如何在220帧动画模型的第70帧触发音频播放事件？

核心逻辑是实时监听动画播放的帧进度，当到达目标帧时触发音频播放，同时避免重复触发。以下是不同引擎的具体实现方式：

通用注意事项 #

• 确保动画资源的帧率设置准确，否则帧计算会出现偏差
• 若动画为循环播放，需在动画结束后重置触发标记，保证每次循环都能正常触发
• 可将判断条件从等于70帧改为大于等于70帧，避免因帧率过高或更新间隔导致的帧跳过问题

Unity 实现 #

方式1：使用 Animator 组件 #

using UnityEngine;

public class FrameAudioTrigger : MonoBehaviour
{
    private Animator _animator;
    private AudioSource _audioSource;
    private bool _hasTriggered;
    [SerializeField] private int targetFrame = 70;

    void Start()
    {
        _animator = GetComponent<Animator>();
        _audioSource = GetComponent<AudioSource>();
        _audioSource.playOnAwake = false;
    }

    void Update()
    {
        if (_animator.isPlaying && !_hasTriggered)
        {
            AnimatorStateInfo stateInfo = _animator.GetCurrentAnimatorStateInfo(0);
            AnimationClip clip = _animator.runtimeAnimatorController.animationClips[0];
            // 计算当前播放帧：动画时长 * 帧率 * 播放进度
            int currentFrame = Mathf.RoundToInt(stateInfo.length * clip.frameRate * stateInfo.normalizedTime);
            
            if (currentFrame >= targetFrame)
            {
                _audioSource.Play();
                _hasTriggered = true;
            }
        }

        // 动画结束后重置触发标记
        if (!_animator.isPlaying)
        {
            _hasTriggered = false;
        }
    }
}

方式2：使用 Animation 组件 #

using UnityEngine;

public class LegacyAnimationTrigger : MonoBehaviour
{
    private Animation _animation;
    private AudioSource _audioSource;
    private bool _triggered;
    public int targetFrame = 70;

    void Start()
    {
        _animation = GetComponent<Animation>();
        _audioSource = GetComponent<AudioSource>();
        _audioSource.playOnAwake = false;
    }

    void Update()
    {
        if (_animation.isPlaying && !_triggered)
        {
            AnimationClip clip = _animation.clip;
            // 计算当前播放帧：播放时间 / 单帧时长
            int currentFrame = Mathf.RoundToInt(_animation[clip.name].time / (1f / clip.frameRate));
            
            if (currentFrame >= targetFrame)
            {
                _audioSource.Play();
                _triggered = true;
            }
        }

        if (!_animation.isPlaying)
        {
            _triggered = false;
        }
    }
}

Unreal Engine 实现 #

方式1：蓝图实现 #

1. 在动画蓝图的动画图表中，添加 Get Animation Current Frame 节点获取当前播放帧
2. 添加布尔变量 bHasTriggered，用于标记是否已触发音频
3. 使用分支节点判断：当前帧 >= 70 且 bHasTriggered == false
4. 满足条件时，调用 Play Sound 2D 或 Play Sound at Location 播放音频，同时将 bHasTriggered 设置为 true
5. 在动画结束时（通过 Is Animation Playing 节点判断），将 bHasTriggered 重置为 false

方式2：C++ 实现 #

#include "Animation/AnimInstance.h"
#include "Audio/AudioComponent.h"
#include "CoreMinimal.h"

UCLASS()
class YOURPROJECT_API UAnimFrameAudioTrigger : public UAnimInstance
{
    GENERATED_BODY()

public:
    UPROPERTY(EditAnywhere, Category = "Trigger")
    int32 TargetFrame = 70;

    UPROPERTY(EditAnywhere, Category = "Audio")
    USoundBase* TargetAudio;

private:
    bool bHasTriggered = false;
    UAudioComponent* AudioComp;

    virtual void NativeInitializeAnimation() override
    {
        Super::NativeInitializeAnimation();
        AActor* Owner = GetOwningActor();
        if (!Owner) return;

        AudioComp = Owner->FindComponentByClass<UAudioComponent>();
        if (!AudioComp)
        {
            AudioComp = NewObject<UAudioComponent>(Owner);
            AudioComp->SetupAttachment(Owner->GetRootComponent());
            AudioComp->RegisterComponent();
        }
    }

    virtual void NativeUpdateAnimation(float DeltaSeconds) override
    {
        Super::NativeUpdateAnimation(DeltaSeconds);
        if (!AudioComp || !TargetAudio || bHasTriggered) return;

        UAnimMontage* CurrentMontage = GetCurrentActiveMontage();
        if (!CurrentMontage)
        {
            bHasTriggered = false;
            return;
        }

        float CurrentTime = GetMontagePosition(CurrentMontage);
        int32 CurrentFrame = FMath::RoundToInt(CurrentTime * CurrentMontage->GetFrameRate());
        
        if (CurrentFrame >= TargetFrame)
        {
            AudioComp->SetSound(TargetAudio);
            AudioComp->Play();
            bHasTriggered = true;
        }
    }
};

内容的提问来源于stack exchange，提问作者fran35