sna/gen3+: Fix sampling of borders around gradients

Incurs a slight loss of precision for the internal gradient, but much
more preferable to the artefacts around the borders with RepeatNone.

Reported-by: Clemens Eisserer <linuxhippy@gmail.com>
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=45016
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>

5 files changed, 6 insertions, 6 deletions

diff --git a/src/sna/gen3_render.c b/src/sna/gen3_render.c
index e7980962..0478709f 100644
--- a/src/sna/gen3_render.c
+++ b/src/sna/gen3_render.c
@@ -2137,7 +2137,7 @@ static Bool gen3_gradient_setup(struct sna *sna,
 
 	channel->pict_format = PICT_a8r8g8b8;
 	channel->card_format = MAPSURF_32BIT | MT_32BIT_ARGB8888;
-	channel->filter = PictFilterBilinear;
+	channel->filter = PictFilterNearest;
 	channel->is_affine = sna_transform_is_affine(picture->transform);
 	if (sna_transform_is_integer_translation(picture->transform, &dx, &dy)) {
 		DBG(("%s: integer translation (%d, %d), removing\n",
diff --git a/src/sna/gen4_render.c b/src/sna/gen4_render.c
index 2e78a921..1868e2fb 100644
--- a/src/sna/gen4_render.c
+++ b/src/sna/gen4_render.c
@@ -1871,7 +1871,7 @@ gen4_composite_linear_init(struct sna *sna,
 	if (!channel->bo)
 		return 0;
 
-	channel->filter = PictFilterBilinear;
+	channel->filter = PictFilterNearest;
 	channel->repeat = picture->repeat ? picture->repeatType : RepeatNone;
 	channel->width  = channel->bo->pitch / 4;
 	channel->height = 1;
@@ -1932,7 +1932,7 @@ gen4_composite_linear_init(struct sna *sna,
 
 	channel->embedded_transform.matrix[0][0] = pixman_double_to_fixed(dx);
 	channel->embedded_transform.matrix[0][1] = pixman_double_to_fixed(dy);
-	channel->embedded_transform.matrix[0][2] = -pixman_double_to_fixed(dx*(x0+dst_x-x) + dy*(y0+dst_y-y));
+	channel->embedded_transform.matrix[0][2] = -pixman_double_to_fixed(dx*(x0+dst_x-x) + dy*(y0+dst_y-y) - .5/sf);
 
 	channel->embedded_transform.matrix[1][0] = 0;
 	channel->embedded_transform.matrix[1][1] = 0;
diff --git a/src/sna/gen5_render.c b/src/sna/gen5_render.c
index c27accd7..1fb7f655 100644
--- a/src/sna/gen5_render.c
+++ b/src/sna/gen5_render.c
@@ -1904,7 +1904,7 @@ gen5_composite_linear_init(struct sna *sna,
 	if (!channel->bo)
 		return 0;
 
-	channel->filter = PictFilterBilinear;
+	channel->filter = PictFilterNearest;
 	channel->repeat = picture->repeat ? picture->repeatType : RepeatNone;
 	channel->width  = channel->bo->pitch / 4;
 	channel->height = 1;
diff --git a/src/sna/gen6_render.c b/src/sna/gen6_render.c
index 3be9195b..5bbe5e3e 100644
--- a/src/sna/gen6_render.c
+++ b/src/sna/gen6_render.c
@@ -2080,7 +2080,7 @@ gen6_composite_linear_init(struct sna *sna,
 	if (!channel->bo)
 		return 0;
 
-	channel->filter = PictFilterBilinear;
+	channel->filter = PictFilterNearest;
 	channel->repeat = picture->repeat ? picture->repeatType : RepeatNone;
 	channel->width  = channel->bo->pitch / 4;
 	channel->height = 1;
diff --git a/src/sna/gen7_render.c b/src/sna/gen7_render.c
index 6917c21e..7dff02fe 100644
--- a/src/sna/gen7_render.c
+++ b/src/sna/gen7_render.c
@@ -2209,7 +2209,7 @@ gen7_composite_linear_init(struct sna *sna,
 	if (!channel->bo)
 		return 0;
 
-	channel->filter = PictFilterBilinear;
+	channel->filter = PictFilterNearest;
 	channel->repeat = picture->repeat ? picture->repeatType : RepeatNone;
 	channel->width  = channel->bo->pitch / 4;
 	channel->height = 1;