Masking support for motion tracks

Added option to use Grease Pencil datablock as a mask for pattern
when doing motion tracking. Option could be found in Tracking Settings
panel.

All strokes would be rasterized separately from each other and every
stroke is treating as a closed spline.

Also added option to apply a mask on track preview which is situated
just after B/B/W channel button under track preview.

9 files changed, 123 insertions, 63 deletions

diff --git a/source/blender/blenkernel/BKE_tracking.h b/source/blender/blenkernel/BKE_tracking.h
index 716b65408e1..11013d54951 100644
--- a/source/blender/blenkernel/BKE_tracking.h
+++ b/source/blender/blenkernel/BKE_tracking.h
@@ -72,14 +72,15 @@ void BKE_tracking_join_tracks(struct MovieTrackingTrack *dst_track, struct Movie
 void BKE_tracking_free(struct MovieTracking *tracking);
 
 struct ImBuf *BKE_tracking_sample_pattern_imbuf(int frame_width, int frame_height,
-                                                struct ImBuf *struct_ibuf, struct MovieTrackingMarker *marker,
+                                                struct ImBuf *struct_ibuf, struct MovieTrackingTrack *track,
+                                                struct MovieTrackingMarker *marker, int use_mask,
                                                 int num_samples_x, int num_samples_y, float pos[2]);
 struct ImBuf *BKE_tracking_get_pattern_imbuf(struct ImBuf *ibuf, struct MovieTrackingTrack *track,
                                              struct MovieTrackingMarker *marker, int anchored, int disable_channels);
 struct ImBuf *BKE_tracking_get_search_imbuf(struct ImBuf *ibuf, struct MovieTrackingTrack *track,
                                             struct MovieTrackingMarker *marker, int anchored, int disable_channels);
-struct ImBuf *BKE_tracking_track_mask_get(struct MovieTracking *tracking, struct MovieTrackingTrack *track,
-                                          struct MovieTrackingMarker *marker, int width, int height);
+float *BKE_tracking_track_mask_get(int frame_width, int frame_height, struct MovieTrackingTrack *track,
+                                   struct MovieTrackingMarker *marker);
 
 void BKE_track_unique_name(struct ListBase *tracksbase, struct MovieTrackingTrack *track);
 
diff --git a/source/blender/blenkernel/intern/movieclip.c b/source/blender/blenkernel/intern/movieclip.c
index 8b91ee29c59..92184a38695 100644
--- a/source/blender/blenkernel/intern/movieclip.c
+++ b/source/blender/blenkernel/intern/movieclip.c
@@ -1039,6 +1039,7 @@ void BKE_movieclip_update_scopes(MovieClip *clip, MovieClipUser *user, MovieClip
 
 	scopes->marker = NULL;
 	scopes->track = NULL;
+	scopes->track_locked = TRUE;
 
 	if (clip) {
 		MovieTrackingTrack *act_track = BKE_tracking_active_track(&clip->tracking);
@@ -1055,6 +1056,8 @@ void BKE_movieclip_update_scopes(MovieClip *clip, MovieClipUser *user, MovieClip
 				ImBuf *ibuf = BKE_movieclip_get_ibuf(clip, user);
 
 				scopes->track_disabled = FALSE;
+				scopes->marker = marker;
+				scopes->track = track;
 
 				if (ibuf && (ibuf->rect || ibuf->rect_float)) {
 					ImBuf *search_ibuf;
@@ -1087,6 +1090,8 @@ void BKE_movieclip_update_scopes(MovieClip *clip, MovieClipUser *user, MovieClip
 
 					scopes->frame_width = ibuf->x;
 					scopes->frame_height = ibuf->y;
+
+					scopes->use_track_mask = track->flag & TRACK_PREVIEW_ALPHA;
 				}
 
