cp

package
v0.0.0-...-793ea6c Latest Latest
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 Go to latest Published: Oct 24, 2021 License: BSD-3-Clause Imports: 4 Imported by: 0

Documentation

Overview

Package cp is a wrapper for the Chipmunk 2D Physics Engine.

More information about Chipmunk can be found at: 

http://chipmunk-physics.net/

This package uses the Chipmunk library, and as such it is also bound by it's license which can be found at: 

https://github.com/slembcke/Chipmunk2D/blob/master/LICENSE.txt

Index

Constants

View Source 
const (
	// Value for cpShape.group signifying that a shape is in no group.
	NO_GROUP = C.CP_NO_GROUP

	// Value for cpShape.layers signifying that a shape is in every layer.
	ALL_CATEGORIES = C.CP_ALL_CATEGORIES

	// cpCollisionType value internally reserved for hashing wildcard handlers.
	WILDCARD_COLLISION_TYPE = C.CP_WILDCARD_COLLISION_TYPE
)
View Source 
const (
	MAX_CONTACTS_PER_ARBITER = C.CP_MAX_CONTACTS_PER_ARBITER
)

Variables

View Source 
var (
	SHAPE_FILTER_ALL  = ShapeFilter{NO_GROUP, ALL_CATEGORIES, ALL_CATEGORIES}
	SHAPE_FILTER_NONE = ShapeFilter{NO_GROUP, 0 &^ ALL_CATEGORIES, 0 &^ ALL_CATEGORIES}
)
View Source 
var (
	TransformIdentity = Transform{1, 0, 0, 1, 0, 0}
)

Identity transform matrix.

View Source 
var (
	// Version string.
	VersionString = C.GoString(C.cpVersionString)
)
View Source 
var (
	// The zero vector.
	Vzero = Vect{0, 0}
)

Functions

func AreaForCircle 

func AreaForCircle(r1, r2 float64) float64

Calculate area of a hollow circle.

r1 and r2 are the inner and outer diameters. A solid circle has an inner diameter of 0.

func AreaForPoly 

func AreaForPoly(verts []Vect, radius float64) float64

Calculate the signed area of a polygon. A Clockwise winding gives positive area.

This is probably backwards from what you expect, but matches Chipmunk's the winding for poly shapes.

func AreaForSegment 

func AreaForSegment(a, b Vect, radius float64) float64

Calculate the area of a fattened (capsule shaped) line segment.

func BodyUpdatePosition 

func BodyUpdatePosition(b *Body, dt float64)

Default position integration function.

func BodyUpdateVelocity 

func BodyUpdateVelocity(b *Body, gravity Vect, damping, dt float64)

Default velocity integration function..

func ConvexHull 

func ConvexHull(count int, verts, result *Vect, first *int, tol float64) int

Calculate the convex hull of a given set of points. Returns the count of points in the hull. 

result must be a pointer to a  cpVect array with at least  count elements.
If  verts ==  result, then  verts will be reduced inplace.

first is an optional pointer to an integer to store where the first vertex
in the hull came from (i.e. verts[first] == result[0])

tol is the allowed amount to shrink the hull when simplifying it. A
tolerance of 0.0 creates an exact hull.

func Fabs 

func Fabs(f float64) float64

Return the absolute value of a cpFloat.

func Fclamp 

func Fclamp(f, min, max float64) float64

Clamp f to be between min and max.

func Fclamp01 

func Fclamp01(f float64) float64

Clamp f to be between 0 and 1.

func Flerp 

func Flerp(f1, f2, t float64) float64

Linearly interpolate (or extrapolate) between f1 and f2 by t percent.

func Flerpconst 

func Flerpconst(f1, f2, d float64) float64

Linearly interpolate from f1 to f2 by no more than d.

func Fmax 

func Fmax(a, b float64) float64

Return the max of two cpFloats.

func Fmin 

func Fmin(a, b float64) float64

Return the min of two cpFloats.

func MomentForBox 

func MomentForBox(m, width, height float64) float64

Calculate the moment of inertia for a solid box.

func MomentForBox2 

func MomentForBox2(m float64, box BB) float64

Calculate the moment of inertia for a solid box.

func MomentForCircle 

func MomentForCircle(m, r1, r2 float64, offset Vect) float64

Calculate the moment of inertia for a circle.

r1 and r2 are the inner and outer diameters. A solid circle has an inner diameter of 0.

func MomentForPoly 

func MomentForPoly(m float64, verts []Vect, offset Vect, radius float64) float64

Calculate the moment of inertia for a solid polygon shape assuming it's center of gravity is at it's centroid. The offset is added to each vertex.

func MomentForSegment 

func MomentForSegment(m float64, a, b Vect, radius float64) float64

Calculate the moment of inertia for a line segment.

Beveling radius is not supported.

func Vcross 

func Vcross(v1, v2 Vect) float64

2D vector cross product analog.

The cross product of 2D vectors results in a 3D vector with only a z component.

This function returns the magnitude of the z value.

func Vdist 

func Vdist(v1, v2 Vect) float64

Returns the distance between v1 and v2.

func Vdistsq 

func Vdistsq(v1, v2 Vect) float64

Returns the squared distance between v1 and v2. Faster than cpvdist() when you only need to compare distances.

func Veql 

func Veql(v1, v2 Vect) bool

Check if two vectors are equal. (Be careful when comparing floating point numbers!)

func Vlength 

func Vlength(v Vect) float64

Returns the length of v.

func Vlengthsq 

func Vlengthsq(v Vect) float64

Returns the squared length of v. Faster than cpvlength() when you only need to compare lengths.

func Vnear 

func Vnear(v1, v2 Vect, dist float64) bool

Returns true if the distance between v1 and v2 is less than dist.

func Vtoangle 

func Vtoangle(v Vect) float64

Returns the angular direction v is pointing in (in radians).

Types

type Arbiter 

type Arbiter struct {
	// contains filtered or unexported fields
}

The Arbiter struct controls pairs of colliding shapes.

They are also used in conjuction with collision handler callbacks allowing you to retrieve information on the collision and control it.

func (*Arbiter) CallWildcardBeginA 

func (a *Arbiter) CallWildcardBeginA(space *Space) bool

func (*Arbiter) CallWildcardBeginB 

func (a *Arbiter) CallWildcardBeginB(space *Space) bool

func (*Arbiter) CallWildcardPostSolveA 

func (a *Arbiter) CallWildcardPostSolveA(space *Space)

func (*Arbiter) CallWildcardPostSolveB 

func (a *Arbiter) CallWildcardPostSolveB(space *Space)

func (*Arbiter) CallWildcardPreSolveA 

func (a *Arbiter) CallWildcardPreSolveA(space *Space) bool

func (*Arbiter) CallWildcardPreSolveB 

func (a *Arbiter) CallWildcardPreSolveB(space *Space) bool

func (*Arbiter) CallWildcardSeparateA 

func (a *Arbiter) CallWildcardSeparateA(space *Space)

func (*Arbiter) CallWildcardSeparateB 

func (a *Arbiter) CallWildcardSeparateB(space *Space)

func (*Arbiter) ContactPointSet 

func (a *Arbiter) ContactPointSet() *ContactPointSet

Return a contact set from an arbiter.

func (*Arbiter) Count 

func (a *Arbiter) Count() int

Get the number of contact points for this arbiter.

func (*Arbiter) Depth 

func (a *Arbiter) Depth(i int) float64

Get the depth of the ith contact point.

func (*Arbiter) Friction 

func (a *Arbiter) Friction() float64

func (*Arbiter) GetNormal 

func (a *Arbiter) GetNormal() Vect

Get the normal of the collision.

func (*Arbiter) Ignore 

func (a *Arbiter) Ignore() bool

func (*Arbiter) IsFirstContact 

func (a *Arbiter) IsFirstContact() bool

Returns true if this is the first step a pair of objects started colliding.

func (*Arbiter) IsRemoval 

func (a *Arbiter) IsRemoval() bool

Returns true if in separate callback due to a shape being removed from the space.

func (*Arbiter) Point1 

func (a *Arbiter) Point1(i int) Vect

Get the position of the ith contact point on the surface of the first shape.

func (*Arbiter) Point2 

func (a *Arbiter) Point2(i int) Vect

Get the position of the ith contact point on the surface of the second shape.

func (*Arbiter) Restitution 

func (a *Arbiter) Restitution() float64

func (*Arbiter) SetContactPointSet 

func (a *Arbiter) SetContactPointSet(set *ContactPointSet)

Replace the contact point set for an arbiter.

