WebSVN - AndroidProjects - Blame - Rev 1441 - /BauzoidTools/BauzoidNET/BauzoidNET/math/Line2.cs

Rev	Author	Line No.	Line
1441	chris	1	using System;
		2	using System.Collections.Generic;
		3	using System.Linq;
		4	using System.Text;
		5	using System.Threading.Tasks;
		6
		7	namespace BauzoidNET.math
		8	{
		9	/** Line segment class. */
		10	public class Line2
		11	{
		12
		13	// Constants========================================================================================
		14
		15	// Embedded Types===================================================================================
		16
		17	// Fields===========================================================================================
		18
		19	public Vector2 a = new Vector2();
		20	public Vector2 b = new Vector2();
		21
		22	// parametric form
		23	private float A = 0.0f;
		24	private float B = 0.0f;
		25	private float C = 0.0f;
		26
		27	private Vector2 mTemp = new Vector2();
		28	private Vector2 mTemp2 = new Vector2();
		29
		30	// Methods==========================================================================================
		31
		32	public Line2()
		33	{
		34	calcParametric();
		35	}
		36
		37	public Line2(float ax, float ay, float bx, float by)
		38	{
		39	set(ax, ay, bx, by);
		40	}
		41
		42	public Line2(Vector2 a, Vector2 b)
		43	{
		44	set(a, b);
		45	}
		46
		47	public void set(float _ax, float _ay, float _bx, float _by)
		48	{
		49	a.x = _ax; a.y = _ay;
		50	b.x = _bx; b.y = _by;
		51	calcParametric();
		52	}
		53
		54	public void set(Vector2 _a, Vector2 _b)
		55	{
		56	a.x = _a.x; a.y = _a.y;
		57	b.x = _b.x; b.y = _b.y;
		58	calcParametric();
		59	}
		60
		61	public void setPointA(float _ax, float _ay)
		62	{
		63	a.x = _ax; a.y = _ay;
		64	calcParametric();
		65	}
		66
		67	public void setPointB(float _bx, float _by)
		68	{
		69	b.x = _bx; b.y = _by;
		70	calcParametric();
		71	}
		72
		73	public Line2 copy()
		74	{
		75	return new Line2(a, b);
		76	}
		77
		78	public Vector2 getMidPoint()
		79	{
		80	return new Vector2(a.x + (b.x - a.x) / 2, a.y + (b.y - a.y) /2);
		81	}
		82
		83	public Vector2 getLineVector()
		84	{
		85	return new Vector2(b.x - a.x, b.y - a.y);
		86	}
		87
		88	public void getLineVector(Vector2 result)
		89	{
		90	result.set(b.x - a.x, b.y - a.y);
		91	}
		92
		93	public void calcParametric()
		94	{
		95	A = getA();
		96	B = getB();
		97	C = getC();
		98	}
		99
		100	public float getLengthSqr()
		101	{
		102	float diffX = a.x - b.x;
		103	float diffY = a.y - b.y;
		104	return (diffXdiffX + diffYdiffY);
		105	}
		106
		107	public float getLength()
		108	{
		109	float length = getLengthSqr();
		110	return (float)(Math.Sqrt(length));
		111	}
		112
		113	/** Check if x, y (which must be collinear to the line segment) lies within the line segment. */
		114	public bool isCollinearPointOnSegment(float x, float y)
		115	{
		116	//Gdx.app.log("BLA", "p: " + x + ", " + y + " [" + ax + ", " + ay + " - " + bx + ", " + by);
		117
		118	float EPSILON = 0.0001f;
		119
		120	if ((x <= (Math.Max(a.x, b.x) + EPSILON)) && (x >= (Math.Min(a.x, b.x) - EPSILON)) &&
		121	(y <= (Math.Max(a.y, b.y) + EPSILON)) && (y >= (Math.Min(a.y, b.y) - EPSILON)))
		122	{
		123	return true;
		124	}
		125
		126	return false;
		127	}
		128
		129	/** Get the A coefficient in the Ax + By = C form. */
		130	public float getA()
		131	{
		132	return b.y - a.y;
		133	}
		134
		135	/** Get the B coefficient in the Ax + By = C form. */
		136	public float getB()
		137	{
		138	return a.x - b.x;
		139	}
		140
		141	/** Get the C coefficient in the Ax + By = C form. */
		142	public float getC()
		143	{
		144	return getA() * a.x + getB() * a.y;
		145	}
		146
		147
		148	/** Get intersection point. */
		149	public Vector2 getLineIntersection(Line2 other)
		150	{
		151	Vector2 result = new Vector2();
		152	if (getLineIntersection(other, result))
		153	return result;
		154
		155	return null;
		156	}
		157
		158	/** Get intersection point (no allocation version). */
		159	public bool getLineIntersection(Line2 other, Vector2 result)
		160	{
		161	// get Ax + By = C form coefficients
		162	float A1 = A;
		163	float B1 = B;