 				IMB_freeImBuf(ibuf);
@@ -1095,8 +1100,7 @@ void BKE_movieclip_update_scopes(MovieClip *clip, MovieClipUser *user, MovieClip
 			if ((track->flag & TRACK_LOCKED) == 0) {
 				float pat_min[2], pat_max[2];
 
-				scopes->marker = marker;
-				scopes->track = track;
+				scopes->track_locked = FALSE;
 
 				/* XXX: would work fine with non-transformed patterns, but would likely fail
 				 *      with transformed patterns, but that would be easier to debug when
diff --git a/source/blender/blenkernel/intern/tracking.c b/source/blender/blenkernel/intern/tracking.c
index 4cfa8461f2e..a9e75449811 100644
--- a/source/blender/blenkernel/intern/tracking.c
+++ b/source/blender/blenkernel/intern/tracking.c
@@ -1052,6 +1052,8 @@ typedef struct TrackContext {
 	int search_area_height;
 	int search_area_width;
 	int framenr;
+
+	float *mask;
 #else
 	int pad;
 #endif
@@ -1158,6 +1160,9 @@ static void track_context_free(void *customdata)
 	if (track_context->search_area)
 		MEM_freeN(track_context->search_area);
 
+	if (track_context->mask)
+		MEM_freeN(track_context->mask);
+
 #else
 	(void)track_context;
 #endif
@@ -1244,14 +1249,16 @@ static void disable_imbuf_channels(ImBuf *ibuf, MovieTrackingTrack *track, int g
 	                                    track->flag & TRACK_DISABLE_GREEN, track->flag & TRACK_DISABLE_BLUE, grayscale);
 }
 
-ImBuf *BKE_tracking_sample_pattern_imbuf(int frame_width, int frame_height,
-                                         ImBuf *search_ibuf, MovieTrackingMarker *marker,
-                                         int num_samples_x, int num_samples_y, float pos[2])
+ImBuf *BKE_tracking_sample_pattern_imbuf(int frame_width, int frame_height, ImBuf *search_ibuf,
+                                         MovieTrackingTrack *track, MovieTrackingMarker *marker,
+                                         int use_mask, int num_samples_x, int num_samples_y,
+                                         float pos[2])
 {
 #ifdef WITH_LIBMV
 	ImBuf *pattern_ibuf;
 	double src_pixel_x[5], src_pixel_y[5];
 	double warped_position_x, warped_position_y;
+	float *mask = NULL;
 
 	pattern_ibuf = IMB_allocImBuf(num_samples_x, num_samples_y, 32, IB_rectfloat);
 	pattern_ibuf->profile = IB_PROFILE_LINEAR_RGB;
@@ -1262,9 +1269,13 @@ ImBuf *BKE_tracking_sample_pattern_imbuf(int frame_width, int frame_height,
 
 	get_marker_coords_for_tracking(frame_width, frame_height, marker, src_pixel_x, src_pixel_y);
 
+	if (use_mask) {
+		mask = BKE_tracking_track_mask_get(frame_width, frame_height, track, marker);
+	}
+
 	libmv_samplePlanarPatch(search_ibuf->rect_float, search_ibuf->x, search_ibuf->y, 4,
 	                        src_pixel_x, src_pixel_y, num_samples_x,
-	                        num_samples_y, pattern_ibuf->rect_float,
+	                        num_samples_y, mask, pattern_ibuf->rect_float,
 	                        &warped_position_x, &warped_position_y);
 
 	if (pos) {
@@ -1272,6 +1283,10 @@ ImBuf *BKE_tracking_sample_pattern_imbuf(int frame_width, int frame_height,
 		pos[1] = warped_position_y;
 	}
 
+	if (mask) {
+		MEM_freeN(mask);
+	}
+
 	return pattern_ibuf;
 #else
 	ImBuf *pattern_ibuf;
@@ -1310,8 +1325,8 @@ ImBuf *BKE_tracking_get_pattern_imbuf(ImBuf *ibuf, MovieTrackingTrack *track, Mo
 
 	search_ibuf = BKE_tracking_get_search_imbuf(ibuf, track, marker, anchored, disable_channels);
 