This can be a very powerful feature, but use it with caution!

func (*Arbiter) SetFriction 

func (a *Arbiter) SetFriction(friction float64)

func (*Arbiter) SetRestitution 

func (a *Arbiter) SetRestitution(restitution float64)

func (*Arbiter) SetSurfaceVelocity 

func (a *Arbiter) SetSurfaceVelocity(vr Vect)

Override the relative surface velocity of the two shapes in contact.

By default this is calculated to be the difference of the two surface velocities clamped to the tangent plane.

func (*Arbiter) SetUserData 

func (a *Arbiter) SetUserData(i interface{})

func (*Arbiter) Shapes 

func (arb *Arbiter) Shapes() (a, b *Shape)

Return the colliding shapes involved for this arbiter.

The order of their cpSpace.collision_type values will match the order set when the collision handler was registered.

func (*Arbiter) SurfaceVelocity 

func (a *Arbiter) SurfaceVelocity() Vect

Get the relative surface velocity of the two shapes in contact.

func (*Arbiter) TotalImpulse 

func (a *Arbiter) TotalImpulse() Vect

Calculate the total impulse including the friction that was applied by this arbiter. This function should only be called from a post-solve, post-step or cpBodyEachArbiter callback.

func (*Arbiter) TotalKE 

func (a *Arbiter) TotalKE() float64

Calculate the amount of energy lost in a collision including static, but not dynamic friction. This function should only be called from a post-solve, post-step or cpBodyEachArbiter callback.

func (*Arbiter) UserData 

func (a *Arbiter) UserData() interface{}

type Array 

type Array C.cpArray

type BB 

type BB struct {
	L float64
	B float64
	R float64
	T float64
}

Chipmunk's axis-aligned 2D bounding box type. (left, bottom, right, top)

func BBNew 

func BBNew(l, b, r, t float64) BB

Convenience constructor for BB structs.

func BBNewForCircle 

func BBNewForCircle(p Vect, r float64) BB

Constructs a BB for a circle with the given position and radius.

func BBNewForExtents 

func BBNewForExtents(c Vect, hw, hh float64) BB

Constructs a BB centered on a point with the given extents (half sizes).

func (BB) Area 

func (bb BB) Area() float64

Returns the area of the bounding box.

func (BB) Center 

func (bb BB) Center() Vect

Returns the center of a bounding box.

func (BB) ClampVect 

func (bb BB) ClampVect(v Vect) Vect

Clamp a vector to a bounding box.

func (BB) ContainsBB 

func (bb BB) ContainsBB(other BB) bool

Returns true if other lies completely within bb.

func (BB) ContainsVect 

func (bb BB) ContainsVect(v Vect) bool

Returns true if bb contains v.

func (BB) Expand 

func (bb BB) Expand(v Vect) BB

Returns a bounding box that holds both bb and v.

func (BB) Intersects 

func (a BB) Intersects(b BB) bool

Returns true if a and b intersect.

func (BB) IntersectsSegment 

func (bb BB) IntersectsSegment(a, b Vect) bool

Return true if the bounding box intersects the line segment with ends a and b.

func (BB) Merge 

func (a BB) Merge(b BB) BB

Returns a bounding box that holds both bounding boxes.

func (BB) MergedArea 

func (a BB) MergedArea(b BB) float64

Merges a and b and returns the area of the merged bounding box.

func (BB) SegmentQuery 

func (bb BB) SegmentQuery(a, b Vect) float64

Returns the fraction along the segment query the BB is hit. Returns INFINITY if it doesn't hit.

func (BB) WrapVect 

func (bb BB) WrapVect(v Vect) Vect

Wrap a vector to a bounding box.

type Bitmask 

type Bitmask uint32

type Body 

type Body struct {
	// contains filtered or unexported fields
}

func BodyNew 

func BodyNew(mass, moment float64) *Body

Allocate and initialize a Body.

func BodyNewKinematic 

func BodyNewKinematic() *Body

Allocate and initialize a Body, and set it as a kinematic body.

func BodyNewStatic 

func BodyNewStatic() *Body

Allocate and initialize a cpBody, and set it as a static body.

func (*Body) Activate 

func (b *Body) Activate()

Wake up a sleeping or idle body.

func (*Body) ActivateStatic 

func (b *Body) ActivateStatic(filter *Shape)

Wake up any sleeping or idle bodies touching a static body.

func (*Body) Angle 

func (b *Body) Angle() float64

Get the angle of the body.

func (*Body) AngularVelocity 

func (b *Body) AngularVelocity() float64

Get the angular velocity of the body.

func (*Body) ApplyForceAtLocalPoint 

func (b *Body) ApplyForceAtLocalPoint(force, point Vect)

Apply a force to a body. Both the force and point are expressed in body local coordinates.

func (*Body) ApplyForceAtWorldPoint 

func (b *Body) ApplyForceAtWorldPoint(force, point Vect)

Apply a force to a body. Both the force and point are expressed in world coordinates.

func (*Body) ApplyImpulseAtLocalPoint 

func (b *Body) ApplyImpulseAtLocalPoint(impulse, point Vect)

Apply an impulse to a body. Both the impulse and point are expressed in body local coordinates.

func (*Body) ApplyImpulseAtWorldPoint 

func (b *Body) ApplyImpulseAtWorldPoint(impulse, point Vect)

Apply an impulse to a body. Both the impulse and point are expressed in world coordinates.

func (*Body) BoxShapeNew 

func (b *Body) BoxShapeNew(width, height, radius float64) *Shape

Allocate and initialize a box shaped polygon shape.

func (*Body) BoxShapeNew2 

func (b *Body) BoxShapeNew2(box BB, radius float64) *Shape

Allocate and initialize an offset box shaped polygon shape.

func (*Body) CenterOfGravity 

func (b *Body) CenterOfGravity() Vect

Get the offset of the center of gravity in body local coordinates.

func (*Body) CircleShapeNew 

func (b *Body) CircleShapeNew(radius float64, offset Vect) *Shape

Allocate and initialize a circle shape.

func (*Body) EachArbiter 

func (b *Body) EachArbiter(f func(b *Body, a *Arbiter))

Returns a slice of all arbiters that are currently active on the body.

func (*Body) EachConstraint 

func (b *Body) EachConstraint(f func(b *Body, c *Constraint))

Returns a slice of all contraints attached to the body and added to the space.

func (*Body) EachShape 

func (b *Body) EachShape(f func(b *Body, s *Shape))

Returns a slice of all shapes attached to the body and added to the space.

func (*Body) Force 

func (b *Body) Force() Vect

Get the force applied to the body for the next time step.

func (*Body) Free 

func (b *Body) Free()

Free is deprecated. Do not use it, it is no-op.

func (*Body) IsSleeping 

func (b *Body) IsSleeping() bool

Returns true if the body is sleeping.

func (*Body) KineticEnergy 

func (b *Body) KineticEnergy() float64

Get the amount of kinetic energy contained by the body.

func (*Body) LocalToWorld 

func (b *Body) LocalToWorld(point Vect) Vect

Convert body relative/local coordinates to absolute/world coordinates.

func (*Body) Mass 

func (b *Body) Mass() float64

Get the mass of the body.

func (*Body) Moment 

func (b *Body) Moment() float64

Get the moment of inertia of the body.

func (*Body) PolyShapeNew 

func (b *Body) PolyShapeNew(verts []Vect, transform Transform, radius float64) *Shape

Allocate and initialize a polygon shape with rounded corners.

