class ShapePolygonBase in Tinman.Terrain.Shapes

Abstract base class for IShape implementations that represent polygons.

abstract class	ShapePolygonBase	extends	ShapeVertices
		base of	ShapePolygonSimpleBase

Configuration

ToConfig

Returns the configuration value that describes this object.

public override sealed method	ToConfig ()
type	ConfigValue
returns		[not-null]	The configuration value.
inherited	ShapeVertices.ToConfig

Remarks:

All configurable objects need to implement this interface. For simple types, it is preferable to delegate to ToValue.

The returned value may be of type Invalid, which means that this object in its current state cannot be described with the configuration API.

Before returning the resulting configuration value, Cache must be called on it, passing this IConfigurable object as parameter.

Public / Attributes

Bounds

Returns the axis-aligned bounding box of this shape.

public override sealed property	Bounds { get }
type	Box2D
value		The axis-aligned bounding box.
inherited	ShapeVertices.Bounds

Remarks:

The bounding box is defined as the smallest possible rectangle that contains all points which have a shape distance of zero or less.

EdgeCount

Returns the number of shape edges.

public virtual property	EdgeCount { get }
type	int32
value	[>=0]	The number of shape edges.
inherited	ShapeBase.EdgeCount

See also:

IShape.EdgeAt

EdgeParity

Defines how the vertex winding of polygon contours is interpreted (outer rings vs. holes).

public override property	EdgeParity { get }
type	int32
value		The parity value: +/- 1 for polygons, 0 for non-polygon shapes.
overrides	ShapeBase.EdgeParity

Remarks:

A polygon contour is classified as an outer ring or a hole according to the sign of its signed area:

outer := sign(Area(contour)) == Parity
hole  := sign(Area(contour)) != Parity

The default value is -1 (i.e. clockwise orientation in a standard Cartesian coordinate system).

Georef

The coordinate system of the shape.

public override property	Georef { get }
type	CoordinateSystem
value	[not-null]	The coordinate system.
inherited	Shape.Georef

Remarks:

The default coordinate system is a local one (see IsLocal) in metres (see Metre).

IsCubemap

Is this a cubemap shape?

public virtual property	IsCubemap { get }
type	bool
value		true if this is a cubemap shape, false if not.
inherited	ShapeBase.IsCubemap

Remarks:

Cubemap shapes have a geographic coordinate system (see IsGeographic) and six separate sub-shapes, one for each cubemap face (see Cubemap)).

See also:

IShape.TransformCubemap
IShape.Face

IsGeometry

Does this shape consist of plain geometry only?

public virtual property	IsGeometry { get }
type	bool
value		true if this shape has plain geometry only, false if not.
inherited	ShapeBase.IsGeometry

Remarks:

Shapes with plain geometry can be rebuilt via Geometry.

SerialType

Returns the serial type of this object.

public property	SerialType { get }
type	ISerialTypeInfo
value	[not-null]	The serial type.
inherited	SerializableBase.SerialType

SerialVersion

Returns the serial data version.

public virtual property	SerialVersion { get }
type	int32
value	[>=1]	The serial data version tag.
inherited	SerializableBase.SerialVersion

Remarks:

An ISerializable implementation is required to support all versions up to the one returned by SerialVersion.

See also:

ISerializable.Serialize
ISerializable.Deserialize

TriangleCount

Returns the number of shape triangles.

public virtual property	TriangleCount { get }
type	int32
value	[>=0]	The number of shape triangles.
inherited	ShapeBase.TriangleCount

Type

The shape type.

public virtual property	Type { get }
type	ShapeType
value		The shape type.
inherited	ShapeBase.Type

VertexCount

Returns the number of shape vertices.

public override sealed property	VertexCount { get }
type	int32
value	[>=0]	The number of shape vertices.
inherited	ShapeVertices.VertexCount

Remarks:

When the vertex count is zero, the shape is defined implicitly. If the vertex count is greater than zero, the shape is explicitly defined by its vertices.

