bullet3/examples/Constraints/ConstraintPhysicsSetup.cpp

#include "ConstraintPhysicsSetup.h"


#include "../CommonInterfaces/CommonRigidBodyBase.h"
#include "../CommonInterfaces/CommonParameterInterface.h"



struct ConstraintPhysicsSetup : public CommonRigidBodyBase
{
	ConstraintPhysicsSetup(struct GUIHelperInterface* helper);
	virtual ~ConstraintPhysicsSetup();
	virtual void initPhysics();

	virtual void stepSimulation(float deltaTime);

	
	virtual void resetCamera()
	{
		float dist = 7;
		float pitch = -44;
		float yaw = 721;
		float targetPos[3]={8,1,-11};
		m_guiHelper->resetCamera(dist,yaw,pitch,targetPos[0],targetPos[1],targetPos[2]);
	}
	

};

ConstraintPhysicsSetup::ConstraintPhysicsSetup(struct GUIHelperInterface* helper)
:CommonRigidBodyBase(helper)
{
}
ConstraintPhysicsSetup::~ConstraintPhysicsSetup()
{
}

static btScalar val;
static btScalar targetVel=0;
static btScalar maxImpulse=10000;
static btHingeAccumulatedAngleConstraint* spDoorHinge=0;
static btScalar actualHingeVelocity=0.f;

static btVector3 btAxisA(0,1,0);

void ConstraintPhysicsSetup::stepSimulation(float deltaTime)
{
	val=spDoorHinge->getAccumulatedHingeAngle()*SIMD_DEGS_PER_RAD;
    if (m_dynamicsWorld)
	{
        spDoorHinge->enableAngularMotor(true,targetVel,maxImpulse);

		m_dynamicsWorld->stepSimulation(deltaTime,10,1./240.);


        btHingeConstraint* hinge = spDoorHinge;

        if (hinge)
        {

            const btRigidBody& bodyA = hinge->getRigidBodyA();
            const btRigidBody& bodyB = hinge->getRigidBodyB();


            btTransform trA = bodyA.getWorldTransform();
            btVector3 angVelA = bodyA.getAngularVelocity();
            btVector3 angVelB = bodyB.getAngularVelocity();

            {
                btVector3 ax1 = trA.getBasis()*hinge->getFrameOffsetA().getBasis().getColumn(2);
                btScalar vel = angVelA.dot(ax1);
                vel -= angVelB.dot(ax1);
                printf("hinge velocity (q) = %f\n", vel);
                actualHingeVelocity=vel;
            }
            btVector3 ortho0,ortho1;
            btPlaneSpace1(btAxisA,ortho0,ortho1);
            {

                btScalar vel2 = angVelA.dot(ortho0);
                vel2 -= angVelB.dot(ortho0);
                printf("hinge orthogonal1 velocity (q) = %f\n", vel2);
            }
            {

                btScalar vel0 = angVelA.dot(ortho1);
                vel0 -= angVelB.dot(ortho1);
                printf("hinge orthogonal0 velocity (q) = %f\n", vel0);
            }
        }
	}
}



void ConstraintPhysicsSetup::initPhysics()
{
	m_guiHelper->setUpAxis(1);

	createEmptyDynamicsWorld();

	m_guiHelper->createPhysicsDebugDrawer(m_dynamicsWorld);
	int mode = 	btIDebugDraw::DBG_DrawWireframe
				+btIDebugDraw::DBG_DrawConstraints
				+btIDebugDraw::DBG_DrawConstraintLimits;
	m_dynamicsWorld->getDebugDrawer()->setDebugMode(mode);


    {
    SliderParams slider("target vel",&targetVel);
    slider.m_minVal=-4;
    slider.m_maxVal=4;
    m_guiHelper->getParameterInterface()->registerSliderFloatParameter(slider);
    }

    {
        SliderParams slider("max impulse",&maxImpulse);
        slider.m_minVal=0;
        slider.m_maxVal=1000;
        m_guiHelper->getParameterInterface()->registerSliderFloatParameter(slider);
    }

    {
        SliderParams slider("actual vel",&actualHingeVelocity);
        slider.m_minVal=-4;
        slider.m_maxVal=4;
        m_guiHelper->getParameterInterface()->registerSliderFloatParameter(slider);
    }

    val=1.f;
    {
        SliderParams slider("angle",&val);
        slider.m_minVal=-720;
        slider.m_maxVal=720;
        m_guiHelper->getParameterInterface()->registerSliderFloatParameter(slider);
    }

	{ // create a door using hinge constraint attached to the world
		btCollisionShape* pDoorShape = new btBoxShape(btVector3(2.0f, 5.0f, 0.2f));
		m_collisionShapes.push_back(pDoorShape);
		btTransform doorTrans;
		doorTrans.setIdentity();
		doorTrans.setOrigin(btVector3(-5.0f, -2.0f, 0.0f));
		btRigidBody* pDoorBody = createRigidBody( 1.0, doorTrans, pDoorShape);
		pDoorBody->setActivationState(DISABLE_DEACTIVATION);
		const btVector3 btPivotA(10.f +  2.1f, -2.0f, 0.0f ); // right next to the door slightly outside

		spDoorHinge = new btHingeAccumulatedAngleConstraint( *pDoorBody, btPivotA, btAxisA );

        m_dynamicsWorld->addConstraint(spDoorHinge);

		spDoorHinge->setDbgDrawSize(btScalar(5.f));
	}
	
	m_guiHelper->autogenerateGraphicsObjects(m_dynamicsWorld);
}

class CommonExampleInterface*    ConstraintCreateFunc(CommonExampleOptions& options)
{
	return new ConstraintPhysicsSetup(options.m_guiHelper);
}