A convex hull will be created from the vertexes.

func (*Body) Position 

func (b *Body) Position() Vect

Get the position of a body.

func (*Body) Rotation 

func (b *Body) Rotation() Vect

Get the rotation vector of the body. (The x basis vector of it's transform.)

func (*Body) SegmentShapeNew 

func (bd *Body) SegmentShapeNew(a, b Vect, radius float64) *Shape

Allocate and initialize a segment shape.

func (*Body) SetAngle 

func (b *Body) SetAngle(a float64)

Set the angle of a body.

func (*Body) SetAngularVelocity 

func (b *Body) SetAngularVelocity(angularVelocity float64)

Set the angular velocity of the body.

func (*Body) SetCenterOfGravity 

func (b *Body) SetCenterOfGravity(cog Vect)

Set the offset of the center of gravity in body local coordinates.

func (*Body) SetForce 

func (b *Body) SetForce(force Vect)

Set the force applied to the body for the next time step.

func (*Body) SetMass 

func (b *Body) SetMass(m float64)

Set the mass of the body.

func (*Body) SetMoment 

func (b *Body) SetMoment(i float64)

Set the moment of inertia of the body.

func (*Body) SetPosition 

func (b *Body) SetPosition(pos Vect)

Set the position of the body.

func (*Body) SetPositionUpdateFunc 

func (b *Body) SetPositionUpdateFunc(f BodyPositionFunc)

Set the callback used to update a body's position.

NOTE: It's not generally recommended to override this.

func (*Body) SetTorque 

func (b *Body) SetTorque(torque float64)

Set the torque applied to the body for the next time step.

func (*Body) SetType 

func (b *Body) SetType(t BodyType)

Set the type of the body.

func (*Body) SetUserData 

func (b *Body) SetUserData(userData interface{})

Set the user data interface assigned to the body.

func (*Body) SetVelocity 

func (b *Body) SetVelocity(velocity Vect)

Set the velocity of the body.

func (*Body) SetVelocityUpdateFunc 

func (b *Body) SetVelocityUpdateFunc(f BodyVelocityFunc)

Set the callback used to update a body's velocity.

func (*Body) Sleep 

func (b *Body) Sleep()

Force a body to fall asleep immediately.

func (*Body) SleepWithGroup 

func (b *Body) SleepWithGroup(group *Body)

Force a body to fall asleep immediately along with other bodies in a group.

func (*Body) Space 

func (b *Body) Space() *Space

Get the space this body is added to.

func (*Body) Torque 

func (b *Body) Torque() float64

Get the torque applied to the body for the next time step.

func (*Body) Type 

func (b *Body) Type() BodyType

Get the type of the body.

func (*Body) UserData 

func (b *Body) UserData() interface{}

Get the user data interface assigned to the body.

func (*Body) Velocity 

func (b *Body) Velocity() Vect

Get the velocity of the body.

func (*Body) VelocityAtLocalPoint 

func (b *Body) VelocityAtLocalPoint(point Vect) Vect

Get the velocity on a body (in world units) at a point on the body in local coordinates.

func (*Body) VelocityAtWorldPoint 

func (b *Body) VelocityAtWorldPoint(point Vect) Vect

Get the velocity on a body (in world units) at a point on the body in world coordinates.

func (*Body) WorldToLocal 

func (b *Body) WorldToLocal(point Vect) Vect

Convert body absolute/world coordinates to relative/local coordinates.

type BodyPositionFunc 

type BodyPositionFunc func(body *Body, dt float64)

Rigid body position update function type.

type BodyType 

type BodyType int

Chipmunk's rigid body type. Rigid bodies hold the physical properties of an object like it's mass, and position and velocity of it's center of gravity. They don't have an shape on their own. They are given a shape by creating collision shapes (cpShape) that point to the body. 

const (
	BODY_TYPE_DYNAMIC   BodyType = C.CP_BODY_TYPE_DYNAMIC
	BODY_TYPE_KINEMATIC BodyType = C.CP_BODY_TYPE_KINEMATIC
	BODY_TYPE_STATIC    BodyType = C.CP_BODY_TYPE_STATIC
)

type BodyVelocityFunc 

type BodyVelocityFunc func(body *Body, gravity Vect, damping, dt float64)

Rigid body velocity update function type.

type CircleShape 

type CircleShape C.cpCircleShape

type CollisionBeginFunc 

type CollisionBeginFunc func(arb *Arbiter, space *Space, userData interface{}) bool

Collision begin event function callback type.

Returning false from a begin callback causes the collision to be ignored until the the separate callback is called when the objects stop colliding.

type CollisionHandler 

type CollisionHandler struct {
	TypeA, TypeB  CollisionType
	BeginFunc     CollisionBeginFunc
	PreSolveFunc  CollisionPreSolveFunc
	PostSolveFunc CollisionPostSolveFunc
	SeparateFunc  CollisionSeparateFunc
	UserData      interface{}
}

type CollisionID 

type CollisionID uint32

type CollisionPostSolveFunc 

type CollisionPostSolveFunc func(arb *Arbiter, space *Space, userData interface{})

Collision post-solve event function callback type.

type CollisionPreSolveFunc 

type CollisionPreSolveFunc func(arb *Arbiter, space *Space, userData interface{}) bool

Collision pre-solve event function callback type.

Returning false from a pre-step callback causes the collision to be ignored until the next step.

type CollisionSeparateFunc 

type CollisionSeparateFunc func(arb *Arbiter, space *Space, userData interface{})

Collision separate event function callback type.

type CollisionType 

type CollisionType uint64

type Constraint 

type Constraint struct {
	// contains filtered or unexported fields
}

func DampedRotarySpringNew 

func DampedRotarySpringNew(a, b *Body, restAngle, stiffness, damping float64) *Constraint

Allocate and initialize a damped rotary spring.

func DampedSpringNew 

func DampedSpringNew(a, b *Body, anchorA, anchorB Vect, restLength, stiffness, damping float64) *Constraint

Allocate and initialize a damped spring.

func GearJointNew 

func GearJointNew(a, b *Body, phase, ratio float64) *Constraint

Allocate and initialize a gear joint.

func GrooveJointNew 

func GrooveJointNew(a, b *Body, grooveA, grooveB, anchorB Vect) *Constraint

Allocate and initialize a groove joint.

func PinJointNew 

func PinJointNew(a, b *Body, anchorA, anchorB Vect) *Constraint

Allocate and initialize a pin joint.

func PivotJointNew 

func PivotJointNew(a, b *Body, pivot Vect) *Constraint

Allocate and initialize a pivot joint.

func PivotJointNew2 

func PivotJointNew2(a, b *Body, anchorA, anchorB Vect) *Constraint

Allocate and initialize a pivot joint with specific anchors.

func RatchetJointNew 

func RatchetJointNew(a, b *Body, phase, ratchet float64) *Constraint

Allocate and initialize a ratchet joint.

func RotaryLimitJointNew 

func RotaryLimitJointNew(a, b *Body, min, max float64) *Constraint

Allocate and initialize a damped rotary limit joint.

func SimpleMotorNew 

func SimpleMotorNew(a, b *Body, rate float64) *Constraint

Allocate and initialize a simple motor.

func SlideJointNew 

func SlideJointNew(a, b *Body, anchorA, anchorB Vect, min, max float64) *Constraint

Allocate and initialize a slide joint.

func (*Constraint) BodyA 

func (c *Constraint) BodyA() *Body

Get the first body the constraint is attached to.

func (*Constraint) BodyB 

func (c *Constraint) BodyB() *Body

Get the second body the constraint is attached to.

func (*Constraint) CollideBodies 

func (c *Constraint) CollideBodies() bool

Get if the two bodies connected by the constraint are allowed to collide or not.

func (*Constraint) DampedRotarySpringDamping 

func (c *Constraint) DampedRotarySpringDamping() float64

Get the damping of the spring.

func (*Constraint) DampedRotarySpringRestAngle 

func (c *Constraint) DampedRotarySpringRestAngle() float64

Get the rest length of the spring.

func (*Constraint) DampedRotarySpringSetDamping 

func (c *Constraint) DampedRotarySpringSetDamping(damping float64)

Set the damping of the spring.

func (*Constraint) DampedRotarySpringSetStiffness 

func (c *Constraint) DampedRotarySpringSetStiffness(stiffness float64)

Set the stiffness of the spring in force/distance.

