From f5e58838c2dc7fbca7f1fe2936b0e575cfe7067b Mon Sep 17 00:00:00 2001
From: Jason Ekstrand <jason@jlekstrand.net>
Date: Fri, 24 Apr 2020 17:45:08 -0500
Subject: [PATCH] intel/fs: Handle non-perspective-correct interpolation on
 gen4-5

Reviewed-by: Dave Airlie <airlied@redhat.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/11125>
---
 src/intel/compiler/brw_fs_visitor.cpp | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/src/intel/compiler/brw_fs_visitor.cpp b/src/intel/compiler/brw_fs_visitor.cpp
index b58ec72e465..ae891703831 100644
--- a/src/intel/compiler/brw_fs_visitor.cpp
+++ b/src/intel/compiler/brw_fs_visitor.cpp
@@ -191,6 +191,13 @@ fs_visitor::emit_interpolation_setup_gfx4()
 
    this->pixel_z = fetch_payload_reg(bld, payload.source_depth_reg);
 
+   /* The SF program automatically handles doing the perspective correction or
+    * not based on wm_prog_data::interp_mode[] so we can use the same pixel
+    * offsets for both perspective and non-perspective.
+    */
+   this->delta_xy[BRW_BARYCENTRIC_NONPERSPECTIVE_PIXEL] =
+      this->delta_xy[BRW_BARYCENTRIC_PERSPECTIVE_PIXEL];
+
    abld = bld.annotate("compute pos.w and 1/pos.w");
    /* Compute wpos.w.  It's always in our setup, since it's needed to
     * interpolate the other attributes.