topical media & game development
#javascript-physics-js-box2d-dynamics-joints-b2PrismaticJoint.js / js
/*
* Copyright (c) 2006-2007 Erin Catto
* 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, and must not be
* misrepresented the original software.
* 3. This notice may not be removed or altered from any source distribution.
*/
// Linear constraint (point-to-line)
// d = p2 - p1 = x2 + r2 - x1 - r1
// C = dot(ay1, d)
// Cdot = dot(d, cross(w1, ay1)) + dot(ay1, v2 + cross(w2, r2) - v1 - cross(w1, r1))
// = -dot(ay1, v1) - dot(cross(d + r1, ay1), w1) + dot(ay1, v2) + dot(cross(r2, ay1), v2)
// J = [-ay1 -cross(d+r1,ay1) ay1 cross(r2,ay1)]
//
// Angular constraint
// C = a2 - a1 + a_initial
// Cdot = w2 - w1
// J = [0 0 -1 0 0 1]
// Motor/Limit linear constraint
// C = dot(ax1, d)
// Cdot = = -dot(ax1, v1) - dot(cross(d + r1, ax1), w1) + dot(ax1, v2) + dot(cross(r2, ax1), v2)
// J = [-ax1 -cross(d+r1,ax1) ax1 cross(r2,ax1)]
var b2PrismaticJoint = Class.create();
Object.extend(b2PrismaticJoint.prototype, b2Joint.prototype);
Object.extend(b2PrismaticJoint.prototype,
{
GetAnchor1: function(){
var b1 = this.m_body1;
//return b2Math.AddVV(b1.m_position, b2Math.b2MulMV(b1.m_R, this.m_localAnchor1));
var tVec = new b2Vec2();
tVec.SetV(this.m_localAnchor1);
tVec.MulM(b1.m_R);
tVec.Add(b1.m_position);
return tVec;
},
GetAnchor2: function(){
var b2 = this.m_body2;
//return b2Math.AddVV(b2.m_position, b2Math.b2MulMV(b2.m_R, this.m_localAnchor2));
var tVec = new b2Vec2();
tVec.SetV(this.m_localAnchor2);
tVec.MulM(b2.m_R);
tVec.Add(b2.m_position);
return tVec;
},
GetJointTranslation: function(){
var b1 = this.m_body1;
var b2 = this.m_body2;
var tMat;
//var r1 = b2Math.b2MulMV(b1.m_R, this.m_localAnchor1);
tMat = b1.m_R;
var r1X = tMat.col1.x * this.m_localAnchor1.x + tMat.col2.x * this.m_localAnchor1.y;
var r1Y = tMat.col1.y * this.m_localAnchor1.x + tMat.col2.y * this.m_localAnchor1.y;
//var r2 = b2Math.b2MulMV(b2.m_R, this.m_localAnchor2);
tMat = b2.m_R;
var r2X = tMat.col1.x * this.m_localAnchor2.x + tMat.col2.x * this.m_localAnchor2.y;
var r2Y = tMat.col1.y * this.m_localAnchor2.x + tMat.col2.y * this.m_localAnchor2.y;
//var p1 = b2Math.AddVV(b1.m_position , r1);
var p1X = b1.m_position.x + r1X;
var p1Y = b1.m_position.y + r1Y;
//var p2 = b2Math.AddVV(b2.m_position , r2);
var p2X = b2.m_position.x + r2X;
var p2Y = b2.m_position.y + r2Y;
//var d = b2Math.SubtractVV(p2, p1);
var dX = p2X - p1X;
var dY = p2Y - p1Y;
//var ax1 = b2Math.b2MulMV(b1.m_R, this.m_localXAxis1);
tMat = b1.m_R;
var ax1X = tMat.col1.x * this.m_localXAxis1.x + tMat.col2.x * this.m_localXAxis1.y;
var ax1Y = tMat.col1.y * this.m_localXAxis1.x + tMat.col2.y * this.m_localXAxis1.y;
//var translation = b2Math.b2Dot(ax1, d);
var translation = ax1X*dX + ax1Y*dY;
return translation;
},
GetJointSpeed: function(){
var b1 = this.m_body1;
var b2 = this.m_body2;
var tMat;
//var r1 = b2Math.b2MulMV(b1.m_R, this.m_localAnchor1);
tMat = b1.m_R;
var r1X = tMat.col1.x * this.m_localAnchor1.x + tMat.col2.x * this.m_localAnchor1.y;
var r1Y = tMat.col1.y * this.m_localAnchor1.x + tMat.col2.y * this.m_localAnchor1.y;
//var r2 = b2Math.b2MulMV(b2.m_R, this.m_localAnchor2);
tMat = b2.m_R;
var r2X = tMat.col1.x * this.m_localAnchor2.x + tMat.col2.x * this.m_localAnchor2.y;
var r2Y = tMat.col1.y * this.m_localAnchor2.x + tMat.col2.y * this.m_localAnchor2.y;
//var p1 = b2Math.AddVV(b1.m_position , r1);
var p1X = b1.m_position.x + r1X;
var p1Y = b1.m_position.y + r1Y;
//var p2 = b2Math.AddVV(b2.m_position , r2);
var p2X = b2.m_position.x + r2X;
var p2Y = b2.m_position.y + r2Y;
//var d = b2Math.SubtractVV(p2, p1);
var dX = p2X - p1X;
var dY = p2Y - p1Y;
//var ax1 = b2Math.b2MulMV(b1.m_R, this.m_localXAxis1);
tMat = b1.m_R;
var ax1X = tMat.col1.x * this.m_localXAxis1.x + tMat.col2.x * this.m_localXAxis1.y;
var ax1Y = tMat.col1.y * this.m_localXAxis1.x + tMat.col2.y * this.m_localXAxis1.y;
var v1 = b1.m_linearVelocity;
