Chapter 3: OpenTK.Math

To help you write cleaner code, OpenTK defines commonly used vectors, quaternions and matrices to extend the standard scalar types. They are generally nicer to handle than the arrays which the C API expects.

For example: OpenTK allows you to set the parameters of GL.Color() in various ways, the color cyan is used in this case.

GL.Color( 0.0f, 1.0f, 1.0f );
 
Vector3 MyColor = new Vector3( 0.0f, 1.0f, 1.0f );
GL.Color( MyColor );
 
// requires the System.Drawing library
GL.Color( Color.Cyan );

Function overloads like this can be found all over OpenTK.Graphics and OpenTK.Audio, where applicable.

Overview
Everything listed below is type-safe, code using these types will work across all supported platforms.

Vectors

  • Half-precision Floating-point
    • Half - new scalar type with 16 Bits of precision. More information can be found here.
    • Vector2h - 2-component vector of the type Half.
    • Vector3h - 3-component vector of the type Half.
    • Vector4h - 4-component vector of the type Half.
  • Single-precision Floating-point
    • Single - standard scalar type with 32 Bits of precision.
    • Vector2 - 2-component vector of the type Single.
    • Vector3 - 3-component vector of the type Single.
    • Vector4 - 4-component vector of the type Single.
  • Double-precision Floating-point
    • Double - standard scalar type with 64 Bits of precision.
    • Vector2d - 2-component vector of the type Double.
    • Vector3d - 3-component vector of the type Double.
    • Vector4d - 4-component vector of the type Double.

Quaternion

  • Quaternion - single-precision floating-point Quaternion using 4 components.
  • Quaterniond - double-precision floating-point Quaternion using 4 components.

Row-Major Matrices

  • Matrix3d - 3x3 double-precision Matrix.
  • Matrix4 - 4x4 single-precision Matrix.
  • Matrix4d - 4x4 double-precision Matrix.

These are all value types (struct), not reference types. The implications of this can be read here.

Casts

For symmetry with established types, all OpenTK.Math types can be cast and allow serialization.

Vector2d TexCoord = new Vector2d( 0.2, 0.5 );
Vector2h HalfTexCoord = (Vector2h)TexCoord;
 
Vector3h Normal = (Vector3h)Vector3.UnitX;

Instance and Static Methods

The exact methods for each struct would be too numberous to list here, the function reference and inline documentation serve that purpose. It might not be obvious that some functionality is only available for instances of the structs, while others are static.

Vector3 Normal = Vector3.UnitX;
Normal.Normalize();
 
Vector4 TransformedVector = Vector4.Transform( Vector4.UnitX, Matrix4.Identity );

Comments

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Tal's picture

Hi! Thanks for your math support just as XNA and SlimDX!
Please add to the math a Plan struct. It very useful for phisics, rays, etc.
It has suggested many times and had not been implacted yet.