如何使用状态机 Phaser 转换到下降状态

Question

我正在使用 Phaser 3 和 typescript 制作平台游戏。我正在使用状态机和播放器控制器来处理播放器移动的逻辑，但似乎无法找到在播放器下降时播放下降动画（'pablo_fall'）的方法。我想也许检查velocity.y，如果它小于零进入下降状态，但我不能在this.sprite.body.velocity.y上使用

import Phaser from 'phaser'
import StateMachine from '../statemachine/StateMachine'


export default class playercontroller {

    private sprite: Phaser.Physics.Matter.Sprite
    private StateMachine: StateMachine
    private cursors: Phaser.Types.Input.Keyboard.CursorKeys

    constructor(sprite: Phaser.Physics.Matter.Sprite, cursors: Phaser.Types.Input.Keyboard.CursorKeys) {
        this.sprite = sprite
        this.cursors = cursors

        this.createAnimations()

        this.StateMachine = new StateMachine(this, 'player')

        this.StateMachine.addState('idle', {
            onEnter: this.idleOnEnter,
            onUpdate: this.idleOnUpdate
        })
            .addState('walk', {
                onEnter: this.walkOnEnter,
                onUpdate: this.walkOnUpdate
            })
            .addState('jump', {
                onEnter: this.jumpOnEnter,
                onUpdate: this.jumpOnUpdate
            })
            .addState('doubleJump',{
                onEnter: this.doubleJumpOnEnter,
                onUpdate: this.doubleJumpOnUpdate
            })
            .setState('idle')

        this.sprite.setOnCollide((data: MatterJS.ICollisionPair) => {
            if (this.StateMachine.isCurrentState('jump')||this.StateMachine.isCurrentState('doubleJump')) {
                this.StateMachine.setState('idle')
            }
        })
    }

    update(dt: number) {
        this.StateMachine.update(dt)
    }

    private idleOnEnter() {
        this.sprite.play('pablo_idle')
    }

    private idleOnUpdate() {
        if (this.cursors.left.isDown || this.cursors.right.isDown) {
            this.StateMachine.setState('walk')
        }

        const spaceJustPressed = Phaser.Input.Keyboard.JustDown(this.cursors.space)
        if (spaceJustPressed) {
            this.StateMachine.setState('jump')
        }
    }

    private walkOnEnter() {
        this.sprite.play('pablo_run')
    }

    private walkOnUpdate() {

        const speed = 5;

        if (this.cursors.left.isDown) {
            this.sprite.flipX = true
            this.sprite.setVelocityX(-speed)
        }

        else if (this.cursors.right.isDown) {
            this.sprite.flipX = false
            this.sprite.setVelocityX(speed)
        }

        else {
            this.sprite.setVelocityX(0)
            this.StateMachine.setState('idle')
        }
        const spaceJustPressed = Phaser.Input.Keyboard.JustDown(this.cursors.space)
        if (spaceJustPressed) {
            this.StateMachine.setState('jump')
        }
    }

    private jumpOnEnter() {
        this.sprite.setVelocityY(-6)
        this.sprite.play('pablo_jump')
    }

    private jumpOnUpdate() {

        const speed = 5;
        let canDoubleJump = true;

        const spaceJustPressed = Phaser.Input.Keyboard.JustDown(this.cursors.space)
        if (spaceJustPressed) {
            this.StateMachine.setState('doubleJump')
        }


        if (this.cursors.left.isDown) {
            this.sprite.flipX = true
            this.sprite.setVelocityX(-speed)
        }

        else if (this.cursors.right.isDown) {
            this.sprite.flipX = false
            this.sprite.setVelocityX(speed)
        }
    }

    private doubleJumpOnEnter(){
        this.sprite.setVelocityY(-6)
        this.sprite.play('pablo_double_jump')
    }

    
    private doubleJumpOnUpdate() {
        
        const speed = 5;

        if (this.cursors.left.isDown) {
            this.sprite.flipX = true
            this.sprite.setVelocityX(-speed)
        }

        else if (this.cursors.right.isDown) {
            this.sprite.flipX = false
            this.sprite.setVelocityX(speed)
        }
    }

    private createAnimations() {

        this.sprite.anims.create({
            key: 'pablo_idle',
            frameRate: 20,
            frames: this.sprite.anims.generateFrameNames('pablo_idle', {
                start: 0,
                end: 10,
                prefix: 'Idle (32x32)-',
                suffix: '.png'
            }),
            repeat: -1
        })
        this.sprite.anims.create({
            key: 'pablo_run',
            frameRate: 20,
            frames: this.sprite.anims.generateFrameNames('pablo_run', {
                start: 0,
                end: 10,
                prefix: 'Run (32x32)-',
                suffix: '.png'
            }),
            repeat: -1

        })
        this.sprite.anims.create({
            key: 'pablo_jump',
            frameRate: 20,
            frames: 'pablo_jump',
            repeat: -1
        })
        this.sprite.anims.create({
            key: 'pablo_fall',
            frameRate: 20,
            frames: 'pablo_fall',
            repeat: -1
        })
        this.sprite.anims.create({
            key: 'pablo_double_jump',
            frameRate: 20,
            frames: this.sprite.anims.generateFrameNames('pablo_double_jump', {
                start: 0,
                end: 5,
                prefix: 'Double Jump (32x32)-',
                suffix: '.png',
            })
        })
    }
}```

Answer 1

我不知道为什么我以前不能使用

        if (this.sprite.body.velocity.y>  0){
            this.sprite.anims.play('pablo_fall')
        }