Scratch

coolhogs wrote:

Hello Scratchers of Help With Scripts,
I am trying to make a physics game... I know people have posted this a hundred times but... I need a great, long, hard script for friction and gravity... I think I already have gravity... but it needs friction... 

Friction is usually done by taking your velocities and multiplying them by a number x where 0<x<1.  Usually, .9<x<1 is a good place to start, since anything lower than .9 slows the sprite down extremely fast.  All you do for a script is:

set 
xvel ▼
 to 
xvel
 * 
.95

I also have a script on my test account that allows you to pick a top speed and a friction to determine how much each press of a key should change your x and y. Here

I've learned it's to everyone's advantage to compile everything you can in one script:

when  clicked
forever
if 
key 
right arrow ▼
 pressed?
change 
xvel ▼
 by 
1
if 
key 
left arrow ▼
 pressed?
change 
xvel ▼
 by 
-1
set 
xvel ▼
 to 
xvel
 * 
.87
change x by 
xvel
if 
touching 
level ▼
?
change y by 
abs ▼
 of 
xvel
 + 
1
if 
touching 
level ▼
?
change y by 
0
 - 
abs ▼
 of 
xvel
 + 
1
change x by 
0
-
xvel
set 
xvel ▼
 to 
xvel
 / 
2
if 
key 
up arrow ▼
 pressed?
change y by 
-1
if 
touching 
level ▼
?
set 
yvel ▼
 to 
10
change y by 
1
if 
yvel
 < 
3
change y by 
-1
if 
not
touching 
level ▼
?
change 
yvel ▼
 by 
-1
change y by 
1
set 
yvel ▼
 to 
yvel
 * 
0.9
change y by 
yvel
if 
touching 
level ▼
?
change y by 
0
 - 
yvel
set 
yvel ▼
 to 
yvel
 / 
2.5