UltimateZoneBuilder/Source/Geometry/Line2D.cs

281 lines
7.9 KiB
C#

#region ================== Copyright (c) 2007 Pascal vd Heiden
/*
* Copyright (c) 2007 Pascal vd Heiden, www.codeimp.com
* This program is released under GNU General Public License
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
*/
#endregion
#region ================== Namespaces
using System;
using System.Collections;
using System.Collections.Generic;
using System.Globalization;
using System.Text;
#endregion
namespace CodeImp.DoomBuilder.Geometry
{
public struct Line2D
{
#region ================== Constants
#endregion
#region ================== Variables
// Coordinates
public Vector2D v1;
public Vector2D v2;
#endregion
#region ================== Constructors
// Constructor
public Line2D(Vector2D v1, Vector2D v2)
{
this.v1 = v1;
this.v2 = v2;
}
// Constructor
public Line2D(Vector2D v1, float x2, float y2)
{
this.v1 = v1;
this.v2 = new Vector2D(x2, y2);
}
// Constructor
public Line2D(float x1, float y1, Vector2D v2)
{
this.v1 = new Vector2D(x1, y1);
this.v2 = v2;
}
// Constructor
public Line2D(float x1, float y1, float x2, float y2)
{
this.v1 = new Vector2D(x1, y1);
this.v2 = new Vector2D(x2, y2);
}
#endregion
#region ================== Statics
// This calculates the length
public static float GetLength(float dx, float dy)
{
// Calculate and return the length
return (float)Math.Sqrt(GetLengthSq(dx, dy));
}
// This calculates the square of the length
public static float GetLengthSq(float dx, float dy)
{
// Calculate and return the length
return dx * dx + dy * dy;
}
// This calculates the normal of a line
public static Vector2D GetNormal(float dx, float dy)
{
return new Vector2D(dx, dy).GetNormal();
}
// This tests if the line intersects with the given line coordinates
public static bool GetIntersection(Vector2D v1, Vector2D v2, float x3, float y3, float x4, float y4)
{
float u_ray, u_line;
return GetIntersection(v1, v2, x3, y3, x4, y4, out u_ray, out u_line);
}
// This tests if the line intersects with the given line coordinates
public static bool GetIntersection(Vector2D v1, Vector2D v2, float x3, float y3, float x4, float y4, out float u_ray)
{
float u_line;
return GetIntersection(v1, v2, x3, y3, x4, y4, out u_ray, out u_line);
}
// This tests if the line intersects with the given line coordinates
public static bool GetIntersection(Vector2D v1, Vector2D v2, float x3, float y3, float x4, float y4, out float u_ray, out float u_line)
{
// Calculate divider
float div = (y4 - y3) * (v2.x - v1.x) - (x4 - x3) * (v2.y - v1.y);
// Can this be tested?
if(div != 0.0f)
{
// Calculate the intersection distance from the line
u_line = ((x4 - x3) * (v1.y - y3) - (y4 - y3) * (v1.x - x3)) / div;
// Calculate the intersection distance from the ray
u_ray = ((v2.x - v1.x) * (v1.y - y3) - (v2.y - v1.y) * (v1.x - x3)) / div;
// Return if intersecting
return (u_ray >= 0.0f) && (u_ray <= 1.0f) && (u_line >= 0.0f) && (u_line <= 1.0f);
}
else
{
// Unable to detect intersection
u_line = float.NaN;
u_ray = float.NaN;
return false;
}
}
// This tests on which side of the line the given coordinates are
// returns < 0 for front (right) side, > 0 for back (left) side and 0 if on the line
public static float GetSideOfLine(Vector2D v1, Vector2D v2, Vector2D p)
{
// Calculate and return side information
return (p.y - v1.y) * (v2.x - v1.x) - (p.x - v1.x) * (v2.y - v1.y);
}
// This returns the shortest distance from given coordinates to line
public static float GetDistanceToLine(Vector2D v1, Vector2D v2, Vector2D p, bool bounded)
{
