I'm trying to create faithful space acceleration, but with int values it gets ridiculous. I want to set the location of my object using doubles so that it doesn't zoom off forever.
GreenGoo wrote ...
2014/8/17
Using setLocation() or some variant with doubles?
Could you not just cast it to an int? setLocation((int)doubleA,(int)doubleB);
It doesn't give the accuracy I'm looking for. When I only increase the velocity by .01 or so per frame, the ship accelerates in lurches.
It doesn't give the accuracy I'm looking for. When I only increase the velocity by .01 or so per frame, the ship accelerates in lurches.
If something doesn't seem to be working and you want help with it then we need to see the code! ;)Are you using getX and getY to get and reset position?
double xVelocity = 0, yVelocity = 0;
double xAcceleration = 0, yAcceleration = 0;
double thrust = 0.01;
public Starship(int rotation)
{
setRotation(rotation);
}
public void act()
{
checkKeys();
moveStars();
checkHit();
weaponFireDelay++;
xVelocity = xVelocity + xAcceleration;
yVelocity = yVelocity + yAcceleration;
this.setLocation(getX() + (int) xVelocity, getY() + (int) yVelocity);
}Oh, and this:
if (Greenfoot.isKeyDown("up") || Greenfoot.isKeyDown("w"))
{
xAcceleration = ((90 - this.getRotation())/90) * thrust;
yAcceleration = (this.getRotation()/90) * thrust;
}Here:
You're using the integer positions from getX() and getY(), and casting the velocity values back to integer as well, which is what is causing the issue.
The easiest solution is to import and use the SmoothMover class (via the menu, Edit - Import class). If you don't want to use it you can always look at the code to see how it works.
this.setLocation(getX() + (int) xVelocity, getY() + (int) yVelocity);
It's in the edit menu. I presume you're running a recent - preferably the most recent - version of Greenfoot?
Two things concern me here.
(1) without the current x and y coordinates tracked as double values, you are losing any attempt to create the smoother, more accurate, movement wanted;
(2) I think you need to re-work how the acceleration values are to change in your last post.
EDIT: I guess I missed the last few minutes of posting trying to figure out how to explain what I thought.
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