sna/video: Correct scaling of source offsets

When applying pan and zoom to a mismatched video, it would inevitably
miscompute the origin and scale factors.

Reported-by: Matti Hamalainen <ccr@tnsp.org>
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=61610
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>

1 files changed, 20 insertions, 15 deletions

diff --git a/src/sna/gen5_render.c b/src/sna/gen5_render.c
index 9a9c223e..8c8a996f 100644
--- a/src/sna/gen5_render.c
+++ b/src/sna/gen5_render.c
@@ -1299,18 +1299,21 @@ gen5_render_video(struct sna *sna,
 		  struct sna_video *video,
 		  struct sna_video_frame *frame,
 		  RegionPtr dstRegion,
-		  short src_w, short src_h,
-		  short drw_w, short drw_h,
-		  short dx, short dy,
 		  PixmapPtr pixmap)
 {
 	struct sna_composite_op tmp;
-	int nbox, pix_xoff, pix_yoff;
+	int dst_width = dstRegion->extents.x2 - dstRegion->extents.x1;
+	int dst_height = dstRegion->extents.y2 - dstRegion->extents.y1;
+	int src_width = frame->src.x2 - frame->src.x1;
+	int src_height = frame->src.y2 - frame->src.y1;
+	float src_offset_x, src_offset_y;
 	float src_scale_x, src_scale_y;
+	int nbox, pix_xoff, pix_yoff;
 	struct sna_pixmap *priv;
 	BoxPtr box;
 
-	DBG(("%s: %dx%d -> %dx%d\n", __FUNCTION__, src_w, src_h, drw_w, drw_h));
+	DBG(("%s: %dx%d -> %dx%d\n", __FUNCTION__,
+	     src_width, src_height, dst_width, dst_height));
 
 	priv = sna_pixmap_force_to_gpu(pixmap, MOVE_READ | MOVE_WRITE);
 	if (priv == NULL)
@@ -1325,7 +1328,7 @@ gen5_render_video(struct sna *sna,
 	tmp.dst.format = sna_format_for_depth(pixmap->drawable.depth);
 	tmp.dst.bo = priv->gpu_bo;
 
-	if (src_w == drw_w && src_h == drw_h)
+	if (src_width == dst_width && src_height == dst_height)
 		tmp.src.filter = SAMPLER_FILTER_NEAREST;
 	else
 		tmp.src.filter = SAMPLER_FILTER_BILINEAR;
@@ -1359,9 +1362,11 @@ gen5_render_video(struct sna *sna,
 	pix_yoff = 0;
 #endif
 
-	/* Use normalized texture coordinates */
-	src_scale_x = ((float)src_w / frame->width) / (float)drw_w;
-	src_scale_y = ((float)src_h / frame->height) / (float)drw_h;
+	src_scale_x = (float)src_width / dst_width / frame->width;
+	src_offset_x = frame->src.x1 / frame->width - dstRegion->extents.x1 * src_scale_x;
+
+	src_scale_y = (float)src_height / dst_height / frame->height;
+	src_offset_y = frame->src.y1 / frame->height - dstRegion->extents.y1 * src_scale_y;
 
 	box = REGION_RECTS(dstRegion);
 	nbox = REGION_NUM_RECTS(dstRegion);
@@ -1376,16 +1381,16 @@ gen5_render_video(struct sna *sna,
 		gen5_get_rectangles(sna, &tmp, 1, gen5_video_bind_surfaces);
 
 		OUT_VERTEX(r.x2, r.y2);
-		OUT_VERTEX_F((box->x2 - dx) * src_scale_x);
-		OUT_VERTEX_F((box->y2 - dy) * src_scale_y);
+		OUT_VERTEX_F(box->x2 * src_scale_x + src_offset_x);
+		OUT_VERTEX_F(box->y2 * src_scale_y + src_offset_y);
 
 		OUT_VERTEX(r.x1, r.y2);
-		OUT_VERTEX_F((box->x1 - dx) * src_scale_x);
-		OUT_VERTEX_F((box->y2 - dy) * src_scale_y);
+		OUT_VERTEX_F(box->x1 * src_scale_x + src_offset_x);
+		OUT_VERTEX_F(box->y2 * src_scale_y + src_offset_y);
 
 		OUT_VERTEX(r.x1, r.y1);
-		OUT_VERTEX_F((box->x1 - dx) * src_scale_x);
-		OUT_VERTEX_F((box->y1 - dy) * src_scale_y);
+		OUT_VERTEX_F(box->x1 * src_scale_x + src_offset_x);
+		OUT_VERTEX_F(box->y1 * src_scale_y + src_offset_y);
 
 		if (!DAMAGE_IS_ALL(priv->gpu_damage)) {
 			sna_damage_add_box(&priv->gpu_damage, &r);