var v2 = b2.m_linearVelocity;
var w1 = b1.m_angularVelocity;
var w2 = b2.m_angularVelocity;
//var speed = b2Math.b2Dot(d, b2Math.b2CrossFV(w1, ax1)) + b2Math.b2Dot(ax1, b2Math.SubtractVV( b2Math.SubtractVV( b2Math.AddVV( v2 , b2Math.b2CrossFV(w2, r2)) , v1) , b2Math.b2CrossFV(w1, r1)));
//var b2D = (dX*(-w1 * ax1Y) + dY*(w1 * ax1X));
//var b2D2 = (ax1X * ((( v2.x + (-w2 * r2Y)) - v1.x) - (-w1 * r1Y)) + ax1Y * ((( v2.y + (w2 * r2X)) - v1.y) - (w1 * r1X)));
var speed = (dX*(-w1 * ax1Y) + dY*(w1 * ax1X)) + (ax1X * ((( v2.x + (-w2 * r2Y)) - v1.x) - (-w1 * r1Y)) + ax1Y * ((( v2.y + (w2 * r2X)) - v1.y) - (w1 * r1X)));
return speed;
},
GetMotorForce: function(invTimeStep){
return invTimeStep * this.m_motorImpulse;
},
SetMotorSpeed: function(speed)
{
this.m_motorSpeed = speed;
},
SetMotorForce: function(force)
{
this.m_maxMotorForce = force;
},
GetReactionForce: function(invTimeStep)
{
var tImp = invTimeStep * this.m_limitImpulse;
var tMat;
//var ax1 = b2Math.b2MulMV(this.m_body1.m_R, this.m_localXAxis1);
tMat = this.m_body1.m_R;
var ax1X = tImp * (tMat.col1.x * this.m_localXAxis1.x + tMat.col2.x * this.m_localXAxis1.y);
var ax1Y = tImp * (tMat.col1.y * this.m_localXAxis1.x + tMat.col2.y * this.m_localXAxis1.y);
//var ay1 = b2Math.b2MulMV(this.m_body1.m_R, this.m_localYAxis1);
var ay1X = tImp * (tMat.col1.x * this.m_localYAxis1.x + tMat.col2.x * this.m_localYAxis1.y);
var ay1Y = tImp * (tMat.col1.y * this.m_localYAxis1.x + tMat.col2.y * this.m_localYAxis1.y);
//return (invTimeStep * this.m_limitImpulse) * ax1 + (invTimeStep * this.m_linearImpulse) * ay1;
return new b2Vec2(ax1X+ay1X, ax1Y+ay1Y);
},
GetReactionTorque: function(invTimeStep)
{
return invTimeStep * this.m_angularImpulse;
},
//--------------- Internals Below ----------------
*
* 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, and must not be
* misrepresented the original software.
* 3. This notice may not be removed or altered from any source distribution.
*/
// Linear constraint (point-to-line)
// d = p2 - p1 = x2 + r2 - x1 - r1
// C = dot(ay1, d)
// Cdot = dot(d, cross(w1, ay1)) + dot(ay1, v2 + cross(w2, r2) - v1 - cross(w1, r1))
// = -dot(ay1, v1) - dot(cross(d + r1, ay1), w1) + dot(ay1, v2) + dot(cross(r2, ay1), v2)
// J = [-ay1 -cross(d+r1,ay1) ay1 cross(r2,ay1)]
//
// Angular constraint
// C = a2 - a1 + a_initial
// Cdot = w2 - w1
// J = [0 0 -1 0 0 1]
// Motor/Limit linear constraint
// C = dot(ax1, d)
// Cdot = = -dot(ax1, v1) - dot(cross(d + r1, ax1), w1) + dot(ax1, v2) + dot(cross(r2, ax1), v2)
// J = [-ax1 -cross(d+r1,ax1) ax1 cross(r2,ax1)]
var b2PrismaticJoint = Class.create();
Object.extend(b2PrismaticJoint.prototype, b2Joint.prototype);
Object.extend(b2PrismaticJoint.prototype,
{
GetAnchor1: function(){
var b1 = this.m_body1;
//return b2Math.AddVV(b1.m_position, b2Math.b2MulMV(b1.m_R, this.m_localAnchor1));
var tVec = new b2Vec2();
tVec.SetV(this.m_localAnchor1);
tVec.MulM(b1.m_R);
tVec.Add(b1.m_position);
return tVec;
},
GetAnchor2: function(){
var b2 = this.m_body2;
//return b2Math.AddVV(b2.m_position, b2Math.b2MulMV(b2.m_R, this.m_localAnchor2));
var tVec = new b2Vec2();
tVec.SetV(this.m_localAnchor2);
tVec.MulM(b2.m_R);
tVec.Add(b2.m_position);
return tVec;
},
GetJointTranslation: function(){
var b1 = this.m_body1;
var b2 = this.m_body2;
var tMat;
//var r1 = b2Math.b2MulMV(b1.m_R, this.m_localAnchor1);
tMat = b1.m_R;
var r1X = tMat.col1.x * this.m_localAnchor1.x + tMat.col2.x * this.m_localAnchor1.y;
var r1Y = tMat.col1.y * this.m_localAnchor1.x + tMat.col2.y * this.m_localAnchor1.y;
//var r2 = b2Math.b2MulMV(b2.m_R, this.m_localAnchor2);
tMat = b2.m_R;
var r2X = tMat.col1.x * this.m_localAnchor2.x + tMat.col2.x * this.m_localAnchor2.y;
var r2Y = tMat.col1.y * this.m_localAnchor2.x + tMat.col2.y * this.m_localAnchor2.y;
//var p1 = b2Math.AddVV(b1.m_position , r1);
var p1X = b1.m_position.x + r1X;
var p1Y = b1.m_position.y + r1Y;
