/// <summary>
/// Returns a polygon in world space representing the 2D FOV through the portal.
/// Polygon is not guaranteed to be non-degenerate which can occur if the viewPoint is edge-on to the portal.
/// </summary>
public static Vector2[] GetFov(IPortal portal, Vector2 viewPoint, float distance, int detail, Transform2 transform)
{
Matrix4 a = transform.GetMatrix();
Vector2[] verts = new Vector2[detail + 2];
Vector2[] portalVerts = Portal.GetVerts(portal);
for (int i = 0; i < portalVerts.Length; i++)
{
Vector4 b = Vector4.Transform(new Vector4(portalVerts[i].X, portalVerts[i].Y, 0, 1), a);
verts[i] = new Vector2(b.X, b.Y);
}
//Minumum distance in order to prevent self intersections.
const float errorMargin = 0.01f;
float distanceMin = Math.Max((verts[0] - viewPoint).Length, (verts[1] - viewPoint).Length) + errorMargin;
distance = Math.Max(distance, distanceMin);
//get the leftmost and rightmost edges of the FOV
verts[verts.Length - 1] = (verts[0] - viewPoint).Normalized() * distance + viewPoint;
verts[2] = (verts[1] - viewPoint).Normalized() * distance + viewPoint;
//find the angle between the edges of the FOV
double angle0 = MathExt.AngleLine(verts[verts.Length - 1], viewPoint);
double angle1 = MathExt.AngleLine(verts[2], viewPoint);
double diff = MathExt.AngleDiff(angle0, angle1);
Debug.Assert(diff <= Math.PI + double.Epsilon && diff >= -Math.PI);
//handle case where lines overlap eachother
/*const double angleDiffMin = 0.0001f;
if (Math.Abs(diff) < angleDiffMin)
{
return new Vector2[0];
}*/
Matrix2 Rot = Matrix2.CreateRotation((float)diff / (detail - 1));
for (int i = 3; i < verts.Length - 1; i++)
{
verts[i] = Vector2Ext.Transform(verts[i - 1] - viewPoint, Rot) + viewPoint;
}
return verts;
}
/// <summary>
/// Get the portal's vertices in world coordinates.
/// </summary>
public static Vector2[] GetWorldVerts(IPortal portal, Transform2 worldTransform)
{
return Vector2Ext.Transform(GetVerts(portal), worldTransform.GetMatrix());
}
public void TransformTest1()
{
Transform2 t0 = new Transform2(new Vector2(1,1), -2, 3.21f);
Transform2 t1 = new Transform2(new Vector2(-100, 2), 3, 123);
Transform2 result = t0.Transform(t1);
Assert.IsTrue(Matrix4Ext.AlmostEqual(result.GetMatrix(), t0.GetMatrix() * t1.GetMatrix()));
}
public void TransformTest8()
{
Transform2 t0 = new Transform2(new Vector2(), 1, 2, true);
Transform2 t1 = new Transform2(new Vector2(), 1, 3.4f, true);
Transform2 result = t0.Transform(t1);
Assert.IsTrue(Matrix4Ext.AlmostEqual(result.GetMatrix(), t0.GetMatrix() * t1.GetMatrix()));
}
public void InvertedTest8()
{
Transform2 t = new Transform2();
t.Position = new Vector2(2, 1);
t.SetScale(new Vector2(-5, 5));
t.Rotation = (float)(Math.PI / 3.4);
Transform2 tInverted = t.Inverted();
Assert.IsTrue(Matrix4Ext.AlmostEqual(t.GetMatrix(), tInverted.GetMatrix().Inverted()));
}
public void InvertedTest4()
{
Transform2 t = new Transform2();
t.SetScale(new Vector2(5, -5));
t.Rotation = (float)Math.PI / 3;
Transform2 tInverted = t.Inverted();
Assert.IsTrue(Matrix4Ext.AlmostEqual(t.GetMatrix(), tInverted.GetMatrix().Inverted()));
}
public void InvertedTest2()
{
Transform2 t = new Transform2();
t.Rotation = 123;
Transform2 tInverted = t.Inverted();
Assert.IsTrue(Matrix4Ext.AlmostEqual(t.GetMatrix(), tInverted.GetMatrix().Inverted()));
}
public void InvertedTest1()
{
Transform2 t = new Transform2();
t.SetScale(new Vector2(5, -5));
Transform2 tInverted = t.Inverted();
Assert.IsTrue(t.GetMatrix() == tInverted.GetMatrix().Inverted());
}
public void InvertedTest0()
{
Transform2 t = new Transform2();
Transform2 tInverted = t.Inverted();
Assert.IsTrue(t.GetMatrix() == tInverted.GetMatrix().Inverted());
}