func (*Constraint) DampedRotarySpringSetTorqueFunc 

func (c *Constraint) DampedRotarySpringSetTorqueFunc(f func(spring *Constraint, relativeAngle float64) float64)

Set the damping rotary spring torque callback function.

func (*Constraint) DampedRotarySpringStiffness 

func (c *Constraint) DampedRotarySpringStiffness() float64

Get the stiffness of the spring in force/distance.

func (*Constraint) DampedRotarySpringTorqueFunc 

func (c *Constraint) DampedRotarySpringTorqueFunc() func(spring *Constraint, relativeAngle float64) float64

Get the damping rotary spring torque callback function.

func (*Constraint) DampedSpringAnchorA 

func (c *Constraint) DampedSpringAnchorA() Vect

Get the location of the first anchor relative to the first body.

func (*Constraint) DampedSpringAnchorB 

func (c *Constraint) DampedSpringAnchorB() Vect

Get the location of the second anchor relative to the second body.

func (*Constraint) DampedSpringDamping 

func (c *Constraint) DampedSpringDamping() float64

Get the damping of the spring.

func (*Constraint) DampedSpringForceFunc 

func (c *Constraint) DampedSpringForceFunc() func(spring *Constraint, dist float64) float64

Get the damping rotary spring torque callback function.

func (*Constraint) DampedSpringRestLength 

func (c *Constraint) DampedSpringRestLength() float64

Get the rest length of the spring.

func (*Constraint) DampedSpringSetAnchorA 

func (c *Constraint) DampedSpringSetAnchorA(anchorA Vect)

Set the location of the first anchor relative to the first body.

func (*Constraint) DampedSpringSetAnchorB 

func (c *Constraint) DampedSpringSetAnchorB(anchorA Vect)

Set the location of the second anchor relative to the second body.

func (*Constraint) DampedSpringSetDamping 

func (c *Constraint) DampedSpringSetDamping(damping float64)

Set the damping of the spring.

func (*Constraint) DampedSpringSetForceFunc 

func (c *Constraint) DampedSpringSetForceFunc(f func(spring *Constraint, dist float64) float64)

Set the damping spring force callback function.

func (*Constraint) DampedSpringSetRestLength 

func (c *Constraint) DampedSpringSetRestLength(restLength float64)

Set the rest length of the spring.

func (*Constraint) DampedSpringSetStiffness 

func (c *Constraint) DampedSpringSetStiffness(stiffness float64)

Set the stiffness of the spring in force/distance.

func (*Constraint) DampedSpringStiffness 

func (c *Constraint) DampedSpringStiffness() float64

Get the stiffness of the spring in force/distance.

func (*Constraint) ErrorBias 

func (c *Constraint) ErrorBias() float64

Get rate at which joint error is corrected.

func (*Constraint) Free 

func (c *Constraint) Free()

Free is deprecated. Do not use it, it is no-op.

func (*Constraint) GearJointPhase 

func (c *Constraint) GearJointPhase() float64

Get the phase offset of the gears.

func (*Constraint) GearJointRatio 

func (c *Constraint) GearJointRatio() float64

Get the angular distance of each ratchet.

func (*Constraint) GearJointSetPhase 

func (c *Constraint) GearJointSetPhase(phase float64)

Set the phase offset of the gears.

func (*Constraint) GearJointSetRatio 

func (c *Constraint) GearJointSetRatio(ratio float64)

Set the ratio of a gear joint.

func (*Constraint) GrooveJointAnchorB 

func (c *Constraint) GrooveJointAnchorB() Vect

Get the location of the second anchor relative to the second body.

func (*Constraint) GrooveJointGrooveA 

func (c *Constraint) GrooveJointGrooveA() Vect

Get the first endpoint of the groove relative to the first body.

func (*Constraint) GrooveJointGrooveB 

func (c *Constraint) GrooveJointGrooveB() Vect

Get the first endpoint of the groove relative to the first body.

func (*Constraint) GrooveJointSetAnchorB 

func (c *Constraint) GrooveJointSetAnchorB(grooveB Vect)

Set the location of the second anchor relative to the second body.

func (*Constraint) GrooveJointSetGrooveA 

func (c *Constraint) GrooveJointSetGrooveA(grooveA Vect)

Set the first endpoint of the groove relative to the first body.

func (*Constraint) GrooveJointSetGrooveB 

func (c *Constraint) GrooveJointSetGrooveB(grooveB Vect)

Set the first endpoint of the groove relative to the first body.

func (*Constraint) Impulse 

func (c *Constraint) Impulse() float64

Get the last impulse applied by this constraint.

func (*Constraint) IsDampedRotarySpring 

func (c *Constraint) IsDampedRotarySpring() bool

Check if a constraint is a damped rotary spring.

func (*Constraint) IsDampedSpring 

func (c *Constraint) IsDampedSpring() bool

Check if a constraint is a damped spring.

func (*Constraint) IsGearJoint 

func (c *Constraint) IsGearJoint() bool

Check if a constraint is a ratchet joint.

func (*Constraint) IsGrooveJoint 

func (c *Constraint) IsGrooveJoint() bool

Check if a constraint is a groove joint.

func (*Constraint) IsPinJoint 

func (c *Constraint) IsPinJoint() bool

Check if a constraint is a pin joint.

func (*Constraint) IsPivotJoint 

func (c *Constraint) IsPivotJoint() bool

Check if a constraint is a pivot joint.

func (*Constraint) IsRatchetJoint 

func (c *Constraint) IsRatchetJoint() bool

Check if a constraint is a ratchet joint.

func (*Constraint) IsRotaryLimitJoint 

func (c *Constraint) IsRotaryLimitJoint() bool

Check if a constraint is a rotary limit joint.

func (*Constraint) IsSimpleMotor 

func (c *Constraint) IsSimpleMotor() bool

Check if a constraint is a simple motor.

func (*Constraint) IsSlideJoint 

func (c *Constraint) IsSlideJoint() bool

Check if a constraint is a slide joint.

func (*Constraint) MaxBias 

func (c *Constraint) MaxBias() float64

Get the maximum rate at which joint error is corrected.

func (*Constraint) MaxForce 

func (c *Constraint) MaxForce() float64

Get the maximum force that this constraint is allowed to use.

func (*Constraint) PinJointAnchorA 

func (c *Constraint) PinJointAnchorA() Vect

Get the location of the first anchor relative to the first body.

func (*Constraint) PinJointAnchorB 

func (c *Constraint) PinJointAnchorB() Vect

Get the location of the second anchor relative to the second body.

func (*Constraint) PinJointDist 

func (c *Constraint) PinJointDist() float64

Get the distance the joint will maintain between the two anchors.

func (*Constraint) PinJointSetAnchorA 

func (c *Constraint) PinJointSetAnchorA(anchorA Vect)

Set the location of the first anchor relative to the first body.

func (*Constraint) PinJointSetAnchorB 

func (c *Constraint) PinJointSetAnchorB(anchorB Vect)

Set the location of the second anchor relative to the second body.

func (*Constraint) PinJointSetDist 

func (c *Constraint) PinJointSetDist(dist float64)

Set the distance the joint will maintain between the two anchors.

func (*Constraint) PivotJointAnchorA 

func (c *Constraint) PivotJointAnchorA() Vect

Get the location of the first anchor relative to the first body.

func (*Constraint) PivotJointAnchorB 

func (c *Constraint) PivotJointAnchorB() Vect

Get the location of the second anchor relative to the second body.

func (*Constraint) PivotJointSetAnchorA 

func (c *Constraint) PivotJointSetAnchorA(anchorA Vect)

Set the location of the first anchor relative to the first body.

func (*Constraint) PivotJointSetAnchorB 

func (c *Constraint) PivotJointSetAnchorB(anchorB Vect)

Set the location of the second anchor relative to the second body.

func (*Constraint) PostSolveFunc 

func (c *Constraint) PostSolveFunc() func(*Constraint, *Space)

Get the post-solve function that is called before the solver runs.

func (*Constraint) PreSolveFunc 

func (c *Constraint) PreSolveFunc() func(*Constraint, *Space)

Get the pre-solve function that is called before the solver runs.

