Thread: A question about an object detecting another.

Hello everyone!
In my absence from this site I have been experimenting with swing and graphics. My problem is this, I have two cows on the screen that move along a grid(each square is 16x16) and I have them print an arrow in the direction of the other cow AS LONG AS IT IS 3 OR LESS SQUARES away. When they print their arrows it's usually facing the opposite direction of the cow they are detecting. The object that is the cow is Testai. If you need more of my code posted in order to help I will! (After all it is just cows moving)
This code is the Testai "detection" code

for(Testai c : testArray)
		{
			//looking right
			if ((int)(c.x - super.x)/16 <= 3 && (c.x - super.x)/16 > 0)
			{
				if ((int)c.y - super.y == 0)
				{
					//shoots right
					PrintScreen.right = true;
				}
				else if((int)c.y - super.y > 0)
				{
					//shoots south east
					PrintScreen.southeast = true;
				}
				else if((int)c.y - super.y < 0)
				{
					//shoots north east
					PrintScreen.northeast = true;
				}
			}
			//looking left
			else if ((int)(c.x - super.x)/16 >= -3 && (c.x - super.x)/16 < 0)
			{
				if ((int)c.y - super.y == 0)
				{
					//shoots left
					PrintScreen.left = true;
				}
				else if((int)c.y - super.y > 0)
				{
					//shoots south west
					PrintScreen.southwest = true;
				}
				else if((int)c.y - super.y < 0)
				{
					//shoots north west
					PrintScreen.northwest = true;
				}
			}
			else if ((int)(c.x - super.x)/16 == 0)
			{
				if ((int)c.y - super.y < 0)
				{
					//shoots down
					PrintScreen.down = true;
				}
				else if ((int)c.y - super.y > 0)
				{
					//shoots up
					PrintScreen.up = true;
				}
			}
		}

This is where the arrows are printed.

for(int s = 0; s < testArray.size(); s++)
		{
			t = testArray.get(s);
			if(up)
			{
				arrow = new ImageIcon("up.png");
				arrowprint = arrow.getImage();
				g2.drawImage(arrowprint,(int)t.getX(),(int)t.getY()-16,this);
				up = false;
			}
			else if(down)
			{
				arrow = new ImageIcon("down.png");
				arrowprint = arrow.getImage();
				g2.drawImage(arrowprint,(int)t.getX(),(int)t.getY()+16,this);
				down = false;
			}
			else if(left)
			{
				arrow = new ImageIcon("left.png");
				arrowprint = arrow.getImage();
				g2.drawImage(arrowprint,(int)t.getX()-16,(int)t.getY(),this);
				left = false;
			}
			else if (right)
			{
				arrow = new ImageIcon("right.png");
				arrowprint = arrow.getImage();
				g2.drawImage(arrowprint,(int)t.getX()+16,(int)t.getY(),this);
				right = false;
			}
			else if(southwest)
			{
				arrow = new ImageIcon("sw.png");
				arrowprint = arrow.getImage();
				g2.drawImage(arrowprint,(int)t.getX()-16,(int)t.getY()+16,this);
				southwest = false;
			}
			else if(southeast)
			{
				arrow = new ImageIcon("se.png");
				arrowprint = arrow.getImage();
				g2.drawImage(arrowprint,(int)t.getX()+16,(int)t.getY()+16,this);
				southeast = false;
			}
			else if(northwest)
			{
				arrow = new ImageIcon("nw.png");
				arrowprint = arrow.getImage();
				g2.drawImage(arrowprint,(int)t.getX()-16,(int)t.getY()-16,this);
				northwest = false;
			}
			else if(northeast)
			{
				arrow = new ImageIcon("ne.png");
				arrowprint = arrow.getImage();
				g2.drawImage(arrowprint,(int)t.getX()+16,(int)t.getY()-16,this);
				northeast = false;
			}
			g2.drawImage(cow,(int)t.getX(),(int)t.getY(),this);
		}

Thanks to all who reply! I don't know if I put this in the right section though.
lil_misfit

What is the object? If AI is involved, what is supposed to possess the intelligence? Is each cow supposed to be independently intelligent, somehow aware of other cows when they are within a 3-square radius, or is there some other overseeing intelligence?

The easy solution is to use a coordinate system. Get each graphic's position in the grid, do the math to determine how far apart they are and in which direction, and if they are in sensory distance, show the arrows. I'm not sure if that solution meets your objective.

The object is my object called Testai and each cow is supposed to have its own intelligence (so far that is moving around and detecting). Would you like me to post the Testai code? I have it so it prints the arrows but the arrows are pointing in the opposite direction. I don't know if it is a printing problem or something wrong with my detect code. I've "traced" my code and it seems fine but the arrows still print in the opposite direction! That is my problem!
Thank you for responding though!
lil_misfit

The "arrows usually facing in the wrong direction," and the arrows ALWAYS pointing in the opposite direction direction are two very different outcomes. If the program ALWAYS calculates the opposite direction, then it's !alwaysRight. It's just a sign (or logic) error. Find the sign error, if you'd like, or just accept the result you're getting and change the sign.