-	pattern_ibuf = BKE_tracking_sample_pattern_imbuf(ibuf->x, ibuf->y, search_ibuf, marker,
-	                                                 num_samples_x, num_samples_y, NULL);
+	pattern_ibuf = BKE_tracking_sample_pattern_imbuf(ibuf->x, ibuf->y, search_ibuf, track, marker,
+	                                                 FALSE, num_samples_x, num_samples_y, NULL);
 
 	IMB_freeImBuf(search_ibuf);
 
@@ -1366,8 +1381,21 @@ static bGPDlayer *track_mask_gpencil_layer_get(MovieTrackingTrack *track)
 	layer = track->gpd->layers.first;
 
 	while (layer) {
-		if (layer->flag & GP_LAYER_ACTIVE)
-			return layer;
+		if (layer->flag & GP_LAYER_ACTIVE) {
+			bGPDframe *frame = layer->frames.first;
+			int ok = FALSE;
+
+			while (frame) {
+				if (frame->strokes.first) {
+					ok = TRUE;
+				}
+
+				frame = frame->next;
+			}
+
+			if (ok)
+				return layer;
+		}
 
 		layer = layer->next;
 	}
@@ -1375,15 +1403,11 @@ static bGPDlayer *track_mask_gpencil_layer_get(MovieTrackingTrack *track)
 	return NULL;
 }
 
-static void track_mask_gpencil_layer_rasterize(MovieTracking *tracking, MovieTrackingMarker *marker,
-                                               bGPDlayer *layer, ImBuf *ibuf, int width, int height)
+static void track_mask_gpencil_layer_rasterize(int frame_width, int frame_height,
+											   MovieTrackingMarker *marker, bGPDlayer *layer,
+                                               float *mask, int mask_width, int mask_height)
 {
 	bGPDframe *frame = layer->frames.first;
-	float *mask;
-	int x, y;
-	float aspy = 1.0f / tracking->camera.pixel_aspect;
-
-	mask = MEM_callocN(ibuf->x * ibuf->y * sizeof(float), "track mask");
 
 	while (frame) {
 		bGPDstroke *stroke = frame->strokes.first;
@@ -1398,11 +1422,11 @@ static void track_mask_gpencil_layer_rasterize(MovieTracking *tracking, MovieTra
 				                               "track mask rasterization points");
 
 				for (i = 0; i < stroke->totpoints; i++, fp += 2) {
-					fp[0] = stroke_points[i].x * width / ibuf->x - marker->search_min[0];
-					fp[1] = stroke_points[i].y * height * aspy / ibuf->x - marker->search_min[1];
+					fp[0] = (stroke_points[i].x - marker->search_min[0]) * frame_width / mask_width;
+					fp[1] = (stroke_points[i].y - marker->search_min[1]) * frame_height / mask_height;
 				}
 
-				PLX_raskterize((float (*)[2])mask_points, stroke->totpoints, mask, ibuf->x, ibuf->y);
+				PLX_raskterize((float (*)[2])mask_points, stroke->totpoints, mask, mask_width, mask_height);
 
 				MEM_freeN(mask_points);
 			}
@@ -1412,45 +1436,26 @@ static void track_mask_gpencil_layer_rasterize(MovieTracking *tracking, MovieTra
 
 		frame = frame->next;
 	}
-
-	for (y = 0; y < ibuf->y; y++) {
-		for (x = 0; x < ibuf->x; x++) {
-			float *pixel = &ibuf->rect_float[4 * (y * ibuf->x + x)];
-			float val = mask[y * ibuf->x + x];
-
-			pixel[0] = val;
-			pixel[1] = val;
-			pixel[2] = val;
-			pixel[3] = 1.0f;
-		}
-	}
-
-	MEM_freeN(mask);
-
-	IMB_rect_from_float(ibuf);
 }
 
