Scratch

You could try putting these into the dragon script:

when gf clicked
forever
wait until <touching [wizard v]?>
change [scoredragon v] by [1]
wait until <not <touching [wizard v]?>>

and put this into the wizard:

when gf clicked
forever
wait until <touching [dragon v]?>
change [scorewizard v] by [1]
wait until <not <touching [dragon v]?>>

scimonster wrote:

You probably need to have a forever block around the if. 

Or use the

 Forever If <> 

Hi-the students say it is working, except that when the sprites touch BOTH get the point.  How can we fix this?  Thanks again.

LiquidMetal wrote:

Mokat wrote:

scimonster wrote:

You probably need to have a forever block around the if. 

Or use the

 Forever If <> 

Do NOT use the forever if.

I learned this the hard way:

Forever if <>
end

Checks if the boolean operation is true, and if it is, executes forever.  It only checks true or false ONCE.  This is something I hope they will fix in Scratch 2.0, as it really confuses new scratchers.

Uh, no it doesn't.  This can be proven with a simple script:

When gf clicked
forever if <key [space  v] pressed?>
change [color  v] effect by (10)

You'll notice that the color only changes when the space key is pressed.



Back to the topic:  It sounds like you'll need to calculate the speed of both characters.  I believe this can be done effectively by waiting a VERY small amount of time (such as a hundredth of a second), calculating the distance between the old position and new position using the distance formula, and using the speed formula (distance / time) to calculate the speed of each character.  Then, update it constantly, and compare the speeds when they touch.

Hopefully, there's an easier way.   

LiquidMetal wrote:

Mokat wrote:

scimonster wrote:

You probably need to have a forever block around the if. 

Or use the

 Forever If <> 

Do NOT use the forever if.

I learned this the hard way:

Forever if <>
end

Checks if the boolean operation is true, and if it is, executes forever.  It only checks true or false ONCE.  This is something I hope they will fix in Scratch 2.0, as it really confuses new scratchers.

no, you have it the wrong way round. Most new scratchers THINK it checks the condition once then loops it forever, but it is the other way round: whenever the condition is true it runs the loop, then checks the condition again and waits until it us true before running the loop again, and it does this for ever. It is equivalent to

forever
if<something>
  do stuff
end

or

forever
wait until <something>
do stuff

But what if both headbang into each other? 

What you should do in my opinion is the velocity method. Or you could add a new feature where you press and hold a key (different for each player) to switch to an "attack mode". This lasts for say 1 second, and when you are in attack mode and hit the other player, your score increases. Otherwise, if you you touch the other player outside attack mode, your score decreases. And attack mode needs a hefty reload period.

Last edited by Hardmath123 (2012-03-28 06:58:21)