UNCLAMPED_FLOAT_TO_CHAN(ncv1->color[0], rSum);
UNCLAMPED_FLOAT_TO_CHAN(ncv1->color[1], gSum);
UNCLAMPED_FLOAT_TO_CHAN(ncv1->color[2], bSum);
/* draw */
SWRAST_CONTEXT(ctx)->SpecLine( ctx, ncv0, ncv1 );
/* restore original colors */
UNCLAMPED_FLOAT_TO_CHAN(ncv1->color[0], rSum);
UNCLAMPED_FLOAT_TO_CHAN(ncv1->color[1], gSum);
UNCLAMPED_FLOAT_TO_CHAN(ncv1->color[2], bSum);
/* draw */
SWRAST_CONTEXT(ctx)->SpecLine( ctx, ncv0, ncv1 );
/* restore original colors */