package jme3tools.navigation;
import java.awt.Point;
import java.text.DecimalFormat;
/*
* To change this template, choose Tools | Templates
* and open the template in the editor.
*/
/**
* A representation of the actual map in terms of lat/long and x,y co-ordinates.
* The Map class contains various helper methods such as methods for determining
* the pixel positions for lat/long co-ordinates and vice versa.
*
* @author Cormac Gebruers
* @author Benjamin Jakobus
* @version 1.0
* @since 1.0
*/
public class MapModel2D {
/* The number of radians per degree */
private final static double RADIANS_PER_DEGREE = 57.2957;
/* The number of degrees per radian */
private final static double DEGREES_PER_RADIAN = 0.0174532925;
/* The map's width in longitude */
public final static int DEFAULT_MAP_WIDTH_LONGITUDE = 360;
/* The top right hand corner of the map */
private Position centre;
/* The x and y co-ordinates for the viewport's centre */
private int xCentre;
private int yCentre;
/* The width (in pixels) of the viewport holding the map */
private int viewportWidth;
/* The viewport height in pixels */
private int viewportHeight;
/* The number of minutes that one pixel represents */
private double minutesPerPixel;
/**
* Constructor
* @param viewportWidth the pixel width of the viewport (component) in which
* the map is displayed
* @since 1.0
*/
public MapModel2D(int viewportWidth) {
try {
this.centre = new Position(0, 0);
} catch (InvalidPositionException e) {
e.printStackTrace();
}
this.viewportWidth = viewportWidth;
// Calculate the number of minutes that one pixel represents along the longitude
calculateMinutesPerPixel(DEFAULT_MAP_WIDTH_LONGITUDE);
// Calculate the viewport height based on its width and the number of degrees (85)
// in our map
viewportHeight = ((int) NavCalculator.computeDMPClarkeSpheroid(0, 85) / (int) minutesPerPixel) * 2;
// viewportHeight = viewportWidth; // REMOVE!!!
// Determine the map's x,y centre
xCentre = viewportWidth / 2;
yCentre = viewportHeight / 2;
}
/**
* Returns the height of the viewport in pixels
* @return the height of the viewport in pixels
* @since 0.1
*/
public int getViewportPixelHeight() {
return viewportHeight;
}
/**
* Calculates the number of minutes per pixels using a given
* map width in longitude
* @param mapWidthInLongitude
* @since 1.0
*/
public void calculateMinutesPerPixel(double mapWidthInLongitude) {
minutesPerPixel = (mapWidthInLongitude * 60) / (double) viewportWidth;
}
/**
* Returns the width of the viewport in pixels
* @return the width of the viewport in pixels
* @since 0.1
*/
public int getViewportPixelWidth() {
return viewportWidth;
}
public void setViewportWidth(int viewportWidth) {
this.viewportWidth = viewportWidth;
}
public void setViewportHeight(int viewportHeight) {
this.viewportHeight = viewportHeight;
}
public void setCentre(Position centre) {
this.centre = centre;
}
/**
* Returns the number of minutes there are per pixel
* @return the number of minutes per pixel
* @since 1.0
*/
public double getMinutesPerPixel() {
return minutesPerPixel;
}
public double getMetersPerPixel() {
return 1853 * minutesPerPixel;
}
public void setMinutesPerPixel(double minutesPerPixel) {
this.minutesPerPixel = minutesPerPixel;
}
/**
* Converts a latitude/longitude position into a pixel co-ordinate
* @param position the position to convert
* @return {@code Point} a pixel co-ordinate
* @since 1.0
*/
public Point toPixel(Position position) {
// Get the distance between position and the centre for calculating
// the position's longitude translation
double distance = NavCalculator.computeLongDiff(centre.getLongitude(),
position.getLongitude());
// Use the distance from the centre to calculate the pixel x co-ordinate
double distanceInPixels = (distance / minutesPerPixel);
// Use the difference in meridional parts to calculate the pixel y co-ordinate
double dmp = NavCalculator.computeDMPClarkeSpheroid(centre.getLatitude(),
position.getLatitude());
int x = 0;
int y = 0;
if (centre.getLatitude() == position.getLatitude()) {
y = yCentre;
}
if (centre.getLongitude() == position.getLongitude()) {
x = xCentre;
}
// Distinguish between northern and southern hemisphere for latitude calculations
if (centre.getLatitude() > 0 && position.getLatitude() > centre.getLatitude()) {
// Centre is north. Position is north of centre
y = yCentre + (int) ((dmp) / minutesPerPixel);
} else if (centre.getLatitude() > 0 && position.getLatitude() < centre.getLatitude()) {
// Centre is north. Position is south of centre
y = yCentre - (int) ((dmp) / minutesPerPixel);
} else if (centre.getLatitude() < 0 && position.getLatitude() > centre.getLatitude()) {
// Centre is south. Position is north of centre
y = yCentre + (int) ((dmp) / minutesPerPixel);
} else if (centre.getLatitude() < 0 && position.getLatitude() < centre.getLatitude()) {
// Centre is south. Position is south of centre
y = yCentre - (int) ((dmp) / minutesPerPixel);
} else if (centre.getLatitude() == 0 && position.getLatitude() > centre.getLatitude()) {
// Centre is at the equator. Position is north of the equator
y = yCentre + (int) ((dmp) / minutesPerPixel);
} else if (centre.getLatitude() == 0 && position.getLatitude() < centre.getLatitude()) {
// Centre is at the equator. Position is south of the equator