See also:

IShape.VertexAt

Public / Methods

Absolute

Returns a shape that returns the absolute distance value (i.e. the outline of this shape).

public virtual method	Absolute ()
type	IShape
returns		[not-null]	The resulting shape.
inherited	ShapeBase.Absolute

Accept

Accepts the given IShapeVisitor object.

public override sealed method	Accept (IShapeVisitor visitor, object userData = null)
params	visitor	[not-null]	The shape visitor object.
	userData		Optional user data. Defaults to null.
overrides	ShapeVertices.Accept

CheckIntersection

Checks the intersection between this shape and the given bounds.

[ThreadSafe]
public virtual method	CheckIntersection (Box2D box, float64 offset = 0)
type	int32
params	box		The box bounds.
	offset		Optional distance offset to apply to this shape for the intersection test. Defaults to 0.
returns			-1 if this shape and box are disjoint. 0 if this shape and box intersect. 1 if box fully contains this shape. 2 if this shape fully contains box.
inherited	ShapeBase.CheckIntersection

Compile

Compiles this shape into the most compact form.

public virtual method	Compile ()
type	IShape
returns		[not-null]	The resulting shape.
inherited	ShapeBase.Compile

Remarks:

Calling this method will not modify the geometry of a shape, only the object model structure.

Deserialize

Initializes the state of this object from the given data stream.

public override method	Deserialize (int32 serialVersion, ISerializer data)
type	ISerializable
params	serialVersion	[>=1]	The serial data version.
	data	[not-null]	The serial data stream.
returns		[not-null]	The deserialized object. This will typically be this, but in some circumstances, another instance may be returned (e.g. singletons).
overrides	ShapeVertices.Deserialize

Remarks:

The Deserialize method will be called immediately after the object has been instantiated via its default constructor.

The provided serialVersion number is guaranteed to be equal to or less than the SerialVersion returned by this object (i.e. ISerializable object must provide backwards compatibility).

See also:

ISerializable.Serialize
ISerializable.SerialVersion

DistanceTo

Computes the smallest distance from the given point to the shape.

[ThreadSafe]
public abstract method	DistanceTo (float64 x, float64 y, float64 maximum = Maths.MaxDouble)
type	float64
params	x		X-coordinate of point.
	y		Y-coordinate of point.
	maximum		The maximum relevant distance. This is a hint for the implementing class which can be exploited in order to optimize performance.
returns			Smallest distance to the shape.
inherited	ShapeBase.DistanceTo

Remarks:

If the point lies outside of the shape, the returned distance will be greater than zero. If the point is inside of the shape, the returned distance will be negative. The returned distance will be zero if the point exactly lies on the shape boundary.

---

Computes the smallest distance from the given point to the shape, additionally returning the corresponding nearest feature point on the shape.

[ThreadSafe]
public virtual method	DistanceTo (float64 x, float64 y, out Vec3I vertices, out Vec3D weights, float64 maximum = Maths.MaxDouble)
type	float64
params	x		X-coordinate of point.
	y		Y-coordinate of point.
	vertices		Shape vertex indices (see VertexAt) that describe the location of the nearest shape feature.
	weights		Location of the nearest shape feature, given as relative weights (i.e. the weight sum is 1) of vertices. The weights are sorted in descending order, i.e. X always holds the greatest weight and Z always holds the smallest weight.
	maximum		The maximum relevant distance. This is a hint for the implementing class which can be exploited in order to optimize performance.
returns			Smallest distance to the shape. All results greater than maximum are considered irrelevant. Implementing methods are free to discard those results.
inherited	ShapeBase.DistanceTo

Remarks:

If the point lies outside of the shape, the returned distance will be greater than zero. If the point is inside of the shape, the returned distance will be negative. The returned distance will be zero if the point exactly lies on the shape boundary.

EdgeAt

Returns a shape edge.

public virtual method	EdgeAt (int32 index)
type	Vec2I
params	index	[0..EdgeCount-1]	The edge index.
returns			The shape edge.
inherited	ShapeBase.EdgeAt

Remarks:

Each edge connects two vertices (see VertexAt), in the direction from X to Y.

All points that lie on an edge have a shape distance of zero.

