Change light.color over time, repeat

Questions & Answers
1

Hi,

I’ve already found some bits of code here but that still doesn’t answer my question. I’m trying to create a day/night cycle. I have 4 colours for each day time. So morning, noon, dusk, night. They are stored in separate variables.

I want the light colour to lerp from one to another in certain amount of time per colour. Can someone write a bit of code and hopefully describe WHY and WHAT’S happening? :slight_smile:

tl;dr I want to cycle between 4 light colours to create a day/night cycle. Also, how do I loop this behaviour?

2

hm, still at work and can’t actually test this right now to write it, but take a look at 72. Unity3d Tutorial - Day Night Cycle Part 1 - YouTube this covers a day / night cycle setup, including time and looping. It’s not actually blending colors but uses a moving sun/moon & blending skyboxes but hope that helps

3

Hello,
here’s my example. I do not use lerp here but if you need that you can substitute the Mathf.Sin with any functions you want. Some code might be redundant to you since I included some timing optimization. The light is updated every t you specify in UPDATE_INTERVAL.
The rest should be straight forward.
Hope it helps.

Note: you might need more precise functions to map the sun colour on time. These were just OK for my purposes.

using UnityEngine;
using System.Collections;

public class DayTimer : MonoBehaviour {
	
	// Update every UPDATE_INTERVAL seconds
	private const int SECONDS_IN_A_DAY = 86400;
	
	// variables to do timing on the update (optimization)
	private const float UPDATE_INTERVAL = 1f;
	private float lastUpdateTime = 0f;
	
	private System.DateTime now = System.DateTime.Now;
	public bool manualControl = false;
	public int currentDayTime = 0;
	
	// Light that should be controlled by the DayTimer
	public Light controlledLight01 = null;

	// Use this for initialization
	void Start () {
		lastUpdateTime = Time.time;
	}
	
	void Update () {
		if(manualControl) {
			
		} else {
			now = System.DateTime.Now;
			currentDayTime = System.Convert.ToInt16(now.Hour)*3600 + System.Convert.ToInt16(now.Minute)*60 + System.Convert.ToInt16(now.Second);
		}
		
		// Update the light every UPDATE_INTERVAL seconds
		if(Time.time > lastUpdateTime + UPDATE_INTERVAL) {
			if(controlledLight01!=null) { // If we have a light
				Light l = controlledLight01.GetComponent<Light>(); // Get the Light component
				// Mathf.Sin doesn't convert automatically to float so the given values need to be converted manually
				float currentDayTimeF = System.Convert.ToSingle(currentDayTime);
				float secondsInADayF = System.Convert.ToSingle(SECONDS_IN_A_DAY);
				Color c = new Color();
				c.r=Mathf.Sin(currentDayTimeF/secondsInADayF * 3.14159f);
				c.g=Mathf.Sin(currentDayTimeF/secondsInADayF * 3.14159f);
				c.b=Mathf.Sin(currentDayTimeF/secondsInADayF * 3.14159f) * 0.3f;
				c.a=1f;
				l.color = c;
				lastUpdateTime = Time.time;
			}
		}
		
	}
}