func (*Constraint) RatchetJointAngle 

func (c *Constraint) RatchetJointAngle() float64

Get the angle of the current ratchet tooth.

func (*Constraint) RatchetJointPhase 

func (c *Constraint) RatchetJointPhase() float64

Get the phase offset of the ratchet.

func (*Constraint) RatchetJointRatchet 

func (c *Constraint) RatchetJointRatchet() float64

Get the angular distance of each ratchet.

func (*Constraint) RatchetJointSetAngle 

func (c *Constraint) RatchetJointSetAngle(angle float64)

Set the angle of the current ratchet tooth.

func (*Constraint) RatchetJointSetPhase 

func (c *Constraint) RatchetJointSetPhase(phase float64)

Get the phase offset of the ratchet.

func (*Constraint) RatchetJointSetRatchet 

func (c *Constraint) RatchetJointSetRatchet(ratchet float64)

Set the angular distance of each ratchet.

func (*Constraint) RotaryLimitJointMax 

func (c *Constraint) RotaryLimitJointMax() float64

Get the maximum distance the joint will maintain between the two anchors.

func (*Constraint) RotaryLimitJointMin 

func (c *Constraint) RotaryLimitJointMin() float64

Get the minimum distance the joint will maintain between the two anchors.

func (*Constraint) RotaryLimitJointSetMax 

func (c *Constraint) RotaryLimitJointSetMax(max float64)

Set the maximum distance the joint will maintain between the two anchors.

func (*Constraint) RotaryLimitJointSetMin 

func (c *Constraint) RotaryLimitJointSetMin(min float64)

Set the minimum distance the joint will maintain between the two anchors.

func (*Constraint) RotarySpringSetRestAngle 

func (c *Constraint) RotarySpringSetRestAngle(restAngle float64)

Set the rest length of the spring.

func (*Constraint) SetCollideBodies 

func (c *Constraint) SetCollideBodies(collideBodies bool)

Set if the two bodies connected by the constraint are allowed to collide or not. (defaults to cpFalse)

func (*Constraint) SetErrorBias 

func (c *Constraint) SetErrorBias(errorBias float64)

Set rate at which joint error is corrected.

Defaults to pow(1.0 - 0.1, 60.0) meaning that it will correct 10% of the error every 1/60th of a second.

func (*Constraint) SetMaxBias 

func (c *Constraint) SetMaxBias(maxBias float64)

Set the maximum rate at which joint error is corrected. (defaults to INFINITY)

func (*Constraint) SetMaxForce 

func (c *Constraint) SetMaxForce(maxForce float64)

Set the maximum force that this constraint is allowed to use. (defaults to INFINITY)

func (*Constraint) SetPostSolveFunc 

func (c *Constraint) SetPostSolveFunc(f func(*Constraint, *Space))

Set the post-solve function that is called before the solver runs.

func (*Constraint) SetPreSolveFunc 

func (c *Constraint) SetPreSolveFunc(f func(*Constraint, *Space))

Set the pre-solve function that is called before the solver runs.

func (*Constraint) SetUserData 

func (c *Constraint) SetUserData(i interface{})

Set the user definable data pointer for this constraint

func (*Constraint) SimpleMotorRate 

func (c *Constraint) SimpleMotorRate() float64

Get the rate of the motor.

func (*Constraint) SimpleMotorSetRate 

func (c *Constraint) SimpleMotorSetRate(rate float64)

Set the rate of the motor.

func (*Constraint) SlideJointAnchorA 

func (c *Constraint) SlideJointAnchorA() Vect

Get the location of the first anchor relative to the first body.

func (*Constraint) SlideJointAnchorB 

func (c *Constraint) SlideJointAnchorB() Vect

Get the location of the second anchor relative to the second body.

func (*Constraint) SlideJointMax 

func (c *Constraint) SlideJointMax() float64

Get the maximum distance the joint will maintain between the two anchors.

func (*Constraint) SlideJointMin 

func (c *Constraint) SlideJointMin() float64

Get the minimum distance the joint will maintain between the two anchors.

func (*Constraint) SlideJointSetAnchorA 

func (c *Constraint) SlideJointSetAnchorA(anchorA Vect)

Set the location of the first anchor relative to the first body.

func (*Constraint) SlideJointSetAnchorB 

func (c *Constraint) SlideJointSetAnchorB(anchorB Vect)

Set the location of the second anchor relative to the second body.

func (*Constraint) SlideJointSetMax 

func (c *Constraint) SlideJointSetMax(max float64)

Set the maximum distance the joint will maintain between the two anchors.

func (*Constraint) SlideJointSetMin 

func (c *Constraint) SlideJointSetMin(min float64)

Set the minimum distance the joint will maintain between the two anchors.

func (*Constraint) Space 

func (c *Constraint) Space() *Space

Get the Space this constraint is added to.

func (*Constraint) UserData 

func (c *Constraint) UserData() interface{}

Get the user definable data pointer for this constraint

type ConstraintPostSolveFunc 

type ConstraintPostSolveFunc func(c *Constraint, space *Space)

Callback function type that gets called after solving a joint.

type ConstraintPreSolveFunc 

type ConstraintPreSolveFunc func(c *Constraint, space *Space)

Callback function type that gets called before solving a joint.

type ContactBufferHeader 

type ContactBufferHeader C.cpContactBufferHeader

type ContactPoint 

type ContactPoint struct {
	// The position of the contact on the surface of each shape.
	Point1, Point2 Vect

	// Penetration distance of the two shapes. Overlapping means it will be
	// negative.
	//
	// This value is calculated as Vdot(Vsub(point2, point1), normal) and is
	// ignored by arbiter.SetContactPointSet().
	Distance float64
}

type ContactPointSet 

type ContactPointSet struct {
	// The number of contact points in the set.
	Count Int

	// The normal of the collision.
	Normal Vect

	// The array of contact points.
	Points [MAX_CONTACTS_PER_ARBITER]ContactPoint
}

A struct that wraps up the important collision data for an arbiter.

type DampedRotarySpring 

type DampedRotarySpring C.cpDampedRotarySpring

type DampedSpring 

type DampedSpring C.cpDampedSpring

type DataPointer 

type DataPointer unsafe.Pointer

type GearJoint 

type GearJoint C.cpGearJoint

type GrooveJoint 

type GrooveJoint C.cpGrooveJoint

type Group 

type Group uint64

type HashSet 

type HashSet C.cpHashSet

type HashValue 

type HashValue uint64

type Int 

type Int C.int

type Mat2x2 

type Mat2x2 struct {
	A float64
	B float64
	C float64
	D float64
}

Row major [[a, b][c, d]]

func Mat2x2New 

func Mat2x2New(a, b, c, d float64) Mat2x2

func (Mat2x2) Transform 

func (m Mat2x2) Transform(v Vect) Vect

type PinJoint 

type PinJoint C.cpPinJoint

type PivotJoint 

type PivotJoint C.cpPivotJoint

type PointQueryInfo 

type PointQueryInfo struct {
	// The nearest shape, nil if no shape was within range.
	Shape *Shape

	// The closest point on the shape's surface. (in world space coordinates)
	Point Vect

	// The distance to the point. The distance is negative if the point is
	// inside the shape.
	Distance float64

	// The gradient of the signed distance function.
	//
	// The same as info.p/info.d, but accurate even for very small values of
	// info.d.
	Gradient Vect
}

Nearest point query info struct.

type PolyShape 

type PolyShape C.cpPolyShape

type RatchetJoint 

type RatchetJoint C.cpRatchetJoint

type RotaryLimitJoint 

type RotaryLimitJoint C.cpRotaryLimitJoint

type SegmentQueryInfo 

type SegmentQueryInfo struct {
	// The shape that was hit, nil if no collision occured.
	Shape *Shape

	// The point of impact.
	Point Vect

	// The normal of the surface hit.
	Normal Vect

	// The normalized distance along the query segment in the range [0, 1].
	Alpha float64
}

Segment query info struct.

type SegmentShape 

type SegmentShape C.cpSegmentShape

type Shape 

type Shape struct {
	// contains filtered or unexported fields
}

The Shape struct defines the shape of a rigid body.

func (*Shape) Area 

func (s *Shape) Area() float64

Get the calculated area of this shape.

func (*Shape) BB 

func (s *Shape) BB() BB

Get the bounding box that contains the shape given it's current position and angle.

func (*Shape) Body 

func (s *Shape) Body() *Body

The cpBody this shape is connected to.

func (*Shape) CacheBB 

func (s *Shape) CacheBB() BB

Update, cache and return the bounding box of a shape based on the body it's attached to.

func (*Shape) CenterOfGravity 

func (s *Shape) CenterOfGravity() Vect

Get the centroid of this shape.

func (*Shape) CircleOffset 

func (s *Shape) CircleOffset() Vect

Get the offset of a circle shape.

func (*Shape) CircleRadius 

func (s *Shape) CircleRadius() float64

Get the radius of a circle shape.

func (*Shape) CircleShapeSetOffset 

func (shape *Shape) CircleShapeSetOffset(offset Vect)

Set the offset of a circle shape.