return (float)Math.Sqrt(GetDistanceToLineSq(v1, v2, p, bounded));
}
// This returns the shortest distance from given coordinates to line
public static float GetDistanceToLineSq(Vector2D v1, Vector2D v2, Vector2D p, bool bounded)
{
// Calculate intersection offset
float u = ((p.x - v1.x) * (v2.x - v1.x) + (p.y - v1.y) * (v2.y - v1.y)) / GetLengthSq(v2.x - v1.x, v2.y - v1.y);
if(bounded)
{
/*
// Limit intersection offset to the line
float lbound = 1f / GetLength(v2.x - v1.x, v2.y - v1.y);
float ubound = 1f - lbound;
if(u < lbound) u = lbound;
if(u > ubound) u = ubound;
*/
if(u < 0f) u = 0f; else if(u > 1f) u = 1f;
}
// Calculate intersection point
Vector2D i = v1 + u * (v2 - v1);
// Return distance between intersection and point
// which is the shortest distance to the line
float ldx = p.x - i.x;
float ldy = p.y - i.y;
return ldx * ldx + ldy * ldy;
}
// This returns the offset coordinates on the line nearest to the given coordinates
public static float GetNearestOnLine(Vector2D v1, Vector2D v2, Vector2D p)
{
// Calculate and return intersection offset
return ((p.x - v1.x) * (v2.x - v1.x) + (p.y - v1.y) * (v2.y - v1.y)) / GetLengthSq(v2.x - v1.x, v2.y - v1.y);
}
// This returns the coordinates at a specific position on the line
public static Vector2D GetCoordinatesAt(Vector2D v1, Vector2D v2, float u)
{
// Calculate and return intersection offset
return new Vector2D(v1.x + u * (v2.x - v1.x), v1.y + u * (v2.y - v1.y));
}
#endregion
#region ================== Methods
// This returns the perpendicular vector by simply making a normal
public Vector2D GetPerpendicular()
{
Vector2D d = GetDelta();
return new Vector2D(-d.y, d.x);
}
// This calculates the angle
public float GetAngle()
{
// Calculate and return the angle
Vector2D d = GetDelta();
return -(float)Math.Atan2(-d.y, d.x) + (float)Math.PI * 0.5f;
}
public Vector2D GetDelta() { return v2 - v1; }
public float GetLength() { return Line2D.GetLength(v2.x - v1.x, v2.y - v1.y); }
public float GetLengthSq() { return Line2D.GetLengthSq(v2.x - v1.x, v2.y - v1.y); }
// Output
public override string ToString()
{
return "(" + v1 + ") - (" + v2 + ")";
}
public bool GetIntersection(float x3, float y3, float x4, float y4)
{
return Line2D.GetIntersection(v1, v2, x3, y3, x4, y4);
}
public bool GetIntersection(float x3, float y3, float x4, float y4, out float u_ray)
{
return Line2D.GetIntersection(v1, v2, x3, y3, x4, y4, out u_ray);
}
public bool GetIntersection(float x3, float y3, float x4, float y4, out float u_ray, out float u_line)
{
return Line2D.GetIntersection(v1, v2, x3, y3, x4, y4, out u_ray, out u_line);
}
public bool GetIntersection(Line2D ray)
{
return Line2D.GetIntersection(v1, v2, ray.v1.x, ray.v1.y, ray.v2.x, ray.v2.y);
}
public bool GetIntersection(Line2D ray, out float u_ray)
{
return Line2D.GetIntersection(v1, v2, ray.v1.x, ray.v1.y, ray.v2.x, ray.v2.y, out u_ray);
}
public bool GetIntersection(Line2D ray, out float u_ray, out float u_line)
{
return Line2D.GetIntersection(v1, v2, ray.v1.x, ray.v1.y, ray.v2.x, ray.v2.y, out u_ray, out u_line);
}
public float GetSideOfLine(Vector2D p)
{
return Line2D.GetSideOfLine(v1, v2, p);
}
public float GetDistanceToLine(Vector2D p, bool bounded)
{
return Line2D.GetDistanceToLine(v1, v2, p, bounded);
}
public float GetDistanceToLineSq(Vector2D p, bool bounded)
{
return Line2D.GetDistanceToLineSq(v1, v2, p, bounded);
}
public float GetNearestOnLine(Vector2D p)
{
return Line2D.GetNearestOnLine(v1, v2, p);
}
public Vector2D GetCoordinatesAt(float u)
{
return Line2D.GetCoordinatesAt(v1, v2, u);
}
#endregion
}
}