Returning Coordinates

The functions in this section return either a single coordinate or a set of coordinates. Each has a const and a non-const version.

The arguments are the same, with one exception:

char c

Only in get_coord(). Indicates which coordinate should be returned. Valid values are 'x', 'X', 'y', 'Y', 'z', 'Z', 'w', and 'W'.

char coords

Indicates the set of coordinates which should be returned or from which the coordinate to be returned should be chosen from. Valid values are 'w' for world_coordinates (the default), 'p' for projective_coordinates, 'u' for user_coordinates, and 'v' for view_coordinates.

const bool do_persp

Only relevant if projective_coordinates, or one of its elements is to be returned. If true, the default, then project() is called, thereby generating values for projective_coordinates. If do_persp is false, then projective_coordinates, or one of its elements, is returned unchanged, which may sometimes be useful.

const bool do_apply

If true (the default), apply_transform() is called, thereby updating the world_coordinates. Otherwise, it's not, so that the values stored in world_coordinates remain unchanged. Note that if coords is 'p' and do_persp is true, apply_transform() will be called in project() whether do_apply is true or false. If for some reason, one wanted get projective_coordinates, or one of its values, based on the projection of world_coordinates without first updating them, one would have to call reset_transform() before calling one of these functions. It would probably be a good idea to save transform before doing so.

Focus* f

Indicates what Focus is to be used for projection. Only relevant if coords is 'p', i.e., projective_coordinates, or one of its elements, is to be returned. The default is 0, in which case f points to the global variable default_focus.

const unsigned short proj

Indicates what form of projection is to be used. Only relevant if coords is 'p', i.e., projective_coordinates, or one of its elements, is to be returned. The default is Projections::PERSP, which causes the perspective projection to be applied.

real factor

Passed to project(). The values of the x and y coordinates in projective_coordinates are multiplied by factor. Only relevant if coords is 'p', i.e., projective_coordinates, or one of its elements, is to be returned. The default is 1.

valarray <real> get_all_coords ([char coords = 'w', [const bool do_persp = true, [const bool do_apply = true, [Focus* f = 0, [const unsigned short proj = Projections::PERSP, [real factor = 1]]]]]])

Function

Returns one of the sets of coordinates; world_coordinates by default. Returns a complete set of coordinates: 'w' for world_coordinates, 'p' for projective_coordinates, 'u' for user_coordinates, or'v' for view_coordinates.

real get_coord (char c, [char coords = 'w', [const bool do_persp = true, [const bool do_apply = true, [Focus* f = 0, [const unsigned short proj = Projections::PERSP, [real factor = 1]]]]]])

Function

Returns one coordinate, x, y, z, or w, from the set of coordinates indicated (or world_coordinates, by default).

real get_x ([char coords = 'w', [const bool do_persp = true, [const bool do_apply = true, [Focus* f = 0, [const unsigned short proj = Projections::PERSP, [real factor = 1]]]]]])

Function

Returns the x-coordinate from the set of coordinates indicated (or world_coordinates, by default).

real get_y ([char coords = 'w', [const bool do_persp = true, [const bool do_apply = true, [Focus* f = 0, [const unsigned short proj = Projections::PERSP, [real factor = 1]]]]]])

Function

Returns the y-coordinate from the set of coordinates indicated (or world_coordinates, by default).

real get_z ([char coords = 'w', [const bool do_persp = true, [const bool do_apply = true, [Focus* f = 0, [const unsigned short proj = Projections::PERSP, [real factor = 1]]]]]])

Function

Returns the z-coordinate from the set of coordinates indicated (or world_coordinates, by default).

real get_w ([char coords = 'w', [const bool do_persp = true, [const bool do_apply = true, [Focus* f = 0, [const unsigned short proj = Projections::PERSP, [real factor = 1]]]]]])

Function

Returns the w-coordinate from the set of coordinates indicated (or world_coordinates, by default).