[Mesa-dev] [PATCH 1/2] i965: Use true AA line distance on G45/Ironlake.

[Kenneth Graunke]

The original Broadwater and Crestline platforms computed antialiased
line distances using "manhattan" distance, aka a + b = c.  Eaglelake
and Cantiga added "true" distance, aka a^2 + b^2 = c^2, which is
obviously superior.

The G45 documentation indicates that the old manhattan distance setting
is "only for debug purposes" and should never be used.  The Ironlake
documentation no longer mentions AALINEDISTANCE_MANHATTAN, though it
does still contain the narrative about the feature.

At any rate, we should use it.

Cc: rafael.antognolli at intel.com
---
 src/mesa/drivers/dri/i965/brw_sf_state.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/mesa/drivers/dri/i965/brw_sf_state.c b/src/mesa/drivers/dri/i965/brw_sf_state.c
index e919f5d14b4..d50ceb12133 100644
--- a/src/mesa/drivers/dri/i965/brw_sf_state.c
+++ b/src/mesa/drivers/dri/i965/brw_sf_state.c
@@ -265,7 +265,7 @@ static void upload_sf_unit( struct brw_context *brw )
    /* _NEW_PROGRAM | _NEW_POINT */
    sf->sf7.use_point_size_state = !(ctx->VertexProgram.PointSizeEnabled ||
 				    ctx->Point._Attenuated);
-   sf->sf7.aa_line_distance_mode = 0;
+   sf->sf7.aa_line_distance_mode = brw->is_g4x || brw->gen == 5;
 
    /* might be BRW_NEW_PRIMITIVE if we have to adjust pv for polygons:
     * _NEW_LIGHT
-- 
2.12.2