Help with movement script please

[4Cuties]

I'm trying to get a MC to move when the arrow keys are pressed. I can get it to move at a constant speed with no problem, but i want it to slowly accelerate when the keys are pressed and slowly decelerate when the keys are released. Deceleration is my biggest problem. This is what i have so far:

onClipEvent (load) {
this.speed = 0;
this.accel = 0.5;
this.maxspeed = 5;
this.minspeed = 0.5;l
}
onClipEvent (enterFrame) {
if (Key.isDown(Key.RIGHT) || Key.isDown(Key.LEFT) || Key.isDown(Key.UP) || Key.isDown(Key.DOWN)) {
if (Key.isDown(Key.RIGHT)) {
this.speed += this.accel;
this._x = _x+this.speed;
if (this.speed>=this.maxspeed) {
this.speed = this.maxspeed;
}
}
if (Key.isDown(Key.LEFT)) {
this.speed += this.accel;
this._x = _x-this.speed;
if (this.speed>=this.maxspeed) {
this.speed = this.maxspeed;
}
}
if (Key.isDown(Key.UP)) {
this.speed += this.accel;
this._y = _y-this.speed;
if (this.speed>=this.maxspeed) {
this.speed = this.maxspeed;
}
}
if (Key.isDown(Key.DOWN)) {
this.speed += this.accel;
this._y = _y+this.speed;
if (this.speed>=this.maxspeed) {
this.speed = this.maxspeed;
}
}
} else if (!Key.isDown(Key.RIGHT) && !Key.isDown(Key.RIGHT) && !Key.isDown(Key.UP) && !Key.isDown(Key.DOWN)) {
}
}

I've tried putting in the opposite of the above functions in the else if function, but that obviously just gets it to stop, not decelerate. After a lot of trial and error... i just decided to ask for help. what should i put in the else if function? anybody's help would be appreciated. thanks

[Johnny]

can you put

speed-- (substitue -- with -= .2 or something if it's slowing down too fast)

in onEnterFrame, and just make sure it doesn't drop below 0 with an else statment?

[Johnny]

Nvm... forget I said that.

I need to wake up a bit.

[4Cuties]

no... it doesn't know which direction to slow down in. if you're pressing the right arrow key, and let go, that kind of script wouldn't determine which direction to go in, so it will either go instantly in the one direction you choose, or not move at all (if you script it for all four directions, they will all cancel each other out).

[Johnny]

His code is using speed to universally speed up everything. Direction doesn't matter, it just needs to reduce speed by accel every frame until speed reaches 0 again, when a key is not being pressed.

[4Cuties]

yes, but once the speed value has been changed, the program won't know whether to add or subtract it from x or y. There's those four possibilities, and i don't know how to code it to know when to use which one.

[Runouw]

I think this is what you mean...

onClipEvent (load) {
this.speed = 0;
this.accel = 0.5;
this.maxspeed = 5;
this.minspeed = 0.5;
this.decel = 0.8;
}
onClipEvent (enterFrame) {
if (Key.isDown(Key.RIGHT) && !Key.isDown(Key.LEFT)) {
xspeed += accel;
xspeed = Math.max(xspeed, minspeed);
xspeed = Math.min(xspeed, maxspeed);
}
if (Key.isDown(Key.LEFT) && !Key.isDown(Key.RIGHT)) {
xspeed -= accel;
xspeed = Math.max(xspeed, -minspeed);
xspeed = Math.min(xspeed, -maxspeed);
}
if (Key.isDown(Key.UP) && !Key.isDown(Key.DOWN)) {
yspeed -= accel;
yspeed = Math.max(yspeed, -minspeed);
yspeed = Math.min(yspeed, -maxspeed);
}
if (Key.isDown(Key.DOWN) && !Key.isDown(Key.UP)) {
yspeed += accel;
yspeed = Math.max(yspeed, minspeed);
yspeed = Math.min(yspeed, maxspeed);
}
if (!Key.isDown(Key.RIGHT) && !Key.isDown(Key.LEFT)) {
xspeed *= decel;
}
if (!Key.isDown(Key.UP) && !Key.isDown(Key.DOWN)) {
yspeed *= decel;
}
_y += yspeed;
_x += xspeed;
}

I added a few changes to the code and made it multiply by a number to slow down, instead of subtract.