-ImBuf *BKE_tracking_track_mask_get(MovieTracking *tracking, MovieTrackingTrack *track, MovieTrackingMarker *marker,
-                                   int width, int height)
+float *BKE_tracking_track_mask_get(int frame_width, int frame_height,
+                                   MovieTrackingTrack *track, MovieTrackingMarker *marker)
 {
-	ImBuf *ibuf;
+	float *mask = NULL;
 	bGPDlayer *layer = track_mask_gpencil_layer_get(track);
 	int mask_width, mask_height;
 
-	mask_width = (marker->search_max[0] - marker->search_min[0]) * width;
-	mask_height = (marker->search_max[1] - marker->search_min[1]) * height;
-
-	ibuf = IMB_allocImBuf(mask_width, mask_height, 32, IB_rect | IB_rectfloat);
+	mask_width = (marker->search_max[0] - marker->search_min[0]) * frame_width;
+	mask_height = (marker->search_max[1] - marker->search_min[1]) * frame_height;
 
 	if (layer) {
-		track_mask_gpencil_layer_rasterize(tracking, marker, layer, ibuf, width, height);
-	}
-	else {
-		float white[4] = {1.0f, 1.0f, 1.0f, 1.0f};
-		IMB_rectfill(ibuf, white);
+		mask = MEM_callocN(mask_width * mask_height * sizeof(float), "track mask");
+
+		track_mask_gpencil_layer_rasterize(frame_width, frame_height, marker, layer,
+		                                   mask, mask_width, mask_height);
 	}
 
-	return ibuf;
+	return mask;
 }
 
 #ifdef WITH_LIBMV
@@ -1676,7 +1681,7 @@ int BKE_tracking_next(MovieTrackingContext *context)
 	frame_width = destination_ibuf->x;
 	frame_height = destination_ibuf->y;
 
-	#pragma omp parallel for private(a) shared(destination_ibuf, ok) if (map_size>1)
+	//#pragma omp parallel for private(a) shared(destination_ibuf, ok) if (map_size>1)
 	for (a = 0; a < map_size; a++) {
 		TrackContext *track_context = NULL;
 		MovieTrackingTrack *track;
@@ -1724,7 +1729,7 @@ int BKE_tracking_next(MovieTrackingContext *context)
 				double src_pixel_y[5];
 
 				/* settings for the tracker */
-				struct libmv_trackRegionOptions options;
+				struct libmv_trackRegionOptions options = {0};
 				struct libmv_trackRegionResult result;
 
 				float *patch_new;
@@ -1744,6 +1749,14 @@ int BKE_tracking_next(MovieTrackingContext *context)
 					track_context->search_area_width = width;
 
 					IMB_freeImBuf(reference_ibuf);
+
+					if ((track->algorithm_flag & TRACK_ALGORITHM_FLAG_USE_MASK) != 0) {
+						if (track_context->mask)
+							MEM_freeN(track_context->mask);
+
+						track_context->mask = BKE_tracking_track_mask_get(frame_width, frame_height,
+						                                                  track, marker);
+					}
 				}
 
 				/* for now track to the same search area dimension as marker has got for current frame
@@ -1765,6 +1778,9 @@ int BKE_tracking_next(MovieTrackingContext *context)
 				options.minimum_correlation = track->minimum_correlation;
 				options.sigma = 0.9;
 
+				if ((track->algorithm_flag & TRACK_ALGORITHM_FLAG_USE_MASK) != 0)
+					options.image1_mask = track_context->mask;
+
 				/* Convert the marker corners and center into pixel coordinates in the search/destination images. */
 				get_marker_coords_for_tracking(frame_width, frame_height, &track_context->marker, src_pixel_x, src_pixel_y);
 				get_marker_coords_for_tracking(frame_width, frame_height, marker, dst_pixel_x, dst_pixel_y);
@@ -1790,7 +1806,7 @@ int BKE_tracking_next(MovieTrackingContext *context)
 
 				marker_search_scale_after_tracking(marker, &marker_new);
 
