Package arc.math.geom

Class Intersector

java.lang.Object

arc.math.geom.Intersector

public final class Intersector
extends Object

Class offering various static methods for intersection testing between different geometric objects.

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	Intersector.MinimumTranslationVector	Minimum translation required to separate two polygons.

Constructor Summary

Constructors

Constructor	Description
Intersector()

Method Summary

Modifier and Type	Method	Description
static float	distanceLinePoint(float startX, float startY, float endX, float endY, float pointX, float pointY)	Returns the distance between the given line and point.
static float	distanceLinePoint(Vec2 start, Vec2 end, Vec2 point)	Returns the distance between the given line and point.
static float	distanceSegmentPoint(float startX, float startY, float endX, float endY, float pointX, float pointY)	Returns the distance between the given segment and point.
static float	distanceSegmentPoint(Vec2 start, Vec2 end, Vec2 point)	Returns the distance between the given segment and point.
static boolean	intersectLinePolygon(Vec2 p1, Vec2 p2, Polygon polygon)	Check whether the given line and Polygon intersect.
static boolean	intersectLines(float x1, float y1, float x2, float y2, float x3, float y3, float x4, float y4, Vec2 intersection)	Intersects the two lines and returns the intersection point in intersection.
static boolean	intersectLines(Vec2 p1, Vec2 p2, Vec2 p3, Vec2 p4, Vec2 intersection)	Intersects the two lines and returns the intersection point in intersection.
static boolean	intersectPolygons(float[] p1, float[] p2)
static boolean	intersectPolygons(Polygon p1, Polygon p2, Polygon overlap)	Intersects two convex polygons with clockwise vertices and sets the overlap polygon resulting from the intersection.
static float	intersectRayRay(Vec2 start1, Vec2 direction1, Vec2 start2, Vec2 direction2)	Intersect two 2D Rays and return the scalar parameter of the first ray at the intersection point.
static boolean	intersectRectangles(Rect rect1, Rect rect2, Rect intersection)	Determines whether the given rectangles intersect and, if they do, sets the supplied intersection rectangle to the area of overlap.
static boolean	intersectSegmentCircle(Vec2 start, Vec2 end, Vec2 center, float squareRadius)	Returns whether the given line segment intersects the given circle.
static float	intersectSegmentCircleDisplace(Vec2 start, Vec2 end, Vec2 point, float radius, Vec2 displacement)	Checks whether the line segment and the circle intersect and returns by how much and in what direction the line has to move away from the circle to not intersect.
static boolean	intersectSegmentPolygon(Vec2 p1, Vec2 p2, Polygon polygon)	Check whether the given line segment and Polygon intersect.
static boolean	intersectSegmentRectangle(float startX, float startY, float endX, float endY, Rect rect)	Determines whether the given rectangle and segment intersect
static boolean	intersectSegmentRectangle(Vec2 start, Vec2 end, Rect rect)	intersectSegmentRectangle(float, float, float, float, Rect)
static boolean	intersectSegments(float x1, float y1, float x2, float y2, float x3, float y3, float x4, float y4, Vec2 intersection)
static boolean	intersectSegments(Vec2 p1, Vec2 p2, Vec2 p3, Vec2 p4, Vec2 intersection)	Intersects the two line segments and returns the intersection point in intersection.
static boolean	isInPolygon(float[] polygon, int offset, int count, float x, float y)	Returns true if the specified point is in the polygon.
static boolean	isInPolygon(Seq<Vec2> polygon, Vec2 point)	Checks whether the given point is in the polygon.
static boolean	isInRegularPolygon(int sides, float cx, float cy, float radius, float rotation, float x, float y)
static boolean	isInsideHexagon(float cx, float cy, float d, float x, float y)
static boolean	isInTriangle(float px, float py, float ax, float ay, float bx, float by, float cx, float cy)	Returns true if the given point is inside the triangle.
static boolean	isInTriangle(Vec2 p, Vec2 a, Vec2 b, Vec2 c)	Returns true if the given point is inside the triangle.
static boolean	isInTriangle(Vec3 point, Vec3 t1, Vec3 t2, Vec3 t3)	Returns whether the given point is inside the triangle.
static Vec2	nearestSegmentPoint(float startX, float startY, float endX, float endY, float pointX, float pointY, Vec2 nearest)	Returns a point on the segment nearest to the specified point.
static Vec2	nearestSegmentPoint(Vec2 start, Vec2 end, Vec2 point, Vec2 nearest)	Returns a point on the segment nearest to the specified point.
static boolean	overlapConvexPolygons(float[] verts1, float[] verts2, Intersector.MinimumTranslationVector mtv)
static boolean	overlapConvexPolygons(float[] verts1, int offset1, int count1, float[] verts2, int offset2, int count2, Intersector.MinimumTranslationVector mtv)	Check whether polygons defined by the given counter-clockwise wound vertex arrays overlap.
static boolean	overlapConvexPolygons(Polygon p1, Polygon p2)	Check whether specified counter-clockwise wound convex polygons overlap.
static boolean	overlapConvexPolygons(Polygon p1, Polygon p2, Intersector.MinimumTranslationVector mtv)	Check whether specified counter-clockwise wound convex polygons overlap.
static boolean	overlaps(Circle c1, Circle c2)
static boolean	overlaps(Circle c, Rect r)
static boolean	overlaps(Rect r1, Rect r2)
static boolean	overlapsRect(float x1, float y1, float w1, float h1, float x2, float y2, float w2, float h2)
static int	pointLineSide(float linePoint1X, float linePoint1Y, float linePoint2X, float linePoint2Y, float pointX, float pointY)
static int	pointLineSide(Vec2 linePoint1, Vec2 linePoint2, Vec2 point)	Determines on which side of the given line the point is.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Details