[4Cuties]

thanks mirage, i can see the concept that you're trying to apply, but for some reason it isn't working. I'm using mx 2004. would that make a difference?

[Johnny]

He forgot to define xspeed and yspeed. I changed the bottom part and combined the !Key.isDowns.

This works. Just tested.

onClipEvent (load) {
this.xspeed = 0;
this.yspeed = 0;
this.accel = 0.5;
this.maxspeed = 5;
this.minspeed = 0.5;
this.decel = 0.8;
}
onClipEvent (enterFrame) {
if (Key.isDown(Key.RIGHT) && !Key.isDown(Key.LEFT)) {
xspeed += accel;
xspeed = Math.max(xspeed, minspeed);
xspeed = Math.min(xspeed, maxspeed);
}
if (Key.isDown(Key.LEFT) && !Key.isDown(Key.RIGHT)) {
xspeed -= accel;
xspeed = Math.max(xspeed, -minspeed);
xspeed = Math.min(xspeed, -maxspeed);
}
if (Key.isDown(Key.UP) && !Key.isDown(Key.DOWN)) {
yspeed -= accel;
yspeed = Math.max(yspeed, -minspeed);
yspeed = Math.min(yspeed, -maxspeed);
}
if (Key.isDown(Key.DOWN) && !Key.isDown(Key.UP)) {
yspeed += accel;
yspeed = Math.max(yspeed, minspeed);
yspeed = Math.min(yspeed, maxspeed);
}
if (!Key.isDown(Key.RIGHT) && !Key.isDown(Key.LEFT)&&!Key.isDown(Key.UP) && !Key.isDown(Key.DOWN)) {
xspeed *= decel;
yspeed *= decel;
}
_y += yspeed;
_x += xspeed;
}

[Johnny]

Acually, tested it again with the !Key.Downs combined and uncombined and his does transition better when you're moving to and from diagonals.

[4Cuties]

nearly works, but when going up and left, it doesn't accelerate, it goes instantly to the maximum speed. not sure why

[4Cuties]

Okay, i finally got it to work pretty much flawlessly. Thanks so much for your help guys

[Runouw]

Oops that mas my fault there, you see in the part when it's going up, and left. Try changeing the "min" with the "max"

Heres the whole code again with the glitch fixed:

onClipEvent (load) {
this.speed = 0;
this.accel = 0.5;
this.maxspeed = 5;
this.minspeed = 0.5;
this.decel = 0.8;
}
onClipEvent (enterFrame) {
if (Key.isDown(Key.RIGHT) && !Key.isDown(Key.LEFT)) {
xspeed += accel;
xspeed = Math.max(xspeed, minspeed);
xspeed = Math.min(xspeed, maxspeed);
}
if (Key.isDown(Key.LEFT) && !Key.isDown(Key.RIGHT)) {
xspeed -= accel;
xspeed = Math.min(xspeed, -minspeed);
xspeed = Math.max(xspeed, -maxspeed);
}
if (Key.isDown(Key.UP) && !Key.isDown(Key.DOWN)) {
yspeed -= accel;
yspeed = Math.min(yspeed, -minspeed);
yspeed = Math.max(yspeed, -maxspeed);
}
if (Key.isDown(Key.DOWN) && !Key.isDown(Key.UP)) {
yspeed += accel;
yspeed = Math.max(yspeed, minspeed);
yspeed = Math.min(yspeed, maxspeed);
}
if (!Key.isDown(Key.RIGHT) && !Key.isDown(Key.LEFT)) {
xspeed *= decel;
}
if (!Key.isDown(Key.UP) && !Key.isDown(Key.DOWN)) {
yspeed *= decel;
}
_y += yspeed;
_x += xspeed;
}

The !key.isdowns need to be separated for the _x and _y. Otherwise if you hold down one button after going diagonal, you still go diagonal.....

I think this should work. Sorry if it doesn't.