'as-is', without any express or implied warranty. 7 In no event will the authors be held liable for any damages arising from the use of this software. 8 Permission is granted to anyone to use this software for any purpose, 9 including commercial applications, and to alter it and redistribute it freely, 10 subject to the following restrictions: 11 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. 12 2. Altered source versions must be plainly marked as such, and must not be misrepresented as being the original software. 13 3. This notice may not be removed or altered from any source distribution. 14 */ 15 16 #ifndef BT_DEFORMABLE_CONTACT_CONSTRAINT_H 17 #define BT_DEFORMABLE_CONTACT_CONSTRAINT_H 18 #include "btSoftBody.h" 19 20 // btDeformableContactConstraint is an abstract class specifying the method that each type of contact constraint needs to implement 21 class btDeformableContactConstraint 22 { 23 public: 24 // True if the friction is static 25 // False if the friction is dynamic 26 bool m_static; 27 const btContactSolverInfo* m_infoGlobal; 28 29 // normal of the contact 30 btVector3 m_normal; 31 btDeformableContactConstraint(const btVector3 & normal,const btContactSolverInfo & infoGlobal)32 btDeformableContactConstraint(const btVector3& normal, const btContactSolverInfo& infoGlobal) : m_static(false), m_normal(normal), m_infoGlobal(&infoGlobal) 33 { 34 } 35 btDeformableContactConstraint(bool isStatic,const btVector3 & normal,const btContactSolverInfo & infoGlobal)36 btDeformableContactConstraint(bool isStatic, const btVector3& normal, const btContactSolverInfo& infoGlobal) : m_static(isStatic), m_normal(normal), m_infoGlobal(&infoGlobal) 37 { 38 } 39 btDeformableContactConstraint()40 btDeformableContactConstraint() : m_static(false) {} 41 btDeformableContactConstraint(const btDeformableContactConstraint & other)42 btDeformableContactConstraint(const btDeformableContactConstraint& other) 43 : m_static(other.m_static), m_normal(other.m_normal), m_infoGlobal(other.m_infoGlobal) 44 { 45 } 46 ~btDeformableContactConstraint()47 virtual ~btDeformableContactConstraint() {} 48 49 // solve the constraint with inelastic impulse and return the error, which is the square of normal component of velocity diffrerence 50 // the constraint is solved by calculating the impulse between object A and B in the contact and apply the impulse to both objects involved in the contact 51 virtual btScalar solveConstraint(const btContactSolverInfo& infoGlobal) = 0; 52 53 // get the velocity of the object A in the contact 54 virtual btVector3 getVa() const = 0; 55 56 // get the velocity of the object B in the contact 57 virtual btVector3 getVb() const = 0; 58 59 // get the velocity change of the soft body node in the constraint 60 virtual btVector3 getDv(const btSoftBody::Node*) const = 0; 61 62 // apply impulse to the soft body node and/or face involved 63 virtual void applyImpulse(const btVector3& impulse) = 0; 64 65 // scale the penetration depth by erp 66 virtual void setPenetrationScale(btScalar scale) = 0; 67 }; 68 69 // 70 // Constraint that a certain node in the deformable objects cannot move 71 class btDeformableStaticConstraint : public btDeformableContactConstraint 72 { 73 public: 74 btSoftBody::Node* m_node; 75 btDeformableStaticConstraint(btSoftBody::Node * node,const btContactSolverInfo & infoGlobal)76 btDeformableStaticConstraint(btSoftBody::Node* node, const btContactSolverInfo& infoGlobal) : m_node(node), btDeformableContactConstraint(false, btVector3(0, 0, 0), infoGlobal) 77 { 78 } btDeformableStaticConstraint()79 btDeformableStaticConstraint() {} btDeformableStaticConstraint(const btDeformableStaticConstraint & other)80 btDeformableStaticConstraint(const btDeformableStaticConstraint& other) 81 : m_node(other.m_node), btDeformableContactConstraint(other) 82 { 83 } 84 ~btDeformableStaticConstraint()85 virtual ~btDeformableStaticConstraint() {} 86 solveConstraint(const