Intersector

public Intersector()

Method Details

intersectPolygons

public static boolean intersectPolygons(float[] p1,
 float[] p2)

isInTriangle

public static boolean isInTriangle(Vec3 point,
 Vec3 t1,
 Vec3 t2,
 Vec3 t3)

Returns whether the given point is inside the triangle. This assumes that the point is on the plane of the triangle. No check is performed that this is the case.

Parameters:

point - the point

t1 - the first vertex of the triangle

t2 - the second vertex of the triangle

t3 - the third vertex of the triangle

Returns:

whether the point is in the triangle

isInsideHexagon

public static boolean isInsideHexagon(float cx,
 float cy,
 float d,
 float x,
 float y)

Returns:

whether x,y is inside the hexagon with radius d centered at cx, cy.

isInRegularPolygon

public static boolean isInRegularPolygon(int sides,
 float cx,
 float cy,
 float radius,
 float rotation,
 float x,
 float y)

Returns:

whether the specified x,y is inside a regular polygon.

isInTriangle

public static boolean isInTriangle(Vec2 p,
 Vec2 a,
 Vec2 b,
 Vec2 c)

Returns true if the given point is inside the triangle.

isInTriangle

public static boolean isInTriangle(float px,
 float py,
 float ax,
 float ay,
 float bx,
 float by,
 float cx,
 float cy)

Returns true if the given point is inside the triangle.

pointLineSide

public static int pointLineSide(Vec2 linePoint1,
 Vec2 linePoint2,
 Vec2 point)

Determines on which side of the given line the point is. Returns -1 if the point is on the left side of the line, 0 if the point is on the line and 1 if the point is on the right side of the line. Left and right are relative to the lines direction which is linePoint1 to linePoint2.

pointLineSide

public static int pointLineSide(float linePoint1X,
 float linePoint1Y,
 float linePoint2X,
 float linePoint2Y,
 float pointX,
 float pointY)

isInPolygon

public static boolean isInPolygon(Seq<Vec2> polygon,
 Vec2 point)

Checks whether the given point is in the polygon.

Parameters:

polygon - The polygon vertices passed as an array

point - The point

Returns:

true if the point is in the polygon

isInPolygon

public static boolean isInPolygon(float[] polygon,
 int offset,
 int count,
 float x,
 float y)

Returns true if the specified point is in the polygon.

Parameters:

offset - Starting polygon index.

count - Number of array indices to use after offset.

intersectPolygons

public static boolean intersectPolygons(Polygon p1,
 Polygon p2,
 Polygon overlap)

Intersects two convex polygons with clockwise vertices and sets the overlap polygon resulting from the intersection. Follows the Sutherland-Hodgman algorithm.

