如何解决Rapier KCC与传感器碰撞事件未触发及角色被推回问题？

问题描述 #

我在使用Rapier的运动学角色控制器（KCC）时遇到两个问题：

• KCC无法忽略与传感器的碰撞，角色会被传感器推回
• 碰撞事件未触发，怀疑与上述问题相关
  尝试修改碰撞组后仍无效果。

相关代码 #

角色控制器创建代码 #

// Create Capsule shape
let shape = new Capsule(0.25, 0.25);

// Create body/collider descriptions
let rigidBodyDesc = new RigidBodyDesc(RigidBodyType['KinematicPositionBased']);
let colliderDesc = new ColliderDesc(shape);

// Create body/collider from world
let body = world.createRigidBody(rigidBodyDesc);
let collider = world.createCollider(colliderDesc, body);

// Create Kinematic Character Controller
let controller = world.createCharacterController(0.01);

地面创建代码 #

// Create TriMesh shape
let shape = new TriMeshShape(vertices, indices, TriMeshFlags['FIX_INTERNAL_EDGES']);
let rigidBodyDesc = new RigidBodyDesc(RigidBodyType['Fixed']);
let colliderDesc = new ColliderDesc(shape);

// Create body/collider from world
let body = world.createRigidBody(rigidBodyDesc);
let collider = world.createCollider(colliderDesc, body);

传感器立方体创建代码 #

// Create Cuboid shape
let shape = new Cuboid(0.5, 0.5, 0.5);

// Create body/collider descriptions
let rigidBodyDesc = new RigidBodyDesc(RigidBodyType['Fixed']);
let colliderDesc = new ColliderDesc(shape).setSensor(true);

// Create body/collider from world
let body = world.createRigidBody(rigidBodyDesc);
let collider = world.createCollider(colliderDesc, body);

碰撞事件检测代码 #

let events = new EventQueue(true);

function update() {
  // Compute world
  world.step(events);

  // Review events
  events.drainCollisionEvents(function(handle1, handle2, started) {
    console.log(handle1, handle2, started);
  });
}

解决步骤 #

1. 配置碰撞组与过滤器 #

Rapier的KCC默认会和所有碰撞体交互，包括传感器。需给角色、地面、传感器分配不同碰撞组，让KCC只与地面交互：

// 定义碰撞组常量
const GROUP_CHARACTER = 0b0001;
const GROUP_GROUND = 0b0010;
const GROUP_SENSOR = 0b0100;

// 修改角色碰撞体配置
let colliderDesc = new ColliderDesc(shape)
  .setCollisionGroups(GROUP_CHARACTER)
  .setSolverGroups(GROUP_CHARACTER & ~GROUP_SENSOR); // 排除传感器组

// 修改传感器碰撞体配置
let colliderDesc = new ColliderDesc(shape)
  .setSensor(true)
  .setCollisionGroups(GROUP_SENSOR);

2. 给KCC设置碰撞过滤规则 #

单独为KCC配置过滤，确保它跳过传感器：

controller.setCollisionFilter({
  groups: GROUP_CHARACTER,
  mask: GROUP_GROUND, // 只检测地面组
});

3. 修正传感器事件捕获逻辑 #

传感器触发的是接触事件而非碰撞事件，需用drainContactEvents处理：

function update() {
  world.step(events);

  // 处理传感器接触事件
  events.drainContactEvents(function(handle1, handle2, started) {
    const collider1 = world.getCollider(handle1);
    const collider2 = world.getCollider(handle2);
    if (collider1.isSensor() || collider2.isSensor()) {
      console.log("传感器接触:", handle1, handle2, started);
    }
  });

  // 处理普通碰撞事件
  events.drainCollisionEvents(function(handle1, handle2, started) {
    console.log("碰撞事件:", handle1, handle2, started);
  });
}

4. 使用KCC内置方法移动角色 #

必须通过computeMovement计算移动，而非直接修改刚体位置，这样KCC才会应用过滤规则：

// 示例：计算并应用移动
const desiredDelta = new Vector(1, 0, 0); // 期望移动方向
const movement = controller.computeMovement(
  body.translation(),
  desiredDelta,
  0.0, // 最大爬坡坡度
  Vector.zero()
);

body.setNextKinematicTranslation(movement.translation());

内容的提问来源于stack exchange，提问作者doppler