| HOpenGL Libraries (OpenGL package) | Source code | Contents | Index

Graphics.Rendering.OpenGL.GLU.Tessellation |

Portability | portable
Stability | stable
Maintainer | sven.panne@aedion.de

Contents

Polygon description
Combining vertices
Tessellation parameters
Tessellator type
Contour extraction
Triangulation
Tessellation into primitives

Description
This module corresponds to chapter 5 (Polygon Tessellation) of the GLU specs.
Synopsis

data AnnotatedVertex v = AnnotatedVertex (Vertex3 GLdouble) v
newtype ComplexContour v = ComplexContour [AnnotatedVertex v]
newtype ComplexPolygon v = ComplexPolygon [ComplexContour v]
data WeightedProperties v = WeightedProperties (GLclampf, v) (GLclampf, v) (GLclampf, v) (GLclampf, v)
type Combiner v = Vertex3 GLdouble -> WeightedProperties v -> v

data TessWinding

= TessWindingOdd
| TessWindingNonzero
| TessWindingPositive
| TessWindingNegative
| TessWindingAbsGeqTwo

type Tolerance = GLdouble
type Tessellator p v = TessWinding -> Tolerance -> Normal3 GLdouble -> Combiner v -> ComplexPolygon v -> IO (p v)
newtype SimpleContour v = SimpleContour [AnnotatedVertex v]
newtype PolygonContours v = PolygonContours [SimpleContour v]
extractContours :: Storable v => Tessellator PolygonContours v
type TriangleVertex v = AnnotatedVertex (v, EdgeFlag)
data Triangle v = Triangle (TriangleVertex v) (TriangleVertex v) (TriangleVertex v)
newtype Triangulation v = Triangulation [Triangle v]
triangulate :: Storable v => Tessellator Triangulation v
data Primitive v = Primitive PrimitiveMode [AnnotatedVertex v]
newtype SimplePolygon v = SimplePolygon [Primitive v]
tessellate :: Storable v => Tessellator SimplePolygon v

Polygon description
data AnnotatedVertex v

The basic building block in tessellation is a 3D vertex with an associated property, e.g. color, texture coordinates, etc.
Constructors

AnnotatedVertex (Vertex3 GLdouble) v |

Instances

Eq v => Eq (AnnotatedVertex v)
Ord v => Ord (AnnotatedVertex v)
Storable v => Storable (AnnotatedVertex v)

newtype ComplexContour v

A complex contour, which can be self-intersecting and/or concave.
Constructors

ComplexContour [AnnotatedVertex v] |

Instances

Eq v => Eq (ComplexContour v)
Ord v => Ord (ComplexContour v)

newtype ComplexPolygon v

A complex (possibly concave) polygon, represented by one or more complex and possibly intersecting contours.
Constructors

ComplexPolygon [ComplexContour v] |

Instances

Eq v => Eq (ComplexPolygon v)
Ord v => Ord (ComplexPolygon v)

Combining vertices
data WeightedProperties v

Four vertex properties (cf. `AnnotatedVertex`) with associated weigths summing up to 1.0.
Constructors

WeightedProperties (GLclampf, v) (GLclampf, v) (GLclampf, v) (GLclampf, v) |

Instances

Eq v => Eq (WeightedProperties v)
Ord v => Ord (WeightedProperties v)

type Combiner v = Vertex3 GLdouble -> WeightedProperties v -> v
A function combining given vertex properties into a property for a newly generated vertex
Tessellation parameters
data TessWinding

Constructors

TessWindingOdd |
TessWindingNonzero |
TessWindingPositive |
TessWindingNegative |
TessWindingAbsGeqTwo |

Instances

Eq TessWinding
Ord TessWinding
Show TessWinding

type Tolerance = GLdouble
The relative tolerance under which two vertices can be combined (see `Combiner`). Multiplication with the largest coordinate magnitude of all polygon vertices yields the maximum distance between two mergeable vertices. Note that merging is optional and the tolerance is only a hint.
Tessellator type
type Tessellator p v = TessWinding -> Tolerance -> Normal3 GLdouble -> Combiner v -> ComplexPolygon v -> IO (p v)
A general tessellator type. Before tessellation of a complex polygon, all its vertices are projected into a plane perpendicular to the given normal. If the given normal is `Normal3 0 0 0`, a fitting plane of all vertices is used.
Contour extraction
newtype SimpleContour v

A simple, non-self-intersecting contour
Constructors

SimpleContour [AnnotatedVertex v] |

Instances

Eq v => Eq (SimpleContour v)
Ord v => Ord (SimpleContour v)

newtype PolygonContours v

The contours of a complex polygon, represented by one or more non-intersecting simple contours
Constructors

PolygonContours [SimpleContour v] |

Instances

Eq v => Eq (PolygonContours v)
Ord v => Ord (PolygonContours v)

extractContours :: Storable v => Tessellator PolygonContours v
Triangulation
type TriangleVertex v = AnnotatedVertex (v, EdgeFlag)
A triangle vertex with additional information about the edge it begins
data Triangle v

A triangle, represented by three triangle vertices
Constructors

Triangle (TriangleVertex v) (TriangleVertex v) (TriangleVertex v) |

Instances

Eq v => Eq (Triangle v)
Ord v => Ord (Triangle v)

newtype Triangulation v

A triangulation of a complex polygon
Constructors

Triangulation [Triangle v] |

Instances

Eq v => Eq (Triangulation v)
Ord v => Ord (Triangulation v)

triangulate :: Storable v => Tessellator Triangulation v
Tessellation into primitives
data Primitive v

Constructors

Primitive PrimitiveMode [AnnotatedVertex v] |

Instances

Eq v => Eq (Primitive v)
Ord v => Ord (Primitive v)

newtype SimplePolygon v

Constructors

SimplePolygon [Primitive v] |

Instances

Eq v => Eq (SimplePolygon v)
Ord v => Ord (SimplePolygon v)

tessellate :: Storable v => Tessellator SimplePolygon v
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