// CS 2510 Spring 2011
// Lab 4: Follow.java
import world.*;
import image.*;
import tester.*;

// Represents a Cartesian point, X/Y come from the
//    super class, Posn.
class CartPt extends Posn{

    CartPt(int x, int y){
        super(x,y);
    }

    /* Template:
     *   Fields
     *     ... this.x ... -- int
     *     ... this.y ... -- int
     */
}

// Represents a simple World where the location moves toward
//    a target, which is replaced on mouse clicks.
class Follow extends World{
    CartPt loc;
    CartPt targ;
    
    Follow(CartPt loc, CartPt targ){
        this.loc = loc;
        this.targ = targ;
    }

    /**********************************
     * Need to design these methods...

         // Draw a dot, star, or something interesting at the location
         Scene onDraw(){ ... }
         // Move the location closer to the target
         //   Motion equations:
         //     lx' = lx + (tx - lx)/20
         //     ly' = ly + (ty - ly)/20
         //   Eventually (tx - lx)/20 will become 0, and motion "stops"
         Follow onTick(){ ... }
         // Reset the target location if "button-down"
         Follow onMouse(int x, int y, String me){ ... }
    */
}

// Examples
class FollowExamples{
    FollowExamples(){}

    Follow start = new Follow(new CartPt(0,0), new CartPt(200,200));
    World result = start.bigBang();

    // Tests for methods...
}