I am implementing SW rasterization. I want to clip triangles against the z = -near (so that strange things don't happen after the perspective divide). I would like to do the clipping right after the vertex shader - that is right after the vertices are multiplied by the MVP matrix and before they are divided by the w coordinate (they are in homogenous clip space), so I would really clip against the z = -w plane. However, after clipping the triangles, new vertices have to be created replacing the clipped ones. Attribute values for these new vertices have to be interpolated based on the distance of the clipped vertex to the z = -w plane relative to the total length of the edge that was clipped.
I know that if I clipped in view space I could get away with simple linear interpolation of the vertex attributes. Is this still true in homogenous clip space (since we have not done perspective division yet)?