How do you make an open world game?

vandjac

I was really interested in making a top-down open world fantasy game, but I couldn't figure out how to have the objects go off the screen when it is out of the range of the character, but then come back in when the character is within the range of it. I would really appreciate it if you could help me with this!

ErnieParke

You will need these variables, although you probably already have them:

*scroll x/y
*enemy x/y

In this case, all you need to do is this:

set x to (((0) - (scroll x)) + (enemy x))
set y to (((0) - (scroll y)) + (enemy y))
if <<(x position) = (((0) - (scroll x)) + (enemy x))> and <(y position) = (((0) - (scroll y)) + (enemy y))>>
  show
else
  hide
end

The code works because if a sprite is off screen, the sprite cannot go to that position. It has to stay on screen. So if the sprite goes to the position but is not at it, it is off screen, at which point we can hide it. Make sense?

Showing,

ErnieParke

Last edited by ErnieParke (March 29, 2016 15:52:05)

Carpit999

ErnieParke wrote:
You will need these variables, although you probably already have them:

*scroll x/y
*enemy x/y

In this case, all you need to do is this:
set x to (((0) - (scroll x)) + (enemy x))
set y to (((0) - (scroll y)) + (enemy y))
if <<(x position) = (((0) - (scroll x)) + (enemy x))> and <(y position) = (((0) - (scroll y)) + (enemy y))>>
  show
else
  hide
end
The code works because if a sprite is off screen, the sprite cannot go to that position. It has to stay on screen. So if the sprite goes to the position but is not at it, it is off screen, at which point we can hide it. Make sense?

Showing,

ErnieParke

Well, that might work, but there IS a simpler way (well, it may be simpler):
(Put this in all the sprites you want to disappear when off screen)

when green flag clicked
forever
    
repeat (any number)
if <<(x position) > [240]> or <<(x position) < [-240]> or <<(y position) > [180]> or <(y position) < [-180]>>>> then
hide
end
if <<(x position) < [240]> and <<(x position) > [-240]> and <<(y position) < [180]> and <(y position) > [-180]>>>> then
show

end

ErnieParke

@Carpit999:
That method actually has a tiny flaw. Most sprites can actually move beyond -240 to 240 and -180 and 180. It would be nice to still shows sprites then, no?

My thoughts,

ErnieParke

Carpit999

ErnieParke wrote:
@Carpit999:
That method actually has a tiny flaw. Most sprites can actually move beyond -240 to 240 and -180 and 180. It would be nice to still shows sprites then, no?

My thoughts,

ErnieParke

The center of the sprite is where the sprite actually is.

asivi

ErnieParke wrote:
You will need these variables, although you probably already have them:

*scroll x/y
*enemy x/y

In this case, all you need to do is this:
set x to (((0) - (scroll x)) + (enemy x))
set y to (((0) - (scroll y)) + (enemy y))
if <<(x position) = (((0) - (scroll x)) + (enemy x))> and <(y position) = (((0) - (scroll y)) + (enemy y))>>
  show
else
  hide
end
The code works because if a sprite is off screen, the sprite cannot go to that position. It has to stay on screen. So if the sprite goes to the position but is not at it, it is off screen, at which point we can hide it. Make sense?

Showing,

ErnieParke

If i am not wrong the conditions for xposition and yposition are always true.

ErnieParke

@asivi:
If you are off screen, the conditions for x position and y position are not correct. Try this script, and you should see:

set x to (9000)
set y to (9000)
if <<(x position) = (9000)> and <(y position) = (9000)>> then
  show
else
  hide
end

@Carpit999:
You are correct. The interesting part is that Scratch allows the center of the sprite to go outside of the -240/240/-180/180 region by a little bit, depending on the dimensions of the sprite.

Clarifying,

ErnieParke

Carpit999

ErnieParke wrote:
@asivi:
If you are off screen, the conditions for x position and y position are not correct. Try this script, and you should see:
set x to (9000)
set y to (9000)
if <<(x position) = (9000)> and <(y position) = (9000)>> then
  show
else
  hide
end
@Carpit999:
You are correct. The interesting part is that Scratch allows the center of the sprite to go outside of the -240/240/-180/180 region by a little bit, depending on the dimensions of the sprite.

