Image following line

Hi, I have a question about Images. Is there a way to make an image trace/follow a line? If so, can you please explain on how to do it? I want know how to make the image trace a line from point A to point B.

Reading parts of this might help you http://www.java-gaming.org/index.php?topic=25402.0. I have yet to add this feature myself so that is all I can provide, good luck!

Or you meant follow complex line like tower defense, with all of that curves?

direction of line: D=|B-A|
parameterize: F(t) =Dt+A
where ‘t’ is on [0,1]

brain-dump untested pseudocode:


public void setup(Vect2f a, Vect2f b)
{
  // store initial point 
  x0 = a.x;
  y1 = a.y;

  // compute and store direction of line 
  dx = b.x-x0;
  dy = b.y-y0;

  // compute and store length of the line segment
  len = (float)(Math.sqrt(dx*dx+dy*dy));

  // normalize direction
  float t = 1.f/len;
  dx *= t;
  dy *= t;
}

/** Set 'r' to the blah, blah and returns 'r'. */
public Vect2f position(Vect2f r, float t)
{
  r.x = x0 + t*dx;
  r.y = y0 + t*dy;
  
  return r;
}

I meant more of, just following a straight line.

Just set the y to a number and never change the y, but every update add to the x of the image.

If you want it to go up add to the y instead of the x.
Sorry if any spelling mistakes I’m on my phone

Never change X -> vertical move.
Never change Y -> horizontal move.

All lines are straight. :slight_smile:

Yeah I think he means any line not just vertical/horiz lines.

Yea, that’s what I was asking for. I understand how to make Vert and Horiz lines, just wondering how to make an image follow a line that has a certain amount of degrees to it.