486 lines
14 KiB
C++
486 lines
14 KiB
C++
/*************************************************************************/
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/* body_pair_2d_sw.cpp */
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/*************************************************************************/
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/* This file is part of: */
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/* GODOT ENGINE */
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/* http://www.godotengine.org */
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/*************************************************************************/
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/* Copyright (c) 2007-2014 Juan Linietsky, Ariel Manzur. */
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/* */
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/* Permission is hereby granted, free of charge, to any person obtaining */
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/* a copy of this software and associated documentation files (the */
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/* "Software"), to deal in the Software without restriction, including */
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/* without limitation the rights to use, copy, modify, merge, publish, */
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/* distribute, sublicense, and/or sell copies of the Software, and to */
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/* permit persons to whom the Software is furnished to do so, subject to */
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/* the following conditions: */
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/* */
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/* The above copyright notice and this permission notice shall be */
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/* included in all copies or substantial portions of the Software. */
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/* */
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/* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, */
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/* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF */
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/* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.*/
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/* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY */
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/* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, */
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/* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE */
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/* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. */
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/*************************************************************************/
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#include "body_pair_2d_sw.h"
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#include "collision_solver_2d_sw.h"
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#include "space_2d_sw.h"
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#define POSITION_CORRECTION
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#define ACCUMULATE_IMPULSES
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void BodyPair2DSW::_add_contact(const Vector2& p_point_A,const Vector2& p_point_B,void *p_self) {
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BodyPair2DSW *self = (BodyPair2DSW *)p_self;
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self->_contact_added_callback(p_point_A,p_point_B);
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}
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void BodyPair2DSW::_contact_added_callback(const Vector2& p_point_A,const Vector2& p_point_B) {
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// check if we already have the contact
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Vector2 local_A = A->get_inv_transform().basis_xform(p_point_A);
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Vector2 local_B = B->get_inv_transform().basis_xform(p_point_B-offset_B);
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int new_index = contact_count;
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ERR_FAIL_COND( new_index >= (MAX_CONTACTS+1) );
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Contact contact;
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contact.acc_normal_impulse=0;
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contact.acc_bias_impulse=0;
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contact.acc_tangent_impulse=0;
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contact.local_A=local_A;
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contact.local_B=local_B;
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contact.reused=true;
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contact.normal=(p_point_A-p_point_B).normalized();
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// attempt to determine if the contact will be reused
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real_t recycle_radius_2 = space->get_contact_recycle_radius() * space->get_contact_recycle_radius();
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for (int i=0;i<contact_count;i++) {
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Contact& c = contacts[i];
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if (
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c.local_A.distance_squared_to( local_A ) < (recycle_radius_2) &&
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c.local_B.distance_squared_to( local_B ) < (recycle_radius_2) ) {
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contact.acc_normal_impulse=c.acc_normal_impulse;
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contact.acc_tangent_impulse=c.acc_tangent_impulse;
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contact.acc_bias_impulse=c.acc_bias_impulse;
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new_index=i;
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break;
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}
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}
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// figure out if the contact amount must be reduced to fit the new contact
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if (new_index == MAX_CONTACTS) {
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// remove the contact with the minimum depth
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int least_deep=-1;
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real_t min_depth=1e10;
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for (int i=0;i<=contact_count;i++) {
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Contact& c = (i==contact_count)?contact:contacts[i];
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Vector2 global_A = A->get_transform().basis_xform(c.local_A);
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Vector2 global_B = B->get_transform().basis_xform(c.local_B)+offset_B;
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Vector2 axis = global_A - global_B;
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float depth = axis.dot( c.normal );
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if (depth<min_depth) {
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min_depth=depth;
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least_deep=i;
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}
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}
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ERR_FAIL_COND(least_deep==-1);
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if (least_deep < contact_count) { //replace the last deep contact by the new one
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contacts[least_deep]=contact;
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}
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return;
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}
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contacts[new_index]=contact;
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if (new_index==contact_count) {
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contact_count++;
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}
