c++ - 检测与子弹的碰撞

Question

我用 Ogre3D 制作了一个应用程序，已经生成了子弹的对象，现在我需要做的就是检测对象之间的碰撞。

我看了CollisionInterfaceDemo的demo，不太符合我的需求。

检测假设 3 个球体之间的碰撞所需的步骤是什么，只知道它是否发生碰撞(我不关心碰撞点)？

我只知道我可以通过设置变换来移动 CollisionObject。

Answer 1

如果您使用的是 Bullet，可以查看几个演示来帮助您入门。

但基本上，这里是概要(其中大部分摘自他们的示例):

在你的标题或你的物理系统所在的地方:

btDefaultCollisionConfiguration*        mPhysicsConfig;
btCollisionDispatcher*                  mPhysicsDispatcher;
btBroadphaseInterface*                  mPhysicsCache;
btSequentialImpulseConstraintSolver*    mPhysicsSolver;
btDiscreteDynamicsWorld*                mPhysicsWorld;
btAlignedObjectArray<btCollisionShape*> mPhysicsShapes;

首先(初始化):

///collision configuration contains default setup for memory, collision setup.
mPhysicsConfig = new btDefaultCollisionConfiguration();

///use the default collision dispatcher. For parallel processing you can use a diffent dispatcher (see Extras/BulletMultiThreaded)
mPhysicsDispatcher = new    btCollisionDispatcher(mPhysicsConfig);

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

///the default constraint solver. For parallel processing you can use a different solver (see Extras/BulletMultiThreaded)
mPhysicsSolver = new btSequentialImpulseConstraintSolver;
mPhysicsWorld = new btDiscreteDynamicsWorld(mPhysicsDispatcher,mPhysicsCache,mPhysicsSolver,mPhysicsConfig);
mPhysicsWorld->setGravity(btVector3(0,-9.81f,0));

每一帧(这通常在更新函数中进行):

mPhysicsWorld->stepSimulation( timestep , 10 );

添加一个球体(指针返回只是为了在创建后更容易访问):

btRigidBody* MyPhysicsSystem::CreateSphere(float sx, float px, float py, float pz, float mass)
{
    btCollisionShape* colShape = new btSphereShape(btScalar(sx));
    mPhysicsShapes.push_back(colShape);

    btTransform startTransform;
    startTransform.setIdentity();

    btScalar    tMass(mass);

    //rigidbody is dynamic if and only if mass is non zero, otherwise static
    bool isDynamic = (tMass != 0.f);

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

    startTransform.setOrigin(btVector3(px,py,pz));

    //using motionstate is recommended, it provides interpolation capabilities, and only synchronizes 'active' objects
    btDefaultMotionState* myMotionState = new btDefaultMotionState(startTransform);
    btRigidBody::btRigidBodyConstructionInfo rbInfo(tMass,myMotionState,colShape,localInertia);
    btRigidBody* body = new btRigidBody(rbInfo);
    mPhysicsWorld->addRigidBody(body);
    return body;
}

就是这样!

重申一下:

1. 初始化子弹模拟所需的东西。
2. 创建一个对象并将其添加到子弹的“世界”。
3. 按某个时间步每帧更新该世界。

Bullet 将为您处理碰撞。如果您需要某种方式在碰撞发生时完成功能，我相信您可以指定一个自定义回调作为将要发生的碰撞行为。

• 这是项目符号引用的链接: http://bulletphysics.com/Bullet/BulletFull/
• 完整概述检测和响应与子弹的碰撞: http://www.bulletphysics.org/mediawiki-1.5.8/index.php?title=Collision_Callbacks_and_Triggers

希望这对您有所帮助!