Implement per-frame track reprojection error visualization

It is now possible to display per-frame track reprojection
error in curve view of clip editor. Simply enable corresponding
option in filter buttons.

Currently displayed using blue color which might confuse with
average reprojection error, further color tweaks are possible
and easy.

Also changed icon track x/y curves. Better icons here are
really appreciated.

1 files changed, 109 insertions, 4 deletions

diff --git a/source/blender/editors/space_clip/clip_graph_draw.c b/source/blender/editors/space_clip/clip_graph_draw.c
index 80b844464db..16845bb10fb 100644
--- a/source/blender/editors/space_clip/clip_graph_draw.c
+++ b/source/blender/editors/space_clip/clip_graph_draw.c
@@ -116,7 +116,7 @@ static void tracking_segment_start_cb(void *userdata, MovieTrackingTrack *track,
 	glBegin(GL_LINE_STRIP);
 }
 
-static void tracking_segment_end_cb(void *UNUSED(userdata))
+static void tracking_segment_end_cb(void *UNUSED(userdata), int UNUSED(coord))
 {
 	glEnd();
 
@@ -151,7 +151,7 @@ static void tracking_segment_knot_cb(void *userdata, MovieTrackingTrack *track,
 	}
 }
 
-static void draw_tracks_curves(View2D *v2d, SpaceClip *sc)
+static void draw_tracks_motion_curves(View2D *v2d, SpaceClip *sc)
 {
 	MovieClip *clip = ED_space_clip_get_clip(sc);
 	MovieTracking *tracking = &clip->tracking;
@@ -191,6 +191,108 @@ static void draw_tracks_curves(View2D *v2d, SpaceClip *sc)
 	                                   &userdata, tracking_segment_knot_cb, NULL, NULL);
 }
 
+typedef struct TrackErrorCurveUserData {
+	MovieTracking *tracking;
+	MovieTrackingObject *tracking_object;
+	MovieTrackingTrack *active_track;
+	bool matrix_initialized;
+	int matrix_frame;
+	float projection_matrix[4][4];
+	int width, height;
+	float aspy;
+} TrackErrorCurveUserData;
+
+static void tracking_error_segment_point_cb(void *userdata,
+                                            MovieTrackingTrack *track, MovieTrackingMarker *marker,
+                                            int coord, int scene_framenr, float UNUSED(value))
+{
+	if (coord == 1) {
+		TrackErrorCurveUserData *data = (TrackErrorCurveUserData *) userdata;
+		float reprojected_position[4], bundle_position[4], marker_position[2], delta[2];
+		float reprojection_error;
+
+		if (!data->matrix_initialized || data->matrix_frame != scene_framenr) {
+			BKE_tracking_get_projection_matrix(data->tracking, data->tracking_object,
+			                                   scene_framenr, data->width, data->height,
+			                                   data->projection_matrix);
+		}
+
+		copy_v3_v3(bundle_position, track->bundle_pos);
+		bundle_position[3] = 1;
+
+		mul_v4_m4v4(reprojected_position, data->projection_matrix, bundle_position);
+		reprojected_position[0] = (reprojected_position[0] /
+		                          (reprojected_position[3] * 2.0f) + 0.5f) * data->width;
+		reprojected_position[1] = (reprojected_position[1] /
+		                          (reprojected_position[3] * 2.0f) + 0.5f) * data->height * data->aspy;
+
+		BKE_tracking_distort_v2(data->tracking, reprojected_position, reprojected_position);
+
+		marker_position[0] = (marker->pos[0] + track->offset[0]) * data->width;
+		marker_position[1] = (marker->pos[1] + track->offset[1]) * data->height * data->aspy;
+
+		sub_v2_v2v2(delta, reprojected_position, marker_position);
+		reprojection_error = len_v2(delta);
+
+		glVertex2f(scene_framenr, reprojection_error);
+	}
+}
+
+static void tracking_error_segment_start_cb(void *userdata, MovieTrackingTrack *track, int coord)
+{
+	if (coord == 1) {
+		TrackErrorCurveUserData *data = (TrackErrorCurveUserData *) userdata;
+		float col[4] = {0.0f, 0.0f, 1.0f, 1.0f};
+
+		if (track == data->active_track) {
+			col[3] = 1.0f;
+			glLineWidth(2.0f);
+		}
+		else {
+			col[3] = 0.5f;
+			glLineWidth(1.0f);
+		}
+
+		glColor4fv(col);
+
+		glBegin(GL_LINE_STRIP);
+	}
+}
+
+static void tracking_error_segment_end_cb(void *UNUSED(userdata), int coord)
+{
+	if (coord == 1) {
+		glEnd();
+		glLineWidth(1.0f);
+	}
+}
+
+static void draw_tracks_error_curves(SpaceClip *sc)
+{
+	MovieClip *clip = ED_space_clip_get_clip(sc);
+	MovieTracking *tracking = &clip->tracking;
+	TrackErrorCurveUserData data;
+
+	data.tracking = tracking;
+	data.tracking_object = BKE_tracking_object_get_active(tracking);
+	data.active_track = BKE_tracking_track_get_active(tracking);
+	data.matrix_initialized = false;
+	BKE_movieclip_get_size(clip, &sc->user, &data.width, &data.height);
+	data.aspy = 1.0f / tracking->camera.pixel_aspect;
+
+	if (!data.width || !data.height) {
+		return;
+	}
+
+	clip_graph_tracking_values_iterate(sc,
+	                                   (sc->flag & SC_SHOW_GRAPH_SEL_ONLY) != 0,
+	                                   (sc->flag & SC_SHOW_GRAPH_HIDDEN) != 0,
+	                                   &data,
+	                                   tracking_error_segment_point_cb,
+	                                   tracking_error_segment_start_cb,
+	                                   tracking_error_segment_end_cb);
+}
+
 static void draw_frame_curves(SpaceClip *sc)
 {
 	MovieClip *clip = ED_space_clip_get_clip(sc);
@@ -237,8 +339,11 @@ void clip_draw_graph(SpaceClip *sc, ARegion *ar, Scene *scene)
 	UI_view2d_grid_free(grid);
 
 	if (clip) {
-		if (sc->flag & SC_SHOW_GRAPH_TRACKS)
-			draw_tracks_curves(v2d, sc);
+		if (sc->flag & SC_SHOW_GRAPH_TRACKS_MOTION)
+			draw_tracks_motion_curves(v2d, sc);
+
+		if (sc->flag & SC_SHOW_GRAPH_TRACKS_ERROR)
+			draw_tracks_error_curves(sc);
 
 		if (sc->flag & SC_SHOW_GRAPH_FRAMES)
 			draw_frame_curves(sc);