You may also want to have a pose object that defines the relative position and orientation of the object in space, for both 2D and 3D. This is closely related to a transform but in many cases more useful/easier to use. Given an object with one pose you can simply provide a function with the object, pose and the new desired pose, rather than having to construct a transform from one to the other. Of course this is not exclusive to the transform functions, and they should exist as well.

On Tue, May 28, 2013 at 7:26 PM, Adam Wulkiewicz <adam.wulkiewicz@gmail.com> wrote:

Hi,/.../

Adam Wulkiewicz wrote:

Hi,

I've been thinking about additional concepts like vector, matrix, etc.

and how they could be used in Boost.Geometry. In our context they

probably should be seen only as translation and rotation representations.

So I think about following use cases:

In the free time you may check extensions/algebra. For now there is only Vector concept and some algorithms (for now only for vectors defined in cartesian cs). Basically this is what is implemented now:

typedef bg::model::point<

double, 3, ::boost::geometry::cs::cartesian> p3d;

typedef bg::model::box<p3d> b3d;

typedef ag::model::vector<double, 3> v3d;

v3d v;

bg::set<0>(v, 1);

bg::set<1>(v, 2);

bg::set<3>(v, 3);

double x = bg::get<0>(v);

double y = bg::get<1>(v);

double z = bg::get<2>(v);

bg::assign_values(v, 10, 11, 12);

bg::assign_zero(v);

// get vector

p3d p1, p2;

bg::translation(p1, p2, v);

v = bg::return_translation<v3d>(p1, p2);

// translate point

bg::translate(p1, v);

bg::translated(p1, v, p2);

p2 = bg::return_translated<p3d>(p1, v);

// translate box

b3d b1, b2;

bg::translate(b1, v);

bg::translated(b1, v, b2);

b2 = bg::return_translated<b3d>(b1, v);

I was probably too hasty with the rotation proposal and must think more about it.

Another thing, if we have transformations in the future, it would probably be good to replace translate() and rotate() with one transform() function working for vectors, rotation and transformation matrices, quaternions, etc.

And then replace translation() by some more general name like vector_between().

Regards,

Adam

_______________________________________________

Geometry mailing list

Geometry@lists.boost.org

http://lists.boost.org/mailman/listinfo.cgi/geometry