Library
Module
Module type
Parameter
Class
Class type
Basic types for computer graphics.
Gg
defines types and functions for floats, vectors, points, matrices, quaternions, sizes, axis aligned boxes, colors, color profiles, linear bigarrays and raster data.
Consult the basics. Open the module to use it, this defines only modules and types in your scope.
Release 0.9.1 - Daniel Bünzli <daniel.buenzl i@erratique.ch>
module Float : sig ... end
Floating point number utilities.
The following type are defined so that they can be used in vector modules. The matrix modules are here.
An n-dimensional vector v
is a sequence of n, zero indexed, floating point components. We write v
i the ith component of a vector.
module type V = sig ... end
Implemented by all vector types.
module V2 : sig ... end
module V3 : sig ... end
module V4 : sig ... end
An n-dimensional point p
is a vector of the corresponding dimension. The components of the vector are the point's coordinates.
type p2 = v2
The type for 2D points.
type p3 = v3
The type for 3D points.
module type P = sig ... end
Implemented by all point types.
module P2 : sig ... end
module P3 : sig ... end
Unit quaternions represent rotations in 3D space. They allow to smoothly interpolate between orientations. A quaternion is a 4D vector, whose components x
, y
, z
, w
represents the quaternion x
i+ y
j + z
k + w
.
type quat = v4
The type for quaternions.
module Quat : sig ... end
An mxn matrix a
is an array of m rows and n columns of floating point elements. We write a
ij the element of a
located at the ith row and jth column.
Matrix constructors specify matrix elements in row-major order so that matrix definitions look mathematically natural with proper code indentation. However elements are stored and iterated over in column-major order.
module type M = sig ... end
Implemented by all (square) matrix types.
module M2 : sig ... end
module M3 : sig ... end
module M4 : sig ... end
An n-dimensional size s
represents extents in n-dimensional space.
type size2 = v2
The type for sizes in 2D space.
type size3 = v3
The type for sizes in 3D space.
module type Size = sig ... end
Implemented by all size types.
module Size1 : sig ... end
In 1D space, width is the extent along the x-axis.
module Size2 : sig ... end
In 2D space, width is the extent along the x-axis and height the extent along the y-axis.
module Size3 : sig ... end
In 3D space, width is the extent along the x-axis, height the extent along the y-axis and depth the extent along the z-axis.
An n-dimensional axis-aligned box b
is defined by an n-dimensional point o
, its origin, and an n-dimensional size s
. Operations on boxes with negative sizes are undefined.
The space S(b
) spanned by b
is [o
0; o
0 + s
0] x ... x [o
n-1; o
n-1 + s
n-1]. The extremum points of this space are the box's corners. There is a distinguished n-dimensional empty
box such that S(empty
) is empty.
The type for 1D axis-aligned boxes (closed intervals).
The type for 2D axis-aligned boxes (rectangles).
The type for 3D axis-aligned boxes (cuboids).
module type Box = sig ... end
Implemented by all axis-aligned box types.
module Box1 : sig ... end
module Box2 : sig ... end
module Box3 : sig ... end
module Color : sig ... end
Colors and color profiles.
The type for linear bigarrays.
type buffer = [
| `Int8 of (int, Bigarray.int8_signed_elt) bigarray
| `Int16 of (int, Bigarray.int16_signed_elt) bigarray
| `Int32 of (int32, Bigarray.int32_elt) bigarray
| `Int64 of (int64, Bigarray.int64_elt) bigarray
| `UInt8 of (int, Bigarray.int8_unsigned_elt) bigarray
| `UInt16 of (int, Bigarray.int16_unsigned_elt) bigarray
| `UInt32 of (int32, Bigarray.int32_elt) bigarray
| `UInt64 of (int64, Bigarray.int64_elt) bigarray
| `Float16 of (int, Bigarray.int16_unsigned_elt) bigarray
| `Float32 of (float, Bigarray.float32_elt) bigarray
| `Float64 of (float, Bigarray.float64_elt) bigarray
]
The type for linear bigarray buffers.
module Ba : sig ... end
Linear bigarrays and bigarray buffers.
module Raster : sig ... end
Raster data.
Gg
is designed to be opened in your module. This defines only types and modules in your scope, no values. Thus to use Gg
start with :
open Gg
In the toplevel, if you installed Gg
with ocamlfind, requiring Gg
:
> #require "gg";;
automatically opens Gg
and installs printers for the types.
Most types and their functions are defined with the following conventions. The type is first defined in Gg
, like v2
for 2D vectors, a module for it follows. The name of the module is the type name capitalized, e.g. V2
for 2D vectors and it has the following definitions:
t
equal to the original toplevel type (V2.t
).dim
, an int
value that indicates the dimensionality of the type (V2.dim
).v
, a constructor for the type (V2.v
).pp
to convert values to a textual representation for debugging purposes and toplevel interaction V2.pp
).equal
and compare
the standard functions that make a module a good functor argument (V2.equal
, V2.compare
).equal_f
and compare_f
which compare like equal
and compare
but allow to use a client provided function to compare floats (V2.equal_f
, V2.compare_f
).ltr
and tr
to apply linear and affine transforms on the type (V2.ltr
, V2.tr
).V2.x
), constants (e.g. V2.zero
), functions (e.g. V2.dot
) and predicates (e.g. V2.exists
) specific to the type.V2
, V3
, V4
for vectors, usually share a common signature. This common signature is collected in a module type defined in Gg
, this signature is V
for vectors.Some types are defined as simple abreviations. For example the type p2
for 2D points is equal to v2
. These types also have a module whose name is the type name capitalized, P2
in our example. However this module only provides alternate constructors, constants and accessors and the extended functionality specific to the type. You should fallback on the module of the abreviated type (V2
in our example) for other operations. The aim of these types is to make your code and signatures semantically clearer without the burden of explicit conversions.
Finally there are some types and modules like Color
whose structure is different because they provide specific functionality.
Here are a few other conventions :
M4.scale3
indicates scale in 3D space while M4.scale4
scale in 4D space.V2.tr
).of_
conventions. Thus to convert a value of type t'
to a value of type t
look for the function named T.of_t'
.To conclude note that it is sometimes hard to find the right place for a function. If you cannot find a function look into each of the modules of the types you want to act upon.
Values of type color
are in a linear sRGB space as this is the space to work in if you want to process colors correctly (e.g. for blending). The constructor Color.v_srgb
takes its parameters from a non-linear sRGB space and converts them to linear sRGB.
# let c = Color.v_srgb 0.5 0.5 0.5 1.0;;
- : Gg.color = (0.214041 0.214041 0.214041 1)
This is the constructor you are likely to use when you specify color constants (e.g. to specify a color value matching a CSS color). If you need an sRGB color back from a color
value use Color.to_srgb
:
# Color.to_srgba c;;
- : Gg.Color.srgba = (0.5 0.5 0.5 1)
Float.pp
that output a lossless textual representation of floats. While the actual format is subject to change it will remain compatible with float_of_string
.Set.Make
and Map.Make
. However this will use Pervasives.compare
and thus binary comparison between floats. Depending on the intended use this may be sensible or not. Comparisons with alternate functions to compare floats can be defined by using the functions named compare_f
(e.g. V2.compare_f
). An alternate float comparison function is Float.compare_tol
that combines relative and absolute float comparison in a single test, see Float.equal_tol
for the details.Float
module are undefined on certain arguments but do not raise Invalid_argument
on those. As usual do not rely on the behaviour of functions on undefined arguments, these are subject to change.