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}
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void BodyPair2DSW::_validate_contacts() {
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//make sure to erase contacts that are no longer valid
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real_t max_separation = space->get_contact_max_separation();
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real_t max_separation2 = max_separation*max_separation;
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for (int i=0;i<contact_count;i++) {
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Contact& c = contacts[i];
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bool erase=false;
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if (c.reused==false) {
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//was left behind in previous frame
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erase=true;
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} else {
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c.reused=false;
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Vector2 global_A = A->get_transform().basis_xform(c.local_A);
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Vector2 global_B = B->get_transform().basis_xform(c.local_B)+offset_B;
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Vector2 axis = global_A - global_B;
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float depth = axis.dot( c.normal );
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if (depth < -max_separation || (global_B + c.normal * depth - global_A).length_squared() > max_separation2) {
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erase=true;
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}
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}
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if (erase) {
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// contact no longer needed, remove
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if ((i+1) < contact_count) {
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// swap with the last one
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SWAP( contacts[i], contacts[ contact_count-1 ] );
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}
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i--;
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contact_count--;
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}
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}
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}
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bool BodyPair2DSW::_test_ccd(float p_step,Body2DSW *p_A, int p_shape_A,const Matrix32& p_xform_A,Body2DSW *p_B, int p_shape_B,const Matrix32& p_xform_B,bool p_swap_result) {
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Vector2 motion = p_A->get_linear_velocity()*p_step;
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real_t mlen = motion.length();
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if (mlen<CMP_EPSILON)
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return false;
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Vector2 mnormal = motion / mlen;
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real_t min,max;
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p_A->get_shape(p_shape_A)->project_rangev(mnormal,p_xform_A,min,max);
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bool fast_object = mlen > (max-min)*0.3; //going too fast in that direction
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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
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return false;
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}
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//cast a segment from support in motion normal, in the same direction of motion by motion length
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//support is the worst case collision point, so real collision happened before
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int a;
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Vector2 s[2];
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p_A->get_shape(p_shape_A)->get_supports(p_xform_A.basis_xform(mnormal).normalized(),s,a);
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Vector2 from = p_xform_A.xform(s[0]);
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Vector2 to = from + motion;
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Matrix32 from_inv = p_xform_B.affine_inverse();
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Vector2 local_from = from_inv.xform(from-mnormal*mlen*0.1); //start from a little inside the bounding box
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Vector2 local_to = from_inv.xform(to);
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Vector2 rpos,rnorm;
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if (!p_B->get_shape(p_shape_B)->intersect_segment(local_from,local_to,rpos,rnorm))
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return false;
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//ray hit something
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Vector2 hitpos = p_xform_B.xform(rpos);
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Vector2 contact_A = to;
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Vector2 contact_B = hitpos;
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//create a contact
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if (p_swap_result)
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_contact_added_callback(contact_B,contact_A);
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else
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_contact_added_callback(contact_A,contact_B);
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return true;
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}
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bool BodyPair2DSW::setup(float p_step) {
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//cannot collide
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if ((A->get_layer_mask()&B->get_layer_mask())==0 || A->has_exception(B->get_self()) || B->has_exception(A->get_self()) || (A->get_mode()<=Physics2DServer::BODY_MODE_KINEMATIC && B->get_mode()<=Physics2DServer::BODY_MODE_KINEMATIC && A->get_max_contacts_reported()==0 && B->get_max_contacts_reported()==0)) {
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collided=false;
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return false;
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}
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//use local A coordinates to avoid numerical issues on collision detection
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offset_B = B->get_transform().get_origin() - A->get_transform().get_origin();
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_validate_contacts();
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Vector2 offset_A = A->get_transform().get_origin();
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Matrix32 xform_Au = A->get_transform().untranslated();
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Matrix32 xform_A = xform_Au * A->get_shape_transform(shape_A);
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Matrix32 xform_Bu = B->get_transform();
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xform_Bu.elements[2]-=A->get_transform().get_origin();
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Matrix32 xform_B = xform_Bu * B->get_shape_transform(shape_B);
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Shape2DSW *shape_A_ptr=A->get_shape(shape_A);
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Shape2DSW *shape_B_ptr=B->get_shape(shape_B);
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Vector2 motion_A,motion_B;
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if (A->get_continuous_collision_detection_mode()==Physics2DServer::CCD_MODE_CAST_SHAPE) {
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motion_A=A->get_motion();
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}
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if (B->get_continuous_collision_detection_mode()==Physics2DServer::CCD_MODE_CAST_SHAPE) {
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motion_B=B->get_motion();
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}
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//faster to set than to check..
