Tangent space

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3 comments, last by Rattenhirn 14 years, 3 months ago
Is tangent space transformed while world matrix changed? For example, vertex structure is with position and texture coordinate,a polygon is constituted by four verticls. vertexStruct { D3DXVECTOR4 pos; D3DXVECTOR2 tex; }; vertexStruct polygon[4]= { {-1,-1,0,1, 0,0}, { 1,-1,0,1, 0,1}, { 1, 1,0,1, 1,1}, {-1, 1,0,1, 1,0}, }; what's the tangent, binormal, normal are? When the polygon is transformed by rotation matrix Tr and translate matrix Tt, what will the tangent, binormal, normal be? Thank you very much.
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if the vertices are transformed by a modelview matrix M, then the normals, bitangent and tangents must be transformed by the inverse transpose of the upper left (3x3) part of M, often referred to as the "Normal Matrix".
"I am a donut! Ask not how many tris/batch, but rather how many batches/frame!" -- Matthias Wloka & Richard Huddy, (GDC, DirectX 9 Performance)

http://www.silvermace.com/ -- My personal website
Thank you,silvermace.

How to compute the initial tangent, binormal, normal? DO they be built from
texture coordinates instead of position coordinates?
Will someone give me the answer?thank you.
First things that pop up after a quick google search:
http://www.terathon.com/code/tangent.html
http://www.3dkingdoms.com/weekly/weekly.php?a=37

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