[Mesa-dev] [PATCH 4/5] i965: Scissor to the viewport when rendering points/lines.

[Kenneth Graunke]

We're about to start allowing wide points/lines whose vertices are
outside the viewport past the clipper.  This scissoring hack ensures
that any fragments generated are still restricted to the viewport.

It is not necessary on Gen8+ as those platforms already discard
fragments which are outside the viewport.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=94453
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=94454
Signed-off-by: Kenneth Graunke <kenneth at whitecape.org>
---
 src/mesa/drivers/dri/i965/gen6_sf_state.c | 5 +++--
 src/mesa/drivers/dri/i965/gen7_sf_state.c | 8 +++++---
 2 files changed, 8 insertions(+), 5 deletions(-)

diff --git a/src/mesa/drivers/dri/i965/gen6_sf_state.c b/src/mesa/drivers/dri/i965/gen6_sf_state.c
index 685fbdc..3626686 100644
--- a/src/mesa/drivers/dri/i965/gen6_sf_state.c
+++ b/src/mesa/drivers/dri/i965/gen6_sf_state.c
@@ -349,8 +349,9 @@ upload_sf_state(struct brw_context *brw)
        unreachable("not reached");
    }
 
-   /* _NEW_SCISSOR */
-   if (ctx->Scissor.EnableFlags)
+   /* _NEW_SCISSOR _NEW_POLYGON BRW_NEW_GEOMETRY_PROGRAM BRW_NEW_PRIMITIVE */
+   if (ctx->Scissor.EnableFlags ||
+       is_drawing_points(brw) || is_drawing_lines(brw))
       dw3 |= GEN6_SF_SCISSOR_ENABLE;
 
    /* _NEW_POLYGON */
diff --git a/src/mesa/drivers/dri/i965/gen7_sf_state.c b/src/mesa/drivers/dri/i965/gen7_sf_state.c
index b1f13ac..7c98c73 100644
--- a/src/mesa/drivers/dri/i965/gen7_sf_state.c
+++ b/src/mesa/drivers/dri/i965/gen7_sf_state.c
@@ -188,8 +188,9 @@ upload_sf_state(struct brw_context *brw)
       dw2 |= GEN6_SF_CULL_NONE;
    }
 
-   /* _NEW_SCISSOR */
-   if (ctx->Scissor.EnableFlags)
+   /* _NEW_SCISSOR _NEW_POLYGON BRW_NEW_GEOMETRY_PROGRAM BRW_NEW_PRIMITIVE */
+   if (ctx->Scissor.EnableFlags ||
+       is_drawing_points(brw) || is_drawing_lines(brw))
       dw2 |= GEN6_SF_SCISSOR_ENABLE;
 
    /* _NEW_LINE */
@@ -254,7 +255,8 @@ const struct brw_tracked_state gen7_sf_state = {
                _NEW_POLYGON |
                _NEW_PROGRAM |
                _NEW_SCISSOR,
-      .brw   = BRW_NEW_CONTEXT,
+      .brw   = BRW_NEW_CONTEXT |
+               BRW_NEW_PRIMITIVE,
    },
    .emit = upload_sf_state,
 };
-- 
2.7.2