-				#pragma omp critical
+				//#pragma omp critical
 				{
 					if (context->first_time) {
 						/* check if there's no keyframe/tracked markers before tracking marker.
diff --git a/source/blender/editors/interface/interface_draw.c b/source/blender/editors/interface/interface_draw.c
index 7b69e820467..22aa1031f48 100644
--- a/source/blender/editors/interface/interface_draw.c
+++ b/source/blender/editors/interface/interface_draw.c
@@ -1550,7 +1550,8 @@ void ui_draw_but_TRACKPREVIEW(ARegion *ar, uiBut *but, uiWidgetColors *UNUSED(wc
 			IMB_freeImBuf(scopes->track_preview);
 
 		tmpibuf = BKE_tracking_sample_pattern_imbuf(scopes->frame_width, scopes->frame_height,
-		                                            scopes->track_search, &scopes->undist_marker,
+		                                            scopes->track_search, scopes->track,
+		                                            &scopes->undist_marker, scopes->use_track_mask,
 		                                            width, height, scopes->track_pos);
 
 		if (tmpibuf->rect_float)
@@ -1582,6 +1583,12 @@ void ui_draw_but_TRACKPREVIEW(ARegion *ar, uiBut *but, uiWidgetColors *UNUSED(wc
 		if (width > 0 && height > 0) {
 			drawibuf = scopes->track_preview;
 
+			if (scopes->use_track_mask) {
+				glColor4f(0.0f, 0.0f, 0.0f, 0.3f);
+				uiSetRoundBox(15);
+				uiDrawBox(GL_POLYGON, rect.xmin - 1, rect.ymin, rect.xmax + 1, rect.ymax + 1, 3.0f);
+			}
+
 			glaDrawPixelsSafe(rect.xmin, rect.ymin + 1, drawibuf->x, drawibuf->y,
 			                  drawibuf->x, GL_RGBA, GL_UNSIGNED_BYTE, drawibuf->rect);
 
diff --git a/source/blender/editors/interface/interface_handlers.c b/source/blender/editors/interface/interface_handlers.c
index a2adbd7a143..4615906b0da 100644
--- a/source/blender/editors/interface/interface_handlers.c
+++ b/source/blender/editors/interface/interface_handlers.c
@@ -4201,7 +4201,7 @@ static int ui_numedit_but_TRACKPREVIEW(bContext *C, uiBut *but, uiHandleButtonDa
 		scopes->track_preview_height = (but->y2 - but->y1) + (data->dragstarty - my);
 	}
 	else {
-		if (scopes->marker) {
+		if (!scopes->track_locked) {
 			if (scopes->marker->framenr != scopes->framenr)
 				scopes->marker = BKE_tracking_ensure_marker(scopes->track, scopes->framenr);
 
diff --git a/source/blender/editors/space_clip/space_clip.c b/source/blender/editors/space_clip/space_clip.c
index 534ab8eeb95..9a8e0de3e84 100644
--- a/source/blender/editors/space_clip/space_clip.c
+++ b/source/blender/editors/space_clip/space_clip.c
@@ -215,6 +215,15 @@ static void clip_scopes_tag_refresh(ScrArea *sa)
 	sc->scopes.ok = FALSE;
 }
 
