CODEWITHSUNDEEP
openglglslnormalization
TheAmateurProgrammer
TheAmateurProgrammer

Reputation: 9392

What does it mean to normalize a value?

I'm currently studying lighting in OpenGL, which utilizes a function in GLSL called normalize. According to OpenGL docs, it says that it "calculates the normalized product of two vectors". However, it still doesn't explain what "normalized" mean. I have tried look for what a normalized product is on Google, however I can't seem to find anything about it. Can anyone explain what normalizing means and provide a few example of a normalized value?

Upvotes: 38

Views: 47736

Answers (3)

Alfonso Murrieta
Alfonso Murrieta

Reputation: 26

It's something complicated to explain if you don't know too much about vectors or even vectorial algebra. (You can check this article about general concepts as vector, normal vector or even normalization procedure ) Check it

But the procedure or concept of "normalize" refers to the process of making something standard or “normal.”

In the case of vectors, let’s assume for the moment that a standard vector has a length of 1. To normalize a vector, therefore, is to take a vector of any length and, keeping it pointing in the same direction, change its length to 1, turning it into what is called a unit vector.

Upvotes: 0

momatrix
momatrix

Reputation: 309

It's a mathematical term and this link explains its meaning in quite simple terms:

Operations in 2D and 3D computer graphics are often performed using copies of vectors that have been normalized ie. converted to unit vectors... Normalizing a vector involves two steps:

  1. calculate its length, then,
  2. divide each of its (xy or xyz) components by its length...

Upvotes: 17

benzado
benzado

Reputation: 84348

I think the confusion comes from the idea of normalizing "a value" as opposed to "a vector"; if you just think of a single number as a value, normalization doesn't make any sense. Normalization is only useful when applied to a vector.

A vector is a sequence of numbers; in 3D graphics it is usually a coordinate expressed as v = <x,y,z>.

Every vector has a magnitude or length, which can be found using Pythagora's theorem: |v| = sqrt(x^2 + y^2 + z^2) This is basically the length of a line from the origin <0,0,0> to the point expressed by the vector.

A vector is normal if its length is 1. That's it!

To normalize a vector means to change it so that it points in the same direction (think of that line from the origin) but its length is one.

The main reason we use normal vectors is to represent a direction; for example, if you are modeling a light source that is an infinite distance away, you can't give precise coordinates for it. But you can indicate where to find it from a particular point by using a normal vector.

Upvotes: 52

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