Deleting plotted image from a figure if conditions are met

Hi, I am trying to make a game where one progresses vertically upwards by bouncing off platforms and the platforms underneath disappear once they are off the screen. I reckon this should be done by deleting them from the plot, but I don't know how to do this. This is my platform generating loop which makes 50 random platforms:

%Generate platform field
xpf = [];
ypf = [];
platformrecord = [];

for n = 1:1:50
    hold on
    xpf = [xpf randi(512)];
    ypf = [ypf randi(30)];
    platformcentre = [xpf(n) ypf(n)+70*(n-1)];
    pfgen(48,16);
end

where pfgen() draws the platform image out of a random selection of 4 images, as below

function pfgen(x,y)
%generates a platform at specified x and y coordinates.

global platformcentre

n = randi(4);
d = randi(2);

platforms = [".\Assets\art\bin\simpleplatform-48x16-v1.png"...
             ".\Assets\art\bin\simpleplatform-48x16-v2.png"...
             ".\Assets\art\bin\simpleplatform-48x16-v3.png"...
             ".\Assets\art\bin\simpleplatform-48x16-v4.png"
             ];
if d == 1
    [pfimage, map, alphachannel] = imread(platforms(n));
    imagesc('XData',[platformcentre(1)-x/2 platformcentre(1)+x/2], ...
                 'YData',[platformcentre(2)-y/2 platformcentre(2)+y/2], ...
                 'CData',flip(pfimage,1), ...
                 'AlphaData',flip(alphachannel,1));
else
    [pfimage, map, alphachannel] = imread(platforms(n));
    pfimage = flip(pfimage,1);
    alphachannel = flip(alphachannel,1);
    imagesc('XData',[platformcentre(1)-x/2 platformcentre(1)+x/2], ...
                 'YData',[platformcentre(2)-y/2 platformcentre(2)+y/2], ...
                 'CData',flip(pfimage,2), ...
                 'AlphaData',flip(alphachannel,2));
end

Is there a way to say if the y-coordinate of my platform is less than the lowest y-coordinate visible, to remove said platform from the plot? Thanks.

Answer 1

[Philippe Lebel]

If you get the handle of the plot like so:

h = plot(1,1,'Xr')

you can just delete the handle and the data disapears

delete(h)

like wise for imagesc you can do:

doge = true;
h = imagesc
% wow such image
% very pixel
if doge
    delete(h)
end
% such blank
% many empty

[Daniel Goh]

Ah, thank you, this works! I did not know that deleting the handle deletes the plot.