y = yCentre - (int) ((dmp) / minutesPerPixel);
}
// Distinguish between western and eastern hemisphere for longitude calculations
if (centre.getLongitude() < 0 && position.getLongitude() < centre.getLongitude()) {
// Centre is west. Position is west of centre
x = xCentre - (int) distanceInPixels;
} else if (centre.getLongitude() < 0 && position.getLongitude() > centre.getLongitude()) {
// Centre is west. Position is south of centre
x = xCentre + (int) distanceInPixels;
} else if (centre.getLongitude() > 0 && position.getLongitude() < centre.getLongitude()) {
// Centre is east. Position is west of centre
x = xCentre - (int) distanceInPixels;
} else if (centre.getLongitude() > 0 && position.getLongitude() > centre.getLongitude()) {
// Centre is east. Position is east of centre
x = xCentre + (int) distanceInPixels;
} else if (centre.getLongitude() == 0 && position.getLongitude() > centre.getLongitude()) {
// Centre is at the equator. Position is east of centre
x = xCentre + (int) distanceInPixels;
} else if (centre.getLongitude() == 0 && position.getLongitude() < centre.getLongitude()) {
// Centre is at the equator. Position is west of centre
x = xCentre - (int) distanceInPixels;
}
// Distinguish between northern and souterhn hemisphere for longitude calculations
return new Point(x, y);
}
/**
* Converts a pixel position into a mercator position
* @param p {@link Point} object that you wish to convert into
* longitude / latiude
* @return the converted {@code Position} object
* @since 1.0
*/
public Position toPosition(Point p) {
double lat, lon;
Position pos = null;
try {
Point pixelCentre = toPixel(new Position(0, 0));
// Get the distance between position and the centre
double xDistance = distance(xCentre, p.getX());
double yDistance = distance(pixelCentre.getY(), p.getY());
double lonDistanceInDegrees = (xDistance * minutesPerPixel) / 60;
double mp = (yDistance * minutesPerPixel);
// If we are zoomed in past a certain point, then use linear search.
// Otherwise use binary search
if (getMinutesPerPixel() < 0.05) {
lat = findLat(mp, getCentre().getLatitude());
if (lat == -1000) {
System.out.println("lat: " + lat);
}
} else {
lat = findLat(mp, 0.0, 85.0);
}
lon = (p.getX() < xCentre ? centre.getLongitude() - lonDistanceInDegrees
: centre.getLongitude() + lonDistanceInDegrees);
if (p.getY() > pixelCentre.getY()) {
lat = -1 * lat;
}
if (lat == -1000 || lon == -1000) {
return pos;
}
pos = new Position(lat, lon);
} catch (InvalidPositionException ipe) {
ipe.printStackTrace();
}
return pos;
}
/**
* Calculates distance between two points on the map in pixels
* @param a
* @param b
* @return distance the distance between a and b in pixels
* @since 1.0
*/
private double distance(double a, double b) {
return Math.abs(a - b);
}
/**
* Defines the centre of the map in pixels
* @param p <code>Point</code> object denoting the map's new centre
* @since 1.0
*/
public void setCentre(Point p) {
try {
Position newCentre = toPosition(p);
if (newCentre != null) {
centre = newCentre;
}
} catch (Exception e) {
e.printStackTrace();
}
}
/**
* Sets the map's xCentre
* @param xCentre
* @since 1.0
*/
public void setXCentre(int xCentre) {
this.xCentre = xCentre;
}
/**
* Sets the map's yCentre
* @param yCentre
* @since 1.0
*/
public void setYCentre(int yCentre) {
this.yCentre = yCentre;
}
/**
* Returns the pixel (x,y) centre of the map
* @return {@link Point) object marking the map's (x,y) centre
* @since 1.0
*/
public Point getPixelCentre() {
return new Point(xCentre, yCentre);
}
/**
* Returns the {@code Position} centre of the map
* @return {@code Position} object marking the map's (lat, long) centre
* @since 1.0
*/
public Position getCentre() {
return centre;
}
/**
* Uses binary search to find the latitude of a given MP.
*
* @param mp maridian part
* @param low
* @param high
* @return the latitude of the MP value
* @since 1.0
*/
private double findLat(double mp, double low, double high) {
DecimalFormat form = new DecimalFormat("#.####");
mp = Math.round(mp);
double midLat = (low + high) / 2.0;
// ctr is used to make sure that with some
// numbers which can't be represented exactly don't inifitely repeat
double guessMP = NavCalculator.computeDMPClarkeSpheroid(0, (float) midLat);
while (low <= high) {
if (guessMP == mp) {
return midLat;
} else {
if (guessMP > mp) {
high = midLat - 0.0001;
} else {
low = midLat + 0.0001;
}
}
midLat = Double.valueOf(form.format(((low + high) / 2.0)));
guessMP = NavCalculator.computeDMPClarkeSpheroid(0, (float) midLat);
guessMP = Math.round(guessMP);
}
return -1000;
}
/**
* Uses linear search to find the latitude of a given MP
* @param mp the meridian part for which to find the latitude
* @param previousLat the previous latitude. Used as a upper / lower bound
* @return the latitude of the MP value
*/
private double findLat(double mp, double previousLat) {
DecimalFormat form = new DecimalFormat("#.#####");
mp = Double.parseDouble(form.format(mp));
double guessMP;
for (double lat = previousLat - 0.25; lat < previousLat + 1; lat += 0.00001) {
guessMP = NavCalculator.computeDMPClarkeSpheroid(0, lat);
guessMP = Double.parseDouble(form.format(guessMP));
if (guessMP == mp || Math.abs(guessMP - mp) < 0.001) {
return lat;
}
}
return -1000;
}
}