Torque in Bullet

I'm working on a game which involves spaceships. We're using OGRE and Bullet.

The player's ship is supposed to pitch and yaw with the mouse -- moving the mouse left will yaw the ship left, for example. The problem is, I can't figure out how to apply torque in Bullet.

Before we started integrating Bullet, our solution was to directly modify the OGRE scene node like so (using OIS for input):

bool Game::mouseMoved(const OIS::MouseEvent &event) {
    shipNode->yaw(Ogre::Degree(-event.state.X.rel));
    shipNode->pitch(Ogre::Degree(event.state.Y.rel));
    return true;
}

And that worked fine.

Now that we're using Bullet, my plan was to apply torque to the rigid body, like so:

bool Game::mouseMoved(const OIS::MouseEvent &event) {
    //shipNode->yaw(Ogre::Degree(-event.state.X.rel));
    //shipNode->pitch(Ogre::Degree(event.state.Y.rel));
    shipRigidBody->applyTorqueImpulse(btVector3(-event.state.X.rel, event.state.Y.rel, 0));
    return true;
}

Then, after stepping the simulation, update the scene node's orientation, like so:

void Game::update(const Ogre::FrameEvent &event) {
    // ... snip ...
    physicsWorld->stepSimulation(event.timeSinceLastFrame, 10);

    btTransform shipTransform;
    shipMotionState->getWorldTransform(shipTransform);
    shipNode->setPosition(shipTransform.getOrigin().x(), /* ... snip ... */);
    shipNode->setOrientation(shipTransform.getRotation().getAngle(), shipTransform.getRotation().getAxis().x(), /* ... snip ... */);
}

But with this setup, I can't orient the ship at all.

Next, I tried just applying a torque impulse of (100, 10, 200) every frame no matter what, then printing out shipTransform.getRotation().getAngle()) . Always 0. At this point, I became extremely confused, since you'd think that always applying torque would make the body's orientation change.

So, my question is: Am I missing something stupid about btRigidBody::applyTorqueImpulse() ? Or am I barking up the wrong tree entirely?

---

PS: shipRigidBody is constructed like this:

    shipMotionState = new btDefaultMotionState(btTransform(btQuaternion(0, 0, 0, 1), btVector3(0, 100, 0)));
    shipShape = new btBoxShape(btVector3(50, 20, 75));
    shipShape->calculateLocalInertia(btScalar(1), btVector3(0, 0, 0));
    shipRigidBody = new btRigidBody(btRigidBody::btRigidBodyConstructionInfo(1, shipMotionState, shipShape));

I also have code which accelerates the ship forwards or backwards based on keyboard input, and that code (which uses btRigidBody::applyCentralImpulse() ) is working fine.

链接地址: http://www.djcxy.com/p/95472.html

上一篇: 碰撞后移除物体（子弹物理）

下一篇: 子弹转矩