I'm making a game, and the character is going to be permanently in the center of the world. How can I make it that the actor turns in the direction of the mouse?
thefutureisnow wrote ...
2012/5/21
Mouse Direction
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You should check out the Actor API, there might be a method that could help you out
Look around Greenfoot scenarios too, that's a very useful kind of thing to know, lots of people have their own attempts at it! And yeah, check out the API, there's lots of stuff in there that can be used for lots of different tasks.
Never mind, I just found out about the java.lang.Math library, there I can use the inverse tangent. Thanks!
Lol well I was referencing the built-in command turnTowards(int x,int y) that does everything for you without needing any mathematics, but doing it by yourself is good too. Plus, knowing the math behind the routines you use is always a good thing!
@thefutureisnow
java.lang.Math contains some VERY helpful stuff for trying to do more abstract things in Java. You can accomplish a lot since you make your own methods from the ground up.
@Builderboy2005
Where is the documentation for that command?
While in Greenfoot, right click the Actor icon, and click Open Documentation
Sorry to say this, but if I wanted to state the X and Y values of the mouse, could I write it as following?
Because it seems to be giving me an error in the compiling that says as following:
"cannot find symbol - variable getX"
And it refers to the getX in the previous code. Am I doing something wrong here?
public void act()
{
// These are declaring the X and Y variables of the mouse location as mX and mY
int mX = MouseInfo.getX;
int mY = MouseInfo.getY;
}
No, MouseInfo is a class, not an object. Methods are only avaliable to a class if they are static, and getX() and getY() are not static. In order to use getX() and getY(), you will need an object that is of the class MouseInfo. One way to get such an object is to use the Greenfoot.getMouseInfo() method. You might notice that Greenfoot is a class, and getMouseInfo() is a static method. This method returns a MouseInfo object, which we can store and then use to get the mouse information.
MouseInfo mouse; //Going to be our MouseInfo object
int mX,mY; //Going to be our variables keeping track of the mouse position
public void act(){
mouse = Greenfoot.getMouseInfo(); //Gets the mouse info
if(mouse!=null){ //The mouse info can sometimes be Null, so check for that
mX = mouse.getX(); //If the mouse is not Null, update the position variables
mY = mouse.getY();
}
}oops!!!, dang, that was a stupid mistake!
So do I need to create a class called "mouse" or will it automatically use the mouse?
Never mind, I've got it all now. Thanks everyone!!!
I am unsure what you mean. I think part of the problem is that you might not know the specific differences between Classes and Objects. In the code I posted, 'MouseInfo' is a class, while 'mouse' is an object.
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