Webcam colored object tracking, how to leave a lasting path from centroid of an object

So I have already have a code that tracks two object's centroids/borders/distances, and I would like to further add to this to track the position of the objects and leave a lasting path of the trail of the object's centroids.

Most examples I have examined only use this for an imported video, so if anyone knows any resources that use a live webcam video for this task would be very helpful.

Here is the section of my code for annotate the image with aforementioned plots, just wondering how I need to go about creating this trail that will stay on the output figure

imshow(RGB);

imshow(redYellowOverlay);

hold on;

plot(rjMean,riMean, 'g-x', 'LineWidth',5)

plot(yjMean,yiMean, 'g-x', 'LineWidth',5)

plot([rjMean,yjMean],[riMean,yiMean],'b','LineWidth',2);

RGB is the snapshot taken from the webcam, redYellowOverlay is the border code, ri/rj/yi/yj means are the centroid coordinates and all plot() lines are plotting of centroids/distances onto the figure