+static void clip_scopes_check_gpencil_change(ScrArea *sa)
+{
+	SpaceClip *sc = (SpaceClip *)sa->spacedata.first;
+
+	if (sc->gpencil_src == SC_GPENCIL_SRC_TRACK) {
+		clip_scopes_tag_refresh(sa);
+	}
+}
+
 static void clip_stabilization_tag_refresh(ScrArea *sa)
 {
 	SpaceClip *sc = (SpaceClip *) sa->spacedata.first;
@@ -400,6 +409,7 @@ static void clip_listener(ScrArea *sa, wmNotifier *wmn)
 			switch (wmn->data) {
 				case ND_ANIMPLAY:
 				case ND_GPENCIL:
+					clip_scopes_check_gpencil_change(sa);
 					ED_area_tag_redraw(sa);
 					break;
 			}
diff --git a/source/blender/makesdna/DNA_movieclip_types.h b/source/blender/makesdna/DNA_movieclip_types.h
index b5ab7898bd9..19004dbc8b8 100644
--- a/source/blender/makesdna/DNA_movieclip_types.h
+++ b/source/blender/makesdna/DNA_movieclip_types.h
@@ -90,7 +90,8 @@ typedef struct MovieClip {
 } MovieClip;
 
 typedef struct MovieClipScopes {
-	int ok;                         /* 1 means scopes are ok and recalculation is unneeded */
+	short ok;                       /* 1 means scopes are ok and recalculation is unneeded */
+	short use_track_mask;           /* whether track's mask should be applied on preview */
 	int track_preview_height;       /* height of track preview widget */
 	int frame_width, frame_height;  /* width and height of frame for which scopes are calculated */
 	struct MovieTrackingMarker undist_marker;   /* undistorted position of marker used for pattern sampling */
@@ -98,7 +99,7 @@ typedef struct MovieClipScopes {
 	struct ImBuf *track_preview;    /* ImBuf displayed in track preview */
 	float track_pos[2];             /* sub-pizel position of marker in track ImBuf */
 	short track_disabled;           /* active track is disabled, special notifier should be drawn */
-	char pad[2];
+	short track_locked;             /* active track is locked, no transformation should be allowed */
 	int framenr;                    /* frame number scopes are created for */
 	struct MovieTrackingTrack *track;   /* track scopes are created for */
 	struct MovieTrackingMarker *marker; /* marker scopes are created for */
diff --git a/source/blender/makesdna/DNA_tracking_types.h b/source/blender/makesdna/DNA_tracking_types.h
index 6ca63f2c1c9..84ae1835751 100644
--- a/source/blender/makesdna/DNA_tracking_types.h
+++ b/source/blender/makesdna/DNA_tracking_types.h
@@ -287,6 +287,7 @@ enum {
 #define TRACK_USE_2D_STAB   (1 << 8)
 #define TRACK_PREVIEW_GRAYSCALE (1 << 9)
 #define TRACK_DOPE_SEL      (1 << 10)
+#define TRACK_PREVIEW_ALPHA (1 << 11)
 
 /* MovieTrackingTrack->motion_model */
 #define TRACK_MOTION_MODEL_TRANSLATION                 0
@@ -297,8 +298,9 @@ enum {
 #define TRACK_MOTION_MODEL_HOMOGRAPHY                  5
 
 /* MovieTrackingTrack->algorithm_flag */
-#define TRACK_ALGORITHM_FLAG_USE_BRUTE 1
-#define TRACK_ALGORITHM_FLAG_USE_NORMALIZATION 2
+#define TRACK_ALGORITHM_FLAG_USE_BRUTE			(1 << 0)
+#define TRACK_ALGORITHM_FLAG_USE_NORMALIZATION	(1 << 2)
+#define TRACK_ALGORITHM_FLAG_USE_MASK			(1 << 3)
 
 /* MovieTrackingTrack->adjframes */
 #define TRACK_MATCH_KEYFRAME        0
diff --git a/source/blender/makesrna/intern/rna_tracking.c b/source/blender/makesrna/intern/rna_tracking.c
index f1f962f6701..c95d04d005a 100644
--- a/source/blender/makesrna/intern/rna_tracking.c
+++ b/source/blender/makesrna/intern/rna_tracking.c
@@ -637,13 +637,19 @@ static void rna_def_trackingSettings(BlenderRNA *brna)
 	RNA_def_property_enum_items(prop, tracker_motion_model);
 	RNA_def_property_ui_text(prop, "Motion model", "Default motion model to use for tracking");
 
