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powerpoint56 · 2012-06-10 19:30:41

So, I'm doing this car racing game where your car can go in any direction and it changes scroll-x/scroll-y appropriately. I found a script I could use to make it scroll in any direction:

when gf clicked
forever
change [scroll-x v] by (([sin v] of (direction)) * (x-velocity))
change [scroll-y v] by (([cos v] of (direction)) * (y-velocity))
end

But now I'm totally dumbfounded. What do I set the velocities to? What do I do to make the screen move when the arrow keys? I know how to do regular scrolling with x and y, but not anything of the sort above.
Thanks! smile

Last edited by powerpoint56 (2012-06-11 16:47:20)

chanmanpartyman · 2012-06-10 19:49:33

Just make it one variable, velocity. You're probably looking for:

when gf clicked
forever
change [scroll x v] by (([sin v] of (direction)) * (velocity))
change [scroll y v] by (([cos v] of (direction)) * (velocity))
if <key [up arrow v] pressed?>
 change [velocity v] by (1)
end
set [velocity v] to ((velocity) * (0.87))

EDIT: 501st post!

Last edited by chanmanpartyman (2012-06-10 19:50:28)

Wes64 · 2012-06-11 04:29:53

Do you understand trig? If you don't ill be glad to summarize what this script does and why it works.

powerpoint56 · 2012-06-11 16:45:31

chanmanpartyman wrote:

Just make it one variable, velocity. You're probably looking for:

when gf clicked
forever
change [scroll x v] by (([sin v] of (direction)) * (velocity))
change [scroll y v] by (([cos v] of (direction)) * (velocity))
if <key [up arrow v] pressed?>
 change [velocity v] by (1)
end
set [velocity v] to ((velocity) * (0.87))

EDIT: 501st post!

Thanks!!!

powerpoint56 · 2012-06-11 16:46:37

Wes64 wrote:
Do you understand trig? If you don't ill be glad to summarize what this script does and why it works.

Thanks! Can you?

Wes64 · 2012-06-11 18:28:12

powerpoint56 wrote:
Wes64 wrote:
Do you understand trig? If you don't ill be glad to summarize what this script does and why it works.
Thanks! Can you?

So in very rough, basic terms...

Imagine a circle with a radius. No matter what direction the radius is pointed in, it always is the same length, right? Basically, sin(Direction) and cos(Direction) describe a radius of that circle. They give you the slope of that radius.

So in the script, your "radius" length is equal to the velocity variable, and the sin and cos give you the slope of that radius. Because you have the slope, you can scroll in any direction, and the velocity thing makes it smooth.

powerpoint56 · 2012-06-16 19:21:25

Thank you for explaining! smile tongue

captaincrunch · 2012-06-18 17:36:45

is it possable to make x volocity in a scrolling game?

powerpoint56 · 2012-06-20 19:48:43

captaincrunch wrote:
is it possable to make x volocity in a scrolling game?

Yes. Here's what I'd do:

when gf clicked
forever
change [scroll-x v] by (x-velocity)
if <key [right-arrow v] pressed?>
change (x-velocity) by (-1) //same with below (if left-arrow pressed)
end
if <key [left-arrow v] pressed?>
change (x-velocity) by (1)
end
set (x-velocity) to (((x-velocity)*(0.95)))
end

Of course, then you would set the other sprites to "scroll x + 480 * ?" like usual.
I think this will work; I'll go check and edit if I need to.

powerpoint56 · 2012-06-20 19:51:31

powerpoint56 wrote:
captaincrunch wrote:
is it possable to make x volocity in a scrolling game?
I think this will work; I'll go check and edit if I need to.

Works!

Wes64 · 2012-06-21 03:11:29

powerpoint56 wrote:
captaincrunch wrote:
is it possable to make x volocity in a scrolling game?
Yes. Here's what I'd do:
when gf clicked
forever
change [scroll-x v] by (x-velocity)
if <key [right-arrow v] pressed?>
change [x-velocity v] by [-1] //same with below (if left-arrow pressed)
end
if <key [left-arrow v] pressed?>
change [x-velocity v] by (1)
end
set [x-velocity v] to <(x-velocity) * [0.95]>
Of course, then you would set the other sprites to "scroll x + 480 * ?" like usual.
I think this will work; I'll go check and edit if I need to.

Fixed

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archived forums

#1 2012-06-10 19:30:41

ScrollY and ScrollX in any Direction

#2 2012-06-10 19:49:33

Re: ScrollY and ScrollX in any Direction

#3 2012-06-11 04:29:53

Re: ScrollY and ScrollX in any Direction

#4 2012-06-11 16:45:31

Re: ScrollY and ScrollX in any Direction

chanmanpartyman wrote:

#5 2012-06-11 16:46:37

Re: ScrollY and ScrollX in any Direction

Wes64 wrote:

#6 2012-06-11 18:28:12

Re: ScrollY and ScrollX in any Direction

powerpoint56 wrote:

Wes64 wrote:

#7 2012-06-16 19:21:25

Re: ScrollY and ScrollX in any Direction

#8 2012-06-18 17:36:45

Re: ScrollY and ScrollX in any Direction

#9 2012-06-20 19:48:43

Re: ScrollY and ScrollX in any Direction

captaincrunch wrote:

#10 2012-06-20 19:51:31

Re: ScrollY and ScrollX in any Direction

powerpoint56 wrote:

captaincrunch wrote:

#11 2012-06-21 03:11:29

Re: ScrollY and ScrollX in any Direction

powerpoint56 wrote:

captaincrunch wrote:

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