/// <summary>
/// Get intersection points between a straight line and circle.
/// </summary>
/// <param name="line">The straight line used for the intersection.</param>
/// <param name="circle">The circle used for the intersection.</param>
/// <param name="intersections"></param>
/// <returns></returns>
public bool GetIntersection(StraightLine line, Circle circle, out Vector2[] intersections)
{
float g = line.Gradient;
float i = line.Intercept;
Vector2 c = circle.Transform.PositionGlobal;
float r = circle.Radius;
//Setup polynomial equation
float A = 1 + g * g;
float B = -2 * c.X - 2 * g * i + 2 * c.Y * g;
float C = c.X * c.X + g * g + 2 * c.Y * i + c.Y * c.Y - r * r;
float[] xSolutions = m_solver.Poly_2(A, B, C);
intersections = new Vector2[xSolutions.Length];
if (xSolutions.Length == 0)
{
return(false);
}
for (int j = 0; j < intersections.Length; ++j)
{
intersections[j].X = xSolutions[j];
intersections[j].Y = g * intersections[j].X + i;
}
return(true);
}
public Vector2 GetProjectionPoint(StraightLine screen, Vector2 projector)
{
Vector2 pointA = new Vector2(0, screen.GetY(0));
Vector2 AB = screen.Direction;
Vector2 AX = Vector2.Subtract(projector, pointA);
return(pointA + AB * GetProjectionRatio(AB, AX));
}
public bool Intersects(Circle circle, StraightLine line)
{
//Circle center - Projection vector
Vector2 XP = GetProjectionPoint(line, circle.Transform.PositionGlobal) - circle.Transform.PositionGlobal;
if (XP.Length() < circle.Radius)
{
return(true);
}
return(false);
}
public bool BelongsToLine(StraightLine L2)
{
if (IsVertical != L2.IsVertical)
{
return(false);
}
if (IsVertical && L2.IsVertical)
{
return(A_Global.X == L2.GetX(0));
}
return(Gradient == L2.Gradient &&
Intercept == L2.Intercept);
}
/// <summary>
/// Returns true if the lines are equal, false if they are not.
/// </summary>
/// <param name="lineA">First line to test.</param>
/// <param name="lineB">Second Line to test.</param>
/// <param name="intersection">The point of intersection.</param>
/// <returns>True if the lines are equal</returns>
public bool GetIntersection(StraightLine lineA, StraightLine lineB, out Vector2 intersection)
{
float x;
float y;
bool aV = lineA.IsVertical;
bool bV = lineB.IsVertical;
intersection = new Vector2();
//Lines are equal: intersection.
if (lineA.Equals(lineB))
{
return(true);
}
//Lines are parallel: no intersection.
if (lineA.IsParallel(lineB))
{
return(false);
}
if (aV && !bV)
{
x = -lineA.C / lineA.A;
y = (-lineB.A * x - lineB.C) / lineB.B;
intersection = new Vector2(x, y);
return(true);
}
if (!aV && bV)
{
x = lineB.GetX(0);
y = (-lineA.A * x - lineA.C) / lineA.B;
intersection = new Vector2(x, y);
return(true);
}
if (!aV && !bV)
{
x = (lineB.Intercept - lineA.Intercept) / (lineA.Gradient - lineB.Gradient);
y = lineA.Gradient * x + lineA.Intercept;
intersection = new Vector2(x, y);
return(true);
}
throw new Exception("Well that wasn't supposed to happen...");
}
public bool IsEqual(StraightLine L2)
{
return(A == L2.A && B == L2.B && C == L2.C);
}
public bool IsParallel(StraightLine L2)
{
return((IsVertical && L2.IsVertical) ||
Gradient == L2.Gradient);
}
public bool Intersects(Circle circle, StraightLine line)
{
//Circle center - Projection vector
Vector2 XP = GetProjectionPoint(line, circle.Transform.PositionGlobal) - circle.Transform.PositionGlobal;
if (XP.Length() < circle.Radius)
return true;
return false;
}
public Vector2 GetProjectionPoint(StraightLine screen, Vector2 projector)
{
Vector2 pointA = new Vector2(0, screen.GetY(0));
Vector2 AB = screen.Direction;
Vector2 AX = Vector2.Subtract(projector, pointA);
return pointA + AB * GetProjectionRatio(AB, AX);
}
/// <summary>
/// Returns true if the lines are equal, false if they are not.
/// </summary>
/// <param name="lineA">First line to test.</param>
/// <param name="lineB">Second Line to test.</param>
/// <param name="intersection">The point of intersection.</param>
/// <returns>True if the lines are equal</returns>
public bool GetIntersection(StraightLine lineA, StraightLine lineB, out Vector2 intersection)
{
float x;
float y;
bool aV = lineA.IsVertical;
bool bV = lineB.IsVertical;
intersection = new Vector2();
//Lines are equal: intersection.
if (lineA.Equals(lineB))
return true;
//Lines are parallel: no intersection.
if (lineA.IsParallel(lineB))
return false;
if (aV && !bV)
{
x = -lineA.C / lineA.A;
y = (-lineB.A * x - lineB.C) / lineB.B;
intersection = new Vector2(x, y);
return true;
}
if (!aV && bV)
{
x = lineB.GetX(0);
y = (-lineA.A * x - lineA.C) / lineA.B;
intersection = new Vector2(x, y);
return true;
}
if (!aV && !bV)
{
x = (lineB.Intercept - lineA.Intercept) / (lineA.Gradient - lineB.Gradient);
y = lineA.Gradient * x + lineA.Intercept;
intersection = new Vector2(x, y);
return true;
}
throw new Exception("Well that wasn't supposed to happen...");
}
/// <summary>
/// Get intersection points between a straight line and circle.
/// </summary>
/// <param name="line">The straight line used for the intersection.</param>
/// <param name="circle">The circle used for the intersection.</param>
/// <param name="intersections"></param>
/// <returns></returns>
public bool GetIntersection(StraightLine line, Circle circle, out Vector2[] intersections)
{
float g = line.Gradient;
float i = line.Intercept;
Vector2 c = circle.Transform.PositionGlobal;
float r = circle.Radius;
//Setup polynomial equation
float A = 1 + g * g;
float B = -2 * c.X - 2 * g * i + 2 * c.Y * g;
float C = c.X * c.X + g * g + 2 * c.Y * i + c.Y * c.Y - r * r;
float[] xSolutions = m_solver.Poly_2(A, B, C);
intersections = new Vector2[xSolutions.Length];
if (xSolutions.Length == 0)
return false;
for(int j = 0; j < intersections.Length; ++j)
{
intersections[j].X = xSolutions[j];
intersections[j].Y = g * intersections[j].X + i;
}
return true;
}
public bool IsParallel(StraightLine L2)
{
return (IsVertical && L2.IsVertical)
|| Gradient == L2.Gradient;
}
public bool BelongsToLine(StraightLine L2)
{
if (IsVertical != L2.IsVertical)
return false;
if (IsVertical && L2.IsVertical)
return A_Global.X == L2.GetX(0);
return Gradient == L2.Gradient
&& Intercept == L2.Intercept;
}
public bool IsEqual(StraightLine L2)
{
return A == L2.A && B == L2.B && C == L2.C;
}
