hi math experts,
i have a question and i need deep understanding of normal map TBN matrix generation formula.
I see from lots of tutorials such as in learnopengl.com or in ogldev
https://learnopengl.com/#!Advanced-Lighting/Normal-Mapping
http://ogldev.atspace.co.uk/www/tutorial26/tutorial26.html
that the formula goes something like this.
E1=ΔU1T+ΔV1B
E2=ΔU2T+ΔV2B
U1, U2, V1, V2 are texture coordinates
T and B are Tangent and Bitangent vectors
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But i just dont understand how the above formula was created and why is the formula like that?
I understand we need to get two vectors that is why the difference of U and V vectors are computed to form a vector,
but i dont understand why it needs to be dot products to T and added to difference of V vectors and dot product to B.
in summary, i dont fully understand the formula itself..
I need elementary explanation please
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