Module org.dyn4j

Package org.dyn4j.collision.narrowphase

Class Sat

Object

Sat

All Implemented Interfaces:

ContainmentDetector, NarrowphaseDetector

public class Sat
extends Object
implements NarrowphaseDetector, ContainmentDetector

Implementation of the Separating Axis Theorem (SAT) for collision detection.

Sat states that "if two Convex objects are not penetrating, there exists an axis (vector) for which the projection of the objects does not overlap."

The axes that must be tested are all the edge normals of both Convex Shapes. For each edge normal we project the Convex Shapes onto it yielding a 1 dimensional Interval. If any Interval doesn't overlap, then we can conclude the Convex Shapes do not intersect. If all the Intervals overlap, then we can conclude that the Convex Shapes intersect.

If the Convex Shapes are penetrating, a Penetration object can be built from the Intervals with the least overlap. The normal will be the edge normal of the Interval and the depth will be the Interval overlap.

Since:

1.0.0

Version:

4.2.1

Author:

William Bittle

See Also:

SAT (Separating Axis Theorem)

Constructor Summary

Constructors

Constructor	Description
Sat()

Method Summary

Modifier and Type	Method	Description
boolean	contains(Convex convex1, Transform transform1, Convex convex2, Transform transform2, Containment containment)	Returns true if one of the Convex Shapes are contained in the other.4
boolean	detect(Convex convex1, Transform transform1, Convex convex2, Transform transform2)	Returns true if the two Convex Shapes intersect.
boolean	detect(Convex convex1, Transform transform1, Convex convex2, Transform transform2, Penetration penetration)	Returns true if the two Convex Shapes intersect and fills the Penetration object with the penetration vector and depth.

Methods inherited from class Object

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

Constructor Detail

Sat

public Sat()

Method Detail

detect

public boolean detect(Convex convex1,
                      Transform transform1,
                      Convex convex2,
                      Transform transform2,
                      Penetration penetration)

Description copied from interface: NarrowphaseDetector

Returns true if the two Convex Shapes intersect and fills the Penetration object with the penetration vector and depth.

NOTE: It's the responsibility of the caller to clear the given Penetration object before calling this method.

Specified by:

detect in interface NarrowphaseDetector

Parameters:

convex1 - the first Convex Shape

transform1 - the first Shape's Transform

convex2 - the second Convex Shape

transform2 - the second Shape's Transform

penetration - the Penetration object to fill

Returns:

boolean

detect

public boolean detect(Convex convex1,
                      Transform transform1,
                      Convex convex2,
                      Transform transform2)

Description copied from interface: NarrowphaseDetector

Returns true if the two Convex Shapes intersect.

Used to quickly test if two Convex Shapes intersect without incurring the cost of determining Penetration.

Specified by:

detect in interface NarrowphaseDetector

Parameters:

convex1 - the first Convex Shape

transform1 - the first Shape's Transform

convex2 - the second Convex Shape

transform2 - the second Shape's Transform

Returns:

boolean

contains

public boolean contains(Convex convex1,
                        Transform transform1,
                        Convex convex2,
                        Transform transform2,
                        Containment containment)

Description copied from interface: ContainmentDetector

Returns true if one of the Convex Shapes are contained in the other.4

NOTE: It's the responsibility of the caller to clear the given Containment object before calling this method.

Specified by:

contains in interface ContainmentDetector

Parameters:

convex1 - the first Shape

transform1 - the first Shape's Transform

convex2 - the second Shape

transform2 - the second Shape's Transform

containment - the Containment object to fill

Returns:

boolean true if one of the Convex Shapes is contained in the other