public void TestDistance() {
Vector p1 = new Vector(0, 0);
Vector p2 = new Vector(3, 4);
Assert.IsTrue(p1.Distance(p2) == 5, "Distance calc 1 failed");
Assert.IsTrue(p1.Distance2(p2) == 25, "Distance2 calc 1 failed");
Assert.IsTrue(new Vector(1, 1).Closest(p1, new Vector(2, 0)) == new Vector(1, 0), "Closest point 1 failed.");
//Same test for point that is already on the line
Assert.IsTrue(new Vector(1, 0).Closest(p1, new Vector(2, 0)) == new Vector(1, 0), "Closest point 3 failed.");
}
public void TestEquality() {
Vector p1 = new Vector(0, 0);
Vector p2 = new Vector(1, 0);
Vector p3 = new Vector(0, 0);
Assert.IsTrue(p1 == p3, "Equality test to same coordinates failed.");
Assert.IsFalse(p1 == p2, "Equality test for 2 different points failed");
Assert.IsFalse(p1 != p3, "Inequality test to same point failed.");
Assert.IsTrue(p1 != p2, "Inequality test for 2 different points failed");
}
public void TestMath() {
Vector p1 = new Vector(0, 0);
Vector p2 = new Vector(1, -1);
Assert.IsTrue(p1 + p2 == new Vector(1, -1), "Vector addition 1 failed.");
Assert.IsTrue(p1 - p2 == new Vector(-1, 1), "Vector subtraction 1 failed.");
Assert.IsTrue(p2 * 3 == new Vector(3, -3), "Vector multiplication 1 failed.");
Assert.IsTrue(new Vector(2, 3).Dot(new Vector(3, 2)) == 12, "Dot 1 failed");
Assert.IsTrue(new Vector(2, 3).PerpDot(new Vector(3, 2)) == -5, "PerpDot 1 failed");
//Perp dot on same line
Assert.IsTrue(new Vector(2, 3).PerpDot(new Vector(4, 6)) == 0, "PerpDot 3 failed");
}
public void TestAngleDetection() {
//Calculates angle to a point in each cardinal direction
var tests = new List<KeyValuePair<Vector, double>>();
tests.Add(new KeyValuePair<Vector, double>(new Vector(1, 0), 0d));
tests.Add(new KeyValuePair<Vector, double>(new Vector(1, 1), Math.PI / 4));
tests.Add(new KeyValuePair<Vector, double>(new Vector(0, 1), Math.PI / 2));
tests.Add(new KeyValuePair<Vector, double>(new Vector(-1, 1), 3 * Math.PI / 4));
tests.Add(new KeyValuePair<Vector, double>(new Vector(-1, 0), Math.PI));
tests.Add(new KeyValuePair<Vector, double>(new Vector(-1, -1), -3 * Math.PI / 4));
tests.Add(new KeyValuePair<Vector, double>(new Vector(0, -1), -Math.PI / 2));
tests.Add(new KeyValuePair<Vector, double>(new Vector(1, -1), -Math.PI / 4));
string format = "AngleTo fails on {0}. Expected {1}, got {2}";
Vector origin = new Vector(0, 0);
foreach (var test in tests) {
double angle = origin.AngleTo(test.Key);
Assert.IsTrue(angle == test.Value, string.Format(format, test.Value, test.Key, angle));
}
}
public void TestAngleProjection() {
//Test GetPointAt in all 8 cardinal directions. Origin assumed to be in top-left
var tests = new List<KeyValuePair<double, Vector>>();
tests.Add(new KeyValuePair<double, Vector>(0d, new Vector(1, 0)));
tests.Add(new KeyValuePair<double, Vector>(Math.PI / 4, new Vector(1, -1)));
tests.Add(new KeyValuePair<double, Vector>(Math.PI / 2, new Vector(0, -1)));
tests.Add(new KeyValuePair<double, Vector>(3 * Math.PI / 4, new Vector(-1, -1)));
tests.Add(new KeyValuePair<double, Vector>(Math.PI, new Vector(-1, 0)));
tests.Add(new KeyValuePair<double, Vector>(-3 * Math.PI / 4, new Vector(-1, 1)));
tests.Add(new KeyValuePair<double, Vector>(-Math.PI / 2, new Vector(0, 1)));
tests.Add(new KeyValuePair<double, Vector>(-Math.PI / 4, new Vector(1, 1)));
string format = "GetPointAt fails on {0}. Expected {1}, got {2}";
Vector origin = new Vector(0, 0);
foreach (var pair in tests) {
double hypotenuse = origin.Distance(pair.Value);
Vector point = origin.GetPointAt(hypotenuse, pair.Key);
Assert.IsTrue(point == pair.Value,
string.Format(format, pair.Key, pair.Value, point));
}
}
/// <summary>
/// Perpendicular dot product (determinant) of the vector.
/// Positive if the point lies counterclockwise to the vector, negative
/// if clockwise, and 0 if it lies on the same line.
/// </summary>
public double PerpDot(Vector other) {
return -Y * other.X + X * other.Y;
}
/// <summary>
/// Dot product of this vector and the other
/// </summary>
public double Dot(Vector other) {
return X * other.X + Y * other.Y;
}
/// <summary>
/// Angle from this point to another. Assumes Origin (0,0) is top-left
/// </summary>
public double AngleTo(Vector other) {
return Math.Atan2(other.Y - Y, other.X - X);
}
/// <summary>
/// Distance squared to the other point (faster than Euclidean calc)
/// </summary>
/// <param name="t"></param>
/// <param name="other"></param>
/// <returns></returns>
public double Distance2(Vector other) {
return (other.X - X) * (other.X - X) + (other.Y - Y) * (other.Y - Y);
}
/// <summary>
/// Euclidean distance from this point to the other
/// </summary>
public double Distance(Vector other) {
return Math.Sqrt((other.X - X) * (other.X - X) + (other.Y - Y) * (other.Y - Y));
}
public Vector(Vector other) {
X = other.X;
Y = other.Y;
}
/// <summary>
/// On the line described by the 2 other points, return the point closest to this one.
/// </summary>
public Vector Closest(Vector a, Vector b) {
double da = b.Y - a.Y;
double db = a.X - b.X;
double c1 = db * a.X + db * a.Y;
double c2 = -db * this.X + da * this.Y;
double det = da * da + db * db;
double cx = 0;
double cy = 0;
if (det != 0) {
cx = (da * c1 - db * c2) / det;
cy = (da * c2 + db * c1) / det;
}
else {
// The point is already on the line
cx = this.X;
cy = this.Y;
}
return new Vector(cx, cy);
}
public Point(Vector other) {
X = (int)(other.X);
Y = (int)(other.Y);
}