See also:

IShapeInfo.EdgeCount

EdgeWalk

Returns the neighbouring edges for walking along a polygon contour.

public virtual method	EdgeWalk (int32 index)
type	Vec2I
params	index	[0..EdgeCount-1]	The edge index.
returns			Index of neighbouring edge (see IShape): X points to previous edge, Y points to next edge. The component will be -1 if there is no neighbouring edge (i.e. the contour is not closed). Both components will be -1 for non-polygon shapes.
inherited	ShapeBase.EdgeWalk

Face

Returns the shape on the given cubemap face.

public virtual method	Face (CubemapFace face)
type	IShape
params	face		The cubemap face.
returns			The shape or null if there are no shape parts on the given cubemap face.
inherited	ShapeBase.Face

Remarks:

Passing NegZ to an ordinary shape will return this. Cubemap shapes (see TransformCubemap) will return an aggregated shape for each cubemap face, or null.

Cubemap shapes are used by IHeightmapShape and IPixelPyramidShape objects.

Invert

Inverts this shape.

public virtual method	Invert ()
type	IShape
returns		[not-null]	The inverted shape.
inherited	ShapeBase.Invert

Maximum

Returns a composite shape that returns the maximum distance value (i.e. intersection of this shape and the given one).

public virtual method	Maximum (IShape shape)
type	IShape
params	shape	[not-null]	The other shape.
returns		[not-null]	The resulting shape.
inherited	ShapeBase.Maximum

Minimum

Returns a composite shape that returns the minimum distance value (i.e. the union of this shape and the given one).

public virtual method	Minimum (IShape shape)
type	IShape
params	shape	[not-null]	The other shape.
returns		[not-null]	The resulting shape.
inherited	ShapeBase.Minimum

Offset

Applies a distance offset to this shape.

public virtual method	Offset (float64 offset)
type	IShape
params	offset		The distance offset to apply.
returns		[not-null]	The resulting shape.
inherited	ShapeBase.Offset

Serialize

Serializes the current state of this object to the given data stream.

public override method	Serialize (ISerializer data)
params	data	[not-null]	The serial data stream.
overrides	ShapeVertices.Serialize

See also:

ISerializable.Deserialize
ISerializable.SerialVersion

TransformCoordinates

Transforms this shape using the given 2D homogeneous matrix.

public virtual method	TransformCoordinates (Mat3D matrix)
type	IShape
params	matrix		The 2D homogeneous matrix.
returns		[not-null]	The transforming shape.
inherited	ShapeBase.TransformCoordinates

Remarks:

Shape coordinates of this shape are multiplied with matrix using Mul2 (w = 1) in order to produce shape coordinates of the returned shape.

TransformCoordinateSystem

Transforms this shape to the given coordinate system.

public virtual method	TransformCoordinateSystem (CoordinateSystem target, float64 accuracy = 0)
type	IShape
params	target	[not-null]	The target coordinate system.
	accuracy	[>=0]	Optional accuracy to use for subdivision of edges. Given as a maximum error in the target coordinate system (see target. HorizontalUnit). Set to 0 to disable edge subdivision. Defaults to 0.
returns		[not-null]	The transforming shape.
inherited	ShapeBase.TransformCoordinateSystem

Remarks:

Transformation cannot be performed from resp. to a local coordinate system (see IsLocal). A transformation between two local coordinate system is possible, but only a conversion regarding unit of measure (see LocalUnit) and coordinate system flags (see CoordinateSystemFlags) is done.

Implicit shapes cannot be transformed (see IShape).

