Hi I have a space fighter game where the protector would shoot through asteroids to defeat the enemy ships. My problem is I want to create a floating/vibrating effect for the asteroid movement where they move back and forth just by for example 5px.
DavidTshitenda wrote ...
2018/9/5
Back and forth movement
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private int xMiddle;
private int direction = Greenfoot.getRandomNumber(2)*2-1; //+1 or -1
private int speed = 1; //only needed if something else than 1
public void addedToWorld(World w)
{
xMiddle = getX();
}
public void act()
{
setLocation(getX()+direction*speed);
if (getX()<xMiddle-4 || getX()>xMiddle+4) direction *= -1; //change direction of movement
}Sorry for omitting code as I didn’t have any. The setLocation doesn’t have a y value and I am getting a error.
The asteroid are all moving in different directions. If I was clear earlier I am sorry so basically I want all the asteroids to move in the same direction, so it’s 5 pixels forward and the 5 pixels back and this action should be repeated until the game is complete.
So in essence I want the actor to move 5 pixels in the y axis then back to its original position using maybe a loop.
The above code separates the asteroids
Yes, I forgot to include to y-value.
Yes, you were unclear. Maybe this is better?
Not sure why I wanted to save the x-value.
private static int direction = Greenfoot.getRandomNumber(2)*2-1;
private int speed = 1;
public void act()
{
setLocation(getX()+direction*speed, getY());
}
public static void changeDirection()
{
direction *= -1;
}//in world
private int directionTimer = 5;
public void act()
{
if (--directionTimer==0)
{
Asteroid.changeDirection();
directionTimer=10;
}
}The above code still separates my asteroids, if this makes sense all I want to do is move it forward (move(5)) and then back (move(-5)) but this movement is looped. If think about it its the same as saying if it’s at the top of the world move to the bottom of the world then back with this whole movement looped. But what I want to do is restrict it so that it doesn’t touch the top of the world it only goes a few pixels forward then back then forward again with this whole movement being looped. I will screenshot what I am talking about next sorry for all that
They should move in sync with the code I posted. Could you show how you tried to implement it? And show what exactly happens?
I have uploaded my scenario to my profile you can check it out
The scenario I uploaded does not do what I am asking it does the bit of code you gave me but I will upload the scenario with the action I am trying to perform in a bit.
You forgot to add the 'static' to the direction-variable.
You could do something like this:
private int dirY = 1;
private int distY = 0;
public void act()
{
setLocation(getX(), getY()+dirY);
distY = (distY+1)%5;
if (distY == 0) dirY = -dirY;
}Super_hippo if I do that static thing then I get a “non static variable cannot be referenced from a static context” error.
Thanks danpost it works
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