//var p2 = b2Math.AddVV(b2.m_position , r2);
var p2X = b2.m_position.x + r2X;
var p2Y = b2.m_position.y + r2Y;
//var d = b2Math.SubtractVV(p2, p1);
var dX = p2X - p1X;
var dY = p2Y - p1Y;
//var ax1 = b2Math.b2MulMV(b1.m_R, this.m_localXAxis1);
tMat = b1.m_R;
var ax1X = tMat.col1.x * this.m_localXAxis1.x + tMat.col2.x * this.m_localXAxis1.y;
var ax1Y = tMat.col1.y * this.m_localXAxis1.x + tMat.col2.y * this.m_localXAxis1.y;
//var translation = b2Math.b2Dot(ax1, d);
var translation = ax1X*dX + ax1Y*dY;
return translation;
},
GetJointSpeed: function(){
var b1 = this.m_body1;
var b2 = this.m_body2;
var tMat;
//var r1 = b2Math.b2MulMV(b1.m_R, this.m_localAnchor1);
tMat = b1.m_R;
var r1X = tMat.col1.x * this.m_localAnchor1.x + tMat.col2.x * this.m_localAnchor1.y;
var r1Y = tMat.col1.y * this.m_localAnchor1.x + tMat.col2.y * this.m_localAnchor1.y;
//var r2 = b2Math.b2MulMV(b2.m_R, this.m_localAnchor2);
tMat = b2.m_R;
var r2X = tMat.col1.x * this.m_localAnchor2.x + tMat.col2.x * this.m_localAnchor2.y;
var r2Y = tMat.col1.y * this.m_localAnchor2.x + tMat.col2.y * this.m_localAnchor2.y;
//var p1 = b2Math.AddVV(b1.m_position , r1);
var p1X = b1.m_position.x + r1X;
var p1Y = b1.m_position.y + r1Y;
//var p2 = b2Math.AddVV(b2.m_position , r2);
var p2X = b2.m_position.x + r2X;
var p2Y = b2.m_position.y + r2Y;
//var d = b2Math.SubtractVV(p2, p1);
var dX = p2X - p1X;
var dY = p2Y - p1Y;
//var ax1 = b2Math.b2MulMV(b1.m_R, this.m_localXAxis1);
tMat = b1.m_R;
var ax1X = tMat.col1.x * this.m_localXAxis1.x + tMat.col2.x * this.m_localXAxis1.y;
var ax1Y = tMat.col1.y * this.m_localXAxis1.x + tMat.col2.y * this.m_localXAxis1.y;
var v1 = b1.m_linearVelocity;
var v2 = b2.m_linearVelocity;
var w1 = b1.m_angularVelocity;
var w2 = b2.m_angularVelocity;
//var speed = b2Math.b2Dot(d, b2Math.b2CrossFV(w1, ax1)) + b2Math.b2Dot(ax1, b2Math.SubtractVV( b2Math.SubtractVV( b2Math.AddVV( v2 , b2Math.b2CrossFV(w2, r2)) , v1) , b2Math.b2CrossFV(w1, r1)));
//var b2D = (dX*(-w1 * ax1Y) + dY*(w1 * ax1X));
//var b2D2 = (ax1X * ((( v2.x + (-w2 * r2Y)) - v1.x) - (-w1 * r1Y)) + ax1Y * ((( v2.y + (w2 * r2X)) - v1.y) - (w1 * r1X)));
var speed = (dX*(-w1 * ax1Y) + dY*(w1 * ax1X)) + (ax1X * ((( v2.x + (-w2 * r2Y)) - v1.x) - (-w1 * r1Y)) + ax1Y * ((( v2.y + (w2 * r2X)) - v1.y) - (w1 * r1X)));
return speed;
},
GetMotorForce: function(invTimeStep){
return invTimeStep * this.m_motorImpulse;
},
SetMotorSpeed: function(speed)
{
this.m_motorSpeed = speed;
},
SetMotorForce: function(force)
{
this.m_maxMotorForce = force;
},
GetReactionForce: function(invTimeStep)
{
var tImp = invTimeStep * this.m_limitImpulse;
var tMat;
//var ax1 = b2Math.b2MulMV(this.m_body1.m_R, this.m_localXAxis1);
tMat = this.m_body1.m_R;
var ax1X = tImp * (tMat.col1.x * this.m_localXAxis1.x + tMat.col2.x * this.m_localXAxis1.y);
var ax1Y = tImp * (tMat.col1.y * this.m_localXAxis1.x + tMat.col2.y * this.m_localXAxis1.y);
//var ay1 = b2Math.b2MulMV(this.m_body1.m_R, this.m_localYAxis1);
var ay1X = tImp * (tMat.col1.x * this.m_localYAxis1.x + tMat.col2.x * this.m_localYAxis1.y);
var ay1Y = tImp * (tMat.col1.y * this.m_localYAxis1.x + tMat.col2.y * this.m_localYAxis1.y);
//return (invTimeStep * this.m_limitImpulse) * ax1 + (invTimeStep * this.m_linearImpulse) * ay1;
return new b2Vec2(ax1X+ay1X, ax1Y+ay1Y);
},
GetReactionTorque: function(invTimeStep)
{
return invTimeStep * this.m_angularImpulse;
},
//--------------- Internals Below -------------------
initialize: function(def){
// The constructor for b2Joint
// initialize instance variables for references
this.m_node1 = new b2JointNode();
this.m_node2 = new b2JointNode();
//
this.m_type = def.type;
this.m_prev = null;
this.m_next = null;
this.m_body1 = def.body1;
this.m_body2 = def.body2;
this.m_collideConnected = def.collideConnected;
this.m_islandFlag = false;
this.m_userData = def.userData;
//
// initialize instance variables for references
this.m_localAnchor1 = new b2Vec2();
