fix capsule to hull contact generation, add weld joint with an alternative constraint model

include/bounce/bounce.h

@@ -41,6 +41,7 @@
 
 #include <bounce/dynamics/joints/mouse_joint.h>
 #include <bounce/dynamics/joints/spring_joint.h>
+#include <bounce/dynamics/joints/weld_joint.h>
 #include <bounce/dynamics/joints/sphere_joint.h>
 #include <bounce/dynamics/joints/revolute_joint.h>
 #include <bounce/dynamics/joints/cone_joint.h>

include/bounce/dynamics/body.h

@@ -243,6 +243,7 @@ private:
 	friend class b3JointSolver;
 	friend class b3MouseJoint;
 	friend class b3SpringJoint;
+	friend class b3WeldJoint;
 	friend class b3RevoluteJoint;
 	friend class b3SphereJoint;
 	friend class b3ConeJoint;

include/bounce/dynamics/joints/joint.h

@@ -33,6 +33,7 @@ enum b3JointType
 	e_unknownJoint,
 	e_mouseJoint,
 	e_springJoint,
+	e_weldJoint,
 	e_revoluteJoint,
 	e_sphereJoint,
 	e_coneJoint,

include/bounce/dynamics/joints/weld_joint.h

@@ -0,0 +1,99 @@
+/*
+* Copyright (c) 2016-2016 Irlan Robson http://www.irlan.net
+*
+* 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 as such, and must not be
+* misrepresented as being the original software.
+* 3. This notice may not be removed or altered from any source distribution.
+*/
+
+#ifndef B3_WELD_JOINT_H
+#define B3_WELD_JOINT_H
+
+#include <bounce/dynamics/joints/joint.h>
+
+struct b3WeldJointDef : public b3JointDef
+{
+	b3WeldJointDef()
+	{
+		type = e_weldJoint;
+		localAnchorA.SetZero();
+		localAnchorB.SetZero();
+		relativeRotation.SetIdentity();
+	}
+
+	// Initialize this definition from bodies and world anchor point.
+	void Initialize(b3Body* bodyA, b3Body* bodyB, const b3Vec3& anchor);
+
+	// The joint anchor relative body A's origin.
+	b3Vec3 localAnchorA;
+
+	// The joint anchor relative body B's origin.
+	b3Vec3 localAnchorB;
+
+	// The initial relative rotation from body A to body B.
+	b3Quat relativeRotation;
+};
+
+// A weld joint removes the relative rotation between two bodies. 
+// You need to specify the relative rotation and the local anchor points. 
+// @todo Soft this constraint.
+class b3WeldJoint : public b3Joint
+{
+public:
+	// Get the anchor point on body A in world coordinates.
+	b3Vec3 GetAnchorA() const;
+
+	// Get the anchor point on body B in world coordinates.
+	b3Vec3 GetAnchorB() const;
+
+	// Draw this joint.
+	void Draw(b3Draw* draw) const;
+private:
+	friend class b3Joint;
+	friend class b3JointManager;
+	friend class b3JointSolver;
+
+	b3WeldJoint(const b3WeldJointDef* def);
+
+	virtual void InitializeConstraints(const b3SolverData* data);
+	virtual void WarmStart(const b3SolverData* data);
+	virtual void SolveVelocityConstraints(const b3SolverData* data);
+	virtual bool SolvePositionConstraints(const b3SolverData* data);
+
+	// Solver shared
+	b3Vec3 m_localAnchorA;
+	b3Vec3 m_localAnchorB;
+	
+	b3Quat m_dq0;
+
+	// Solver temp
+	u32 m_indexA;
+	u32 m_indexB;
+	float32 m_mA;
+	float32 m_mB;
+	b3Mat33 m_iA;
+	b3Mat33 m_iB;
+	b3Vec3 m_localCenterA;
+	b3Vec3 m_localCenterB;
+
+	// Point-to-point
+	b3Vec3 m_rA;
+	b3Vec3 m_rB;
+	b3Vec3 m_impulse;
+	b3Mat33 m_mass;
+
+	b3Vec3 m_axisImpulse;
+	//b3Vec3 m_velocityBias;
+};
+
+#endif