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collided = CollisionSolver2DSW::solve(shape_A_ptr,xform_A,motion_A,shape_B_ptr,xform_B,motion_B,_add_contact,this,&sep_axis);
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if (!collided) {
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//test ccd (currently just a raycast)
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if (A->get_continuous_collision_detection_mode()==Physics2DServer::CCD_MODE_CAST_RAY && A->get_mode()>Physics2DServer::BODY_MODE_KINEMATIC) {
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if (_test_ccd(p_step,A,shape_A,xform_A,B,shape_B,xform_B))
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collided=true;
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}
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if (B->get_continuous_collision_detection_mode()==Physics2DServer::CCD_MODE_CAST_RAY && B->get_mode()>Physics2DServer::BODY_MODE_KINEMATIC) {
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if (_test_ccd(p_step,B,shape_B,xform_B,A,shape_A,xform_A,true))
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collided=true;
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}
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if (!collided)
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return false;
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}
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real_t max_penetration = space->get_contact_max_allowed_penetration();
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float bias = 0.3f;
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if (shape_A_ptr->get_custom_bias() || shape_B_ptr->get_custom_bias()) {
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if (shape_A_ptr->get_custom_bias()==0)
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bias=shape_B_ptr->get_custom_bias();
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else if (shape_B_ptr->get_custom_bias()==0)
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bias=shape_A_ptr->get_custom_bias();
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else
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bias=(shape_B_ptr->get_custom_bias()+shape_A_ptr->get_custom_bias())*0.5;
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}
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cc=0;
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real_t inv_dt = 1.0/p_step;
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for (int i = 0; i < contact_count; i++) {
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Contact& c = contacts[i];
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Vector2 global_A = xform_Au.xform(c.local_A);
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Vector2 global_B = xform_Bu.xform(c.local_B);
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real_t depth = c.normal.dot(global_A - global_B);
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if (depth<=0 || !c.reused) {
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c.active=false;
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continue;
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}
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c.active=true;
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int gather_A = A->can_report_contacts();
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int gather_B = B->can_report_contacts();
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c.rA = global_A;
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c.rB = global_B-offset_B;
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if (gather_A | gather_B) {
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//Vector2 crB( -B->get_angular_velocity() * c.rB.y, B->get_angular_velocity() * c.rB.x );
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global_A+=offset_A;
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global_B+=offset_A;
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if (gather_A) {
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Vector2 crB( -B->get_angular_velocity() * c.rB.y, B->get_angular_velocity() * c.rB.x );
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A->add_contact(global_A,-c.normal,depth,shape_A,global_B,shape_B,B->get_instance_id(),B->get_self(),crB+B->get_linear_velocity());
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}
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if (gather_B) {
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Vector2 crA( -A->get_angular_velocity() * c.rA.y, A->get_angular_velocity() * c.rA.x );
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B->add_contact(global_B,c.normal,depth,shape_B,global_A,shape_A,A->get_instance_id(),A->get_self(),crA+A->get_linear_velocity());
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}
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}
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if (A->is_shape_set_as_trigger(shape_A) || B->is_shape_set_as_trigger(shape_B) || (A->get_mode()<=Physics2DServer::BODY_MODE_KINEMATIC && B->get_mode()<=Physics2DServer::BODY_MODE_KINEMATIC)) {
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c.active=false;
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collided=false;
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continue;
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}
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// Precompute normal mass, tangent mass, and bias.
