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Diffstat (limited to 'extern/bullet2/src/BulletSoftBody/btDeformableMousePickingForce.h')
| -rw-r--r-- | extern/bullet2/src/BulletSoftBody/btDeformableMousePickingForce.h | 162 |
1 files changed, 162 insertions, 0 deletions
diff --git a/extern/bullet2/src/BulletSoftBody/btDeformableMousePickingForce.h b/extern/bullet2/src/BulletSoftBody/btDeformableMousePickingForce.h new file mode 100644 index 00000000000..d218d962149 --- /dev/null +++ b/extern/bullet2/src/BulletSoftBody/btDeformableMousePickingForce.h @@ -0,0 +1,162 @@ +/* + Written by Xuchen Han <xuchenhan2015@u.northwestern.edu> + + 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. + */ + +#ifndef BT_MOUSE_PICKING_FORCE_H +#define BT_MOUSE_PICKING_FORCE_H + +#include "btDeformableLagrangianForce.h" + +class btDeformableMousePickingForce : public btDeformableLagrangianForce +{ + // If true, the damping force will be in the direction of the spring + // If false, the damping force will be in the direction of the velocity + btScalar m_elasticStiffness, m_dampingStiffness; + const btSoftBody::Face& m_face; + btVector3 m_mouse_pos; + btScalar m_maxForce; + +public: + typedef btAlignedObjectArray<btVector3> TVStack; + btDeformableMousePickingForce(btScalar k, btScalar d, const btSoftBody::Face& face, btVector3 mouse_pos, btScalar maxForce = 0.3) : m_elasticStiffness(k), m_dampingStiffness(d), m_face(face), m_mouse_pos(mouse_pos), m_maxForce(maxForce) + { + } + + virtual void addScaledForces(btScalar scale, TVStack& force) + { + addScaledDampingForce(scale, force); + addScaledElasticForce(scale, force); + } + + virtual void addScaledExplicitForce(btScalar scale, TVStack& force) + { + addScaledElasticForce(scale, force); + } + + virtual void addScaledDampingForce(btScalar scale, TVStack& force) + { + for (int i = 0; i < 3; ++i) + { + btVector3 v_diff = m_face.m_n[i]->m_v; + btVector3 scaled_force = scale * m_dampingStiffness * v_diff; + if ((m_face.m_n[i]->m_x - m_mouse_pos).norm() > SIMD_EPSILON) + { + btVector3 dir = (m_face.m_n[i]->m_x - m_mouse_pos).normalized(); + scaled_force = scale * m_dampingStiffness * v_diff.dot(dir) * dir; + } + force[m_face.m_n[i]->index] -= scaled_force; + } + } + + virtual void addScaledElasticForce(btScalar scale, TVStack& force) + { + btScalar scaled_stiffness = scale * m_elasticStiffness; + for (int i = 0; i < 3; ++i) + { + btVector3 dir = (m_face.m_n[i]->m_q - m_mouse_pos); + btVector3 scaled_force = scaled_stiffness * dir; + if (scaled_force.safeNorm() > m_maxForce) + { + scaled_force.safeNormalize(); + scaled_force *= m_maxForce; + } + force[m_face.m_n[i]->index] -= scaled_force; + } + } + + virtual void addScaledDampingForceDifferential(btScalar scale, const TVStack& dv, TVStack& df) + { + btScalar scaled_k_damp = m_dampingStiffness * scale; + for (int i = 0; i < 3; ++i) + { + btVector3 local_scaled_df = scaled_k_damp * dv[m_face.m_n[i]->index]; + if ((m_face.m_n[i]->m_x - m_mouse_pos).norm() > SIMD_EPSILON) + { + btVector3 dir = (m_face.m_n[i]->m_x - m_mouse_pos).normalized(); + local_scaled_df = scaled_k_damp * dv[m_face.m_n[i]->index].dot(dir) * dir; + } + df[m_face.m_n[i]->index] -= local_scaled_df; + } + } + + virtual void buildDampingForceDifferentialDiagonal(btScalar scale, TVStack& diagA) {} + + virtual double totalElasticEnergy(btScalar dt) + { + double energy = 0; + for (int i = 0; i < 3; ++i) + { + btVector3 dir = (m_face.m_n[i]->m_q - m_mouse_pos); + btVector3 scaled_force = m_elasticStiffness * dir; + if (scaled_force.safeNorm() > m_maxForce) + { + scaled_force.safeNormalize(); + scaled_force *= m_maxForce; + } + energy += 0.5 * scaled_force.dot(dir); + } + return energy; + } + + virtual double totalDampingEnergy(btScalar dt) + { + double energy = 0; + for (int i = 0; i < 3; ++i) + { + btVector3 v_diff = m_face.m_n[i]->m_v; + btVector3 scaled_force = m_dampingStiffness * v_diff; + if ((m_face.m_n[i]->m_x - m_mouse_pos).norm() > SIMD_EPSILON) + { + btVector3 dir = (m_face.m_n[i]->m_x - m_mouse_pos).normalized(); + scaled_force = m_dampingStiffness * v_diff.dot(dir) * dir; + } + energy -= scaled_force.dot(m_face.m_n[i]->m_v) / dt; + } + return energy; + } + + virtual void addScaledElasticForceDifferential(btScalar scale, const TVStack& dx, TVStack& df) + { + btScalar scaled_stiffness = scale * m_elasticStiffness; + for (int i = 0; i < 3; ++i) + { + btVector3 dir = (m_face.m_n[i]->m_q - m_mouse_pos); + btScalar dir_norm = dir.norm(); + btVector3 dir_normalized = (dir_norm > SIMD_EPSILON) ? dir.normalized() : btVector3(0, 0, 0); + int id = m_face.m_n[i]->index; + btVector3 dx_diff = dx[id]; + btScalar r = 0; // rest length is 0 for picking spring + btVector3 scaled_df = btVector3(0, 0, 0); + if (dir_norm > SIMD_EPSILON) + { + scaled_df -= scaled_stiffness * dir_normalized.dot(dx_diff) * dir_normalized; + scaled_df += scaled_stiffness * dir_normalized.dot(dx_diff) * ((dir_norm - r) / dir_norm) * dir_normalized; + scaled_df -= scaled_stiffness * ((dir_norm - r) / dir_norm) * dx_diff; + } + df[id] += scaled_df; + } + } + + void setMousePos(const btVector3& p) + { + m_mouse_pos = p; + } + + virtual btDeformableLagrangianForceType getForceType() + { + return BT_MOUSE_PICKING_FORCE; + } +}; + +#endif /* btMassSpring_h */ |