This function is used for mutating collision shapes. Chipmunk does not have any way to get velocity information on changing shapes, so the results will be unrealistic. This function is considered 'unsafe' by Chipmunk.

func (*Shape) CircleShapeSetRadius 

func (shape *Shape) CircleShapeSetRadius(radius float64)

Set the radius of a circle shape.

This function is used for mutating collision shapes. Chipmunk does not have any way to get velocity information on changing shapes, so the results will be unrealistic. This function is considered 'unsafe' by Chipmunk.

func (*Shape) CollisionType 

func (s *Shape) CollisionType() CollisionType

Get the collision type of this shape.

func (*Shape) Density 

func (s *Shape) Density() float64

Get the density of the shape if you are having Chipmunk calculate mass properties for you.

func (*Shape) Elasticity 

func (s *Shape) Elasticity() float64

Get the elasticity of this shape.

func (*Shape) Filter 

func (s *Shape) Filter() ShapeFilter

Get the collision filtering parameters of this shape.

func (*Shape) Free 

func (s *Shape) Free()

Free is deprecated. Do not use it, it is no-op.

func (*Shape) Friction 

func (s *Shape) Friction() float64

Get the friction of this shape.

func (*Shape) Mass 

func (s *Shape) Mass() float64

Get the mass of the shape if you are having Chipmunk calculate mass properties for you.

func (*Shape) Moment 

func (s *Shape) Moment() float64

Get the calculated moment of inertia for this shape.

func (*Shape) PointQuery 

func (s *Shape) PointQuery(p Vect) (out *PointQueryInfo, d float64)

Perform a nearest point query. It finds the closest point on the surface of shape to a specific point.

The value returned is the distance between the points. A negative distance means the point is inside the shape.

func (*Shape) PolyCount 

func (s *Shape) PolyCount() int

Get the number of verts in a polygon shape.

func (*Shape) PolyRadius 

func (s *Shape) PolyRadius() float64

Get the radius of a polygon shape.

func (*Shape) PolyShapeSetRadius 

func (shape *Shape) PolyShapeSetRadius(radius float64)

Set the radius of a poly shape.

This function is used for mutating collision shapes. Chipmunk does not have any way to get velocity information on changing shapes, so the results will be unrealistic. This function is considered 'unsafe' by Chipmunk.

func (*Shape) PolyShapeSetVerts 

func (shape *Shape) PolyShapeSetVerts(verts []Vect, transform Transform)

Set the vertexes of a poly shape.

This function is used for mutating collision shapes. Chipmunk does not have any way to get velocity information on changing shapes, so the results will be unrealistic. This function is considered 'unsafe' by Chipmunk.

func (*Shape) PolyShapeSetVertsRaw 

func (shape *Shape) PolyShapeSetVertsRaw(verts []Vect)

Set the vertexes of a poly shape.

This function is used for mutating collision shapes. Chipmunk does not have any way to get velocity information on changing shapes, so the results will be unrealistic. This function is considered 'unsafe' by Chipmunk.

func (*Shape) PolyVert 

func (s *Shape) PolyVert(index int) Vect

Get the ith vertex of a polygon shape.

func (*Shape) SegmentA 

func (s *Shape) SegmentA() Vect

Get the first endpoint of a segment shape.

func (*Shape) SegmentB 

func (s *Shape) SegmentB() Vect

Get the second endpoint of a segment shape.

func (*Shape) SegmentNormal 

func (s *Shape) SegmentNormal() Vect

Get the normal of a segment shape.

func (*Shape) SegmentQuery 

func (s *Shape) SegmentQuery(a, b Vect, radius float64) (info *SegmentQueryInfo, ret bool)

Perform a segment query against a shape.

func (*Shape) SegmentRadius 

func (s *Shape) SegmentRadius() float64

Get the first endpoint of a segment shape.

func (*Shape) SegmentSetNeighbors 

func (s *Shape) SegmentSetNeighbors(prev, next Vect)

Let Chipmunk know about the geometry of adjacent segments to avoid colliding with endcaps.

func (*Shape) SegmentShapeSetEndpoints 

func (shape *Shape) SegmentShapeSetEndpoints(a, b Vect)

Set the endpoints of a segment shape.

This function is used for mutating collision shapes. Chipmunk does not have any way to get velocity information on changing shapes, so the results will be unrealistic. This function is considered 'unsafe' by Chipmunk.

func (*Shape) SegmentShapeSetRadius 

func (shape *Shape) SegmentShapeSetRadius(radius float64)

Set the radius of a segment shape.

This function is used for mutating collision shapes. Chipmunk does not have any way to get velocity information on changing shapes, so the results will be unrealistic. This function is considered 'unsafe' by Chipmunk.

func (*Shape) Sensor 

func (s *Shape) Sensor() bool

Get if the shape is set to be a sensor or not.

func (*Shape) SetBody 

func (s *Shape) SetBody(b *Body)

Set the cpBody this shape is connected to.

Can only be used if the shape is not currently added to a space.

func (*Shape) SetCollisionType 

func (s *Shape) SetCollisionType(collisionType CollisionType)

Set the collision type of this shape.

func (*Shape) SetDensity 

func (s *Shape) SetDensity(density float64)

Set the density of this shape to have Chipmunk calculate mass properties for you.

func (*Shape) SetElasticity 

func (s *Shape) SetElasticity(elasticity float64)

Set the elasticity of this shape.

func (*Shape) SetFilter 

func (s *Shape) SetFilter(filter ShapeFilter)

Set the collision filtering parameters of this shape.

func (*Shape) SetFriction 

func (s *Shape) SetFriction(friction float64)

Set the friction of this shape.

func (*Shape) SetMass 

func (s *Shape) SetMass(mass float64)

Set the mass of this shape to have Chipmunk calculate mass properties for you.

func (*Shape) SetSensor 

func (s *Shape) SetSensor(sensor bool)

Set if the shape is a sensor or not.

func (*Shape) SetSurfaceVelocity 

func (s *Shape) SetSurfaceVelocity(surfaceVelocity Vect)

Set the surface velocity of this shape.

func (*Shape) SetUserData 

func (s *Shape) SetUserData(i interface{})

Set the user definable data pointer of this shape.

func (*Shape) ShapesCollide 

func (a *Shape) ShapesCollide(b *Shape) ContactPointSet

Return contact information about two shapes.

func (*Shape) Space 

func (s *Shape) Space() *Space

The cpSpace this body is added to.

func (*Shape) SurfaceVelocity 

func (s *Shape) SurfaceVelocity() Vect

Get the surface velocity of this shape.

func (*Shape) Update 

func (s *Shape) Update(transform Transform) BB

Update, cache and return the bounding box of a shape with an explicit transformation.

func (*Shape) UserData 

func (s *Shape) UserData() interface{}

Get the user definable data interface of this shape.

type ShapeFilter 

type ShapeFilter struct {
	Group      Group
	Categories Bitmask
	Mask       Bitmask
}

func ShapeFilterNew 

func ShapeFilterNew(group Group, categories, mask Bitmask) ShapeFilter

type SimpleMotorJoint 

type SimpleMotorJoint C.cpSimpleMotorJoint

type SlideJoint 

type SlideJoint C.cpSlideJoint

type Space 

type Space struct {
	// contains filtered or unexported fields
}

func SpaceNew 

func SpaceNew() *Space

Allocate and initialize a cpSpace.

func (*Space) AddBody 

func (s *Space) AddBody(body *Body) *Body

Add a rigid body to the simulation.

func (*Space) AddCollisionHandler 

func (s *Space) AddCollisionHandler(a, b CollisionType, handler *CollisionHandler)

func (*Space) AddConstraint 

func (s *Space) AddConstraint(constraint *Constraint) *Constraint

Add a constraint to the simulation.

func (*Space) AddDefaultCollisionHandler 

func (s *Space) AddDefaultCollisionHandler()

func (*Space) AddPostStepCallback 

func (s *Space) AddPostStepCallback(f func())

Schedule a post-step callback to be called when space.Step() finishes.

func (*Space) AddShape 

func (s *Space) AddShape(shape *Shape) *Shape

Add a collision shape to the simulation.