this.m_localAnchor2 = new b2Vec2();
this.m_localXAxis1 = new b2Vec2();
this.m_localYAxis1 = new b2Vec2();
this.m_linearJacobian = new b2Jacobian();
this.m_motorJacobian = new b2Jacobian();
//
//super(def);
var tMat;
var tX;
var tY;
//this.m_localAnchor1 = b2Math.b2MulTMV(this.m_body1.m_R, b2Math.SubtractVV(def.anchorPoint , this.m_body1.m_position));
tMat = this.m_body1.m_R;
tX = (def.anchorPoint.x - this.m_body1.m_position.x);
tY = (def.anchorPoint.y - this.m_body1.m_position.y);
this.m_localAnchor1.Set((tX*tMat.col1.x + tY*tMat.col1.y), (tX*tMat.col2.x + tY*tMat.col2.y));
//this.m_localAnchor2 = b2Math.b2MulTMV(this.m_body2.m_R, b2Math.SubtractVV(def.anchorPoint , this.m_body2.m_position));
tMat = this.m_body2.m_R;
tX = (def.anchorPoint.x - this.m_body2.m_position.x);
tY = (def.anchorPoint.y - this.m_body2.m_position.y);
this.m_localAnchor2.Set((tX*tMat.col1.x + tY*tMat.col1.y), (tX*tMat.col2.x + tY*tMat.col2.y));
//this.m_localXAxis1 = b2Math.b2MulTMV(this.m_body1.m_R, def.axis);
tMat = this.m_body1.m_R;
tX = def.axis.x;
tY = def.axis.y;
this.m_localXAxis1.Set((tX*tMat.col1.x + tY*tMat.col1.y), (tX*tMat.col2.x + tY*tMat.col2.y));
//this.m_localYAxis1 = b2Math.b2CrossFV(1.0, this.m_localXAxis1);
this.m_localYAxis1.x = -this.m_localXAxis1.y;
this.m_localYAxis1.y = this.m_localXAxis1.x;
this.m_initialAngle = this.m_body2.m_rotation - this.m_body1.m_rotation;
this.m_linearJacobian.SetZero();
this.m_linearMass = 0.0;
this.m_linearImpulse = 0.0;
this.m_angularMass = 0.0;
this.m_angularImpulse = 0.0;
this.m_motorJacobian.SetZero();
this.m_motorMass = 0.0;
this.m_motorImpulse = 0.0;
this.m_limitImpulse = 0.0;
this.m_limitPositionImpulse = 0.0;
this.m_lowerTranslation = def.lowerTranslation;
this.m_upperTranslation = def.upperTranslation;
this.m_maxMotorForce = def.motorForce;
this.m_motorSpeed = def.motorSpeed;
this.m_enableLimit = def.enableLimit;
this.m_enableMotor = def.enableMotor;
},
PrepareVelocitySolver: function(){
var b1 = this.m_body1;
var b2 = this.m_body2;
var tMat;
// Compute the effective masses.
//b2Vec2 r1 = b2Mul(b1->m_R, this.m_localAnchor1);
tMat = b1.m_R;
var r1X = tMat.col1.x * this.m_localAnchor1.x + tMat.col2.x * this.m_localAnchor1.y;
var r1Y = tMat.col1.y * this.m_localAnchor1.x + tMat.col2.y * this.m_localAnchor1.y;
//b2Vec2 r2 = b2Mul(b2->m_R, this.m_localAnchor2);
tMat = b2.m_R;
var r2X = tMat.col1.x * this.m_localAnchor2.x + tMat.col2.x * this.m_localAnchor2.y;
var r2Y = tMat.col1.y * this.m_localAnchor2.x + tMat.col2.y * this.m_localAnchor2.y;
//float32 invMass1 = b1->m_invMass, invMass2 = b2->m_invMass;
var invMass1 = b1.m_invMass;
var invMass2 = b2.m_invMass;
//float32 invI1 = b1->m_invI, invI2 = b2->m_invI;
var invI1 = b1.m_invI;
var invI2 = b2.m_invI;
// Compute point to line constraint effective mass.
// J = [-ay1 -cross(d+r1,ay1) ay1 cross(r2,ay1)]
//b2Vec2 ay1 = b2Mul(b1->m_R, this.m_localYAxis1);
tMat = b1.m_R;
var ay1X = tMat.col1.x * this.m_localYAxis1.x + tMat.col2.x * this.m_localYAxis1.y;
var ay1Y = tMat.col1.y * this.m_localYAxis1.x + tMat.col2.y * this.m_localYAxis1.y;
//b2Vec2 e = b2->m_position + r2 - b1->m_position;
var eX = b2.m_position.x + r2X - b1.m_position.x;
var eY = b2.m_position.y + r2Y - b1.m_position.y;
//this.m_linearJacobian.Set(-ay1, -b2Math.b2Cross(e, ay1), ay1, b2Math.b2Cross(r2, ay1));
this.m_linearJacobian.linear1.x = -ay1X;
this.m_linearJacobian.linear1.y = -ay1Y;
this.m_linearJacobian.linear2.x = ay1X;
this.m_linearJacobian.linear2.y = ay1Y;
this.m_linearJacobian.angular1 = -(eX * ay1Y - eY * ay1X);
this.m_linearJacobian.angular2 = r2X * ay1Y - r2Y * ay1X;
this.m_linearMass = invMass1 + invI1 * this.m_linearJacobian.angular1 * this.m_linearJacobian.angular1 +
invMass2 + invI2 * this.m_linearJacobian.angular2 * this.m_linearJacobian.angular2;
//b2Settings.b2Assert(this.m_linearMass > Number.MIN_VALUE);
this.m_linearMass = 1.0 / this.m_linearMass;
// Compute angular constraint effective mass.