TransformCubemap

Transforms this shape to a geographic cubemap coordinate system.

public virtual method	TransformCubemap (float64 accuracy = 0)
type	IShape
params	accuracy	[>=0]	Optional accuracy to use for subdivision of edges. Given as a maximum error in the target coordinate system (see Face). Set to 0 to disable edge subdivision. Defaults to 0.
returns		[not-null]	The transforming cubemap shape.
inherited	ShapeBase.TransformCubemap

See also:

CoordinateSystem.ToCubemapFace

TransformGeometry

Transforms this shape to the given coordinate system.

public virtual method	TransformGeometry (CoordinateSystemTransform transform, float64 accuracy = 0)
type	IShape
params	transform	[not-null]	The coordinate system transformation to apply.
	accuracy	[>=0]	Optional accuracy to use for subdivision of edges. Given as a maximum error in the target coordinate system (see transform. Target. HorizontalUnit). Set to 0 to disable edge subdivision. Defaults to 0.
returns			The transformed shape or null if the transformed shape is empty or if the transformation is not possible (see remarks).
inherited	ShapeBase.TransformGeometry

Remarks:

Transformation cannot be performed from resp. to a local coordinate system (see IsLocal). A transformation between two local coordinate system is possible, but only a conversion regarding unit of measure (see LocalUnit) and coordinate system flags (see CoordinateSystemFlags) is done.

Implicit shapes cannot be transformed (see IShape).

TriangleAt

Returns a shape triangle.

public virtual method	TriangleAt (int32 index)
type	Vec3I
params	index	[0..TriangleCount-1]	The triangle index.
returns			The shape triangle.
inherited	ShapeBase.TriangleAt

Remarks:

Each triangle connects three vertices (see IShape), in the order X, Y, Z, where X <Y and X < Z. The vertex winding is chosen so that the signed triangle area is positive (see Area).

VertexAt

Returns a shape vertex.

public override method	VertexAt (int32 index)
type	Vec2D
params	index	[0..VertexCount-1]	The vertex index.
returns			The shape vertex.
inherited	ShapeVertices.VertexAt

Remarks:

All vertices have a shape distance of zero.

See also:

IShapeInfo.VertexCount

Protected / Attributes

epsilon

A 'very small' positive value in the scale of this shape.

protected field	epsilon
type	float64
inherited	ShapeVertices.epsilon

negative

The polygon parity is negative?

protected field	negative
type	bool

vertices

The list of shape vertices.

protected field	vertices
type	Vec2D[]
inherited	ShapeVertices.vertices

Protected / Constructors

ShapePolygonBase

Creates a new instance of ShapePolygonBase.

protected constructor	ShapePolygonBase (ISerialTypeInfo serialId)
params	serialId	[not-null]	The serial type ID.

---

Creates a new instance of ShapePolygonBase.

protected constructor	ShapePolygonBase (ISerialTypeInfo serialId, bool negative, Vec2D[] vertices, CoordinateSystem georef)
params	serialId	[not-null]	The serial type ID.
	negative		Polygon has negative parity?
	vertices	[not-null]	The shape vertices.
	georef		Optional georeference.

Protected / Methods

DistanceTo

Computes the signed distance from the given point towards the polygon border.

protected method	DistanceTo (float64 x, float64 y, float64 distance, Vec3I vertices, Vec3D weights)
type	float64
params	x		X-coordinate of point.
	y		Y-coordinate of point.
	distance		Absolute distance of point to polygon border (see remarks).
	vertices		The polygon contour segment that corresponds to distance.
	weights		Relative vertex weights of vertices.
returns			The signed distance (negative is inside, positive is outside).

Remarks:

The absolute distance from a point to the polygon border can be computed by using the DistancePointToLineSegment method or by using a spatial quadtree of line segments (see SpatialQuadtree).

The vertices and weights parameters are interpreted as follows:

weights.Z = 0
weights.X >= weights.Y >= 0
weights.X + weights.Y = 1

point = this.vertices[vertices.X] * weights.X
      + this.vertices[vertices.Y] * weights.Y

distance = | point - (x,y) |

Additional information is encoded into vertices:

Distance to polygon vertex (weights.X == 1):
  vertices.X := vertex index of point (see above).
  vertices.Y := index of previous contour vertex or negative if not existent
  vertices.Z := index of next contour vertex of negative if not existent

Distance to polygon edge (weights.X < 1):
  vertices.X := index of nearest edge vertex.
  vertices.Y := index of farthest edge vertex.
  vertices.Z := The polygon edge direction, expressed with X and Y:
                +1 : X->Y
                -1 : Y->X