World Normal?

wenglish

hello, this is probably a simple question, but how do i get the world normal in my shaders? this has been strangely difficult to find info on...

ZacD

It's often called object space or model space. It's basically the same thing, but works in model space instead of world space.

wenglish

hmm i dont understand. wouldn't model space be inherently really different from world space? (relitive to the model, as opposed to relative to the world?)

ZacD

Object and world space normal maps are generated the same way, each axis is represented by a color so the top button left right front and back all have a different color. Object space just means the engine can keep track of rotations on the model so it will still light correctly after rotations. They are the same thing, just implemented differently. They should look exactly the same if you bake each one out on the same model.

wenglish

mmmm i think im getting it. thanks ZacD

ZacD

I found a good write up that explains it more, http://www.surlybird.com/tutorials/TangentSpace/

Vailias

Object space is not world space. Lawless is right on that. For example, if you're building a deposit shader you'll want world up, not object up.

To do that you'll need to transform the normal data into world space by matrix multiplication.
so something like this

float4 mapNormal = Tex2d( NormalMaptexture, VertexShader.PassedInUVs)
Float4 worldNormal = mul(_Object2World,mapNormal)

wenglish

whats a deposit shader? also, ive got a line of code that gets the result im after but i am hazy on why. it looks like this

                Out.worldNormal = normalize (mul(float4(In.normal, 0.0), _World2Object).xyz);

Farfarer

Sample code here:

http://forum.unity3d.com/threads/97942-Cannot-get-worldnormal-in-surf-shader