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Diffstat (limited to 'servers/physics_3d/body_pair_3d_sw.cpp')
| -rw-r--r-- | servers/physics_3d/body_pair_3d_sw.cpp | 495 |
1 files changed, 495 insertions, 0 deletions
diff --git a/servers/physics_3d/body_pair_3d_sw.cpp b/servers/physics_3d/body_pair_3d_sw.cpp new file mode 100644 index 0000000000..9c3c847afe --- /dev/null +++ b/servers/physics_3d/body_pair_3d_sw.cpp @@ -0,0 +1,495 @@ +/*************************************************************************/ +/* body_pair_sw.cpp */ +/*************************************************************************/ +/* This file is part of: */ +/* GODOT ENGINE */ +/* https://godotengine.org */ +/*************************************************************************/ +/* Copyright (c) 2007-2020 Juan Linietsky, Ariel Manzur. */ +/* Copyright (c) 2014-2020 Godot Engine contributors (cf. AUTHORS.md). */ +/* */ +/* Permission is hereby granted, free of charge, to any person obtaining */ +/* a copy of this software and associated documentation files (the */ +/* "Software"), to deal in the Software without restriction, including */ +/* without limitation the rights to use, copy, modify, merge, publish, */ +/* distribute, sublicense, and/or sell copies of the Software, and to */ +/* permit persons to whom the Software is furnished to do so, subject to */ +/* the following conditions: */ +/* */ +/* The above copyright notice and this permission notice shall be */ +/* included in all copies or substantial portions of the Software. */ +/* */ +/* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, */ +/* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF */ +/* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.*/ +/* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY */ +/* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, */ +/* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE */ +/* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. */ +/*************************************************************************/ + +#include "body_pair_3d_sw.h" + +#include "collision_solver_3d_sw.h" +#include "core/os/os.h" +#include "space_3d_sw.h" + +/* +#define NO_ACCUMULATE_IMPULSES +#define NO_SPLIT_IMPULSES + +#define NO_FRICTION +*/ + +#define NO_TANGENTIALS +/* BODY PAIR */ + +//#define ALLOWED_PENETRATION 0.01 +#define RELAXATION_TIMESTEPS 3 +#define MIN_VELOCITY 0.0001 +#define MAX_BIAS_ROTATION (Math_PI / 8) + +void BodyPair3DSW::_contact_added_callback(const Vector3 &p_point_A, const Vector3 &p_point_B, void *p_userdata) { + + BodyPair3DSW *pair = (BodyPair3DSW *)p_userdata; + pair->contact_added_callback(p_point_A, p_point_B); +} + +void BodyPair3DSW::contact_added_callback(const Vector3 &p_point_A, const Vector3 &p_point_B) { + + // check if we already have the contact + + //Vector3 local_A = A->get_inv_transform().xform(p_point_A); + //Vector3 local_B = B->get_inv_transform().xform(p_point_B); + + Vector3 local_A = A->get_inv_transform().basis.xform(p_point_A); + Vector3 local_B = B->get_inv_transform().basis.xform(p_point_B - offset_B); + + int new_index = contact_count; + + ERR_FAIL_COND(new_index >= (MAX_CONTACTS + 1)); + + Contact contact; + + contact.acc_normal_impulse = 0; + contact.acc_bias_impulse = 0; + contact.acc_bias_impulse_center_of_mass = 0; + contact.acc_tangent_impulse = Vector3(); + contact.local_A = local_A; + contact.local_B = local_B; + contact.normal = (p_point_A - p_point_B).normalized(); + contact.mass_normal = 0; // will be computed in setup() + + // attempt to determine if the contact will be reused + real_t contact_recycle_radius = space->get_contact_recycle_radius(); + + for (int i = 0; i < contact_count; i++) { + + Contact &c = contacts[i]; + if (c.local_A.distance_squared_to(local_A) < (contact_recycle_radius * contact_recycle_radius) && + c.local_B.distance_squared_to(local_B) < (contact_recycle_radius * contact_recycle_radius)) { + + contact.acc_normal_impulse = c.acc_normal_impulse; + contact.acc_bias_impulse = c.acc_bias_impulse; + contact.acc_bias_impulse_center_of_mass = c.acc_bias_impulse_center_of_mass; + contact.acc_tangent_impulse = c.acc_tangent_impulse; + new_index = i; + break; + } + } + + // figure out if the contact amount must be reduced to fit the new contact + + if (new_index == MAX_CONTACTS) { + + // remove the contact with the minimum depth + + int least_deep = -1; + real_t min_depth = 1e10; + + for (int i = 0; i <= contact_count; i++) { + + Contact &c = (i == contact_count) ? contact : contacts[i]; + Vector3 global_A = A->get_transform().basis.xform(c.local_A); + Vector3 global_B = B->get_transform().basis.xform(c.local_B) + offset_B; + + Vector3 axis = global_A - global_B; + real_t depth = axis.dot(c.normal); + + if (depth < min_depth) { + + min_depth = depth; + least_deep = i; + } + } + + ERR_FAIL_COND(least_deep == -1); + + if (least_deep < contact_count) { //replace the last deep contact by the new one + + contacts[least_deep] = contact; + } + + return; + } + + contacts[new_index] = contact; + + if (new_index == contact_count) { + + contact_count++; + } +} + +void BodyPair3DSW::validate_contacts() { + + //make sure to erase contacts that are no longer valid + + real_t contact_max_separation = space->get_contact_max_separation(); + for (int i = 0; i < contact_count; i++) { + + Contact &c = contacts[i]; + + Vector3 global_A = A->get_transform().basis.xform(c.local_A); + Vector3 global_B = B->get_transform().basis.xform(c.local_B) + offset_B; + Vector3 axis = global_A - global_B; + real_t depth = axis.dot(c.normal); + + if (depth < -contact_max_separation || (global_B + c.normal * depth - global_A).length() > contact_max_separation) { + // contact no longer needed, remove + + if ((i + 1) < contact_count) { + // swap with the last one + SWAP(contacts[i], contacts[contact_count - 1]); + } + + i--; + contact_count--; + } + } +} + +bool BodyPair3DSW::_test_ccd(real_t p_step, Body3DSW *p_A, int p_shape_A, const Transform &p_xform_A, Body3DSW *p_B, int p_shape_B, const Transform &p_xform_B) { + + Vector3 motion = p_A->get_linear_velocity() * p_step; + real_t mlen = motion.length(); + if (mlen < CMP_EPSILON) + return false; + + Vector3 mnormal = motion / mlen; + + real_t min, max; + p_A->get_shape(p_shape_A)->project_range(mnormal, p_xform_A, min, max); + bool fast_object = mlen > (max - min) * 0.3; //going too fast in that direction + + if (!fast_object) { //did it move enough in this direction to even attempt raycast? let's say it should move more than 1/3 the size of the object in that axis + return false; + } + + //cast a segment from support in motion normal, in the same direction of motion by motion length + //support is the worst case collision point, so real collision happened before + Vector3 s = p_A->get_shape(p_shape_A)->get_support(p_xform_A.basis.xform(mnormal).normalized()); + Vector3 from = p_xform_A.xform(s); + Vector3 to = from + motion; + + Transform from_inv = p_xform_B.affine_inverse(); + + Vector3 local_from = from_inv.xform(from - mnormal * mlen * 0.1); //start from a little inside the bounding box + Vector3 local_to = from_inv.xform(to); + + Vector3 rpos, rnorm; + if (!p_B->get_shape(p_shape_B)->intersect_segment(local_from, local_to, rpos, rnorm)) { + return false; + } + + //shorten the linear velocity so it does not hit, but gets close enough, next frame will hit softly or soft enough + Vector3 hitpos = p_xform_B.xform(rpos); + + real_t newlen = hitpos.distance_to(from) - (max - min) * 0.01; + p_A->set_linear_velocity((mnormal * newlen) / p_step); + + return true; +} + +real_t combine_bounce(Body3DSW *A, Body3DSW *B) { + return CLAMP(A->get_bounce() + B->get_bounce(), 0, 1); +} + +real_t combine_friction(Body3DSW *A, Body3DSW *B) { + return ABS(MIN(A->get_friction(), B->get_friction())); +} + +bool BodyPair3DSW::setup(real_t p_step) { + + //cannot collide + if (!A->test_collision_mask(B) || A->has_exception(B->get_self()) || B->has_exception(A->get_self()) || (A->get_mode() <= PhysicsServer3D::BODY_MODE_KINEMATIC && B->get_mode() <= PhysicsServer3D::BODY_MODE_KINEMATIC && A->get_max_contacts_reported() == 0 && B->get_max_contacts_reported() == 0)) { + collided = false; + return false; + } + + if (A->is_shape_set_as_disabled(shape_A) || B->is_shape_set_as_disabled(shape_B)) { + collided = false; + return false; + } + + offset_B = B->get_transform().get_origin() - A->get_transform().get_origin(); + + validate_contacts(); + + Vector3 offset_A = A->get_transform().get_origin(); + Transform xform_Au = Transform(A->get_transform().basis, Vector3()); + Transform xform_A = xform_Au * A->get_shape_transform(shape_A); + + Transform xform_Bu = B->get_transform(); + xform_Bu.origin -= offset_A; + Transform xform_B = xform_Bu * B->get_shape_transform(shape_B); + + Shape3DSW *shape_A_ptr = A->get_shape(shape_A); + Shape3DSW *shape_B_ptr = B->get_shape(shape_B); + + bool collided = CollisionSolver3DSW::solve_static(shape_A_ptr, xform_A, shape_B_ptr, xform_B, _contact_added_callback, this, &sep_axis); + this->collided = collided; + + if (!collided) { + + //test ccd (currently just a raycast) + + if (A->is_continuous_collision_detection_enabled() && A->get_mode() > PhysicsServer3D::BODY_MODE_KINEMATIC && B->get_mode() <= PhysicsServer3D::BODY_MODE_KINEMATIC) { + _test_ccd(p_step, A, shape_A, xform_A, B, shape_B, xform_B); + } + + if (B->is_continuous_collision_detection_enabled() && B->get_mode() > PhysicsServer3D::BODY_MODE_KINEMATIC && A->get_mode() <= PhysicsServer3D::BODY_MODE_KINEMATIC) { + _test_ccd(p_step, B, shape_B, xform_B, A, shape_A, xform_A); + } + + return false; + } + + real_t max_penetration = space->get_contact_max_allowed_penetration(); + + real_t bias = (real_t)0.3; + + if (shape_A_ptr->get_custom_bias() || shape_B_ptr->get_custom_bias()) { + + if (shape_A_ptr->get_custom_bias() == 0) + bias = shape_B_ptr->get_custom_bias(); + else if (shape_B_ptr->get_custom_bias() == 0) + bias = shape_A_ptr->get_custom_bias(); + else + bias = (shape_B_ptr->get_custom_bias() + shape_A_ptr->get_custom_bias()) * 0.5; + } + + real_t inv_dt = 1.0 / p_step; + + for (int i = 0; i < contact_count; i++) { + + Contact &c = contacts[i]; + c.active = false; + + Vector3 global_A = xform_Au.xform(c.local_A); + Vector3 global_B = xform_Bu.xform(c.local_B); + + real_t depth = c.normal.dot(global_A - global_B); + + if (depth <= 0) { + c.active = false; + continue; + } + + c.active = true; + +#ifdef DEBUG_ENABLED + + if (space->is_debugging_contacts()) { + space->add_debug_contact(global_A + offset_A); + space->add_debug_contact(global_B + offset_A); + } +#endif + + c.rA = global_A - A->get_center_of_mass(); + c.rB = global_B - B->get_center_of_mass() - offset_B; + + // contact query reporting... + + if (A->can_report_contacts()) { + Vector3 crA = A->get_angular_velocity().cross(c.rA) + A->get_linear_velocity(); + A->add_contact(global_A, -c.normal, depth, shape_A, global_B, shape_B, B->get_instance_id(), B->get_self(), crA); + } + + if (B->can_report_contacts()) { + Vector3 crB = B->get_angular_velocity().cross(c.rB) + B->get_linear_velocity(); + B->add_contact(global_B, c.normal, depth, shape_B, global_A, shape_A, A->get_instance_id(), A->get_self(), crB); + } + + c.active = true; + + // Precompute normal mass, tangent mass, and bias. + Vector3 inertia_A = A->get_inv_inertia_tensor().xform(c.rA.cross(c.normal)); + Vector3 inertia_B = B->get_inv_inertia_tensor().xform(c.rB.cross(c.normal)); + real_t kNormal = A->get_inv_mass() + B->get_inv_mass(); + kNormal += c.normal.dot(inertia_A.cross(c.rA)) + c.normal.dot(inertia_B.cross(c.rB)); + c.mass_normal = 1.0f / kNormal; + + c.bias = -bias * inv_dt * MIN(0.0f, -depth + max_penetration); + c.depth = depth; + + Vector3 j_vec = c.normal * c.acc_normal_impulse + c.acc_tangent_impulse; + A->apply_impulse(c.rA + A->get_center_of_mass(), -j_vec); + B->apply_impulse(c.rB + B->get_center_of_mass(), j_vec); + c.acc_bias_impulse = 0; + c.acc_bias_impulse_center_of_mass = 0; + + c.bounce = combine_bounce(A, B); + if (c.bounce) { + + Vector3 crA = A->get_angular_velocity().cross(c.rA); + Vector3 crB = B->get_angular_velocity().cross(c.rB); + Vector3 dv = B->get_linear_velocity() + crB - A->get_linear_velocity() - crA; + //normal impule + c.bounce = c.bounce * dv.dot(c.normal); + } + } + + return true; +} + +void BodyPair3DSW::solve(real_t p_step) { + + if (!collided) + return; + + for (int i = 0; i < contact_count; i++) { + + Contact &c = contacts[i]; + if (!c.active) + continue; + + c.active = false; //try to deactivate, will activate itself if still needed + + //bias impulse + + Vector3 crbA = A->get_biased_angular_velocity().cross(c.rA); + Vector3 crbB = B->get_biased_angular_velocity().cross(c.rB); + Vector3 dbv = B->get_biased_linear_velocity() + crbB - A->get_biased_linear_velocity() - crbA; + + real_t vbn = dbv.dot(c.normal); + + if (Math::abs(-vbn + c.bias) > MIN_VELOCITY) { + + real_t jbn = (-vbn + c.bias) * c.mass_normal; + real_t jbnOld = c.acc_bias_impulse; + c.acc_bias_impulse = MAX(jbnOld + jbn, 0.0f); + + Vector3 jb = c.normal * (c.acc_bias_impulse - jbnOld); + + A->apply_bias_impulse(c.rA + A->get_center_of_mass(), -jb, MAX_BIAS_ROTATION / p_step); + B->apply_bias_impulse(c.rB + B->get_center_of_mass(), jb, MAX_BIAS_ROTATION / p_step); + + crbA = A->get_biased_angular_velocity().cross(c.rA); + crbB = B->get_biased_angular_velocity().cross(c.rB); + dbv = B->get_biased_linear_velocity() + crbB - A->get_biased_linear_velocity() - crbA; + + vbn = dbv.dot(c.normal); + + if (Math::abs(-vbn + c.bias) > MIN_VELOCITY) { + + real_t jbn_com = (-vbn + c.bias) / (A->get_inv_mass() + B->get_inv_mass()); + real_t jbnOld_com = c.acc_bias_impulse_center_of_mass; + c.acc_bias_impulse_center_of_mass = MAX(jbnOld_com + jbn_com, 0.0f); + + Vector3 jb_com = c.normal * (c.acc_bias_impulse_center_of_mass - jbnOld_com); + + A->apply_bias_impulse(A->get_center_of_mass(), -jb_com, 0.0f); + B->apply_bias_impulse(B->get_center_of_mass(), jb_com, 0.0f); + } + + c.active = true; + } + + Vector3 crA = A->get_angular_velocity().cross(c.rA); + Vector3 crB = B->get_angular_velocity().cross(c.rB); + Vector3 dv = B->get_linear_velocity() + crB - A->get_linear_velocity() - crA; + + //normal impulse + real_t vn = dv.dot(c.normal); + + if (Math::abs(vn) > MIN_VELOCITY) { + + real_t jn = -(c.bounce + vn) * c.mass_normal; + real_t jnOld = c.acc_normal_impulse; + c.acc_normal_impulse = MAX(jnOld + jn, 0.0f); + + Vector3 j = c.normal * (c.acc_normal_impulse - jnOld); + + A->apply_impulse(c.rA + A->get_center_of_mass(), -j); + B->apply_impulse(c.rB + B->get_center_of_mass(), j); + + c.active = true; + } + + //friction impulse + + real_t friction = combine_friction(A, B); + + Vector3 lvA = A->get_linear_velocity() + A->get_angular_velocity().cross(c.rA); + Vector3 lvB = B->get_linear_velocity() + B->get_angular_velocity().cross(c.rB); + + Vector3 dtv = lvB - lvA; + real_t tn = c.normal.dot(dtv); + + // tangential velocity + Vector3 tv = dtv - c.normal * tn; + real_t tvl = tv.length(); + + if (tvl > MIN_VELOCITY) { + + tv /= tvl; + + Vector3 temp1 = A->get_inv_inertia_tensor().xform(c.rA.cross(tv)); + Vector3 temp2 = B->get_inv_inertia_tensor().xform(c.rB.cross(tv)); + + real_t t = -tvl / + (A->get_inv_mass() + B->get_inv_mass() + tv.dot(temp1.cross(c.rA) + temp2.cross(c.rB))); + + Vector3 jt = t * tv; + + Vector3 jtOld = c.acc_tangent_impulse; + c.acc_tangent_impulse += jt; + + real_t fi_len = c.acc_tangent_impulse.length(); + real_t jtMax = c.acc_normal_impulse * friction; + + if (fi_len > CMP_EPSILON && fi_len > jtMax) { + + c.acc_tangent_impulse *= jtMax / fi_len; + } + + jt = c.acc_tangent_impulse - jtOld; + + A->apply_impulse(c.rA + A->get_center_of_mass(), -jt); + B->apply_impulse(c.rB + B->get_center_of_mass(), jt); + + c.active = true; + } + } +} + +BodyPair3DSW::BodyPair3DSW(Body3DSW *p_A, int p_shape_A, Body3DSW *p_B, int p_shape_B) : + Constraint3DSW(_arr, 2) { + + A = p_A; + B = p_B; + shape_A = p_shape_A; + shape_B = p_shape_B; + space = A->get_space(); + A->add_constraint(this, 0); + B->add_constraint(this, 1); + contact_count = 0; + collided = false; +} + +BodyPair3DSW::~BodyPair3DSW() { + + A->remove_constraint(this); + B->remove_constraint(this); +} |