From 72b0a57cfa99e55ad6e1b4ddcd486c202ee1f22d Mon Sep 17 00:00:00 2001 From: Brian Date: Tue, 18 Sep 2007 12:50:20 -0600 Subject: additional comments for tri_persp_coeff() --- src/mesa/pipe/softpipe/sp_prim_setup.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/src/mesa/pipe/softpipe/sp_prim_setup.c b/src/mesa/pipe/softpipe/sp_prim_setup.c index c64a4e9708..d0baf0734b 100644 --- a/src/mesa/pipe/softpipe/sp_prim_setup.c +++ b/src/mesa/pipe/softpipe/sp_prim_setup.c @@ -428,6 +428,10 @@ static void tri_linear_coeff( struct setup_stage *setup, /** * Compute a0, dadx and dady for a perspective-corrected interpolant, * for a triangle. + * We basically multiply the vertex value by 1/w before computing + * the plane coefficients (a0, dadx, dady). + * Later, when we compute the value at a particular fragment position we'll + * divide the interpolated value by the interpolated W at that fragment. */ static void tri_persp_coeff( struct setup_stage *setup, unsigned slot, -- cgit v1.2.3