[游戏开发]【Unity策略模式】角色攻击策略的不同 （不使用collider||Trigger）

/// <summary>
/// 攻击策略
/// </summary>
public abstract class AttackStrategy
{
    /// <summary>
    /// 攻击
    /// </summary>
    /// <param name="attackTarget">攻击目标</param>
    /// <returns>给攻击目标造成的伤害</returns>
    public abstract float Attack(Transform attacker, Transform attackTarget);
}

/// <summary>
/// 扇形攻击策略
/// </summary>
public class SectorAttackStrategy : AttackStrategy
{
    //半径
    private float skillRadius;
    //角度
    private float skillAngle;
    //技能释放方向
    private Vector3 skillDir;
    //最大伤害
    private float maxDamage;

    public SectorAttackStrategy(float skillRadius, float skillAngle, Vector2 skillDir,float maxDamage)
    {
        this.skillRadius = skillRadius;
        this.skillAngle = skillAngle;
        this.skillDir = skillDir;
        this.maxDamage = maxDamage;
    }

    public override float Attack(Transform attacker,Transform attackTarget)
    {
        //计算攻击者指向被攻击者的方向向量
        Vector3 direction = attackTarget.position - attacker.position;
        //计算两者距离
        float distance = direction.magnitude;
        //如果与敌人的距离超越技能半径
        if (distance > skillRadius)
            return 0;
        //计算敌人与玩家的方向与技能方向的夹角
        float enemyAngle = Vector3.Angle(direction, skillDir);
        //攻击目标不再扇形范围内
        if (enemyAngle > skillAngle / 2)
            return 0;
        //返回伤害【越近伤害越高】
        return (skillRadius - distance)/skillRadius * maxDamage;
    }
}

/// <summary>
/// 圆形攻击策略
/// </summary>
public class CircleAttackStrategy : AttackStrategy
{
    //技能位置
    private Vector3 skillPosition;
    //技能半径
    private float skillRadius;
    //高伤害半径
    private float maxDamageRadius;
    //内层的最大伤害
    private float maxDamage;
    //外层的最校伤害
    private float minDamage;
    
    public CircleAttackStrategy(Vector3 skillPosition, float skillRadius,float maxDamageRadius, float maxDamage, float minDamage)
    {
        this.skillPosition = skillPosition;
        this.skillRadius = skillRadius;
        this.maxDamageRadius = maxDamageRadius;
        this.maxDamage = maxDamage;
        this.minDamage = minDamage;
    }

    public override float Attack(Transform attacker, Transform attackTarget)
    {
        //攻击目标与技能圆心的距离
        float distance = Vector3.Distance(skillPosition, attackTarget.position);
        //不在攻击范围内
        if (distance > skillRadius)
            return 0;
        //在高伤害圈内
        if (distance < maxDamageRadius)
            return maxDamage;
        //在低伤害环内
        return minDamage;
    }
}

/// <summary>
/// 矩形攻击策略
/// </summary>
public class RectangleAttackStrategy : AttackStrategy
{
    private float distance;
    private float length;
    private float width;
    private float damage;

    public RectangleAttackStrategy(float distance, float length, float width,float damage)
    {
        this.distance = distance;
        this.length = length;
        this.width = width;
        this.damage = damage;
    }

    public override float Attack(Transform attacker, Transform attackTarget)
    {
        //计算技能中心的坐标
        Vector3 skillCenter = attacker.forward * distance + attacker.position;
        //技能中心点指向目标的方向向量
        Vector3 dir = attackTarget.position - skillCenter;
        //求这个方向向量在角色水平和垂直方向的投影向量
        Vector3 rightProjection = Vector3.Project(dir, attacker.right);
        Vector3 forwardProjection = Vector3.Project(dir, attacker.forward);
        //判断长度【不在矩形范围内】
        if (rightProjection.magnitude > length / 2
            || forwardProjection.magnitude > width / 2)
            return 0;
        //在范围内
        return damage;
    }
}

public class Hero
{
    private Transform _transform;

    public Transform Transform
    {
        get => _transform;
        set => _transform = value;
    }

    public Hero(Transform transform)
    {
        _transform = transform;
    }

    public void Attack(Hero target,AttackStrategy attackStrategy)
    {
        float damage = attackStrategy.Attack(_transform, target._transform);

        if (damage == 0)
        {
            Debug.Log("敌人未受到技能伤害...");
        }
        else
        {
            Debug.Log("敌人受到了" + damage + "点伤害");
        }
    }
}