Clarifying,

ErnieParke

Moving beyong -240,240,180,and -180 is because in the “costumes” thingy, you can set the center of the costume with the “+” button. This acts as the center of the sprite and therefore the actual coordinates of every sprite are at the set center. By default, SCRATCH costumes are automagically in the center. Get it?

vandjac

ErnieParke wrote:
You will need these variables, although you probably already have them:

*scroll x/y
*enemy x/y

In this case, all you need to do is this:
set x to (((0) - (scroll x)) + (enemy x))
set y to (((0) - (scroll y)) + (enemy y))
if <<(x position) = (((0) - (scroll x)) + (enemy x))> and <(y position) = (((0) - (scroll y)) + (enemy y))>>
  show
else
  hide
end
The code works because if a sprite is off screen, the sprite cannot go to that position. It has to stay on screen. So if the sprite goes to the position but is not at it, it is off screen, at which point we can hide it. Make sense?

Showing,

ErnieParke

So this would make the sprites come back on the screen in the right positions? Thanks for all the help!

Carpit999

vandjac wrote:
ErnieParke wrote:
You will need these variables, although you probably already have them:

*scroll x/y
*enemy x/y

In this case, all you need to do is this:
set x to (((0) - (scroll x)) + (enemy x))
set y to (((0) - (scroll y)) + (enemy y))
if <<(x position) = (((0) - (scroll x)) + (enemy x))> and <(y position) = (((0) - (scroll y)) + (enemy y))>>
  show
else
  hide
end
The code works because if a sprite is off screen, the sprite cannot go to that position. It has to stay on screen. So if the sprite goes to the position but is not at it, it is off screen, at which point we can hide it. Make sense?

Showing,

ErnieParke
So this would make the sprites come back on the screen in the right positions? Thanks for all the help!

Mine would too

vandjac

Would that work with clones too?

vandjac

ErnieParke wrote:
You will need these variables, although you probably already have them:

*scroll x/y
*enemy x/y

In this case, all you need to do is this:
set x to (((0) - (scroll x)) + (enemy x))
set y to (((0) - (scroll y)) + (enemy y))
if <<(x position) = (((0) - (scroll x)) + (enemy x))> and <(y position) = (((0) - (scroll y)) + (enemy y))>>
  show
else
  hide
end
The code works because if a sprite is off screen, the sprite cannot go to that position. It has to stay on screen. So if the sprite goes to the position but is not at it, it is off screen, at which point we can hide it. Make sense?

Showing,

ErnieParke

Also, do you put this script into the character or in an object?

vandjac

Never mind my previous comment I think I figured it out.

vandjac

How would you make an object start off of the screen?

ErnieParke

vandjac wrote:
How would you make an object start off of the screen?

To make the object start off of the screen, just set enemy x and y to something off screen. The code above will handle positioning and if the Sprite should show or not.

vandjac wrote:
Would that work with clones too?

It should, although you will need to make sure enemy x and y are for this Sprite only, so that each clone can get a copy of it.

Answering,

ErnieParke

vandjac

So how would you make a bunch of clones that are all in different places?

ErnieParke

vandjac wrote:
So how would you make a bunch of clones that are all in different places?

Like this:

when gf clicked
hide
repeat (50)
  create clone of [myself v]
end

when I start as a clone
set [enemy x v] to (pick random (-500) to (500))
set [enemy y v] to (pick random (-500) to (500))
forever
  ...//enemy code
end

Again, remember that (enemy x) and (enemy y) need to be for this sprite only.

Showing,

ErnieParke

Carpit999

vandjac wrote:
How would you make an object start off of the screen?

when green flag clicked
go to x: (636) y: (74467)

vandjac

I was wondering how to make other sprites move also.

Carpit999

Make them move opposite of player.

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