this.m_angularMass = 1.0 / (invI1 + invI2);
// Compute motor and limit terms.
if (this.m_enableLimit || this.m_enableMotor)
{
// The motor and limit share a Jacobian and effective mass.
//b2Vec2 ax1 = b2Mul(b1->m_R, this.m_localXAxis1);
tMat = b1.m_R;
var ax1X = tMat.col1.x * this.m_localXAxis1.x + tMat.col2.x * this.m_localXAxis1.y;
var ax1Y = tMat.col1.y * this.m_localXAxis1.x + tMat.col2.y * this.m_localXAxis1.y;
//this.m_motorJacobian.Set(-ax1, -b2Cross(e, ax1), ax1, b2Cross(r2, ax1));
this.m_motorJacobian.linear1.x = -ax1X; this.m_motorJacobian.linear1.y = -ax1Y;
this.m_motorJacobian.linear2.x = ax1X; this.m_motorJacobian.linear2.y = ax1Y;
this.m_motorJacobian.angular1 = -(eX * ax1Y - eY * ax1X);
this.m_motorJacobian.angular2 = r2X * ax1Y - r2Y * ax1X;
this.m_motorMass = invMass1 + invI1 * this.m_motorJacobian.angular1 * this.m_motorJacobian.angular1 +
invMass2 + invI2 * this.m_motorJacobian.angular2 * this.m_motorJacobian.angular2;
//b2Settings.b2Assert(this.m_motorMass > Number.MIN_VALUE);
this.m_motorMass = 1.0 / this.m_motorMass;
if (this.m_enableLimit)
{
//b2Vec2 d = e - r1;
var dX = eX - r1X;
var dY = eY - r1Y;
//float32 jointTranslation = b2Dot(ax1, d);
var jointTranslation = ax1X * dX + ax1Y * dY;
if (b2Math.b2Abs(this.m_upperTranslation - this.m_lowerTranslation) < 2.0 * b2Settings.b2_linearSlop)
{
this.m_limitState = b2Joint.e_equalLimits;
}
else if (jointTranslation <= this.m_lowerTranslation)
{
if (this.m_limitState != b2Joint.e_atLowerLimit)
{
this.m_limitImpulse = 0.0;
}
this.m_limitState = b2Joint.e_atLowerLimit;
}
else if (jointTranslation >= this.m_upperTranslation)
{
if (this.m_limitState != b2Joint.e_atUpperLimit)
{
this.m_limitImpulse = 0.0;
}
this.m_limitState = b2Joint.e_atUpperLimit;
}
else
{
this.m_limitState = b2Joint.e_inactiveLimit;
this.m_limitImpulse = 0.0;
}
}
}
if (this.m_enableMotor == false)
{
this.m_motorImpulse = 0.0;
}
if (this.m_enableLimit == false)
{
this.m_limitImpulse = 0.0;
}
if (b2World.s_enableWarmStarting)
{
//b2Vec2 P1 = this.m_linearImpulse * this.m_linearJacobian.linear1 + (this.m_motorImpulse + this.m_limitImpulse) * this.m_motorJacobian.linear1;
var P1X = this.m_linearImpulse * this.m_linearJacobian.linear1.x + (this.m_motorImpulse + this.m_limitImpulse) * this.m_motorJacobian.linear1.x;
var P1Y = this.m_linearImpulse * this.m_linearJacobian.linear1.y + (this.m_motorImpulse + this.m_limitImpulse) * this.m_motorJacobian.linear1.y;
//b2Vec2 P2 = this.m_linearImpulse * this.m_linearJacobian.linear2 + (this.m_motorImpulse + this.m_limitImpulse) * this.m_motorJacobian.linear2;
var P2X = this.m_linearImpulse * this.m_linearJacobian.linear2.x + (this.m_motorImpulse + this.m_limitImpulse) * this.m_motorJacobian.linear2.x;
var P2Y = this.m_linearImpulse * this.m_linearJacobian.linear2.y + (this.m_motorImpulse + this.m_limitImpulse) * this.m_motorJacobian.linear2.y;
//float32 L1 = this.m_linearImpulse * this.m_linearJacobian.angular1 - this.m_angularImpulse + (this.m_motorImpulse + this.m_limitImpulse) * this.m_motorJacobian.angular1;
var L1 = this.m_linearImpulse * this.m_linearJacobian.angular1 - this.m_angularImpulse + (this.m_motorImpulse + this.m_limitImpulse) * this.m_motorJacobian.angular1;
//float32 L2 = this.m_linearImpulse * this.m_linearJacobian.angular2 + this.m_angularImpulse + (this.m_motorImpulse + this.m_limitImpulse) * this.m_motorJacobian.angular2;
var L2 = this.m_linearImpulse * this.m_linearJacobian.angular2 + this.m_angularImpulse + (this.m_motorImpulse + this.m_limitImpulse) * this.m_motorJacobian.angular2;
//b1->m_linearVelocity += invMass1 * P1;
b1.m_linearVelocity.x += invMass1 * P1X;
b1.m_linearVelocity.y += invMass1 * P1Y;
//b1->m_angularVelocity += invI1 * L1;
b1.m_angularVelocity += invI1 * L1;
//b2->m_linearVelocity += invMass2 * P2;
b2.m_linearVelocity.x += invMass2 * P2X;
b2.m_linearVelocity.y += invMass2 * P2Y;
//b2->m_angularVelocity += invI2 * L2;
b2.m_angularVelocity += invI2 * L2;
}
else
{
this.m_linearImpulse = 0.0;
this.m_angularImpulse = 0.0;
this.m_limitImpulse = 0.0;
this.m_motorImpulse = 0.0;
}
this.m_limitPositionImpulse = 0.0;
},
SolveVelocityConstraints: function(step){
var b1 = this.m_body1;
var b2 = this.m_body2;
var invMass1 = b1.m_invMass;
var invMass2 = b2.m_invMass;
var invI1 = b1.m_invI;
var invI2 = b2.m_invI;
var oldLimitImpulse;
// Solve linear constraint.
