I want to create a line that is created by the movement of an Actor, like, a "pen down" tool, That draws a line in the path of the moving actor. How can I do this‽
Razzo wrote ...
2012/3/14
Lines
Well, there are two different ways to do this. One way is to draw directly onto the World as a canvas, and the other one is to add Actors that have a particular image but don't do much. To be honest, I've never drawn onto the screen before, so I'll let someone who has answer that part. But, I can explain how to trail Actors to create images. Try something like this:
The Ink class would then look something like this:
You probably want to have the "whateverImageYouWant" just be a simple circle image, but you can try experimenting with other images.
Trailing Actors is more versatile but slows your program down more.
I hope this helps.
public void act()
{
//after your normal code....
//add this call to addInk()
addInk();
}
//then you define addInk()
public void addInk()
{
if(hasMoved()) //check if has moved to not add Ink twice in same place.
getWorld().addObject(new Ink(), getX(), getY());
}
//hasMoved you'd define here...
public void hasMoved()
{
boolean moved = (lastX != getX() && lastY != getY());
//you'd have to define lastX and lastY as "int"s at the top of your class
lastX = getX();
lastY = getY();
return moved;
}
public class Ink extends Actor
{
private int frame; //to add in animation.
public Ink()
{
setImage(whateverImageYouWant);
frame = 0;
}
public void act()
{
//if you don't care for the animation, just don't have anything in the act method.
blot();
}
public void blot()
{
//this will just make the image fill out over time, as opposed to staying constant.
if(frame < 5) {
getImage().scale(frame*4 + 1, frame*4 + 1);
frame++;
}
}
}
Okay thanks., I have the line drawn fine now, But how can I detect that it is there, it is too "thin" to detect using getColorat (They are a distict color so this method should work okay) Because im using move(3), and they are 1 pixel wide, I could speed up the simulation time, but how could I do it without doing that?
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