Determining line orientation using vertex shaders

Posted by Brett on Stack Overflow See other posts from Stack Overflow or by Brett
Published on 2010-04-01T11:21:42Z Indexed on 2010/04/01 13:13 UTC
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Filed under:

opengl

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c++

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geometry

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shader

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glsl

Hi,
I want to be able to calculate the direction of a line to eye coordinates and store this value for every pixel on the line using a vertex and fragment shader. My idea was to calculate the direction gradient using atan2(Gy/Gx) after a modelview tranformation for each pair of vertices then quantize this value as a color intensity to pass to a fragment shader. How can I get access to the positions of pairs of vertices to achieve this or is there another method I should use?
Thanks

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