var linearCdot = this.m_linearJacobian.Compute(b1.m_linearVelocity, b1.m_angularVelocity, b2.m_linearVelocity, b2.m_angularVelocity);
var linearImpulse = -this.m_linearMass * linearCdot;
this.m_linearImpulse += linearImpulse;
//b1->m_linearVelocity += (invMass1 * linearImpulse) * this.m_linearJacobian.linear1;
b1.m_linearVelocity.x += (invMass1 * linearImpulse) * this.m_linearJacobian.linear1.x;
b1.m_linearVelocity.y += (invMass1 * linearImpulse) * this.m_linearJacobian.linear1.y;
//b1->m_angularVelocity += invI1 * linearImpulse * this.m_linearJacobian.angular1;
b1.m_angularVelocity += invI1 * linearImpulse * this.m_linearJacobian.angular1;
//b2->m_linearVelocity += (invMass2 * linearImpulse) * this.m_linearJacobian.linear2;
b2.m_linearVelocity.x += (invMass2 * linearImpulse) * this.m_linearJacobian.linear2.x;
b2.m_linearVelocity.y += (invMass2 * linearImpulse) * this.m_linearJacobian.linear2.y;
//b2.m_angularVelocity += invI2 * linearImpulse * this.m_linearJacobian.angular2;
b2.m_angularVelocity += invI2 * linearImpulse * this.m_linearJacobian.angular2;
// Solve angular constraint.
var angularCdot = b2.m_angularVelocity - b1.m_angularVelocity;
var angularImpulse = -this.m_angularMass * angularCdot;
this.m_angularImpulse += angularImpulse;
b1.m_angularVelocity -= invI1 * angularImpulse;
b2.m_angularVelocity += invI2 * angularImpulse;
// Solve linear motor constraint.
if (this.m_enableMotor && this.m_limitState != b2Joint.e_equalLimits)
{
var motorCdot = this.m_motorJacobian.Compute(b1.m_linearVelocity, b1.m_angularVelocity, b2.m_linearVelocity, b2.m_angularVelocity) - this.m_motorSpeed;
var motorImpulse = -this.m_motorMass * motorCdot;
var oldMotorImpulse = this.m_motorImpulse;
this.m_motorImpulse = b2Math.b2Clamp(this.m_motorImpulse + motorImpulse, -step.dt * this.m_maxMotorForce, step.dt * this.m_maxMotorForce);
motorImpulse = this.m_motorImpulse - oldMotorImpulse;
//b1.m_linearVelocity += (invMass1 * motorImpulse) * this.m_motorJacobian.linear1;
b1.m_linearVelocity.x += (invMass1 * motorImpulse) * this.m_motorJacobian.linear1.x;
b1.m_linearVelocity.y += (invMass1 * motorImpulse) * this.m_motorJacobian.linear1.y;
//b1.m_angularVelocity += invI1 * motorImpulse * this.m_motorJacobian.angular1;
b1.m_angularVelocity += invI1 * motorImpulse * this.m_motorJacobian.angular1;
//b2->m_linearVelocity += (invMass2 * motorImpulse) * this.m_motorJacobian.linear2;
b2.m_linearVelocity.x += (invMass2 * motorImpulse) * this.m_motorJacobian.linear2.x;
b2.m_linearVelocity.y += (invMass2 * motorImpulse) * this.m_motorJacobian.linear2.y;
//b2->m_angularVelocity += invI2 * motorImpulse * this.m_motorJacobian.angular2;
b2.m_angularVelocity += invI2 * motorImpulse * this.m_motorJacobian.angular2;
}
// Solve linear limit constraint.
