virtualx-engine/thirdparty/bullet/BulletDynamics/ConstraintSolver/btSolverBody.h

/*
Bullet Continuous Collision Detection and Physics Library
Copyright (c) 2003-2006 Erwin Coumans  https://bulletphysics.org

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 BT_SOLVER_BODY_H
#define BT_SOLVER_BODY_H

class btRigidBody;
#include "LinearMath/btVector3.h"
#include "LinearMath/btMatrix3x3.h"

#include "LinearMath/btAlignedAllocator.h"
#include "LinearMath/btTransformUtil.h"

///Until we get other contributions, only use SIMD on Windows, when using Visual Studio 2008 or later, and not double precision
#ifdef BT_USE_SSE
#define USE_SIMD 1
#endif  //

#ifdef USE_SIMD

struct btSimdScalar
{
	SIMD_FORCE_INLINE btSimdScalar()
	{
	}

	SIMD_FORCE_INLINE btSimdScalar(float fl)
		: m_vec128(_mm_set1_ps(fl))
	{
	}

	SIMD_FORCE_INLINE btSimdScalar(__m128 v128)
		: m_vec128(v128)
	{
	}
	union {
		__m128 m_vec128;
		float m_floats[4];
		int m_ints[4];
		btScalar m_unusedPadding;
	};
	SIMD_FORCE_INLINE __m128 get128()
	{
		return m_vec128;
	}

	SIMD_FORCE_INLINE const __m128 get128() const
	{
		return m_vec128;
	}

	SIMD_FORCE_INLINE void set128(__m128 v128)
	{
		m_vec128 = v128;
	}

	SIMD_FORCE_INLINE operator __m128()
	{
		return m_vec128;
	}
	SIMD_FORCE_INLINE operator const __m128() const
	{
		return m_vec128;
	}

	SIMD_FORCE_INLINE operator float() const
	{
		return m_floats[0];
	}
};

///@brief Return the elementwise product of two btSimdScalar
SIMD_FORCE_INLINE btSimdScalar
operator*(const btSimdScalar& v1, const btSimdScalar& v2)
{
	return btSimdScalar(_mm_mul_ps(v1.get128(), v2.get128()));
}

///@brief Return the elementwise product of two btSimdScalar
SIMD_FORCE_INLINE btSimdScalar
operator+(const btSimdScalar& v1, const btSimdScalar& v2)
{
	return btSimdScalar(_mm_add_ps(v1.get128(), v2.get128()));
}

#else
#define btSimdScalar btScalar
#endif

///The btSolverBody is an internal datastructure for the constraint solver. Only necessary data is packed to increase cache coherence/performance.
ATTRIBUTE_ALIGNED16(struct)
btSolverBody
{
	BT_DECLARE_ALIGNED_ALLOCATOR();
	btTransform m_worldTransform;
	btVector3 m_deltaLinearVelocity;
	btVector3 m_deltaAngularVelocity;
	btVector3 m_angularFactor;
	btVector3 m_linearFactor;
	btVector3 m_invMass;
	btVector3 m_pushVelocity;
	btVector3 m_turnVelocity;
	btVector3 m_linearVelocity;
	btVector3 m_angularVelocity;
	btVector3 m_externalForceImpulse;
	btVector3 m_externalTorqueImpulse;

	btRigidBody* m_originalBody;
	void setWorldTransform(const btTransform& worldTransform)
	{
		m_worldTransform = worldTransform;
	}

	const btTransform& getWorldTransform() const
	{
		return m_worldTransform;
	}

	SIMD_FORCE_INLINE void getVelocityInLocalPointNoDelta(const btVector3& rel_pos, btVector3& velocity) const
	{
		if (m_originalBody)
			velocity = m_linearVelocity + m_externalForceImpulse + (m_angularVelocity + m_externalTorqueImpulse).cross(rel_pos);
		else
			velocity.setValue(0, 0, 0);
	}

	SIMD_FORCE_INLINE void getVelocityInLocalPointObsolete(const btVector3& rel_pos, btVector3& velocity) const
	{
		if (m_originalBody)
			velocity = m_linearVelocity + m_deltaLinearVelocity + (m_angularVelocity + m_deltaAngularVelocity).cross(rel_pos);
		else
			velocity.setValue(0, 0, 0);
	}

	SIMD_FORCE_INLINE void getAngularVelocity(btVector3 & angVel) const
	{
		if (m_originalBody)
			angVel = m_angularVelocity + m_deltaAngularVelocity;
		else
			angVel.setValue(0, 0, 0);
	}