btContactSolverInfo & infoGlobal)87 virtual btScalar solveConstraint(const btContactSolverInfo& infoGlobal) 88 { 89 return 0; 90 } 91 getVa()92 virtual btVector3 getVa() const 93 { 94 return btVector3(0, 0, 0); 95 } 96 getVb()97 virtual btVector3 getVb() const 98 { 99 return btVector3(0, 0, 0); 100 } 101 getDv(const btSoftBody::Node * n)102 virtual btVector3 getDv(const btSoftBody::Node* n) const 103 { 104 return btVector3(0, 0, 0); 105 } 106 applyImpulse(const btVector3 & impulse)107 virtual void applyImpulse(const btVector3& impulse) {} setPenetrationScale(btScalar scale)108 virtual void setPenetrationScale(btScalar scale) {} 109 }; 110 111 // 112 // Anchor Constraint between rigid and deformable node 113 class btDeformableNodeAnchorConstraint : public btDeformableContactConstraint 114 { 115 public: 116 const btSoftBody::DeformableNodeRigidAnchor* m_anchor; 117 118 btDeformableNodeAnchorConstraint(const btSoftBody::DeformableNodeRigidAnchor& c, const btContactSolverInfo& infoGlobal); 119 btDeformableNodeAnchorConstraint(const btDeformableNodeAnchorConstraint& other); btDeformableNodeAnchorConstraint()120 btDeformableNodeAnchorConstraint() {} ~btDeformableNodeAnchorConstraint()121 virtual ~btDeformableNodeAnchorConstraint() 122 { 123 } 124 virtual btScalar solveConstraint(const btContactSolverInfo& infoGlobal); 125 126 // object A is the rigid/multi body, and object B is the deformable node/face 127 virtual btVector3 getVa() const; 128 // get the velocity of the deformable node in contact 129 virtual btVector3 getVb() const; getDv(const btSoftBody::Node * n)130 virtual btVector3 getDv(const btSoftBody::Node* n) const 131 { 132 return btVector3(0, 0, 0); 133 } 134 virtual void applyImpulse(const btVector3& impulse); 135 setPenetrationScale(btScalar scale)136 virtual void setPenetrationScale(btScalar scale) {} 137 }; 138 139 // 140 // Constraint between rigid/multi body and deformable objects 141 class btDeformableRigidContactConstraint : public btDeformableContactConstraint 142 { 143 public: 144 btVector3 m_total_normal_dv; 145 btVector3 m_total_tangent_dv; 146 btScalar m_penetration; 147 btScalar m_total_split_impulse; 148 bool m_binding; 149 const btSoftBody::DeformableRigidContact* m_contact; 150 151 btDeformableRigidContactConstraint(const btSoftBody::DeformableRigidContact& c, const btContactSolverInfo& infoGlobal); 152 btDeformableRigidContactConstraint(const btDeformableRigidContactConstraint& other); btDeformableRigidContactConstraint()153 btDeformableRigidContactConstraint() : m_binding(false) {} ~btDeformableRigidContactConstraint()154 virtual ~btDeformableRigidContactConstraint() 155 { 156 } 157 158 // object A is the rigid/multi body, and object B is the deformable node/face 159 virtual btVector3 getVa() const; 160 161 // get the split impulse velocity of the deformable face at the contact point 162 virtual btVector3 getSplitVb() const = 0; 163 164 // get the split impulse velocity of the rigid/multibdoy at the contaft 165 virtual btVector3 getSplitVa() const; 166 167 virtual btScalar solveConstraint(const btContactSolverInfo& infoGlobal); 168 setPenetrationScale(btScalar scale)169 virtual void setPenetrationScale(btScalar scale) 170 { 171 m_penetration *= scale; 172 } 173 174 btScalar solveSplitImpulse(const btContactSolverInfo& infoGlobal); 175 176 virtual void applySplitImpulse(const btVector3& impulse) = 0; 177 }; 178 179 // 180 // Constraint between rigid/multi body and deformable objects nodes 181 class btDeformableNodeRigidContactConstraint : public btDeformableRigidContactConstraint 182 { 183 public: 184 // the deformable node in contact 185 btSoftBody::Node* m_node; 186 187 btDeformableNodeRigidContactConstraint(const btSoftBody::DeformableNodeRigidContact& contact, const btContactSolverInfo& infoGlobal); 188 btDeformableNodeRigidContactConstraint(const btDeformableNodeRigidContactConstraint& other); btDeformableNodeRigidContactConstraint()189 