Parameters:

p1 - The polygon that is being clipped

p2 - The clip polygon

overlap - The intersection of the two polygons (can be null, if an intersection polygon is not needed)

Returns:

Whether the two polygons intersect.

distanceLinePoint

public static float distanceLinePoint(Vec2 start,
 Vec2 end,
 Vec2 point)

Returns the distance between the given line and point. Note the specified line is not a line segment.

distanceLinePoint

public static float distanceLinePoint(float startX,
 float startY,
 float endX,
 float endY,
 float pointX,
 float pointY)

Returns the distance between the given line and point. Note the specified line is not a line segment.

distanceSegmentPoint

public static float distanceSegmentPoint(float startX,
 float startY,
 float endX,
 float endY,
 float pointX,
 float pointY)

Returns the distance between the given segment and point.

distanceSegmentPoint

public static float distanceSegmentPoint(Vec2 start,
 Vec2 end,
 Vec2 point)

Returns the distance between the given segment and point.

nearestSegmentPoint

public static Vec2 nearestSegmentPoint(Vec2 start,
 Vec2 end,
 Vec2 point,
 Vec2 nearest)

Returns a point on the segment nearest to the specified point.

nearestSegmentPoint

public static Vec2 nearestSegmentPoint(float startX,
 float startY,
 float endX,
 float endY,
 float pointX,
 float pointY,
 Vec2 nearest)

Returns a point on the segment nearest to the specified point.

intersectSegmentCircle

public static boolean intersectSegmentCircle(Vec2 start,
 Vec2 end,
 Vec2 center,
 float squareRadius)

Returns whether the given line segment intersects the given circle.

Parameters:

start - The start point of the line segment

end - The end point of the line segment

center - The center of the circle

squareRadius - The squared radius of the circle

Returns:

Whether the line segment and the circle intersect

intersectSegmentCircleDisplace

public static float intersectSegmentCircleDisplace(Vec2 start,
 Vec2 end,
 Vec2 point,
 float radius,
 Vec2 displacement)

Checks whether the line segment and the circle intersect and returns by how much and in what direction the line has to move away from the circle to not intersect.

Parameters:

start - The line segment starting point

end - The line segment end point

point - The center of the circle

radius - The radius of the circle

displacement - The displacement vector set by the method having unit length

Returns:

The displacement or Float.POSITIVE_INFINITY if no intersection is present

intersectRayRay

public static float intersectRayRay(Vec2 start1,
 Vec2 direction1,
 Vec2 start2,
 Vec2 direction2)

Intersect two 2D Rays and return the scalar parameter of the first ray at the intersection point. You can get the intersection point by: Vec2 point(direction1).scl(scalar).add(start1); For more information, check: http://stackoverflow.com/a/565282/1091440

Parameters:

start1 - Where the first ray start

direction1 - The direction the first ray is pointing

start2 - Where the second ray start

direction2 - The direction the second ray is pointing

Returns:

scalar parameter on the first ray describing the point where the intersection happens. May be negative. In case the rays are collinear, Float.POSITIVE_INFINITY will be returned.

intersectLines

public static boolean intersectLines(Vec2 p1,
 Vec2 p2,
 Vec2 p3,
 Vec2 p4,
 Vec2 intersection)

Intersects the two lines and returns the intersection point in intersection.

Parameters:

p1 - The first point of the first line

p2 - The second point of the first line

p3 - The first point of the second line

p4 - The second point of the second line

intersection - The intersection point. May be null.

Returns:

Whether the two lines intersect

intersectLines

public static boolean intersectLines(float x1,
 float y1,
 float x2,
 float y2,
 float x3,
 float y3,
 float x4,
 float y4,
 Vec2 intersection)

Intersects the two lines and returns the intersection point in intersection.

Parameters:

intersection - The intersection point, or null.

Returns:

Whether the two lines intersect

intersectLinePolygon

public static boolean intersectLinePolygon(Vec2 p1,
 Vec2 p2,
 Polygon polygon)

Check whether the given line and Polygon intersect.

