Hello, Devs!
I think math library of Urho3D really needs in some improvements.
Here is my proposal draft about some useful additions to the lib.
The proposal consists of three parts which may refer to each other.
[size=150]1. Subscript [] operator[/size]
Ability to access to elements of Vectors and Matrices by subscript [] operator. Vectors must return float reference and Matrices - major-vector reference. Usage example:
Matrix3x3 m; // create matrix
... // fill matrix with some initial values
m[2][1] = 1.0f; // element at [row:3, col:2] will be modified,
m[0].z = 5.0f; // element at [row:1, col:3] will be modified ("z" was used instead of "z_" since Part 2)
// cross product will be accomplished between first and second rows of matrix
Vector3 cross = m[0].Cross( m[1] ); // "Cross" instead of "CrossProduct" since Part 3
e.g implementation for Vector3:
const float& operator [] ( int i ) const
{
return ( &x_ )[ i ];
}
float& operator [] ( int i )
{
return ( &x_ )[ i ];
}
e.g. implementation for Matrix3x3:
const Vector3& operator [] ( int i ) const
{
return ( ( const Vector3* ) &m00_ )[ i ];
}
Vector4& operator [] ( int i )
{
return ( ( Vector3* ) &m00_ )[ i ];
}
Full list of classes, which should support subscript [] operator:
Vector2
Vector3
Vector4
IntVector2
Matrix3
Matrix3x4
Matrix4
Color
Quaternion (Under doubt, because I've never used quaternions directly through member variables, but only via methods and Euler-values)
[size=150]2. Shorthands for useful member variables[/size]
Ability to access to public fields of high-usage classes through short notation, e.g. “x”, “y” and “z” for Vector3 instead of “x_”, “y_”, “z_”.
This part can be considered as continuation of thread, that i’ve created earlier: http://discourse.urho3d.io/t/math-shorter-aliases-for-public-fields-of-core-classes/1546/1
I offer to introduce an additional rule into coding conventions (http://urho3d.github.io/documentation/HEAD/_coding_conventions.html), because it seems to be reasonable:
If class considered as POD and high-usage, if it has only public member fields (examples: Vector3, Color, Ray), then there must be Shorthands or Properties or Aliases (call as you want) for standard member variables in notation: lower-camelcase, have NOT an underscore appended.
For example, that how could be declared and documented member variables of Vector2:
union
{
/// X coordinate.
float x_;
/// [Shorthand] X coordinate.
float x;
};
union
{
/// Y coordinate.
float y_;
/// [Shorthand] Y coordinate.
float y;
};
or Ray:
union
{
/// Ray origin.
Vector3 origin_;
/// Same as origin_
Vector3 o;
};
union
{
/// Ray direction.
Vector3 direction_;
/// Same as direction_
Vector3 d;
};
With union statements there is no conflict or conformance exception with fifth rule in Coding conventions:
What I’m offering is just an addition to already existed rules.
List of classes (in my opinion) which should have shorthands by default:
Vector2
Vector3
Vector4
IntVector2
IntRect
Color
Rect
Ray
Plane
Sphere
BoundingBox
Under doubt:
Unnecessary since Part 1:
(as matrices usually considered as (two-dimensional) arrays and it is more logically to access to their elements through index)
Matrix3
Matrix3x4
Matrix4
[size=150]Part 3. Shorter methods[/size]
Also it is may be useful to use shorter names for classic methods like
v1.Dot( v2 );
v1.Cross( v2 );
instead of
v1.DotProduct( v2 );
v2.CrossProduct( v2 );
Because they can’t be confused with something else.
[size=150]Conclusion[/size]
My current modification of the math library which I’m using: http://gdurl.com/148O
It’s not a final proposal, but an opening point for discussion and suggestions. I really like the Urho3D and want it to be even better.
I thought about making a pull request as guy with nick franck22000 advised me, but I’ve never did make it before. So in order to not spend time for reading git help I’ve decided just to create this thread, as I think every day Urho3D have new user and we can save him from PITA 
