package lecture17;

import com.jme3.app.SimpleApplication;
import com.jme3.collision.CollisionResults;
import com.jme3.light.DirectionalLight;
import com.jme3.material.Material;
import com.jme3.math.ColorRGBA;
import com.jme3.math.FastMath;
import com.jme3.math.Quaternion;
import com.jme3.math.Vector3f;
import com.jme3.scene.Geometry;
import com.jme3.scene.Node;
import com.jme3.scene.shape.Box;
import com.jme3.scene.shape.Sphere;

public class Example01 extends SimpleApplication {

    Geometry floor1, floor2, floor3;
    Node boxes;
    Geometry ball;
    Vector3f floor2Normal = new Vector3f(-1f, 2f, 0).normalize();
    Vector3f floor3Normal = new Vector3f(1f, 2f, 0).normalize();
    float mass = 1f;
    float viscosity = 0.1f;
    float energyLoss = 0.95f;
    Vector3f gravity = new Vector3f(0, -9.8f, 0);
    Vector3f force = new Vector3f(0, 0, 0);
    Vector3f velocity = new Vector3f(3, 0, 0);
    Vector3f acceleration = new Vector3f(0, 0, 0);

    protected Geometry boxFromNormal(String name, Vector3f n) {
        Box b = new Box(10f, 1f, 10f);
        Geometry bg = new Geometry(name, b);
        Material mat = new Material(assetManager, "Common/MatDefs/Light/Lighting.j3md");
        mat.setBoolean("UseMaterialColors", true);
        mat.setColor("Ambient", ColorRGBA.Gray);
        mat.setColor("Diffuse", ColorRGBA.Gray);
        bg.setMaterial(mat);

        Quaternion q = new Quaternion();
        q.fromAxes(n.cross(Vector3f.UNIT_Z), n, Vector3f.UNIT_Z);
        bg.setLocalRotation(q);
        return bg;
    }

    public void simpleInitApp() {
        DirectionalLight sun = new DirectionalLight();
        sun.setDirection(new Vector3f(1, -5, -7));
        sun.setColor(ColorRGBA.White);
        rootNode.addLight(sun);

        boxes = new Node("boxes");

        floor1 = boxFromNormal("floor1", Vector3f.UNIT_Y);
        boxes.attachChild(floor1);


        floor2 = boxFromNormal("floor2", floor2Normal);
        floor2.setLocalTranslation(18.5f, 4.5f, 0);
        boxes.attachChild(floor2);



        floor3 = boxFromNormal("floor3", floor3Normal);
        floor3.setLocalTranslation(-18.5f, 4.5f, 0);
        boxes.attachChild(floor3);

        rootNode.attachChild(boxes);


        Sphere s = new Sphere(60, 60, 1.5f);
        ball = new Geometry("Sphere", s);

        Material mat = new Material(assetManager, "Common/MatDefs/Light/Lighting.j3md");
        mat.setBoolean("UseMaterialColors", true);
        mat.setColor("Ambient", ColorRGBA.Red);
        mat.setColor("Diffuse", ColorRGBA.Red);


        ball.setMaterial(mat);
        ball.move(5, 20, 0);
        rootNode.attachChild(ball);

        cam.setLocation(new Vector3f(0, 10, 100));
        cam.lookAt(Vector3f.ZERO, Vector3f.UNIT_Y);

    }

    @Override
    public void simpleUpdate(float tpf) {
        acceleration = gravity.add(force.divide(mass));
        velocity = velocity.add(acceleration.mult(tpf));
        force = velocity.mult(-viscosity);

        ball.move(velocity.mult(tpf));

        CollisionResults results = new CollisionResults();
        boxes.collideWith(ball.getWorldBound(), results);
        if (results.size() > 0) {
            String closestGeom = results.getClosestCollision().getGeometry().getName();
            if (closestGeom.equals("floor1")) {
                velocity.setY(FastMath.abs(energyLoss * velocity.getY()));

            } else if (closestGeom.equals("floor2")) {
                float projVal = velocity.dot(floor2Normal);
                Vector3f projection = floor2Normal.mult(projVal);
                Vector3f parall = velocity.subtract(projection);
                velocity = parall.add(floor2Normal.mult(energyLoss * FastMath.abs(projVal)));
            } else if (closestGeom.equals("floor3")) {
                float projVal = velocity.dot(floor3Normal);
                Vector3f projection = floor3Normal.mult(projVal);
                Vector3f parall = velocity.subtract(projection);
                velocity = parall.add(floor3Normal.mult(energyLoss * FastMath.abs(projVal)));
            }
        }
    }

    public static void main(String[] args) {
        Example01 app = new Example01();
        app.start();
    }
}