OpenGL-2.2.3.0: A binding for the OpenGL graphics system

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

Graphics.Rendering.OpenGL.GLU.Tessellation

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