Mathf.FloorToInt

public static int FloorToInt (float f);

説明

f 以下の最大の整数を返します。

using UnityEngine;
using System.Collections;

public class ExampleClass : MonoBehaviour {
    void Example() {
        Debug.Log(Mathf.FloorToInt(10.0F));
        Debug.Log(Mathf.FloorToInt(10.2F));
        Debug.Log(Mathf.FloorToInt(10.7F));
        Debug.Log(Mathf.FloorToInt(-10.0F));
        Debug.Log(Mathf.FloorToInt(-10.2F));
        Debug.Log(Mathf.FloorToInt(-10.7F));
    }
}