/*******************************************************************************
 * Copyright 2011 See AUTHORS file.
 * 
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * 
 *   http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 ******************************************************************************/

package com.badlogic.gdx.tests.utils;

import com.badlogic.gdx.Gdx;
import com.badlogic.gdx.InputAdapter;
import com.badlogic.gdx.graphics.PerspectiveCamera;
import com.badlogic.gdx.math.Matrix4;
import com.badlogic.gdx.math.Plane;
import com.badlogic.gdx.math.Vector2;
import com.badlogic.gdx.math.Vector3;

public class PerspectiveCamController extends InputAdapter {
	private final static Vector3 tmpV = new Vector3();
	
	public PerspectiveCamera cam;
	
	enum TransformMode {
		Rotate, Translate, Zoom, None
	}

	Vector3 lookAt = new Vector3();
	TransformMode mode = TransformMode.Translate;
	boolean translated = false;

	public PerspectiveCamController (PerspectiveCamera cam) {
		this.cam = cam;
	}

	@Override
	public boolean touchDown (int x, int y, int pointer, int button) {
		mode = TransformMode.Rotate;
		last.set(x, y);
		tCurr.set(x, y);
		return true;
	}

	@Override
	public boolean touchUp (int x, int y, int pointer, int button) {
		mode = TransformMode.None;
		return true;
	}

	Vector2 tCurr = new Vector2();
	Vector2 last = new Vector2();
	Vector2 delta = new Vector2();
	Vector2 currWindow = new Vector2();
	Vector2 lastWindow = new Vector2();
	Vector3 curr3 = new Vector3();
	Vector3 delta3 = new Vector3();
	Plane lookAtPlane = new Plane(new Vector3(0, 1, 0), 0);
	Matrix4 rotMatrix = new Matrix4();
	Vector3 xAxis = new Vector3(1, 0, 0);
	Vector3 yAxis = new Vector3(0, 1, 0);
	Vector3 point = new Vector3();

	@Override
	public boolean touchDragged (int x, int y, int pointer) {
		if (pointer != 0) return false;
		delta.set(x, y).sub(last);

		if (mode == TransformMode.Rotate) {
			point.set(cam.position).sub(lookAt);

			if (tmpV.set(point).nor().dot(yAxis) < 0.9999f) {
				xAxis.set(cam.direction).crs(yAxis).nor();
				rotMatrix.setToRotation(xAxis, delta.y / 5);
				point.mul(rotMatrix);
			}

			rotMatrix.setToRotation(yAxis, -delta.x / 5);
			point.mul(rotMatrix);

			cam.position.set(point.add(lookAt));
			cam.lookAt(lookAt.x, lookAt.y, lookAt.z);
		}
		if (mode == TransformMode.Zoom) {
			cam.fieldOfView -= -delta.y / 10;
		}
		if (mode == TransformMode.Translate) {
			tCurr.set(x, y);
			translated = true;
		}

		cam.update();
		last.set(x, y);
		return true;
	}

	@Override
	public boolean scrolled (int amount) {
		cam.fieldOfView -= -amount * Gdx.graphics.getDeltaTime() * 100;
		cam.update();
		return true;
	}

}