		164	float C1 = C;
		165
		166	float A2 = other.A;
		167	float B2 = other.B;
		168	float C2 = other.C;
		169
		170	float delta = A1B2 - A2B1;
		171	if (delta == 0)
		172	return false;
		173
		174	float x = (B2C1 - B1C2)/delta;
		175	float y = (A1C2 - A2C1)/delta;
		176
		177	result.set(x, y);
		178
		179	return true;
		180	}
		181
		182
		183	/** Get line segment intersection point. */
		184	public Vector2 getSegmentIntersection(Line2 other)
		185	{
		186	Vector2 result = new Vector2();
		187
		188	if (getSegmentIntersection(other, result))
		189	return result;
		190
		191	return null;
		192	}
		193
		194	/** Get line segment intersection point (no allocation version). */
		195	public bool getSegmentIntersection(Line2 other, Vector2 result)
		196	{
		197	if (!getLineIntersection(other, result))
		198	return false;
		199
		200	if (this.isCollinearPointOnSegment(result.x, result.y) && other.isCollinearPointOnSegment(result.x, result.y))
		201	return true;
		202
		203	return false;
		204	}
		205
		206
		207	/** Check if a segment intersects another. */
		208	public bool intersectsSegment(Line2 other)
		209	{
		210	return getSegmentIntersection(other, mTemp);
		211	}
		212
		213
		214	/** Get the smallest perpendicular vector from point to the line. */
		215	public Vector2 getMinimalVectorFrom(Vector2 point)
		216	{
		217	/*Vector2 closestPoint = getClosestPointFrom(point);
		218
		219	return new Vector2(closestPoint.x - point.x, closestPoint.y - point.y);*/
		220	Vector2 result = new Vector2();
		221	getMinimalVectorFrom(point, result);
		222	return result;
		223	}
		224
		225
		226	/** Get the smallest perpendicular vector from point to the line (no allocation version). */
		227	public void getMinimalVectorFrom(Vector2 point, Vector2 result)
		228	{
		229	//Vector2 closestPoint = getClosestPointFrom(point);
		230	getClosestPointFrom(point, mTemp);
		231	result.set(mTemp.x - point.x, mTemp.y - point.y);
		232
		233	//return new Vector2(closestPoint.x - point.x, closestPoint.y - point.y);
		234	}
		235
		236	/** Get the smallest perpendicular vector from point to the line. */
		237	public Vector2 getMinimalVectorFrom(float px, float py)
		238	{
		239	return getMinimalVectorFrom(new Vector2(px, py));
		240	}
		241
		242
		243	/** Get the closest point on line from a given point. */
		244	public Vector2 getClosestPointFrom(Vector2 point)
		245	{
		246	return getClosestPointFrom(point.x, point.y);
		247	}
		248
		249	/** Get the closest point on line from a given point (no allocation version). */
		250	public void getClosestPointFrom(Vector2 point, Vector2 result)
		251	{
		252	getClosestPointFrom(point.x, point.y, result);
		253	}
		254
		255	/** Get the closest point on line from a given point. */
		256	public Vector2 getClosestPointFrom(float px, float py)
		257	{
		258	Vector2 result = new Vector2();
		259	getClosestPointFrom(px, py, result);
		260	return result;
		261	}
		262
		263	/** Get the closest point on line from a given point (no allocation version). */
		264	public void getClosestPointFrom(float px, float py, Vector2 result)
		265	{
		266	getLineVector(mTemp);
		267
		268	mTemp2.set(px - a.x, py - a.y);
		269
		270	float t = Vector2.dotProduct(mTemp, mTemp2) / mTemp.squaredLength();
		271
		272	t = MathUtil.clamp(t, 0, 1);
		273	result.set(a.x + t * mTemp.x, a.y + t * mTemp.y);
		274	}
		275
		276
		277	/** Get the closest distance from a given point. */
		278	public float getClosestDistanceFrom(Vector2 point)
		279	{
		280	return getClosestDistanceFrom(point.x, point.y);
		281	}
		282
		283	/** Get the closest distance from a given point. */
		284	public float getClosestDistanceFrom(float px, float py)
		285	{
		286	return (float)Math.Sqrt(getClosestSquaredDistanceFrom(px, py));
		287	}
		288
		289	/** Get the closest distance from a given point. */
		290	public float getClosestSquaredDistanceFrom(float px, float py)
		291	{
		292	getClosestPointFrom(px, py, mTemp);
		293
		294	float dx = mTemp.x - px;
		295	float dy = mTemp.y - py;
		296
		297	return (dxdx + dydy);
		298	}
		299	}
		300	}

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