public static bool CheckPosition(Game.GameActivity gameActivity, int playerPosition)
{
// Get the angle between the point and the
// first and last vertices.
double total_angle = GetAngle(gameActivity.gamePlayArea.vertices.Last.Value.Latitude, gameActivity.gamePlayArea.vertices.Last.Value.Longitude, gameActivity.playerArray[playerPosition].currentPosition.Latitude, gameActivity.playerArray[playerPosition].currentPosition.Longitude, gameActivity.gamePlayArea.vertices.First.Value.Latitude, gameActivity.gamePlayArea.vertices.First.Value.Longitude);
// Add the angles from the point
// to each other pair of vertices.
gameActivity.gamePlayArea.verticesNode = gameActivity.gamePlayArea.vertices.First.Next;
while (true)
{
total_angle += GetAngle(gameActivity.gamePlayArea.verticesNode.Previous.Value.Latitude, gameActivity.gamePlayArea.verticesNode.Previous.Value.Longitude, gameActivity.playerArray[playerPosition].currentPosition.Latitude, gameActivity.playerArray[playerPosition].currentPosition.Longitude, gameActivity.gamePlayArea.verticesNode.Value.Latitude, gameActivity.gamePlayArea.verticesNode.Value.Longitude);
if (gameActivity.gamePlayArea.verticesNode.Next != null)
{
gameActivity.gamePlayArea.verticesNode = gameActivity.gamePlayArea.verticesNode.Next;
}
else
{
break;
}
}
// The total angle should be 2 * PI or -2 * PI if
// the point is in the polygon and close to zero
// if the point is outside the polygon.
return(Math.Abs(total_angle) > 0.000001);
}
public static LatLng FindRandomPoint(Game.GameActivity gameActivity)
{
Random random = new Random();
List <Game.Triangle> triangles = Triangulate(gameActivity.gamePlayArea.vertices);
Game.Triangle triangle = triangles[random.Next(0, triangles.Count)];
LatLng v1 = new LatLng(triangle.vertices[1].Latitude - triangle.vertices[0].Latitude, triangle.vertices[1].Longitude - triangle.vertices[0].Longitude);
LatLng v2 = new LatLng(triangle.vertices[2].Latitude - triangle.vertices[0].Latitude, triangle.vertices[2].Longitude - triangle.vertices[0].Longitude);
double a1 = random.NextDouble();
double a2 = random.NextDouble();
v1.Latitude = v1.Latitude * a1;
v1.Longitude = v1.Longitude * a1;
v2.Latitude = v2.Latitude * a2;
v2.Longitude = v2.Longitude * a2;
LatLng x = new LatLng(v1.Latitude + v2.Latitude, v1.Longitude + v2.Longitude);
x.Latitude += triangle.vertices[0].Latitude;
x.Longitude += triangle.vertices[0].Longitude;
return(x);
}
// Find the polygon's centroid.
public static LatLng FindCentroid(Game.GameActivity gameActivity)
{
// Add the first point to the end.
int num_points = gameActivity.gamePlayArea.vertices.Count;
LatLng[] pts = new LatLng[num_points + 1];
gameActivity.gamePlayArea.vertices.CopyTo(pts, 0);
pts[num_points] = gameActivity.gamePlayArea.vertices.First.Value;
// Find the centroid.
double x = 0;
double y = 0;
double second_factor;
for (int i = 0; i < num_points; i++)
{
second_factor = pts[i].Latitude * pts[i + 1].Longitude - pts[i + 1].Latitude * pts[i].Longitude;
x += (pts[i].Latitude + pts[i + 1].Latitude) * second_factor;
y += (pts[i].Longitude + pts[i + 1].Longitude) * second_factor;
}
// Divide by 6 times the polygon's area.
double polygon_area = PolygonArea(gameActivity.gamePlayArea.vertices);
x /= (6 * polygon_area);
y /= (6 * polygon_area);
// If the values are negative, the polygon is
// oriented counterclockwise so reverse the signs.
if (x < 0)
{
x = -x;
y = -y;
}
return(new LatLng(x, y));
}
public static LatLng ExtendLineSegment(Game.GameActivity gameActivity, LatLng firstPoint, LatLng secondPoint)
{
double lenAB = Math.Sqrt(Math.Pow(secondPoint.Latitude - firstPoint.Latitude, 2.0) + Math.Pow(secondPoint.Longitude - firstPoint.Longitude, 2.0));
return(new LatLng(firstPoint.Latitude + (firstPoint.Latitude - secondPoint.Latitude) / lenAB * (ShortestLineSegment(gameActivity.gamePlayArea.vertices) / 1000), firstPoint.Longitude + (firstPoint.Longitude - secondPoint.Longitude) / lenAB * (ShortestLineSegment(gameActivity.gamePlayArea.vertices) / 1000)));
}