	//Optimization for the iterative solver: avoid calculating constant terms involving inertia, normal, relative position
	SIMD_FORCE_INLINE void applyImpulse(const btVector3& linearComponent, const btVector3& angularComponent, const btScalar impulseMagnitude)
	{
		if (m_originalBody)
		{
			m_deltaLinearVelocity += linearComponent * impulseMagnitude * m_linearFactor;
			m_deltaAngularVelocity += angularComponent * (impulseMagnitude * m_angularFactor);
		}
	}

	SIMD_FORCE_INLINE void internalApplyPushImpulse(const btVector3& linearComponent, const btVector3& angularComponent, btScalar impulseMagnitude)
	{
		if (m_originalBody)
		{
			m_pushVelocity += linearComponent * impulseMagnitude * m_linearFactor;
			m_turnVelocity += angularComponent * (impulseMagnitude * m_angularFactor);
		}
	}

	const btVector3& getDeltaLinearVelocity() const
	{
		return m_deltaLinearVelocity;
	}

	const btVector3& getDeltaAngularVelocity() const
	{
		return m_deltaAngularVelocity;
	}

	const btVector3& getPushVelocity() const
	{
		return m_pushVelocity;
	}

	const btVector3& getTurnVelocity() const
	{
		return m_turnVelocity;
	}

	////////////////////////////////////////////////
	///some internal methods, don't use them

	btVector3& internalGetDeltaLinearVelocity()
	{
		return m_deltaLinearVelocity;
	}

	btVector3& internalGetDeltaAngularVelocity()
	{
		return m_deltaAngularVelocity;
	}

	const btVector3& internalGetAngularFactor() const
	{
		return m_angularFactor;
	}

	const btVector3& internalGetInvMass() const
	{
		return m_invMass;
	}

	void internalSetInvMass(const btVector3& invMass)
	{
		m_invMass = invMass;
	}

	btVector3& internalGetPushVelocity()
	{
		return m_pushVelocity;
	}

	btVector3& internalGetTurnVelocity()
	{
		return m_turnVelocity;
	}

	SIMD_FORCE_INLINE void internalGetVelocityInLocalPointObsolete(const btVector3& rel_pos, btVector3& velocity) const
	{
		velocity = m_linearVelocity + m_deltaLinearVelocity + (m_angularVelocity + m_deltaAngularVelocity).cross(rel_pos);
	}

	SIMD_FORCE_INLINE void internalGetAngularVelocity(btVector3 & angVel) const
	{
		angVel = m_angularVelocity + m_deltaAngularVelocity;
	}

	//Optimization for the iterative solver: avoid calculating constant terms involving inertia, normal, relative position
	SIMD_FORCE_INLINE void internalApplyImpulse(const btVector3& linearComponent, const btVector3& angularComponent, const btScalar impulseMagnitude)
	{
		if (m_originalBody)
		{
			m_deltaLinearVelocity += linearComponent * impulseMagnitude * m_linearFactor;
			m_deltaAngularVelocity += angularComponent * (impulseMagnitude * m_angularFactor);
		}
	}

	void writebackVelocity()
	{
		if (m_originalBody)
		{
			m_linearVelocity += m_deltaLinearVelocity;
			m_angularVelocity += m_deltaAngularVelocity;

			//m_originalBody->setCompanionId(-1);
		}
	}

	void writebackVelocityAndTransform(btScalar timeStep, btScalar splitImpulseTurnErp)
	{
		(void)timeStep;
		if (m_originalBody)
		{
			m_linearVelocity += m_deltaLinearVelocity;
			m_angularVelocity += m_deltaAngularVelocity;

			//correct the position/orientation based on push/turn recovery
			btTransform newTransform;
			if (m_pushVelocity[0] != 0.f || m_pushVelocity[1] != 0 || m_pushVelocity[2] != 0 || m_turnVelocity[0] != 0.f || m_turnVelocity[1] != 0 || m_turnVelocity[2] != 0)
			{
				//	btQuaternion orn = m_worldTransform.getRotation();
				btTransformUtil::integrateTransform(m_worldTransform, m_pushVelocity, m_turnVelocity * splitImpulseTurnErp, timeStep, newTransform);
				m_worldTransform = newTransform;
			}
			//m_worldTransform.setRotation(orn);
			//m_originalBody->setCompanionId(-1);
		}
	}
};

#endif  //BT_SOLVER_BODY_H