If the shape is attached to a static body, it will be added as a static shape.

func (*Space) AddWildcardHandler 

func (s *Space) AddWildcardHandler(t CollisionType, handler *CollisionHandler)

func (*Space) BBQuery 

func (s *Space) BBQuery(bb BB, filter ShapeFilter, f SpaceBBQueryFunc, data interface{})

Perform a fast rectangle query on the space calling func for each shape found.

Only the shape's bounding boxes are checked for overlap, not their full shape.

func (*Space) CollisionBias 

func (s *Space) CollisionBias() float64

Determines how fast overlapping shapes are pushed apart. Expressed as a fraction of the error remaining after each second. Defaults to pow(1.0 - 0.1, 60.0) meaning that Chipmunk fixes 10% of overlap each frame at 60Hz.

func (*Space) CollisionPersistence 

func (s *Space) CollisionPersistence() Timestamp

Number of frames that contact information should persist.

Defaults to 3. There is probably never a reason to change this value.

func (*Space) CollisionSlop 

func (s *Space) CollisionSlop() float64

Amount of encouraged penetration between colliding shapes.

Used to reduce oscillating contacts and keep the collision cache warm.

Defaults to 0.1. If you have poor simulation quality, increase this number as much as possible without allowing visible amounts of overlap.

func (*Space) ContainsBody 

func (s *Space) ContainsBody(body *Body) bool

Test if a rigid body has been added to the space.

func (*Space) ContainsConstraint 

func (s *Space) ContainsConstraint(constraint *Constraint) bool

Test if a constraint has been added to the space.

func (*Space) ContainsShape 

func (s *Space) ContainsShape(shape *Shape) bool

Test if a collision shape has been added to the space.

func (*Space) CurrentTimeStep 

func (s *Space) CurrentTimeStep() float64

Returns the current (or most recent) time step used with the given space. Useful from callbacks if your time step is not a compile-time global.

func (*Space) Damping 

func (s *Space) Damping() float64

Damping rate expressed as the fraction of velocity bodies retain each second.

A value of 0.9 would mean that each body's velocity will drop 10% per second.

The default value is 1.0, meaning no damping is applied.

This damping value is different than those of cpDampedSpring and cpDampedRotarySpring.

func (*Space) DebugDraw 

func (s *Space) DebugDraw(options *SpaceDebugDrawOptions)

DebugDraw draws the space using the debug draw options (which includes callbacks for performing the actual drawing). All options fields are entirely optional (callbacks may be nil, etc).

options.Data is arbitrary user data fed into the callbacks (this is just for a 1:1 mapping of chipmunks API, in Go you can just use a closure and access the data itself not storing it inside options.Data).

func (*Space) EachBody 

func (s *Space) EachBody(space *Space, f func(b *Body))

Space/body iterator callback function type.

func (*Space) EachConstraint 

func (s *Space) EachConstraint(space *Space, f func(c *Constraint))

Call f for each shape in the space.

func (*Space) EachShape 

func (s *Space) EachShape(space *Space, f func(s *Shape))

Call f for each shape in the space.

func (*Space) Free 

func (s *Space) Free()

Free is deprecated. Do not use it, it is no-op.

func (*Space) Gravity 

func (s *Space) Gravity() Vect

Gravity to pass to rigid bodies when integrating velocity.

func (*Space) IdleSpeedThreshold 

func (s *Space) IdleSpeedThreshold() float64

Speed threshold for a body to be considered idle.

The default value of 0 means to let the space guess a good threshold based on gravity.

func (*Space) IsLocked 

func (s *Space) IsLocked() bool

returns true from inside a callback when objects cannot be added/removed.

func (*Space) Iterations 

func (s *Space) Iterations() int

Number of iterations to use in the impulse solver to solve contacts and other constraints.

func (*Space) PointQuery 

func (s *Space) PointQuery(point Vect, maxDistance float64, filter ShapeFilter, f SpacePointQueryFunc, data interface{})

Query the space at a point and call f for each shape found.

func (*Space) PointQueryNearest 

func (s *Space) PointQueryNearest(point Vect, maxDistance float64, filter ShapeFilter) (shape *Shape, out *PointQueryInfo)

Query the space at a point and return the nearest shape found. Returns NULL if no shapes were found.

func (*Space) ReindexShape 

func (s *Space) ReindexShape(shape *Shape)

Update the collision detection data for a specific shape in the space.

func (*Space) ReindexShapesForBody 

func (s *Space) ReindexShapesForBody(body *Body)

Update the collision detection data for all shapes attached to a body.

func (*Space) ReindexStatic 

func (s *Space) ReindexStatic()

Update the collision detection info for the static shapes in the space.

func (*Space) RemoveBody 

func (s *Space) RemoveBody(body *Body)

Remove a rigid body from the simulation.

func (*Space) RemoveConstraint 

func (s *Space) RemoveConstraint(constraint *Constraint)

Remove a constraint from the simulation.

func (*Space) RemoveShape 

func (s *Space) RemoveShape(shape *Shape)

Remove a collision shape from the simulation.

func (*Space) SegmentQuery 

func (s *Space) SegmentQuery(start, end Vect, radius float64, filter ShapeFilter, f SpaceSegmentQueryFunc, data interface{})

Perform a directed line segment query (like a raycast) against the space calling f for each shape intersected.

func (*Space) SegmentQueryFirst 

func (s *Space) SegmentQueryFirst(start, end Vect, radius float64, filter ShapeFilter) (shape *Shape, out *SegmentQueryInfo)

Perform a directed line segment query (like a raycast) against the space and return the first shape hit. Returns NULL if no shapes were hit.

func (*Space) SetCollisionBias 

func (s *Space) SetCollisionBias(collisionBias float64)

func (*Space) SetCollisionPersistence 

func (s *Space) SetCollisionPersistence(collisionPersistence Timestamp)

func (*Space) SetCollisionSlop 

func (s *Space) SetCollisionSlop(collisionSlop float64)

func (*Space) SetDamping 

func (s *Space) SetDamping(damping float64)

func (*Space) SetGravity 

func (s *Space) SetGravity(gravity Vect)

func (*Space) SetIdleSpeedThreshold 

func (s *Space) SetIdleSpeedThreshold(idleSpeedThreshold float64)

func (*Space) SetIterations 

func (s *Space) SetIterations(iterations int)

func (*Space) SetSleepTimeThreshold 

func (s *Space) SetSleepTimeThreshold(sleepTimeThreshold float64)

func (*Space) SetUserData 

func (s *Space) SetUserData(i interface{})

func (*Space) ShapeQuery 

func (s *Space) ShapeQuery(shape *Shape, f SpaceShapeQueryFunc, data interface{}) bool

Query a space for any shapes overlapping the given shape and call func for each shape found.

func (*Space) SleepTimeThreshold 

func (s *Space) SleepTimeThreshold() float64

Time a group of bodies must remain idle in order to fall asleep.

Enabling sleeping also implicitly enables the the contact graph.

The default value of INFINITY disables the sleeping algorithm.

func (*Space) StaticBody 

func (s *Space) StaticBody() *Body

The Space provided static body for a given cpSpace.

