Cloning is a pretty neat feature but I realized pretty pretty quickly that there is no particular blocks to identify which specific clone is touching another clone. For instance, I have my bullet, cloned sprites named “Shot” and my enemy cloned sprites named “Baddy”. I can tell if a Shot clone is touching one of the clones of Baddy but if I wanted to identify which particular clones are touching it is kinda difficult. Any one find any good workarounds?

Inside the Baddy object, ‘if touching Shot’ will be true only when this particular clone is touched by a Shot. So each Baddy clone knows when it is touched, but not which particular Shot touched it. Similarly each Shot knows when it touches a Baddy, but not which particular Baddy.

Well the reason I want to know which particular clone is touching which is so that I can check its local variables and other properties.

Here is a realistic example,


We have our hero, “Mario” and the stage is made of 120 cloned tiles. Now, tiles make up both the walls and the background bushes/clouds. Mario should be stopped by a tile as long as its “Walkable” variable is set to 1 rather than 0. Now this is rather annoying since I can't reference specific tile clones directly, I will probably have to use some roundabout way of checking its properties using broadcasts but this is annoying

Check out this project: http://scratch.mit.edu/projects/10063618/

Sometimes it is not necessary to identify a specific clone in order for your scripts to work.

Well, how about you have a sprite that's a ball with physics, and you have 7 clones and you want them to interact. HOW?

archmage wrote:

We have our hero, “Mario” and the stage is made of 120 cloned tiles. Now, tiles make up both the walls and the background bushes/clouds. Mario should be stopped by a tile as long as its “Walkable” variable is set to 1 rather than 0.

Instead of using variables, clone two different tile sprites called Walkable and NotWalkable. Test if Mario is touching NotWalkable.

archmage wrote:

I will probably have to use some roundabout way of checking its properties using broadcasts but this is annoying

Scratch is designed to teach basic programming principles. It's very easy to use, but the cost of that is it also very limited. It was designed to be easy to draw backgrounds and detect background collisions by ‘if touching color’. It wasn't designed for tile-based games, scrolling games, etc. It can be made to do those things but it will take longer and the solutions will feel like hacks. If you find yourself spending a lot of time to work around these limitations it might be less effort to just learn a real programming language that gives you complete freedom.

First, as one said: the beauty of the code design wil be reflected in the beauty of the application. The basic idea of Twitter is made with a simple design. May be this way of thinking is made easier with Scrath than with other languages ? So what you can learn with Scratch is to force you to match a beautiful simple idea with a beautiful design.

The example about physics is a very good example. In physics, each “body” has its own way to behave, just like balls.
But when 2 or more “bodies” are interacting (collision, …) then they become a kind of “aggregated body” that has different laws that are sometimes additive, but sometimes not. How to design this “aggregated body” ?

For instance, let us asume that for each sprite/clone X, Scratch provides you a list L of all other sprite/clone that are touching X.
Now, how to compute the “physical vector of speed” that result from the collision and the “speed vector” and mass of each other sprite/clone they had before the collision?
Let us suppose that all this information is inside each sprite/clone (i.e. in variables that are not shared by other sprites/clones). How to exchange this information between touching sprite/clones ? Scratch should provide a way to communicate between sprite/clones ?

Why not asking Scratchers that like physics, or make a groupe of Scratcher to create some beautiful simple design to solve this problem without too many if … then … else if … then … else if …

How about setting object variables, like “set (sprite 2(clone<touching?>) (xspeed)) to (9)”. A block like that would be amazing. REALLY usefull.

Create a global variable called clone-counter.
Then, create a local variable on the “Shot” sprite called my-num
[scratchblocks
set to 0
repeat
create clone of
wait secs
change (clone-counter) by 1

when I start as a clone
set to (clone-counter)
[/scratchblocks
All you have to do to get the specific clone number is use:
[scratchblocks
( of
[/scratchblocks

The blocks plugin is broken.

For problems like this with clone identity, but not reqarding touch, rather position, I have found that using a list to keep track of the positions of all the clones is quite useful. (Example: you have a variable list in which you store clone Y positions, another where you store their X positions. Using this, it is possible to determine the position of clones.) I advised ScratchUniverse on how to do this, and I believe that he implemented it to keep track of his clones.

Take a look at 3D BallShootArcade if you'd like. It identifies clones with global variables and keeps track of positions via global arrays.

darkness3560 wrote:

Create a global variable called clone-counter.
Then, create a local variable on the “Shot” sprite called my-num
[scratchblocks
set to 0
repeat
create clone of
wait secs
change (clone-counter) by 1

when I start as a clone
set to (clone-counter)
[/scratchblocks
All you have to do to get the specific clone number is use:
[scratchblocks
( of
[/scratchblocks

The blocks plugin is broken.

No it isn't. You forgot brackets ( ] )at the end of the [scratchblocks. See:

set [clone-counter v] to (0)
repeat [however many times]
create clone of [myself v]
wait [0] secs
change (clone-counter) by (1)

when I start as a clone
set [my-num v] to (clone-counter)

All you have to do to get the specific clone number is use:

([my-num v] of [Shot v]

Also, you need parentheses (something) around any inputs.
When there are no parentheses, this happens:

set [variable v] to number

When there are parentheses, it looks normal.
Also, does this kind of block even exist?

([my-num v] of [Shot v])

It doesn't.

@Doonkoo: Actually, that specific block does exist and does allow you to see sprite-specific variables.

archmage wrote:

Cloning is a pretty neat feature but I realized pretty pretty quickly that there is no particular blocks to identify which specific clone is touching another clone. For instance, I have my bullet, cloned sprites named “Shot” and my enemy cloned sprites named “Baddy”. I can tell if a Shot clone is touching one of the clones of Baddy but if I wanted to identify which particular clones are touching it is kinda difficult. Any one find any good workarounds?

If you make a sprite specific variable, it transfers into a clone specific variable. So just do this:
when I start as a clone
Change (Clones) by 1
Set (CloneID) to (Clones)

Dont you just color all of the clones created to find out how many clones are generated

You do not need to make a variable for each enemy. Add the sprites to lists. Example:

if <(Goomba1)<touching [Spiney 298]?> then
add [Goomba1] to [list touching] 
add [Spiney 298] to [list touching what?]
end

when green flag clicked
forever
set [what I'm doing] to [playing destiny]
end

Meteor_mash47 wrote:

Dont you just color all of the clones created to find out how many clones are generated

You may think that, but no.

when green flag clicked
forever
set [what I'm doing] to [playing destiny]
end

Hi, maybe this small example project will help:

http://scratch.mit.edu/projects/23916401

In this project all clones updates a table if they are touching the cat or not. The cat is constantly watching the table and tells everybody which clone who is touching him….also all the other clones can see that a specific clone is touching the cat…

Also made a clone touching clone detection example:

http://scratch.mit.edu/projects/23973803

I created a game where if you click one clone a sprite will change costume?
How do I get a certain clone to be identified as one thing not another?