[游戏开发]Unity ecs physics trigger

Unity DOTS中的物理系统即Unity.Physics，这里使用一个简单的demo（小球弹起效果），来说明一下 碰撞 Trigger。

1、创建sphere（注意，要去掉ShpereCollider），添加Physics Shape，ShapeType 选择 Sphere，PhysicsShape 选择RaiseTriggerEvents；添加 Physics Body。（当然添加ConvertToEntity是必须的，关于ConvertToEntity的使用可以看一下官网demo）

2、创建plane（注意，要去掉MeshCollider），添加Physics Shape，ShapeType 选择 Plane。

3、小球弹起，触发逻辑

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using Unity.Entities;
using Unity.Mathematics;
using Unity.Transforms;
using Unity.Physics;
using Unity.Collections;
using Unity.Physics.Systems;

public class PhysicalSystem : SystemBase
{
    private BuildPhysicsWorld m_buildPhysicsWorld;//物理系统的准备工作，将TriggerCollisionEvents传递给Job
    private StepPhysicsWorld m_stepPhysicsWorld;//物理系统的准备工作，将TriggerCollisionEvents传递给Job

    protected override void OnCreate()
    {
        m_buildPhysicsWorld = World.GetOrCreateSystem<BuildPhysicsWorld>();
        m_stepPhysicsWorld = World.GetOrCreateSystem<StepPhysicsWorld>();
    }

    protected override void OnUpdate()
    {
        TriggerJob triggerJob = new TriggerJob()
        {
            PhysicVelocityGroup = GetComponentDataFromEntity<PhysicsVelocity>()
        };
        Dependency = triggerJob.Schedule(m_stepPhysicsWorld.Simulation, ref m_buildPhysicsWorld.PhysicsWorld, Dependency);
    }
}

public struct TriggerJob : ITriggerEventsJob
{
    /// <summary>
    /// cube和sphere中只有小球添加了PhysicsBody，在转成entity后，只有小球有physicsvelocity
    /// </summary>
    public ComponentDataFromEntity<PhysicsVelocity> PhysicVelocityGroup;

    public void Execute(TriggerEvent triggerEvent)
    {
        if (PhysicVelocityGroup.HasComponent(triggerEvent.EntityA))
        {
            Debug.Log("EntityA is sphere = " + triggerEvent.EntityA);
            var velocity = PhysicVelocityGroup[triggerEvent.EntityA];
            velocity.Linear.y = 10f;//如果是小球改变它的物理速度
            PhysicVelocityGroup[triggerEvent.EntityA] = velocity;
        }

        if (PhysicVelocityGroup.HasComponent(triggerEvent.EntityB))
        {
            Debug.Log("EntityB is sphere = " + triggerEvent.EntityB);
            var velocity = PhysicVelocityGroup[triggerEvent.EntityB];
            velocity.Linear.y = 10f;//如果是小球改变它的物理速度
            PhysicVelocityGroup[triggerEvent.EntityB] = velocity;
        }
    }
}