Box2DX.Dynamics.PrismaticJoint.SolvePositionConstraints C# (CSharp) Метод

        internal override bool SolvePositionConstraints(float baumgarte)
        {
            Body b1 = _body1;
            Body b2 = _body2;

            Vec2 c1 = b1._sweep.C;
            float a1 = b1._sweep.A;

            Vec2 c2 = b2._sweep.C;
            float a2 = b2._sweep.A;

            // Solve linear limit constraint.
            float linearError = 0.0f, angularError = 0.0f;
            bool active = false;
            float C2 = 0.0f;

            Mat22 R1 = new Mat22(a1), R2 = new Mat22(a2);

            Vec2 r1 = Box2DX.Common.Math.Mul(R1, _localAnchor1 - _localCenter1);
            Vec2 r2 = Box2DX.Common.Math.Mul(R2, _localAnchor2 - _localCenter2);
            Vec2 d = c2 + r2 - c1 - r1;

            if (_enableLimit)
            {
                _axis = Box2DX.Common.Math.Mul(R1, _localXAxis1);

                _a1 = Vec2.Cross(d + r1, _axis);
                _a2 = Vec2.Cross(r2, _axis);

                float translation = Vec2.Dot(_axis, d);
                if (Box2DX.Common.Math.Abs(_upperTranslation - _lowerTranslation) < 2.0f * Settings.LinearSlop)
                {
                    // Prevent large angular corrections
                    C2 = Box2DX.Common.Math.Clamp(translation, -Settings.MaxLinearCorrection, Settings.MaxLinearCorrection);
                    linearError = Box2DX.Common.Math.Abs(translation);
                    active = true;
                }
                else if (translation <= _lowerTranslation)
                {
                    // Prevent large linear corrections and allow some slop.
                    C2 = Box2DX.Common.Math.Clamp(translation - _lowerTranslation + Settings.LinearSlop, -Settings.MaxLinearCorrection, 0.0f);
                    linearError = _lowerTranslation - translation;
                    active = true;
                }
                else if (translation >= _upperTranslation)
                {
                    // Prevent large linear corrections and allow some slop.
                    C2 = Box2DX.Common.Math.Clamp(translation - _upperTranslation - Settings.LinearSlop, 0.0f, Settings.MaxLinearCorrection);
                    linearError = translation - _upperTranslation;
                    active = true;
                }
            }

            _perp = Box2DX.Common.Math.Mul(R1, _localYAxis1);

            _s1 = Vec2.Cross(d + r1, _perp);
            _s2 = Vec2.Cross(r2, _perp);

            Vec3 impulse;
            Vec2 C1 = new Vec2();
            C1.X = Vec2.Dot(_perp, d);
            C1.Y = a2 - a1 - _refAngle;

            linearError = Box2DX.Common.Math.Max(linearError, Box2DX.Common.Math.Abs(C1.X));
            angularError = Box2DX.Common.Math.Abs(C1.Y);

            if (active)
            {
                float m1 = _invMass1, m2 = _invMass2;
                float i1 = _invI1, i2 = _invI2;

                float k11 = m1 + m2 + i1 * _s1 * _s1 + i2 * _s2 * _s2;
                float k12 = i1 * _s1 + i2 * _s2;
                float k13 = i1 * _s1 * _a1 + i2 * _s2 * _a2;
                float k22 = i1 + i2;
                float k23 = i1 * _a1 + i2 * _a2;
                float k33 = m1 + m2 + i1 * _a1 * _a1 + i2 * _a2 * _a2;

                _K.Col1.Set(k11, k12, k13);
                _K.Col2.Set(k12, k22, k23);
                _K.Col3.Set(k13, k23, k33);

                Vec3 C = new Vec3();
                C.X = C1.X;
                C.Y = C1.Y;
                C.Z = C2;

                impulse = _K.Solve33(-C);
            }
            else
            {
                float m1 = _invMass1, m2 = _invMass2;
                float i1 = _invI1, i2 = _invI2;

                float k11 = m1 + m2 + i1 * _s1 * _s1 + i2 * _s2 * _s2;
                float k12 = i1 * _s1 + i2 * _s2;
                float k22 = i1 + i2;

                _K.Col1.Set(k11, k12, 0.0f);
                _K.Col2.Set(k12, k22, 0.0f);

                Vec2 impulse1 = _K.Solve22(-C1);
                impulse.X = impulse1.X;
                impulse.Y = impulse1.Y;
                impulse.Z = 0.0f;
            }

            Vec2 P = impulse.X * _perp + impulse.Z * _axis;
            float L1 = impulse.X * _s1 + impulse.Y + impulse.Z * _a1;
            float L2 = impulse.X * _s2 + impulse.Y + impulse.Z * _a2;

            c1 -= _invMass1 * P;
            a1 -= _invI1 * L1;
            c2 += _invMass2 * P;
            a2 += _invI2 * L2;

            // TODO_ERIN remove need for this.
            b1._sweep.C = c1;
            b1._sweep.A = a1;
            b2._sweep.C = c2;
            b2._sweep.A = a2;
            b1.SynchronizeTransform();
            b2.SynchronizeTransform();

            return linearError <= Settings.LinearSlop && angularError <= Settings.AngularSlop;
        }