if (this.m_enableLimit && this.m_limitState != b2Joint.e_inactiveLimit)
{
var limitCdot = this.m_motorJacobian.Compute(b1.m_linearVelocity, b1.m_angularVelocity, b2.m_linearVelocity, b2.m_angularVelocity);
var limitImpulse = -this.m_motorMass * limitCdot;
if (this.m_limitState == b2Joint.e_equalLimits)
{
this.m_limitImpulse += limitImpulse;
}
else if (this.m_limitState == b2Joint.e_atLowerLimit)
{
oldLimitImpulse = this.m_limitImpulse;
this.m_limitImpulse = b2Math.b2Max(this.m_limitImpulse + limitImpulse, 0.0);
limitImpulse = this.m_limitImpulse - oldLimitImpulse;
}
else if (this.m_limitState == b2Joint.e_atUpperLimit)
{
oldLimitImpulse = this.m_limitImpulse;
this.m_limitImpulse = b2Math.b2Min(this.m_limitImpulse + limitImpulse, 0.0);
limitImpulse = this.m_limitImpulse - oldLimitImpulse;
}
//b1->m_linearVelocity += (invMass1 * limitImpulse) * this.m_motorJacobian.linear1;
b1.m_linearVelocity.x += (invMass1 * limitImpulse) * this.m_motorJacobian.linear1.x;
b1.m_linearVelocity.y += (invMass1 * limitImpulse) * this.m_motorJacobian.linear1.y;
//b1->m_angularVelocity += invI1 * limitImpulse * this.m_motorJacobian.angular1;
b1.m_angularVelocity += invI1 * limitImpulse * this.m_motorJacobian.angular1;
//b2->m_linearVelocity += (invMass2 * limitImpulse) * this.m_motorJacobian.linear2;
b2.m_linearVelocity.x += (invMass2 * limitImpulse) * this.m_motorJacobian.linear2.x;
b2.m_linearVelocity.y += (invMass2 * limitImpulse) * this.m_motorJacobian.linear2.y;
//b2->m_angularVelocity += invI2 * limitImpulse * this.m_motorJacobian.angular2;
b2.m_angularVelocity += invI2 * limitImpulse * this.m_motorJacobian.angular2;
}
},
SolvePositionConstraints: function(){
var limitC;
var oldLimitImpulse;
var b1 = this.m_body1;
var b2 = this.m_body2;
var invMass1 = b1.m_invMass;
var invMass2 = b2.m_invMass;
var invI1 = b1.m_invI;
var invI2 = b2.m_invI;
var tMat;
//b2Vec2 r1 = b2Mul(b1->m_R, this.m_localAnchor1);
tMat = b1.m_R;
var r1X = tMat.col1.x * this.m_localAnchor1.x + tMat.col2.x * this.m_localAnchor1.y;
var r1Y = tMat.col1.y * this.m_localAnchor1.x + tMat.col2.y * this.m_localAnchor1.y;
//b2Vec2 r2 = b2Mul(b2->m_R, this.m_localAnchor2);
tMat = b2.m_R;
var r2X = tMat.col1.x * this.m_localAnchor2.x + tMat.col2.x * this.m_localAnchor2.y;
var r2Y = tMat.col1.y * this.m_localAnchor2.x + tMat.col2.y * this.m_localAnchor2.y;
//b2Vec2 p1 = b1->m_position + r1;
var p1X = b1.m_position.x + r1X;
var p1Y = b1.m_position.y + r1Y;
//b2Vec2 p2 = b2->m_position + r2;
var p2X = b2.m_position.x + r2X;
var p2Y = b2.m_position.y + r2Y;
//b2Vec2 d = p2 - p1;
var dX = p2X - p1X;
var dY = p2Y - p1Y;
//b2Vec2 ay1 = b2Mul(b1->m_R, this.m_localYAxis1);
tMat = b1.m_R;
var ay1X = tMat.col1.x * this.m_localYAxis1.x + tMat.col2.x * this.m_localYAxis1.y;
var ay1Y = tMat.col1.y * this.m_localYAxis1.x + tMat.col2.y * this.m_localYAxis1.y;
// Solve linear (point-to-line) constraint.
//float32 linearC = b2Dot(ay1, d);
var linearC = ay1X*dX + ay1Y*dY;
// Prevent overly large corrections.
linearC = b2Math.b2Clamp(linearC, -b2Settings.b2_maxLinearCorrection, b2Settings.b2_maxLinearCorrection);
var linearImpulse = -this.m_linearMass * linearC;
//b1->m_position += (invMass1 * linearImpulse) * this.m_linearJacobian.linear1;
b1.m_position.x += (invMass1 * linearImpulse) * this.m_linearJacobian.linear1.x;
b1.m_position.y += (invMass1 * linearImpulse) * this.m_linearJacobian.linear1.y;
//b1->m_rotation += invI1 * linearImpulse * this.m_linearJacobian.angular1;
b1.m_rotation += invI1 * linearImpulse * this.m_linearJacobian.angular1;
//b1->m_R.Set(b1->m_rotation);
//b2->m_position += (invMass2 * linearImpulse) * this.m_linearJacobian.linear2;
b2.m_position.x += (invMass2 * linearImpulse) * this.m_linearJacobian.linear2.x;
b2.m_position.y += (invMass2 * linearImpulse) * this.m_linearJacobian.linear2.y;
b2.m_rotation += invI2 * linearImpulse * this.m_linearJacobian.angular2;
//b2->m_R.Set(b2->m_rotation);
var positionError = b2Math.b2Abs(linearC);
// Solve angular constraint.
var angularC = b2.m_rotation - b1.m_rotation - this.m_initialAngle;
// Prevent overly large corrections.
angularC = b2Math.b2Clamp(angularC, -b2Settings.b2_maxAngularCorrection, b2Settings.b2_maxAngularCorrection);
var angularImpulse = -this.m_angularMass * angularC;
b1.m_rotation -= b1.m_invI * angularImpulse;
b1.m_R.Set(b1.m_rotation);
b2.m_rotation += b2.m_invI * angularImpulse;
b2.m_R.Set(b2.m_rotation);
var angularError = b2Math.b2Abs(angularC);
// Solve linear limit constraint.
