gl3n - linear algebra and more for D

[Kiith-Sa]

David wrote:

> Hello,
> 
> I am currently working on gl3n - https://bitbucket.org/dav1d/gl3n - gl3n
> provides all the math you need to work with OpenGL, DirectX or just
> vectors and matrices (it's mainly targeted at graphics - gl3n will never
> be more then a pure math library). What it supports:
> 
>   * vectors
>   * matrices
>   * quaternions
>   * interpolation (lerp, slerp, hermite, catmull rom, nearest)
>   * nearly all glsl functions (according to spec 4.1)
>   * some more cool features, like templated types (vectors, matrices,
>     quats), cool ctors, dynamic swizzling
> 
> And the best is, it's MIT licensed ;). Unfortunatly there's no
> documentation yet, but it shouldn't be hard to understand how to use it,
> if you run anytime into troubles just take a look into the source, I did
> add to every part of the lib unittests, so you can see how it works when
> looking at the unittests, furthermore I am very often at #D on freenode.
> But gl3n isn't finished! My current plans are to add more interpolation
> functions and the rest of the glsl defined functions, but I am new to
> graphics programming (about 4 months I am now into OpenGL), so tell me
> what you're missing, the chances are good that I'll implement and add
> it. So let me know what you think about it.
> 
> Before I forget it, a bit of code to show you how to use gl3n:
> 
> ------------------------------------------------------------------------
> vec4 v4 = vec4(1.0f, vec3(2.0f, 3.0f, 4.0f));
> vec4 v4 = vec4(1.0f, vec4(1.0f, 2.0f, 3.0f, 4.0f).xyz)); // "dynamic"
> swizzling with opDispatch
> vec3 v3 = my_3dvec.rgb;
> float[] foo = v4.xyzzzwzyyxw // not useful but possible!
> glUniformMatrix4fv(location, 1, GL_TRUE, mat4.translation(-0.5f, -0.54f,
> 0.42f).rotatex(PI).rotatez(PI/2).value_ptr); // yes they are row major!
> mat3 inv_view = view.rotation;
> mat3 inv_view = mat3(view);
> mat4 m4 = mat4(vec4(1.0f, 2.0f, 3.0f, 4.0f), 5.0f, 6.0f, 7.0f, 8.0f,
> vec4(...) ...);
> 
> struct Camera {
>      vec3 position = vec3(0.0f, 0.0f, 0.0f);
>      quat orientation = quat.identity;
> 
>      Camera rotatex(real alpha) { orientation.rotatex(alpha); return this; }
>      Camera rotatey(real alpha) { orientation.rotatey(alpha); return this; }
>      Camera rotatez(real alpha) { orientation.rotatez(alpha); return this; }
> 
>      Camera move(float x, float y, float z) {
>          position += vec3(x, y, z);
>          return this;
>      }
>      Camera move(vec3 s) {
>          position += s;
>          return this;
>      }
> 
>      @property camera() {
>          //writefln("yaw: %s, pitch: %s, roll: %s",
> degrees(orientation.yaw), degrees(orientation.pitch),
> degrees(orientation.roll));
>          return mat4.translation(position.x, position.y, position.z) *
> orientation.to_matrix!(4,4);
>      }
> }
> 
>          glUniformMatrix4fv(programs.main.view, 1, GL_TRUE,
> cam.camera.value_ptr);
>          glUniformMatrix3fv(programs.main.inv_rot, 1, GL_TRUE,
> cam.orientation.to_matrix!(3,3).inverse.value_ptr);
> ------------------------------------------------------------------------
> 
> I hope this gave you a little introduction of gl3n.
> 
> - dav1d


I looked at your project yesterday (found it on derelict forums) 
and it looks really good. Currently I'm using my own code for 
vectors/matrices but a dedicated library could be better.


My comments:

Not sure if DMD will do a good job optimizing your code atm
(probably no way around this but to wait - uglifying the code would serve
no purpose)

In the future, SSE support would be nice (maybe will be easier to do if we
ever get SSE intrinsics)

Seems like most of the code is in linalg.d - wouldn't it be more maintainable
to have it separated for each struct, and then public import it through one
module for easy usage?

I'm doing a lot of 2D work, and could use at least a rectangle/aabbox struct
(if I use your lib, I'll implement rectangles on top of it anyway).
Some other structs might also be useful (3D aabbox, circle, sphere?)
Although, if you want to be as close to GLSL as possible, this might
not be a good idea.
 
Most D projects are under the Boost license. 
If you want to get this to Phobos, 
(I'd like something like this in Phobos :P)
I recommend using that license 
(IANAL, but I don't see much difference between MIT and Boost)

The GLSL style is good if you want it as close to GLSL as possible,
but it'd be good to have more D-style aliases (again hinting at Phobos).
(Personally I'd probably use the GLSL style, though)