-	/* use_brute */
+	/* default_use_brute */
 	prop = RNA_def_property(srna, "default_use_brute", PROP_BOOLEAN, PROP_NONE);
 	RNA_def_property_boolean_sdna(prop, NULL, "default_algorithm_flag", TRACK_ALGORITHM_FLAG_USE_BRUTE);
 	RNA_def_property_ui_text(prop, "Prepass", "Use a brute-force translation-only initialization when tracking");
 	RNA_def_property_update(prop, NC_MOVIECLIP | ND_DISPLAY, NULL);
 
-	/* default use_normalization */
+	/* default_use_brute */
+	prop = RNA_def_property(srna, "default_use_mask", PROP_BOOLEAN, PROP_NONE);
+	RNA_def_property_boolean_sdna(prop, NULL, "default_algorithm_flag", TRACK_ALGORITHM_FLAG_USE_MASK);
+	RNA_def_property_ui_text(prop, "Use Mask", "Use a grease pencil datablock as a mask to use only specified areas of pattern when tracking");
+	RNA_def_property_update(prop, NC_MOVIECLIP | ND_DISPLAY, NULL);
+
+	/* default_use_normalization */
 	prop = RNA_def_property(srna, "default_use_normalization", PROP_BOOLEAN, PROP_NONE);
 	RNA_def_property_boolean_sdna(prop, NULL, "default_algorithm_flag", TRACK_ALGORITHM_FLAG_USE_NORMALIZATION);
 	RNA_def_property_ui_text(prop, "Normalize", "Normalize light intensities while tracking (slower)");
@@ -965,6 +971,12 @@ static void rna_def_trackingTrack(BlenderRNA *brna)
 	RNA_def_property_update(prop, NC_MOVIECLIP | ND_DISPLAY, NULL);
 
 	/* use_brute */
+	prop = RNA_def_property(srna, "use_mask", PROP_BOOLEAN, PROP_NONE);
+	RNA_def_property_boolean_sdna(prop, NULL, "algorithm_flag", TRACK_ALGORITHM_FLAG_USE_MASK);
+	RNA_def_property_ui_text(prop, "Use Mask", "Use a grease pencil datablock as a mask to use only specified areas of pattern when tracking");
+	RNA_def_property_update(prop, NC_MOVIECLIP | ND_DISPLAY, NULL);
+
+	/* use_normalization */
 	prop = RNA_def_property(srna, "use_normalization", PROP_BOOLEAN, PROP_NONE);
 	RNA_def_property_boolean_sdna(prop, NULL, "algorithm_flag", TRACK_ALGORITHM_FLAG_USE_NORMALIZATION);
 	RNA_def_property_clear_flag(prop, PROP_ANIMATABLE);
@@ -1008,6 +1020,13 @@ static void rna_def_trackingTrack(BlenderRNA *brna)
 	RNA_def_property_ui_text(prop, "Grayscale", "Display what the tracking algorithm sees in the preview");
 	RNA_def_property_update(prop, NC_MOVIECLIP | ND_DISPLAY, NULL);
 
+	/* preview_alpha */
+	prop = RNA_def_property(srna, "use_alpha_preview", PROP_BOOLEAN, PROP_NONE);
+	RNA_def_property_boolean_sdna(prop, NULL, "flag", TRACK_PREVIEW_ALPHA);
+	RNA_def_property_clear_flag(prop, PROP_ANIMATABLE);
+	RNA_def_property_ui_text(prop, "Alpha", "Apply track's mask on displaying preview");
+	RNA_def_property_update(prop, NC_MOVIECLIP | ND_DISPLAY, NULL);
+
 	/* has bundle */
 	prop = RNA_def_property(srna, "has_bundle", PROP_BOOLEAN, PROP_NONE);
 	RNA_def_property_boolean_sdna(prop, NULL, "flag", TRACK_HAS_BUNDLE);