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real_t rnA = c.rA.dot(c.normal);
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real_t rnB = c.rB.dot(c.normal);
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real_t kNormal = A->get_inv_mass() + B->get_inv_mass();
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kNormal += A->get_inv_inertia() * (c.rA.dot(c.rA) - rnA * rnA) + B->get_inv_inertia() * (c.rB.dot(c.rB) - rnB * rnB);
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c.mass_normal = 1.0f / kNormal;
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Vector2 tangent = c.normal.tangent();
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real_t rtA = c.rA.dot(tangent);
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real_t rtB = c.rB.dot(tangent);
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real_t kTangent = A->get_inv_mass() + B->get_inv_mass();
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kTangent += A->get_inv_inertia() * (c.rA.dot(c.rA) - rtA * rtA) + B->get_inv_inertia() * (c.rB.dot(c.rB) - rtB * rtB);
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c.mass_tangent = 1.0f / kTangent;
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c.bias = -bias * inv_dt * MIN(0.0f, -depth + max_penetration);
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c.depth=depth;
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//c.acc_bias_impulse=0;
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#ifdef ACCUMULATE_IMPULSES
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{
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// Apply normal + friction impulse
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Vector2 P = c.acc_normal_impulse * c.normal + c.acc_tangent_impulse * tangent;
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A->apply_impulse(c.rA,-P);
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B->apply_impulse(c.rB, P);
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}
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#endif
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c.bounce=MAX(A->get_bounce(),B->get_bounce());
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if (c.bounce) {
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Vector2 crA( -A->get_angular_velocity() * c.rA.y, A->get_angular_velocity() * c.rA.x );
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Vector2 crB( -B->get_angular_velocity() * c.rB.y, B->get_angular_velocity() * c.rB.x );
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Vector2 dv = B->get_linear_velocity() + crB - A->get_linear_velocity() - crA;
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c.bounce = c.bounce * dv.dot(c.normal);
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}
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}
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return true;
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}
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void BodyPair2DSW::solve(float p_step) {
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if (!collided)
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return;
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for (int i = 0; i < contact_count; ++i) {
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Contact& c = contacts[i];
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cc++;
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if (!c.active)
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continue;
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// Relative velocity at contact
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Vector2 crA( -A->get_angular_velocity() * c.rA.y, A->get_angular_velocity() * c.rA.x );
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Vector2 crB( -B->get_angular_velocity() * c.rB.y, B->get_angular_velocity() * c.rB.x );
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Vector2 dv = B->get_linear_velocity() + crB - A->get_linear_velocity() - crA;
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Vector2 crbA( -A->get_biased_angular_velocity() * c.rA.y, A->get_biased_angular_velocity() * c.rA.x );
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Vector2 crbB( -B->get_biased_angular_velocity() * c.rB.y, B->get_biased_angular_velocity() * c.rB.x );
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Vector2 dbv = B->get_biased_linear_velocity() + crbB - A->get_biased_linear_velocity() - crbA;
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real_t vn = dv.dot(c.normal);
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real_t vbn = dbv.dot(c.normal);
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Vector2 tangent = c.normal.tangent();
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real_t vt = dv.dot(tangent);
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real_t jbn = (c.bias - vbn)*c.mass_normal;
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real_t jbnOld = c.acc_bias_impulse;
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c.acc_bias_impulse = MAX(jbnOld + jbn, 0.0f);
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Vector2 jb = c.normal * (c.acc_bias_impulse - jbnOld);
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A->apply_bias_impulse(c.rA,-jb);
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B->apply_bias_impulse(c.rB, jb);
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real_t jn = -(c.bounce + vn)*c.mass_normal;
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real_t jnOld = c.acc_normal_impulse;
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c.acc_normal_impulse = MAX(jnOld + jn, 0.0f);
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real_t friction = A->get_friction() * B->get_friction();
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real_t jtMax = friction*c.acc_normal_impulse;
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real_t jt = -vt*c.mass_tangent;
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real_t jtOld = c.acc_tangent_impulse;
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c.acc_tangent_impulse = CLAMP(jtOld + jt, -jtMax, jtMax);
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Vector2 j =c.normal * (c.acc_normal_impulse - jnOld) + tangent * ( c.acc_tangent_impulse - jtOld );
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A->apply_impulse(c.rA,-j);
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B->apply_impulse(c.rB, j);
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}
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}
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BodyPair2DSW::BodyPair2DSW(Body2DSW *p_A, int p_shape_A,Body2DSW *p_B, int p_shape_B) : Constraint2DSW(_arr,2) {
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A=p_A;
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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;
|
|
|
|
}
|
|
|
|
|
|
BodyPair2DSW::~BodyPair2DSW() {
|
|
|
|
|
|
A->remove_constraint(this);
|
|
B->remove_constraint(this);
|
|
|
|
}
|