Bullet/HelloWorld - ProMemo

Bulletへもどる

HelloWorld

自由落下のサンプル

ヘッダの読み込み

#include <BulletDynamics/btBulletDynamicsCommon.h>
#include <stdio.h>

main関数始まります

int main(int argc, char** argv)
{

	int i;

世界（World）の設定の前準備

///衝突設定はデフォルト、自分で設定することもできる
btDefaultCollisionConfiguration* collisionConfiguration = new btDefaultCollisionConfiguration();

///衝突計算のディスパッチャー
// 他のディスパッチャーを用いて並列計算することもできるよ (Extras/BulletMultiThreaded　見てね)
btCollisionDispatcher* dispatcher = new	btCollisionDispatcher(collisionConfiguration);

///btDbvtBroadphase is a good general purpose broadphase. You can also try out btAxis3Sweep.
btBroadphaseInterface* overlappingPairCache = new btDbvtBroadphase();

///the default constraint solver
// 他のソルバーを用いて並列計算することもできるよ (Extras/BulletMultiThreaded　見てね)
btSequentialImpulseConstraintSolver* solver = new btSequentialImpulseConstraintSolver;

	//上記の設定を用いて、世界を作成
btDiscreteDynamicsWorld* dynamicsWorld = new btDiscreteDynamicsWorld(dispatcher,overlappingPairCache,solver,collisionConfiguration);
	//重力設定
dynamicsWorld->setGravity(btVector3(0,-10,0));

物体（rigid body）の生成

	//keep track of the shapes
//rigid bodyが存在するあいだは使うよ
btAlignedObjectArray<btCollisionShape*> collisionShapes;

受け止める方の物体を生成

{
	//とりあえず、50x50x50の立方体を生成(地面用)
	btCollisionShape* groundShape = new btBoxShape(btVector3(btScalar(50.),btScalar(50.),btScalar(50.)));
		collisionShapes.push_back(groundShape);

		//初期化
	btTransform groundTransform;
	groundTransform.setIdentity();

	//座標の設定 
	groundTransform.setOrigin(btVector3(0,-56,0));

	btScalar mass(0.);

	//0ならstatic(静止)、それ以外ならDynamicにする
	bool isDynamic = (mass != 0.f);

	btVector3 localInertia(0,0,0);
	if (isDynamic) groundShape->calculateLocalInertia(mass,localInertia);

	//using motionstate is recommended, it provides interpolation capabilities, and only synchronizes 'active' objects
	btDefaultMotionState* myMotionState = new btDefaultMotionState(groundTransform);
	btRigidBody::btRigidBodyConstructionInfo rbInfo(mass,myMotionState,groundShape,localInertia);
	btRigidBody* body = new btRigidBody(rbInfo);

	//物体を世界に追加する
	dynamicsWorld->addRigidBody(body);
}

落ちてくる方の物体を生成

{//次に、1x1x1の立方体を生成(地面用)
	//create a dynamic rigidbody

	btCollisionShape* colShape = new btSphereShape(btScalar(1.));
	collisionShapes.push_back(colShape);

	/// 初期位置を設定
	btTransform startTransform;
	startTransform.setIdentity();

	btScalar	mass(1.f);//重さ

	//0ならstatic(静止)、それ以外ならDynamicにする
	bool isDynamic = (mass != 0.f);

	btVector3 localInertia(0,0,0);
	if (isDynamic) colShape->calculateLocalInertia(mass,localInertia);

		startTransform.setOrigin(btVector3(2,10,0));//座標の設定 
		
		//using motionstate is recommended, it provides interpolation capabilities, and only synchronizes 'active' objects
		btDefaultMotionState* myMotionState = new btDefaultMotionState(startTransform);
		btRigidBody::btRigidBodyConstructionInfo rbInfo(mass,myMotionState,colShape,localInertia);
		btRigidBody* body = new btRigidBody(rbInfo);

		dynamicsWorld->addRigidBody(body);
}

シミュレーション開始

for (i=0;i<100;i++)
{
	dynamicsWorld->stepSimulation(1.f/60.f,10);
		
	//print positions of all objects
	for (int j=dynamicsWorld->getNumCollisionObjects()-1; j>=0 ;j--)
	{
		btCollisionObject* obj = dynamicsWorld->getCollisionObjectArray()[j];
		btRigidBody* body = btRigidBody::upcast(obj);
		if (body && body->getMotionState())
		{//位置を取得して表示
			btTransform trans;
			body->getMotionState()->getWorldTransform(trans);
			printf("world pos = %f,%f,%f\n",float(trans.getOrigin().getX()),float(trans.getOrigin().getY()),float(trans.getOrigin().getZ()));
		}
	}
}

お片づけ

//remove the rigidbodies from the dynamics world and delete them
for (i=dynamicsWorld->getNumCollisionObjects()-1; i>=0 ;i--)
{
	btCollisionObject* obj = dynamicsWorld->getCollisionObjectArray()[i];
	btRigidBody* body = btRigidBody::upcast(obj);
	if (body && body->getMotionState())
	{
		delete body->getMotionState();
	}
	dynamicsWorld->removeCollisionObject( obj );
	delete obj;
}

//delete collision shapes
for (int j=0;j<collisionShapes.size();j++)
{
	btCollisionShape* shape = collisionShapes[j];
	collisionShapes[j] = 0;
	delete shape;
}

//delete dynamics world
delete dynamicsWorld;

//delete solver
delete solver;

//delete broadphase
delete overlappingPairCache;

//delete dispatcher
delete dispatcher;

delete collisionConfiguration;

//next line is optional: it will be cleared by the destructor when the array goes out of scope
collisionShapes.clear();

}