// (C) 2001 SyGem Software

import java.awt.*;
import java.applet.*;

import com.sygem.jazz3d3.*;
import com.sygem.jazz3d3.primitive.Sphere3d;
import com.sygem.jazz3d3.primitive.Line3d;
import com.sygem.jazz3d3.primitive.Landscape3d;

public class landscapeFollow extends Applet implements Runnable {
        Thread m_ce;
        World myWorld;
        int light1;
        int sphereID,landID,rayID;

        final static int landscapeSize = 6;

        //Construct the applet
        public landscapeFollow() {
        }

        //Initialize the applet
        public void init() {

                myWorld = new World(this);
                setLayout(new BorderLayout());
                add("Center",myWorld);

                RenderSolid tex = new RenderSolid();
                tex.setDrawingMode(Render.GOURAUD);

                Sphere3d sp1 = new Sphere3d(10,10,0,1,8);
                sp1.scaleObject(0.2,0.2,0.2);
                Line3d collisionRay = new Line3d(0,1,8,0,0.8,8);
                rayID = sp1.addChild(collisionRay,0,0,0);

		sp1.setColour(255,0,0);
                sp1.setRenderer(tex);
                sphereID = myWorld.addObject(sp1);

                Landscape3d sp2 = new Landscape3d(20012001,0,0,8);
                sp2.fractalize();
                sp2.fractalize();
                sp2.fractalize();
                sp2.fractalize();
                sp2.smooth();
                sp2.generateShape();

                sp2.scaleObject(landscapeSize,1,landscapeSize);
                sp2.setRenderer(tex);
                landID = myWorld.addObject(sp2);

                Light l1 = new Light(0,0,1);
                myWorld.addLight(l1);

                myWorld.getCamera().translateWorld(0,6,-2);
                myWorld.getCamera().pointAt(myWorld.getObject(landID));
        }

        //Start the applet
        public void start() {
                if (m_ce == null) {
                        m_ce = new Thread(this);
                        m_ce.start();
                }
        }

        //Stop the applet
        public void stop() {
                if (m_ce != null) {
                        m_ce.stop();
                        m_ce = null;
                }
        }

        //Destroy the applet
        public void destroy() {
        }

        public void run() {

                double x,y,z;
                x = 0;
                y = 2;
                z = 8;

                double xd,yd,zd;
                xd = 0.02;
                zd = -0.03;

		double xmax = (landscapeSize/2)-0.1;
		double xmin = -xmax;
		double zmax = 8 + xmax;
		double zmin = 8 + xmin;

                myWorld.prep();

                while (true) {

			Object3d sphere = myWorld.getParentObject(sphereID);
			Object3d ray = myWorld.getObject(rayID);
			double curX = sphere.getCenter().getX();
			double curY = sphere.getCenter().getY();
			double curZ = sphere.getCenter().getZ();

			if ((curX >= xmax) || (curX <= xmin)) xd = -xd;
			if ((curZ >= zmax) || (curZ <= zmin)) zd = -zd;

			sphere.translateWorld(xd,0,zd);

			// And now we can do the collision detection...
			Vertex start = ray.getWorldVertex(0);
			Vertex end = ray.getWorldVertex(1);

			if (myWorld.pick(start,end,landID)) {
				double dist = HitPoint.getT() * 0.2; // length of the ray...
				sphere.translateWorld(0,0.1-dist,0);
			} else {
				sphere.translateWorld(0,-0.01,0);
			}

	                myWorld.getCamera().pointAt(sphere);

	                myWorld.prepareCanvas();
	                myWorld.generateImage();
			myWorld.drawImage();
			paint(myWorld.getCanvas(), curY);
			myWorld.finishCanvas();
                }
        }

        void paint(Graphics g, double curY) {
		g.setColor(Color.blue);
		String disp = "Sphere height: "+curY;
		int length = (disp.length() > 21) ? 21 : 1;
		disp = disp.substring(0,length);
		g.drawString(disp,20,40);
	}
}