碰撞体

碰撞体定义物体响应碰撞的实际物理性状，通常在渲染层是不可见的。通过碰撞体组件的设定，物理系统可以判定两个物体是否相交，从而产生碰撞效果。

碰撞体组件概览

我们封装了以下几个常见的碰撞体形状类型，方便用户使用：

1. 盒型碰撞体

import { ColliderComponent, BoxColliderShape } from '@orillusion/core'

// some codes here to create object...
let collider = object.addComponent(ColliderComponent);
collider.shape = new BoxColliderShape();
// set shape parameters...
collider.shape.size = new Vector3(2, 2, 2);

参数	类型	描述
size	Vector3	盒型碰撞体的大小。默认以物体中心为长方体中心，通过新建Vector3实例分别指定长方体沿x、y、z坐标轴的长度大小

2. 球形碰撞体

import { ColliderComponent, BoxColliderShape } from '@orillusion/core'

// some codes here to create object...
let collider = object.addComponent(ColliderComponent);
collider.shape = new SphereColliderShape();
// set shape parameters...
collider.radius = 5;

参数	类型	描述
radius	number	球形碰撞体的半径。默认以物体中心为球体中心

3. 胶囊碰撞体

import { ColliderComponent, BoxColliderShape } from '@orillusion/core'

// some codes here to create object...
let collider = object.addComponent(ColliderComponent);
collider.shape = new CapsuleColliderShape();
// set shape parameters...
collider.radius = 2.5;
collider.height = 10;

参数	类型	描述
radius	number	胶囊碰撞体上下半球体的半径
height	number	胶囊碰撞体的高度，默认以物体中心为胶囊体中心

碰撞体组件应用示例

在为对象添加了刚体组件后，我们再为它添加一个碰撞体，并指定碰撞体的形状类型，便可以让该对象响应碰撞了：

import { Vector3D, Object3D, ColliderComponent, BoxColliderShape } from '@orillusion/core'
import { Rigidbody } from '@orillusion/physics'

let object = new Object3D();
object.addComponent(Rigidbody);
let collider = obj.addComponent(ColliderComponent);
collider.shape = new BoxColliderShape();
collider.shape.size = new Vector3(2, 2, 2);

利用碰撞组件，我们可以模拟出逼真的物理效果，下面我们通过展示一个更复杂的示例，进一步了解物理系统可以实现的效果。

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import { BoxColliderShape, BoxGeometry, Camera3D, ColliderComponent, Color, ComponentBase, DirectLight, Engine3D, AtmosphericComponent, View3D, LitMaterial, HoverCameraController, MeshRenderer, Object3D, PlaneGeometry, Scene3D, Vector2, Vector3 } from '@orillusion/core'
import { Physics, Rigidbody } from '@orillusion/physics'

class Sample_colliders {
    constructor() {}

    addPlane(scene: Scene3D, size: Vector2, pos: Vector3, rot: Vector3) {
        const obj = new Object3D()
        let mr = obj.addComponent(MeshRenderer)
        mr.geometry = new PlaneGeometry(size.x, size.y)
        mr.material = new LitMaterial()
        mr.material.baseColor = new Color(0.04, 0.42, 0.45, 1)
        obj.localPosition = pos
        obj.localRotation = rot
        // add a rigidbody with no mass - static body
        let rigidbody = obj.addComponent(Rigidbody)
        rigidbody.mass = 0
        // add a box collider shape with small y value
        let collider = obj.addComponent(ColliderComponent)
        collider.shape = new BoxColliderShape()
        collider.shape.size = new Vector3(size.x, 0.1, size.y)
        scene.addChild(obj)
        return obj
    }

    loop() {
        if (Physics.isInited) {
            Physics.update()
        }
    }

    async run() {
        // Init physics engine
        await Physics.init()
        // Init Engine3D
        await Engine3D.init({
            canvasConfig: { devicePixelRatio: 1 },
            renderLoop: () => this.loop()
        })

        let scene3D = new Scene3D()
        scene3D.addComponent(AtmosphericComponent)
        let cameraObj = new Object3D()
        let mainCamera = cameraObj.addComponent(Camera3D)
        mainCamera.lookAt(new Vector3(0, 0, 10), new Vector3(0, 0, 0))
        mainCamera.perspective(60, Engine3D.aspect, 1, 5000.0)
        let controller = mainCamera.object3D.addComponent(HoverCameraController)
        controller.setCamera(45, -15, 150, new Vector3(0, 30, 0))
        scene3D.addChild(cameraObj)

        let light: Object3D = new Object3D()
        let component = light.addComponent(DirectLight)
        light.rotationX = 45
        light.rotationY = 30
        component.lightColor = new Color(1.0, 1.0, 1.0, 1.0)
        component.intensity = 20
        scene3D.addChild(light)

        this.addPlane(scene3D, new Vector2(100, 100), new Vector3(0, 0, 0), new Vector3(0, 0, 0))
        scene3D.addComponent(BoxGenerator)

        let view = new View3D()
        view.scene = scene3D
        view.camera = mainCamera
        // start render
        Engine3D.startRenderView(view)
    }
}

class BoxGenerator extends ComponentBase {
    // save last time
    private _lastTime: number = performance.now()

    // a simple loop update
    public onUpdate(): void {
        // get current time
        let now: number = performance.now()
        // add a box every 300ms
        if (now - this._lastTime > 300) {
            // add a box
            this._addBox()
            // remove the first box after 500 boxes
            if (this.object3D.entityChildren.length > 500) this.object3D.removeChildByIndex(4)
            // save current time
            this._lastTime = now
        }
    }

    // add a box
    private _addBox(): void {
        const obj = new Object3D()
        let mr = obj.addComponent(MeshRenderer)
        mr.geometry = new BoxGeometry(5, 5, 5)
        mr.material = new LitMaterial()
        mr.material.baseColor = new Color(Math.random(), Math.random(), Math.random(), 1.0)
        obj.localPosition = new Vector3(Math.random() * 70 - 35, 50, Math.random() * 70 - 35)
        obj.localRotation = new Vector3(Math.random() * 360, Math.random() * 360, Math.random() * 360)
        // add a rigidbody with mass 10
        let rigidbody = obj.addComponent(Rigidbody)
        rigidbody.mass = 10
        // add a box collider shape
        let collider = obj.addComponent(ColliderComponent)
        collider.shape = new BoxColliderShape()
        collider.shape.size = new Vector3(5, 5, 5)

        this.object3D.addChild(obj)
    }
}

new Sample_colliders().run()