【Bullet引擎】剛體類 —— btRigidBody

btRigidBody類主要用於剛體數據的計算。

在模擬剛體動畫過程中，可以使用btRigidBody類獲取所保存的剛體對象，進而控制剛體對象的旋轉和位移。進行剛體模擬計算需要經常用到此類。

API：http://bulletphysics.org/Bullet/BulletFull/classbtRigidBody.html

 

創建剛體對象

    btCollisionShape* colShape = new btBoxShape(btVector3(5, 5, 5));//創建一個基本幾何體
 /// Create Dynamic Objects
 btTransform startTransform; startTransform.setIdentity(); btScalar mass(1.f);
 //rigidbody is dynamic if and only if mass is non zero, otherwise static
    bool isDynamic = (mass != 0.f); btVector3 localInertia(0, 0, 0); if (isDynamic) colShape->calculateLocalInertia(mass, localInertia); startTransform.setOrigin(btVector3(2, 10, 0));//剛體初始位置 //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);

 

從場景中獲取剛體對象

　　btCollisionObject* obj = dynamicsWorld->getCollisionObjectArray()[i];//i為場景中剛體對象的索引
　　btRigidBody* body = btRigidBody::upcast(obj);

 

常用方法：

剛體質心坐標：          

　　body->getCenterOfMassPosition();

 

獲取剛體四元數：      

　　btQuaternion qua = body->getOrientation();

 

剛體旋轉矩陣：         

　　btTransform trans;
　　body->getMotionState()->getWorldTransform(trans);
　　btMatrix3x3 matrix33 = trans.getBasis();

 

向剛體添加外力：

　　body->applyCentralForce(btVector3(2, 1, 0));

 

向剛體添加轉矩：

　　body->applyTorque(btVector3(0, 30, 0));

 

設置剛體變換：

　　btTransform trans;
　　trans.setIdentity();
　　trans.setOrigin(body->getCenterOfMassPosition() - dx);
　　body->setCenterOfMassTransform(trans);

 

 

 剛體對象