btDeformableNodeRigidContactConstraint() {} ~btDeformableNodeRigidContactConstraint()190 virtual ~btDeformableNodeRigidContactConstraint() 191 { 192 } 193 194 // get the velocity of the deformable node in contact 195 virtual btVector3 getVb() const; 196 197 // get the split impulse velocity of the deformable face at the contact point 198 virtual btVector3 getSplitVb() const; 199 200 // get the velocity change of the input soft body node in the constraint 201 virtual btVector3 getDv(const btSoftBody::Node*) const; 202 203 // cast the contact to the desired type getContact()204 const btSoftBody::DeformableNodeRigidContact* getContact() const 205 { 206 return static_cast<const btSoftBody::DeformableNodeRigidContact*>(m_contact); 207 } 208 209 virtual void applyImpulse(const btVector3& impulse); 210 211 virtual void applySplitImpulse(const btVector3& impulse); 212 }; 213 214 // 215 // Constraint between rigid/multi body and deformable objects faces 216 class btDeformableFaceRigidContactConstraint : public btDeformableRigidContactConstraint 217 { 218 public: 219 btSoftBody::Face* m_face; 220 bool m_useStrainLimiting; 221 btDeformableFaceRigidContactConstraint(const btSoftBody::DeformableFaceRigidContact& contact, const btContactSolverInfo& infoGlobal, bool useStrainLimiting); 222 btDeformableFaceRigidContactConstraint(const btDeformableFaceRigidContactConstraint& other); btDeformableFaceRigidContactConstraint()223 btDeformableFaceRigidContactConstraint() : m_useStrainLimiting(false) {} ~btDeformableFaceRigidContactConstraint()224 virtual ~btDeformableFaceRigidContactConstraint() 225 { 226 } 227 228 // get the velocity of the deformable face at the contact point 229 virtual btVector3 getVb() const; 230 231 // get the split impulse velocity of the deformable face at the contact point 232 virtual btVector3 getSplitVb() const; 233 234 // get the velocity change of the input soft body node in the constraint 235 virtual btVector3 getDv(const btSoftBody::Node*) const; 236 237 // cast the contact to the desired type getContact()238 const btSoftBody::DeformableFaceRigidContact* getContact() const 239 { 240 return static_cast<const btSoftBody::DeformableFaceRigidContact*>(m_contact); 241 } 242 243 virtual void applyImpulse(const btVector3& impulse); 244 245 virtual void applySplitImpulse(const btVector3& impulse); 246 }; 247 248 // 249 // Constraint between deformable objects faces and deformable objects nodes 250 class btDeformableFaceNodeContactConstraint : public btDeformableContactConstraint 251 { 252 public: 253 btSoftBody::Node* m_node; 254 btSoftBody::Face* m_face; 255 const btSoftBody::DeformableFaceNodeContact* m_contact; 256 btVector3 m_total_normal_dv; 257 btVector3 m_total_tangent_dv; 258 259 btDeformableFaceNodeContactConstraint(const btSoftBody::DeformableFaceNodeContact& contact, const btContactSolverInfo& infoGlobal); btDeformableFaceNodeContactConstraint()260 btDeformableFaceNodeContactConstraint() {} ~btDeformableFaceNodeContactConstraint()261 virtual ~btDeformableFaceNodeContactConstraint() {} 262 263 virtual btScalar solveConstraint(const btContactSolverInfo& infoGlobal); 264 265 // get the velocity of the object A in the contact 266 virtual btVector3 getVa() const; 267 268 // get the velocity of the object B in the contact 269 virtual btVector3 getVb() const; 270 271 // get the velocity change of the input soft body node in the constraint 272 virtual btVector3 getDv(const btSoftBody::Node*) const; 273 274 // cast the contact to the desired type getContact()275 const btSoftBody::DeformableFaceNodeContact* getContact() const 276 { 277 return static_cast<const btSoftBody::DeformableFaceNodeContact*>(m_contact); 278 } 279 280 virtual void applyImpulse(const btVector3& impulse); 281 setPenetrationScale(btScalar scale)282 virtual void setPenetrationScale(btScalar scale) {} 283 }; 284 #endif /* BT_DEFORMABLE_CONTACT_CONSTRAINT_H */ 285