softpipe: fix out of bounds quad rasterization bug

For some triangles we can generate quads which lie just outside the
surface bounds.  Just check the quad's mask before trying to emit/process
the quad.

Fixes failed assertion in Lightsmark.

1 files changed, 6 insertions, 3 deletions

diff --git a/src/gallium/drivers/softpipe/sp_setup.c b/src/gallium/drivers/softpipe/sp_setup.c
index accc692b66f..e5be65242d6 100644
--- a/src/gallium/drivers/softpipe/sp_setup.c
+++ b/src/gallium/drivers/softpipe/sp_setup.c
@@ -444,7 +444,8 @@ static void flush_spans( struct setup_context *setup )
             mask |= MASK_TOP_RIGHT;
          if (x+1 >= xleft1 && x+1 < xright1)
             mask |= MASK_BOTTOM_RIGHT;
-         EMIT_QUAD( setup, x, setup->span.y, mask );
+         if (mask)
+            EMIT_QUAD( setup, x, setup->span.y, mask );
       }
       break;
 
@@ -458,7 +459,8 @@ static void flush_spans( struct setup_context *setup )
             mask |= MASK_TOP_LEFT;
          if (x+1 >= xleft0 && x+1 < xright0)
             mask |= MASK_TOP_RIGHT;
-         EMIT_QUAD( setup, x, setup->span.y, mask );
+         if (mask)
+            EMIT_QUAD( setup, x, setup->span.y, mask );
       }
       break;
 
@@ -472,7 +474,8 @@ static void flush_spans( struct setup_context *setup )
             mask |= MASK_BOTTOM_LEFT;
          if (x+1 >= xleft1 && x+1 < xright1)
             mask |= MASK_BOTTOM_RIGHT;
-         EMIT_QUAD( setup, x, setup->span.y, mask );
+         if (mask)
+            EMIT_QUAD( setup, x, setup->span.y, mask );
       }
       break;