Mesa (master): i965: Subtract instead of adding when computing y delta in new FS backend.

[Eric Anholt]

Module: Mesa
Branch: master
Commit: 9e96c737f8cb6faebf7c7339cfcf14f80ed8e73c
URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=9e96c737f8cb6faebf7c7339cfcf14f80ed8e73c

Author: Eric Anholt <eric at anholt.net>
Date:   Tue Sep 28 10:18:31 2010 -0700

i965: Subtract instead of adding when computing y delta in new FS backend.

Fixes 7 piglit cases.

---

 src/mesa/drivers/dri/i965/brw_fs.cpp |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/src/mesa/drivers/dri/i965/brw_fs.cpp b/src/mesa/drivers/dri/i965/brw_fs.cpp
index 0595488..723ebca 100644
--- a/src/mesa/drivers/dri/i965/brw_fs.cpp
+++ b/src/mesa/drivers/dri/i965/brw_fs.cpp
@@ -1335,7 +1335,7 @@ fs_visitor::emit_interpolation()
    emit(fs_inst(BRW_OPCODE_ADD,
 		this->delta_y,
 		this->pixel_y,
-		fs_reg(brw_vec1_grf(1, 1))));
+		fs_reg(negate(brw_vec1_grf(1, 1)))));
 
    this->current_annotation = "compute pos.w and 1/pos.w";
    /* Compute wpos.  Unlike many other varying inputs, we usually need it