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Vertex Shaders

Started by fleejay Jan 17, 2002 at 11:53 AM 1 reply 1k views

Original Post

Jan 17, 2002 at 11:53 AM

Hi, I''m looking to write a (direct3d) vertex shader that transforms texture coordinates in a similar way to the D3DTSS_TEXCOORDINDEX renderstate mode D3DTSS_TCI_CAMERASPACEREFLECTIONVECTOR Basically I have an object to world matrix and I want to generate the environment mapping texture coords myself. This is not the same as spherical mapping. Does anyone have any ideas? Many Thanks Fleejay.

S1CA

169

S1CA

Jan 17, 2002 at 12:15 PM

Check out the DirectX 8.1 SDK, in particular the NEW spherical envmap sample which is implemented using a vertex shader.

PART of that shader calculates _exactly_ the same values as D3DTSS_TCI_CAMERASPACEREFLECTIONVECTOR does.

In short:

1. transform the vertex position and normal into camera space. Remember that if you have any non uniform scaling that the normal will need to be transformed by the transposed inverse of the matrix.

2. The reflected view vector is:
r = 2 (n.v) n - v
where:
n = the vertex normal
v = the view vector

--
Simon O''''Connor
Creative Asylum Ltd
www.creative-asylum.com

fleejay

Author

fleejay

Jan 18, 2002 at 3:04 AM

Thankyou!

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