Parameters:

p1 - The first point of the line

p2 - The second point of the line

polygon - The polygon

Returns:

Whether polygon and line intersects

intersectRectangles

public static boolean intersectRectangles(Rect rect1,
 Rect rect2,
 Rect intersection)

Determines whether the given rectangles intersect and, if they do, sets the supplied intersection rectangle to the area of overlap.

Returns:

Whether the rectangles intersect

intersectSegmentRectangle

public static boolean intersectSegmentRectangle(float startX,
 float startY,
 float endX,
 float endY,
 Rect rect)

Determines whether the given rectangle and segment intersect

Parameters:

startX - x-coordinate start of line segment

startY - y-coordinate start of line segment

endX - y-coordinate end of line segment

endY - y-coordinate end of line segment

rect - rectangle that is being tested for collision

Returns:

whether the rectangle intersects with the line segment

intersectSegmentRectangle

public static boolean intersectSegmentRectangle(Vec2 start,
 Vec2 end,
 Rect rect)

intersectSegmentRectangle(float, float, float, float, Rect)

intersectSegmentPolygon

public static boolean intersectSegmentPolygon(Vec2 p1,
 Vec2 p2,
 Polygon polygon)

Check whether the given line segment and Polygon intersect.

Parameters:

p1 - The first point of the segment

p2 - The second point of the segment

Returns:

Whether polygon and segment intersect

intersectSegments

public static boolean intersectSegments(Vec2 p1,
 Vec2 p2,
 Vec2 p3,
 Vec2 p4,
 Vec2 intersection)

Intersects the two line segments and returns the intersection point in intersection.

Parameters:

p1 - The first point of the first line segment

p2 - The second point of the first line segment

p3 - The first point of the second line segment

p4 - The second point of the second line segment

intersection - The intersection point. May be null.

Returns:

Whether the two line segments intersect

intersectSegments

public static boolean intersectSegments(float x1,
 float y1,
 float x2,
 float y2,
 float x3,
 float y3,
 float x4,
 float y4,
 Vec2 intersection)

Parameters:

intersection - May be null.

overlapsRect

public static boolean overlapsRect(float x1,
 float y1,
 float w1,
 float h1,
 float x2,
 float y2,
 float w2,
 float h2)

overlaps

public static boolean overlaps(Circle c1,
 Circle c2)

overlaps

public static boolean overlaps(Rect r1,
 Rect r2)

overlaps

public static boolean overlaps(Circle c,
 Rect r)

overlapConvexPolygons

public static boolean overlapConvexPolygons(Polygon p1,
 Polygon p2)

Check whether specified counter-clockwise wound convex polygons overlap.

Parameters:

p1 - The first polygon.

p2 - The second polygon.

Returns:

Whether polygons overlap.

overlapConvexPolygons

public static boolean overlapConvexPolygons(Polygon p1,
 Polygon p2,
 Intersector.MinimumTranslationVector mtv)

Check whether specified counter-clockwise wound convex polygons overlap. If they do, optionally obtain a Minimum Translation Vector indicating the minimum magnitude vector required to push the polygon p1 out of collision with polygon p2.

Parameters:

p1 - The first polygon.

p2 - The second polygon.

mtv - A Minimum Translation Vector to fill in the case of a collision, or null (optional).

Returns:

Whether polygons overlap.

overlapConvexPolygons

public static boolean overlapConvexPolygons(float[] verts1,
 float[] verts2,
 Intersector.MinimumTranslationVector mtv)

See Also:

• overlapConvexPolygons(float[], int, int, float[], int, int, MinimumTranslationVector)

overlapConvexPolygons

public static boolean overlapConvexPolygons(float[] verts1,
 int offset1,
 int count1,
 float[] verts2,
 int offset2,
 int count2,
 Intersector.MinimumTranslationVector mtv)

Check whether polygons defined by the given counter-clockwise wound vertex arrays overlap. If they do, optionally obtain a Minimum Translation Vector indicating the minimum magnitude vector required to push the polygon defined by verts1 out of the collision with the polygon defined by verts2.

Parameters:

verts1 - Vertices of the first polygon.

verts2 - Vertices of the second polygon.

mtv - A Minimum Translation Vector to fill in the case of a collision, or null (optional).

Returns:

Whether polygons overlap.