DOOM-3-BFG

DOOM 3 BFG Edition
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Force_Spring.cpp (4447B)

      1 /*
      2 ===========================================================================
      3 
      4 Doom 3 BFG Edition GPL Source Code
      5 Copyright (C) 1993-2012 id Software LLC, a ZeniMax Media company. 
      6 
      7 This file is part of the Doom 3 BFG Edition GPL Source Code ("Doom 3 BFG Edition Source Code").  
      8 
      9 Doom 3 BFG Edition Source Code is free software: you can redistribute it and/or modify
     10 it under the terms of the GNU General Public License as published by
     11 the Free Software Foundation, either version 3 of the License, or
     12 (at your option) any later version.
     13 
     14 Doom 3 BFG Edition Source Code is distributed in the hope that it will be useful,
     15 but WITHOUT ANY WARRANTY; without even the implied warranty of
     16 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
     17 GNU General Public License for more details.
     18 
     19 You should have received a copy of the GNU General Public License
     20 along with Doom 3 BFG Edition Source Code.  If not, see <http://www.gnu.org/licenses/>.
     21 
     22 In addition, the Doom 3 BFG Edition Source Code is also subject to certain additional terms. You should have received a copy of these additional terms immediately following the terms and conditions of the GNU General Public License which accompanied the Doom 3 BFG Edition Source Code.  If not, please request a copy in writing from id Software at the address below.
     23 
     24 If you have questions concerning this license or the applicable additional terms, you may contact in writing id Software LLC, c/o ZeniMax Media Inc., Suite 120, Rockville, Maryland 20850 USA.
     25 
     26 ===========================================================================
     27 */
     28 
     29 #pragma hdrstop
     30 #include "../../idlib/precompiled.h"
     31 
     32 #include "../Game_local.h"
     33 
     34 CLASS_DECLARATION( idForce, idForce_Spring )
     35 END_CLASS
     36 
     37 /*
     38 ================
     39 idForce_Spring::idForce_Spring
     40 ================
     41 */
     42 idForce_Spring::idForce_Spring() {
     43 	Kstretch		= 100.0f;
     44 	Kcompress		= 100.0f;
     45 	damping			= 0.0f;
     46 	restLength		= 0.0f;
     47 	physics1		= NULL;
     48 	id1				= 0;
     49 	p1				= vec3_zero;
     50 	physics2		= NULL;
     51 	id2				= 0;
     52 	p2				= vec3_zero;
     53 }
     54 
     55 /*
     56 ================
     57 idForce_Spring::~idForce_Spring
     58 ================
     59 */
     60 idForce_Spring::~idForce_Spring() {
     61 }
     62 
     63 /*
     64 ================
     65 idForce_Spring::InitSpring
     66 ================
     67 */
     68 void idForce_Spring::InitSpring( float Kstretch, float Kcompress, float damping, float restLength ) {
     69 	this->Kstretch = Kstretch;
     70 	this->Kcompress = Kcompress;
     71 	this->damping = damping;
     72 	this->restLength = restLength;
     73 }
     74 
     75 /*
     76 ================
     77 idForce_Spring::SetPosition
     78 ================
     79 */
     80 void idForce_Spring::SetPosition( idPhysics *physics1, int id1, const idVec3 &p1, idPhysics *physics2, int id2, const idVec3 &p2 ) {
     81 	this->physics1 = physics1;
     82 	this->id1 = id1;
     83 	this->p1 = p1;
     84 	this->physics2 = physics2;
     85 	this->id2 = id2;
     86 	this->p2 = p2;
     87 }
     88 
     89 /*
     90 ================
     91 idForce_Spring::Evaluate
     92 ================
     93 */
     94 void idForce_Spring::Evaluate( int time ) {
     95 	float length;
     96 	idMat3 axis;
     97 	idVec3 pos1, pos2, velocity1, velocity2, force, dampingForce;
     98 	impactInfo_t info;
     99 
    100 	pos1 = p1;
    101 	pos2 = p2;
    102 	velocity1 = velocity2 = vec3_origin;
    103 
    104 	if ( physics1 ) {
    105 		axis = physics1->GetAxis( id1 );
    106 		pos1 = physics1->GetOrigin( id1 );
    107 		pos1 += p1 * axis;
    108 		if ( damping > 0.0f ) {
    109 			physics1->GetImpactInfo( id1, pos1, &info );
    110 			velocity1 = info.velocity;
    111 		}
    112 	}
    113 
    114 	if ( physics2 ) {
    115 		axis = physics2->GetAxis( id2 );
    116 		pos2 = physics2->GetOrigin( id2 );
    117 		pos2 += p2 * axis;
    118 		if ( damping > 0.0f ) {
    119 			physics2->GetImpactInfo( id2, pos2, &info );
    120 			velocity2 = info.velocity;
    121 		}
    122 	}
    123 
    124 	force = pos2 - pos1;
    125 	dampingForce = ( damping * ( ((velocity2 - velocity1) * force) / (force * force) ) ) * force;
    126 	length = force.Normalize();
    127 
    128 	// if the spring is stretched
    129 	if ( length > restLength ) {
    130 		if ( Kstretch > 0.0f ) {
    131 			force = ( Square( length - restLength ) * Kstretch ) * force - dampingForce;
    132 			if ( physics1 ) {
    133 				physics1->AddForce( id1, pos1, force );
    134 			}
    135 			if ( physics2 ) {
    136 				physics2->AddForce( id2, pos2, -force );
    137 			}
    138 		}
    139 	}
    140 	else {
    141 		if ( Kcompress > 0.0f ) {
    142 			force = ( Square( length - restLength ) * Kcompress ) * force - dampingForce;
    143 			if ( physics1 ) {
    144 				physics1->AddForce( id1, pos1, -force );
    145 			}
    146 			if ( physics2 ) {
    147 				physics2->AddForce( id2, pos2, force );
    148 			}
    149 		}
    150 	}
    151 }
    152 
    153 /*
    154 ================
    155 idForce_Spring::RemovePhysics
    156 ================
    157 */
    158 void idForce_Spring::RemovePhysics( const idPhysics *phys ) {
    159 	if ( physics1 == phys ) {
    160 		physics1 = NULL;
    161 	}
    162 	if ( physics2 == phys ) {
    163 		physics2 = NULL;
    164 	}
    165 }