if (this.m_enableLimit && this.m_limitState != b2Joint.e_inactiveLimit)
{
//b2Vec2 r1 = b2Mul(b1->m_R, this.m_localAnchor1);
tMat = b1.m_R;
r1X = tMat.col1.x * this.m_localAnchor1.x + tMat.col2.x * this.m_localAnchor1.y;
r1Y = tMat.col1.y * this.m_localAnchor1.x + tMat.col2.y * this.m_localAnchor1.y;
//b2Vec2 r2 = b2Mul(b2->m_R, this.m_localAnchor2);
tMat = b2.m_R;
r2X = tMat.col1.x * this.m_localAnchor2.x + tMat.col2.x * this.m_localAnchor2.y;
r2Y = tMat.col1.y * this.m_localAnchor2.x + tMat.col2.y * this.m_localAnchor2.y;
//b2Vec2 p1 = b1->m_position + r1;
p1X = b1.m_position.x + r1X;
p1Y = b1.m_position.y + r1Y;
//b2Vec2 p2 = b2->m_position + r2;
p2X = b2.m_position.x + r2X;
p2Y = b2.m_position.y + r2Y;
//b2Vec2 d = p2 - p1;
dX = p2X - p1X;
dY = p2Y - p1Y;
//b2Vec2 ax1 = b2Mul(b1->m_R, this.m_localXAxis1);
tMat = b1.m_R;
var ax1X = tMat.col1.x * this.m_localXAxis1.x + tMat.col2.x * this.m_localXAxis1.y;
var ax1Y = tMat.col1.y * this.m_localXAxis1.x + tMat.col2.y * this.m_localXAxis1.y;
//float32 translation = b2Dot(ax1, d);
var translation = (ax1X*dX + ax1Y*dY);
var limitImpulse = 0.0;
if (this.m_limitState == b2Joint.e_equalLimits)
{
// Prevent large angular corrections
limitC = b2Math.b2Clamp(translation, -b2Settings.b2_maxLinearCorrection, b2Settings.b2_maxLinearCorrection);
limitImpulse = -this.m_motorMass * limitC;
positionError = b2Math.b2Max(positionError, b2Math.b2Abs(angularC));
}
else if (this.m_limitState == b2Joint.e_atLowerLimit)
{
limitC = translation - this.m_lowerTranslation;
positionError = b2Math.b2Max(positionError, -limitC);
// Prevent large linear corrections and allow some slop.
limitC = b2Math.b2Clamp(limitC + b2Settings.b2_linearSlop, -b2Settings.b2_maxLinearCorrection, 0.0);
limitImpulse = -this.m_motorMass * limitC;
oldLimitImpulse = this.m_limitPositionImpulse;
this.m_limitPositionImpulse = b2Math.b2Max(this.m_limitPositionImpulse + limitImpulse, 0.0);
limitImpulse = this.m_limitPositionImpulse - oldLimitImpulse;
}
else if (this.m_limitState == b2Joint.e_atUpperLimit)
{
limitC = translation - this.m_upperTranslation;
positionError = b2Math.b2Max(positionError, limitC);
// Prevent large linear corrections and allow some slop.
limitC = b2Math.b2Clamp(limitC - b2Settings.b2_linearSlop, 0.0, b2Settings.b2_maxLinearCorrection);
limitImpulse = -this.m_motorMass * limitC;
oldLimitImpulse = this.m_limitPositionImpulse;
this.m_limitPositionImpulse = b2Math.b2Min(this.m_limitPositionImpulse + limitImpulse, 0.0);
limitImpulse = this.m_limitPositionImpulse - oldLimitImpulse;
}
//b1->m_position += (invMass1 * limitImpulse) * this.m_motorJacobian.linear1;
b1.m_position.x += (invMass1 * limitImpulse) * this.m_motorJacobian.linear1.x;
b1.m_position.y += (invMass1 * limitImpulse) * this.m_motorJacobian.linear1.y;
//b1->m_rotation += invI1 * limitImpulse * this.m_motorJacobian.angular1;
b1.m_rotation += invI1 * limitImpulse * this.m_motorJacobian.angular1;
b1.m_R.Set(b1.m_rotation);
//b2->m_position += (invMass2 * limitImpulse) * this.m_motorJacobian.linear2;
b2.m_position.x += (invMass2 * limitImpulse) * this.m_motorJacobian.linear2.x;
b2.m_position.y += (invMass2 * limitImpulse) * this.m_motorJacobian.linear2.y;
//b2->m_rotation += invI2 * limitImpulse * this.m_motorJacobian.angular2;
b2.m_rotation += invI2 * limitImpulse * this.m_motorJacobian.angular2;
b2.m_R.Set(b2.m_rotation);
}
return positionError <= b2Settings.b2_linearSlop && angularError <= b2Settings.b2_angularSlop;
},
m_localAnchor1: new b2Vec2(),
m_localAnchor2: new b2Vec2(),
m_localXAxis1: new b2Vec2(),
m_localYAxis1: new b2Vec2(),
m_initialAngle: null,
m_linearJacobian: new b2Jacobian(),
m_linearMass: null,
m_linearImpulse: null,
m_angularMass: null,
m_angularImpulse: null,
m_motorJacobian: new b2Jacobian(),
m_motorMass: null,
m_motorImpulse: null,
m_limitImpulse: null,
m_limitPositionImpulse: null,
m_lowerTranslation: null,
m_upperTranslation: null,
m_maxMotorForce: null,
m_motorSpeed: null,
m_enableLimit: null,
m_enableMotor: null,
m_limitState: 0});
(C) Æliens
20/2/2008
You may not copy or print any of this material without explicit permission of the author or the publisher.
In case of other copyright issues, contact the author.