This is merely provided for convenience and you are not required to use it.

func (*Space) Step 

func (s *Space) Step(dt float64)

Step the space forward in time by dt.

func (*Space) UseSpatialHash 

func (s *Space) UseSpatialHash(dim float64, count int)

Switch the space to use a spatial has as it's spatial index.

func (*Space) UserData 

func (s *Space) UserData() interface{}

User definable data interface.

Generally this points to your game's controller or game state class so you can access it when given a cpSpace reference in a callback.

type SpaceArbiterApplyImpulseFunc 

type SpaceArbiterApplyImpulseFunc func(arb *Arbiter)

type SpaceBBQueryFunc 

type SpaceBBQueryFunc func(shape *Shape, data interface{})

Rectangle Query callback function type.

type SpaceDebugColor 

type SpaceDebugColor struct {
	R float32
	G float32
	B float32
	A float32
}

type SpaceDebugDrawCircleImpl 

type SpaceDebugDrawCircleImpl func(pos Vect, angle, radius float64, outlineColor, fillColor SpaceDebugColor, data interface{})

type SpaceDebugDrawColorForShapeImpl 

type SpaceDebugDrawColorForShapeImpl func(shape *Shape, data interface{}) SpaceDebugColor

type SpaceDebugDrawDotImpl 

type SpaceDebugDrawDotImpl func(size float64, pos Vect, color SpaceDebugColor, data interface{})

type SpaceDebugDrawFatSegmentImpl 

type SpaceDebugDrawFatSegmentImpl func(a, b Vect, radius float64, outlineColor, fillColor SpaceDebugColor, data interface{})

type SpaceDebugDrawFlags 

type SpaceDebugDrawFlags int
const (
	SPACE_DEBUG_DRAW_SHAPES           SpaceDebugDrawFlags = C.CP_SPACE_DEBUG_DRAW_SHAPES
	SPACE_DEBUG_DRAW_CONSTRAINTS      SpaceDebugDrawFlags = C.CP_SPACE_DEBUG_DRAW_CONSTRAINTS
	SPACE_DEBUG_DRAW_COLLISION_POINTS SpaceDebugDrawFlags = C.CP_SPACE_DEBUG_DRAW_COLLISION_POINTS
)

type SpaceDebugDrawOptions 

type SpaceDebugDrawOptions struct {
	DrawCircle     SpaceDebugDrawCircleImpl
	DrawSegment    SpaceDebugDrawSegmentImpl
	DrawFatSegment SpaceDebugDrawFatSegmentImpl
	DrawPolygon    SpaceDebugDrawPolygonImpl
	DrawDot        SpaceDebugDrawDotImpl

	ColorForShape SpaceDebugDrawColorForShapeImpl

	Flags               SpaceDebugDrawFlags
	ShapeOutlineColor   SpaceDebugColor
	ConstraintColor     SpaceDebugColor
	CollisionPointColor SpaceDebugColor

	Data interface{}
}

type SpaceDebugDrawPolygonImpl 

type SpaceDebugDrawPolygonImpl func(verts []Vect, radius float64, outlineColor, fillColor SpaceDebugColor, data interface{})

type SpaceDebugDrawSegmentImpl 

type SpaceDebugDrawSegmentImpl func(a, b Vect, color SpaceDebugColor, data interface{})

type SpacePointQueryFunc 

type SpacePointQueryFunc func(shape *Shape, point Vect, distance float64, gradient Vect, data interface{})

Nearest point query callback function type.

type SpaceSegmentQueryFunc 

type SpaceSegmentQueryFunc func(shape *Shape, point, normal Vect, alpha float64, data interface{})

Nearest point query callback function type.

type SpaceShapeQueryFunc 

type SpaceShapeQueryFunc func(shape *Shape, points *ContactPointSet, data interface{})

Shape query callback function type.

type Timestamp 

type Timestamp uint32

type Transform 

type Transform struct {
	A  float64
	B  float64
	C  float64
	D  float64
	Tx float64
	Ty float64
}

Column major affine transform.

func TransformAxialScale 

func TransformAxialScale(axis, pivot Vect, scale float64) Transform

func TransformBoneScale 

func TransformBoneScale(v0, v1 Vect) Transform

func TransformNew 

func TransformNew(a, b, c, d, tx, ty float64) Transform

Construct a new transform matrix.

(a, b) is the x basis vector.

(c, d) is the y basis vector.

(tx, ty) is the translation.

func TransformNewTranspose 

func TransformNewTranspose(a, c, tx, b, d, ty float64) Transform

Construct a new transform matrix in transposed order.

func TransformOrtho 

func TransformOrtho(bb BB) Transform

func TransformRigid 

func TransformRigid(translate Vect, radians float64) Transform

Create a rigid transformation matrix. (translation + rotation)

func TransformRotate 

func TransformRotate(radians float64) Transform

Create a rotation matrix.

func TransformScale 

func TransformScale(scaleX, scaleY float64) Transform

Create a scale matrix.

func TransformTranslate 

func TransformTranslate(translate Vect) Transform

Create a translation matrix.

func (Transform) BB 

func (t Transform) BB(bb BB) BB

Transform a BB.

func (Transform) Inverse 

func (t Transform) Inverse() Transform

Get the inverse of a transform matrix.

func (Transform) Mult 

func (t1 Transform) Mult(t2 Transform) Transform

Multiply two transformation matrices.

func (Transform) Point 

func (t Transform) Point(p Vect) Vect

Transform an absolute point. (i.e. a vertex)

func (Transform) RigidInverse 

func (t Transform) RigidInverse() Transform

Fast inverse of a rigid transformation matrix.

func (Transform) Vect 

func (t Transform) Vect(v Vect) Vect

Transform a vector (i.e. a normal)

func (Transform) Wrap 

func (outer Transform) Wrap(inner Transform) Transform

func (Transform) WrapInverse 

func (outer Transform) WrapInverse(inner Transform) Transform

type Vect 

type Vect struct {
	X float64
	Y float64
}

Chipmunk's 2D vector type.

func CentroidForPoly 

func CentroidForPoly(verts []Vect) Vect

Calculate the natural centroid of a polygon.

func ClosetPointOnSegment 

func ClosetPointOnSegment(p, a, b Vect) Vect

Returns the closest point on the line segment ab, to the point p.

func V 

func V(x, y float64) Vect

Convenience constructor for cpVect structs.

func Vadd 

func Vadd(v1, v2 Vect) Vect

Add two vectors

func Vdot 

func Vdot(v1, v2 Vect) Vect

Vector dot product.

func Vforangle 

func Vforangle(a float64) Vect

Returns the unit length vector for the given angle (in radians).

func Vlerp 

func Vlerp(v1, v2 Vect, t float64) Vect

Linearly interpolate between v1 and v2.

func Vlerpconst 

func Vlerpconst(v1, v2 Vect, d float64) Vect

Linearly interpolate between v1 towards v2 by distance d.

func Vmult 

func Vmult(v Vect, s float64) Vect

Scalar multiplication.

func Vneg 

func Vneg(v Vect) Vect

Negate a vector.

func Vnormalize 

func Vnormalize(v Vect) Vect

Returns a normalized copy of v.

func Vperp 

func Vperp(v Vect) Vect

Returns a perpendicular vector. (90 degree rotation)

func Vproject 

func Vproject(v1, v2 Vect) Vect

Returns the vector projection of v1 onto v2.

func Vrotate 

func Vrotate(v1, v2 Vect) Vect

Uses complex number multiplication to rotate v1 by v2. Scaling will occur if v1 is not a unit vector.

func Vrperp 

func Vrperp(v Vect) Vect

Returns a perpendicular vector. (-90 degree rotation)

func Vslerp 

func Vslerp(v1, v2 Vect, t float64) Vect

Spherical linearly interpolate between v1 and v2.

func Vslerpconst 

func Vslerpconst(v1, v2 Vect, a float64) Vect

Spherical linearly interpolate between v1 towards v2 by no more than angle a radians

func Vsub 

func Vsub(v1, v2 Vect) Vect

Subtract two vectors.

func Vunrotate 

func Vunrotate(v1, v2 Vect) Vect

Inverse of Vrotate().

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