diff options
Diffstat (limited to 'servers/physics/joints/hinge_joint_sw.cpp')
| -rw-r--r-- | servers/physics/joints/hinge_joint_sw.cpp | 438 |
1 files changed, 438 insertions, 0 deletions
diff --git a/servers/physics/joints/hinge_joint_sw.cpp b/servers/physics/joints/hinge_joint_sw.cpp new file mode 100644 index 0000000000..feaf00290d --- /dev/null +++ b/servers/physics/joints/hinge_joint_sw.cpp @@ -0,0 +1,438 @@ +#include "hinge_joint_sw.h" + +static void plane_space(const Vector3& n, Vector3& p, Vector3& q) { + + if (Math::abs(n.z) > 0.707106781186547524400844362) { + // choose p in y-z plane + real_t a = n[1]*n[1] + n[2]*n[2]; + real_t k = 1.0/Math::sqrt(a); + p=Vector3(0,-n[2]*k,n[1]*k); + // set q = n x p + q=Vector3(a*k,-n[0]*p[2],n[0]*p[1]); + } + else { + // choose p in x-y plane + real_t a = n.x*n.x + n.y*n.y; + real_t k = 1.0/Math::sqrt(a); + p=Vector3(-n.y*k,n.x*k,0); + // set q = n x p + q=Vector3(-n.z*p.y,n.z*p.x,a*k); + } +} + +HingeJointSW::HingeJointSW(BodySW* rbA,BodySW* rbB, const Transform& frameA, const Transform& frameB) : JointSW(_arr,2) { + + A=rbA; + B=rbB; + + m_rbAFrame=frameA; + m_rbBFrame=frameB; + // flip axis + m_rbBFrame.basis[0][2] *= real_t(-1.); + m_rbBFrame.basis[1][2] *= real_t(-1.); + m_rbBFrame.basis[2][2] *= real_t(-1.); + + + //start with free + m_lowerLimit = Math_PI; + m_upperLimit = -Math_PI; + + + m_useLimit = false; + m_biasFactor = 0.3f; + m_relaxationFactor = 1.0f; + m_limitSoftness = 0.9f; + m_solveLimit = false; + + tau=0.3; + + m_angularOnly=false; + m_enableAngularMotor=false; + + A->add_constraint(this,0); + B->add_constraint(this,1); + +} + +HingeJointSW::HingeJointSW(BodySW* rbA,BodySW* rbB, const Vector3& pivotInA,const Vector3& pivotInB, + const Vector3& axisInA,const Vector3& axisInB) : JointSW(_arr,2) { + + A=rbA; + B=rbB; + + m_rbAFrame.origin = pivotInA; + + // since no frame is given, assume this to be zero angle and just pick rb transform axis + Vector3 rbAxisA1 = rbA->get_transform().basis.get_axis(0); + + Vector3 rbAxisA2; + real_t projection = axisInA.dot(rbAxisA1); + if (projection >= 1.0f - CMP_EPSILON) { + rbAxisA1 = -rbA->get_transform().basis.get_axis(2); + rbAxisA2 = rbA->get_transform().basis.get_axis(1); + } else if (projection <= -1.0f + CMP_EPSILON) { + rbAxisA1 = rbA->get_transform().basis.get_axis(2); + rbAxisA2 = rbA->get_transform().basis.get_axis(1); + } else { + rbAxisA2 = axisInA.cross(rbAxisA1); + rbAxisA1 = rbAxisA2.cross(axisInA); + } + + m_rbAFrame.basis=Matrix3( rbAxisA1.x,rbAxisA2.x,axisInA.x, + rbAxisA1.y,rbAxisA2.y,axisInA.y, + rbAxisA1.z,rbAxisA2.z,axisInA.z ); + + Quat rotationArc = Quat(axisInA,axisInB); + Vector3 rbAxisB1 = rotationArc.xform(rbAxisA1); + Vector3 rbAxisB2 = axisInB.cross(rbAxisB1); + + m_rbBFrame.origin = pivotInB; + m_rbBFrame.basis=Matrix3( rbAxisB1.x,rbAxisB2.x,-axisInB.x, + rbAxisB1.y,rbAxisB2.y,-axisInB.y, + rbAxisB1.z,rbAxisB2.z,-axisInB.z ); + + //start with free + m_lowerLimit = Math_PI; + m_upperLimit = -Math_PI; + + + m_useLimit = false; + m_biasFactor = 0.3f; + m_relaxationFactor = 1.0f; + m_limitSoftness = 0.9f; + m_solveLimit = false; + + tau=0.3; + + m_angularOnly=false; + m_enableAngularMotor=false; + + A->add_constraint(this,0); + B->add_constraint(this,1); + +} + + + +bool HingeJointSW::setup(float p_step) { + + m_appliedImpulse = real_t(0.); + + if (!m_angularOnly) + { + Vector3 pivotAInW = A->get_transform().xform(m_rbAFrame.origin); + Vector3 pivotBInW = B->get_transform().xform(m_rbBFrame.origin); + Vector3 relPos = pivotBInW - pivotAInW; + + Vector3 normal[3]; + if (relPos.length_squared() > CMP_EPSILON) + { + normal[0] = relPos.normalized(); + } + else + { + normal[0]=Vector3(real_t(1.0),0,0); + } + + plane_space(normal[0], normal[1], normal[2]); + + for (int i=0;i<3;i++) + { + memnew_placement(&m_jac[i], JacobianEntrySW( + A->get_transform().basis.transposed(), + B->get_transform().basis.transposed(), + pivotAInW - A->get_transform().origin, + pivotBInW - B->get_transform().origin, + normal[i], + A->get_inv_inertia(), + A->get_inv_mass(), + B->get_inv_inertia(), + B->get_inv_mass()) ); + } + } + + //calculate two perpendicular jointAxis, orthogonal to hingeAxis + //these two jointAxis require equal angular velocities for both bodies + + //this is unused for now, it's a todo + Vector3 jointAxis0local; + Vector3 jointAxis1local; + + plane_space(m_rbAFrame.basis.get_axis(2),jointAxis0local,jointAxis1local); + + A->get_transform().basis.xform( m_rbAFrame.basis.get_axis(2) ); + Vector3 jointAxis0 = A->get_transform().basis.xform( jointAxis0local ); + Vector3 jointAxis1 = A->get_transform().basis.xform( jointAxis1local ); + Vector3 hingeAxisWorld = A->get_transform().basis.xform( m_rbAFrame.basis.get_axis(2) ); + + memnew_placement(&m_jacAng[0], JacobianEntrySW(jointAxis0, + A->get_transform().basis.transposed(), + B->get_transform().basis.transposed(), + A->get_inv_inertia(), + B->get_inv_inertia())); + + memnew_placement(&m_jacAng[1], JacobianEntrySW(jointAxis1, + A->get_transform().basis.transposed(), + B->get_transform().basis.transposed(), + A->get_inv_inertia(), + B->get_inv_inertia())); + + memnew_placement(&m_jacAng[2], JacobianEntrySW(hingeAxisWorld, + A->get_transform().basis.transposed(), + B->get_transform().basis.transposed(), + A->get_inv_inertia(), + B->get_inv_inertia())); + + + // Compute limit information + real_t hingeAngle = get_hinge_angle(); + +// print_line("angle: "+rtos(hingeAngle)); + //set bias, sign, clear accumulator + m_correction = real_t(0.); + m_limitSign = real_t(0.); + m_solveLimit = false; + m_accLimitImpulse = real_t(0.); + + + + /*if (m_useLimit) { + print_line("low: "+rtos(m_lowerLimit)); + print_line("hi: "+rtos(m_upperLimit)); + }*/ + +// if (m_lowerLimit < m_upperLimit) + if (m_useLimit && m_lowerLimit <= m_upperLimit) + { +// if (hingeAngle <= m_lowerLimit*m_limitSoftness) + if (hingeAngle <= m_lowerLimit) + { + m_correction = (m_lowerLimit - hingeAngle); + m_limitSign = 1.0f; + m_solveLimit = true; + } +// else if (hingeAngle >= m_upperLimit*m_limitSoftness) + else if (hingeAngle >= m_upperLimit) + { + m_correction = m_upperLimit - hingeAngle; + m_limitSign = -1.0f; + m_solveLimit = true; + } + } + + //Compute K = J*W*J' for hinge axis + Vector3 axisA = A->get_transform().basis.xform( m_rbAFrame.basis.get_axis(2) ); + m_kHinge = 1.0f / (A->compute_angular_impulse_denominator(axisA) + + B->compute_angular_impulse_denominator(axisA)); + + return true; +} + +void HingeJointSW::solve(float p_step) { + + Vector3 pivotAInW = A->get_transform().xform(m_rbAFrame.origin); + Vector3 pivotBInW = B->get_transform().xform(m_rbBFrame.origin); + + //real_t tau = real_t(0.3); + + //linear part + if (!m_angularOnly) + { + Vector3 rel_pos1 = pivotAInW - A->get_transform().origin; + Vector3 rel_pos2 = pivotBInW - B->get_transform().origin; + + Vector3 vel1 = A->get_velocity_in_local_point(rel_pos1); + Vector3 vel2 = B->get_velocity_in_local_point(rel_pos2); + Vector3 vel = vel1 - vel2; + + for (int i=0;i<3;i++) + { + const Vector3& normal = m_jac[i].m_linearJointAxis; + real_t jacDiagABInv = real_t(1.) / m_jac[i].getDiagonal(); + + real_t rel_vel; + rel_vel = normal.dot(vel); + //positional error (zeroth order error) + real_t depth = -(pivotAInW - pivotBInW).dot(normal); //this is the error projected on the normal + real_t impulse = depth*tau/p_step * jacDiagABInv - rel_vel * jacDiagABInv; + m_appliedImpulse += impulse; + Vector3 impulse_vector = normal * impulse; + A->apply_impulse(pivotAInW - A->get_transform().origin,impulse_vector); + B->apply_impulse(pivotBInW - B->get_transform().origin,-impulse_vector); + } + } + + + { + ///solve angular part + + // get axes in world space + Vector3 axisA = A->get_transform().basis.xform( m_rbAFrame.basis.get_axis(2) ); + Vector3 axisB = B->get_transform().basis.xform( m_rbBFrame.basis.get_axis(2) ); + + const Vector3& angVelA = A->get_angular_velocity(); + const Vector3& angVelB = B->get_angular_velocity(); + + Vector3 angVelAroundHingeAxisA = axisA * axisA.dot(angVelA); + Vector3 angVelAroundHingeAxisB = axisB * axisB.dot(angVelB); + + Vector3 angAorthog = angVelA - angVelAroundHingeAxisA; + Vector3 angBorthog = angVelB - angVelAroundHingeAxisB; + Vector3 velrelOrthog = angAorthog-angBorthog; + { + //solve orthogonal angular velocity correction + real_t relaxation = real_t(1.); + real_t len = velrelOrthog.length(); + if (len > real_t(0.00001)) + { + Vector3 normal = velrelOrthog.normalized(); + real_t denom = A->compute_angular_impulse_denominator(normal) + + B->compute_angular_impulse_denominator(normal); + // scale for mass and relaxation + velrelOrthog *= (real_t(1.)/denom) * m_relaxationFactor; + } + + //solve angular positional correction + Vector3 angularError = -axisA.cross(axisB) *(real_t(1.)/p_step); + real_t len2 = angularError.length(); + if (len2>real_t(0.00001)) + { + Vector3 normal2 = angularError.normalized(); + real_t denom2 = A->compute_angular_impulse_denominator(normal2) + + B->compute_angular_impulse_denominator(normal2); + angularError *= (real_t(1.)/denom2) * relaxation; + } + + A->apply_torque_impulse(-velrelOrthog+angularError); + B->apply_torque_impulse(velrelOrthog-angularError); + + // solve limit + if (m_solveLimit) + { + real_t amplitude = ( (angVelB - angVelA).dot( axisA )*m_relaxationFactor + m_correction* (real_t(1.)/p_step)*m_biasFactor ) * m_limitSign; + + real_t impulseMag = amplitude * m_kHinge; + + // Clamp the accumulated impulse + real_t temp = m_accLimitImpulse; + m_accLimitImpulse = MAX(m_accLimitImpulse + impulseMag, real_t(0) ); + impulseMag = m_accLimitImpulse - temp; + + + Vector3 impulse = axisA * impulseMag * m_limitSign; + A->apply_torque_impulse(impulse); + B->apply_torque_impulse(-impulse); + } + } + + //apply motor + if (m_enableAngularMotor) + { + //todo: add limits too + Vector3 angularLimit(0,0,0); + + Vector3 velrel = angVelAroundHingeAxisA - angVelAroundHingeAxisB; + real_t projRelVel = velrel.dot(axisA); + + real_t desiredMotorVel = m_motorTargetVelocity; + real_t motor_relvel = desiredMotorVel - projRelVel; + + real_t unclippedMotorImpulse = m_kHinge * motor_relvel;; + //todo: