Version: 2019.2
LanguageEnglish
  • C#

Time.deltaTime

Suggest a change

Success!

Thank you for helping us improve the quality of Unity Documentation. Although we cannot accept all submissions, we do read each suggested change from our users and will make updates where applicable.

Close

Submission failed

For some reason your suggested change could not be submitted. Please <a>try again</a> in a few minutes. And thank you for taking the time to help us improve the quality of Unity Documentation.

Close

Cancel

public static float deltaTime;

Description

The completion time in seconds since the last frame (Read Only).

This property provides the time between the current and previous frame.

Use Time.deltaTime to move a GameObject in the y direction, at n units per second. Multiply n by Time.deltaTime and add to the y component.

MonoBehaviour.FixedUpdate uses fixedDeltaTime instead of deltaTime. Do not rely on Time.deltaTime inside MonoBehaviour.OnGUI. Unity can call OnGUI multiple times per frame. The application use the same deltaTime value per call.

The following example implements a timer. The timer adds deltaTime each frame. The example announces the timer value and resets it to zero when it reaches 2 seconds. The timer does not hit 2.0 when MonoBehaviour.Update adds deltaTime. The test is for the timer moving 2 seconds. The script code removes the reported time, and the timer restarts. The restart is not always exactly 0.0. The speed changes between 0.5 and 2.0 seconds. Time.timeScale stores the chosen time-is-passing scale.

using System.Collections;
using System.Collections.Generic;
using UnityEngine;

// Time.deltaTime example. // // Wait two seconds and display waited time. // This is typically just beyond 2 seconds. // Allow the speed of the time to be increased or decreased. // It can range between 0.5 and 2.0. These changes only // happen when the timer restarts.

public class ScriptExample : MonoBehaviour { private float waitTime = 2.0f; private float timer = 0.0f; private float visualTime = 0.0f; private int width, height; private float value = 10.0f; private float scrollBar = 1.0f;

void Awake() { width = Screen.width; height = Screen.height; Time.timeScale = scrollBar; }

void Update() { timer += Time.deltaTime;

// Check if we have reached beyond 2 seconds. // Subtracting two is more accurate over time than resetting to zero. if (timer > waitTime) { visualTime = timer;

// Remove the recorded 2 seconds. timer = timer - waitTime; Time.timeScale = scrollBar; } }

void OnGUI() { GUIStyle sliderDetails = new GUIStyle(GUI.skin.GetStyle("horizontalSlider")); GUIStyle sliderThumbDetails = new GUIStyle(GUI.skin.GetStyle("horizontalSliderThumb")); GUIStyle labelDetails = new GUIStyle(GUI.skin.GetStyle("label"));

// Set the size of the fonts and the width/height of the slider. labelDetails.fontSize = 6 * (width / 200); sliderDetails.fixedHeight = height / 32; sliderDetails.fontSize = 12 * (width / 200); sliderThumbDetails.fixedHeight = height / 32; sliderThumbDetails.fixedWidth = width / 32;

// Show the slider. Make the scale to be ten times bigger than the needed size. value = GUI.HorizontalSlider(new Rect(width / 8, height / 4, width - (4 * width / 8), height - (2 * height / 4)), value, 5.0f, 20.0f, sliderDetails, sliderThumbDetails);

// Show the value from the slider. Make sure that 0.5, 0.6... 1.9, 2.0 are shown. float v = ((float)Mathf.RoundToInt(value)) / 10.0f; GUI.Label(new Rect(width / 8, height / 3.25f, width - (2 * width / 8), height - (2 * height / 4)), "timeScale: " + v.ToString("f1"), labelDetails); scrollBar = v;

// Display the recorded time in a certain size. labelDetails.fontSize = 14 * (width / 200); GUI.Label(new Rect(width / 8, height / 2, width - (2 * width / 8), height - (2 * height / 4)), "Timer value is: " + visualTime.ToString("f4") + " seconds.", labelDetails); } }
Copyright © 2023 Unity Technologies
优美缔软件(上海)有限公司 版权所有
"Unity"、Unity 徽标及其他 Unity 商标是 Unity Technologies 或其附属机构在美国及其他地区的商标或注册商标。其他名称或品牌是其各自所有者的商标。
公安部备案号:
31010902002961