CODEWITHSUNDEEP
c#
Mureahko
Mureahko

Reputation: 43

How to get value to be from 0 to 1?

I tried to look for an answer for this problem but I guess nobody has needed something like this or it's something super simple that I just can't get my head around. So:

I have a value that changes from 45 to 20.

I'd need a value that goes from 0 to 1 in same time as 45 goes to 20. I know that 45 - 20 = 25 and that would be my 100% and hence the number 1.

I'd implement this in Lerp value like this:

public float minHeight = 10.0f;
public float maxHeight = 30.0f;
public float convertedValue;

convertedValue = ??? (Something like 45 - 20 = 25 = 100%) * 0.01;

newValue = Mathf.Lerp(minHeight, maxHeight, convertedValue);

Hopefully someone can help me. Im fairly new to coding and I was just wondering if this is possible. Thanks for your time!

Upvotes: 4

Views: 6901

Answers (6)

Tim S.
Tim S.

Reputation: 56556

I recognize your Mathf.Lerp as part of the Unity3D APIs. A function there already exists to do what you're trying to do: Mathf.InverseLerp. You should use this.

Upvotes: 2

StuartLC
StuartLC

Reputation: 107317

I believe the calculation matching your explanation would be

newValue = (convertedValue - minHeight) / (maxHeight - minHeight);

i.e. newValue = 0 @ minHeight, and 1 @ maxHeight

Edit

I've never seen Lerp before, but apparantly it is simple linear interpolation.

However, from MSDN

Lerp is defined as 

value1 + (value2 - value1) * amount

i.e. in your example convertedValue should be the fraction, and the answer is the interpolated result, meaning that your question / my (and Esailja's) interpretation thereof is inverted :)

i.e.

Mathf.Lerp(10.0, 30.0, 0.5) = 20.0

whereas

InvertedLerp(10.0, 30.0, 20) = 0.5 // My / Esailja's calc

:)

Upvotes: 7

tommed
tommed

Reputation: 1561


public float AnswerMureahkosQuestion(float input)
{
   const float minValue = 20;
   const float maxValue = 45;
   float range = maxValue - minValue;

   // nominalise to 1
   // NOTE: you don't actually need the *1 but it reads better
   float answer = (input+0.00001/*prevents divbyzero errors*/) / range * 1; 

   // invert so 45 is 0 and 20 is 1
   answer =  1 - answer;
   return answer;
}

Upvotes: 0

hl2mukkel
hl2mukkel

Reputation: 118

How about a property?

public int neededvalue
{
    get
    {
        if (value == 45)
            return 1;
        else if (value == 20)
            return 0
        else
            throw new Exception("wrong input");
    }
}

public float neededvaluealternative
{
    get
    {
        return (value - 20) / (45 - 20)
    }
}

Upvotes: 0

Esailija
Esailija

Reputation: 140228

public float minHeight = 10.0f;
public float maxHeight = 30.0f;

float curHeight = 25.0f;

float newValue = ( curHeight - minHeight ) / ( maxHeight - minHeight );

Upvotes: 1

zen
zen

Reputation: 122

minvalue=20
maxvalue=45
result=(aktvalue-minvalue)/(maxvalue-minvalue)

something like this?

Upvotes: 0

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