should clip against accumulated impulse + real_t clippedMotorImpulse = unclippedMotorImpulse > m_maxMotorImpulse ? m_maxMotorImpulse : unclippedMotorImpulse; + clippedMotorImpulse = clippedMotorImpulse < -m_maxMotorImpulse ? -m_maxMotorImpulse : clippedMotorImpulse; + Vector3 motorImp = clippedMotorImpulse * axisA; + + A->apply_torque_impulse(motorImp+angularLimit); + B->apply_torque_impulse(-motorImp-angularLimit); + + } + } + +} +/* +void HingeJointSW::updateRHS(real_t timeStep) +{ + (void)timeStep; + +} +*/ + +static _FORCE_INLINE_ real_t atan2fast(real_t y, real_t x) +{ + real_t coeff_1 = Math_PI / 4.0f; + real_t coeff_2 = 3.0f * coeff_1; + real_t abs_y = Math::abs(y); + real_t angle; + if (x >= 0.0f) { + real_t r = (x - abs_y) / (x + abs_y); + angle = coeff_1 - coeff_1 * r; + } else { + real_t r = (x + abs_y) / (abs_y - x); + angle = coeff_2 - coeff_1 * r; + } + return (y < 0.0f) ? -angle : angle; +} + + +real_t HingeJointSW::get_hinge_angle() { + const Vector3 refAxis0 = A->get_transform().basis.xform( m_rbAFrame.basis.get_axis(0) ); + const Vector3 refAxis1 = A->get_transform().basis.xform( m_rbAFrame.basis.get_axis(1) ); + const Vector3 swingAxis = B->get_transform().basis.xform( m_rbBFrame.basis.get_axis(1) ); + + return atan2fast( swingAxis.dot(refAxis0), swingAxis.dot(refAxis1) ); +} + + +void HingeJointSW::set_param(PhysicsServer::HingeJointParam p_param, float p_value) { + + switch (p_param) { + + case PhysicsServer::HINGE_JOINT_BIAS: tau=p_value; break; + case PhysicsServer::HINGE_JOINT_LIMIT_UPPER: m_upperLimit=p_value; break; + case PhysicsServer::HINGE_JOINT_LIMIT_LOWER: m_lowerLimit=p_value; break; + case PhysicsServer::HINGE_JOINT_LIMIT_BIAS: m_biasFactor=p_value; break; + case PhysicsServer::HINGE_JOINT_LIMIT_SOFTNESS: m_limitSoftness=p_value; break; + case PhysicsServer::HINGE_JOINT_LIMIT_RELAXATION: m_relaxationFactor=p_value; break; + case PhysicsServer::HINGE_JOINT_MOTOR_TARGET_VELOCITY: m_motorTargetVelocity=p_value; break; + case PhysicsServer::HINGE_JOINT_MOTOR_MAX_IMPULSE: m_maxMotorImpulse=p_value; break; + + } +} + +float HingeJointSW::get_param(PhysicsServer::HingeJointParam p_param) const{ + + switch (p_param) { + + case PhysicsServer::HINGE_JOINT_BIAS: return tau; + case PhysicsServer::HINGE_JOINT_LIMIT_UPPER: return m_upperLimit; + case PhysicsServer::HINGE_JOINT_LIMIT_LOWER: return m_lowerLimit; + case PhysicsServer::HINGE_JOINT_LIMIT_BIAS: return m_biasFactor; + case PhysicsServer::HINGE_JOINT_LIMIT_SOFTNESS: return m_limitSoftness; + case PhysicsServer::HINGE_JOINT_LIMIT_RELAXATION: return m_relaxationFactor; + case PhysicsServer::HINGE_JOINT_MOTOR_TARGET_VELOCITY: return m_motorTargetVelocity; + case PhysicsServer::HINGE_JOINT_MOTOR_MAX_IMPULSE: return m_maxMotorImpulse; + + } + + return 0; +} + +void HingeJointSW::set_flag(PhysicsServer::HingeJointFlag p_flag, bool p_value){ + + print_line(p_flag+": "+itos(p_value)); + switch (p_flag) { + case PhysicsServer::HINGE_JOINT_FLAG_USE_LIMIT: m_useLimit=p_value; break; + case PhysicsServer::HINGE_JOINT_FLAG_ENABLE_MOTOR: m_enableAngularMotor=p_value; break; + } + +} +bool HingeJointSW::get_flag(PhysicsServer::HingeJointFlag p_flag) const{ + + switch (p_flag) { + case PhysicsServer::HINGE_JOINT_FLAG_USE_LIMIT: return m_useLimit; + case PhysicsServer::HINGE_JOINT_FLAG_ENABLE_MOTOR:return m_enableAngularMotor; + } + + return false; +} |