// SPDX-License-Identifier: GPL-2.0-or-later /* * Generic auxiliary routines for 3D axes * * Authors: * Maximilian Albert * * Copyright (C) 2007 authors * * Released under GNU GPL v2+, read the file 'COPYING' for more information. */ #ifndef SEEN_AXIS_MANIP_H #define SEEN_AXIS_MANIP_H #include #include #include #include namespace Proj { enum VPState { VP_FINITE = 0, VP_INFINITE }; // The X-/Y-/Z-axis corresponds to the first/second/third digit // in binary representation, respectively. enum Axis { X = 0, Y = 1, Z = 2, W = 3, NONE }; extern Axis axes[4]; inline char const* string_from_axis(Proj::Axis axis) { switch (axis) { case X: return "X"; break; case Y: return "Y"; break; case Z: return "Z"; break; case W: return "W"; break; case NONE: return "NONE"; break; } return ""; } } // namespace Proj namespace Box3D { const double epsilon = 1e-6; // The X-/Y-/Z-axis corresponds to the first/second/third digit // in binary representation, respectively. enum Axis { X = 1, Y = 2, Z = 4, XY = 3, XZ = 5, YZ = 6, XYZ = 7, NONE = 0 }; // We use the fourth bit in binary representation // to indicate whether a face is front or rear. enum FrontOrRear { // find a better name FRONT = 0, REAR = 8 }; // converts X, Y, Z respectively to 0, 1, 2 (for use as array indices, e.g) inline int axis_to_int(Box3D::Axis axis) { switch (axis) { case Box3D::X: return 0; case Box3D::Y: return 1; case Box3D::Z: return 2; case Box3D::NONE: return -1; default: assert(false); return -1; // help compiler's flow analysis (-Werror=return-value) } } inline Proj::Axis toProj(Box3D::Axis axis) { switch (axis) { case Box3D::X: return Proj::X; case Box3D::Y: return Proj::Y; case Box3D::Z: return Proj::Z; case Box3D::NONE: return Proj::NONE; default: assert(false); return Proj::NONE; // help compiler's flow analysis (-Werror=return-value) } } extern Axis axes[3]; extern Axis planes[3]; extern FrontOrRear face_positions [2]; } // namespace Box3D namespace Proj { inline Box3D::Axis toAffine(Proj::Axis axis) { switch (axis) { case Proj::X: return Box3D::X; case Proj::Y: return Box3D::Y; case Proj::Z: return Box3D::Z; case Proj::NONE: return Box3D::NONE; default: assert(false); return Box3D::NONE; // help compiler's flow analysis (-Werror=return-value) } } } // namespace Proj namespace Box3D { /* * Identify the axes X, Y, Z with the numbers 0, 1, 2. * A box's face is identified by the axis perpendicular to it. * For a rear face, add 3. */ // Given a bit sequence that unambiguously specifies the face of a 3D box, // return a number between 0 and 5 corresponding to that particular face // (which is normally used to index an array). Return -1 if the bit sequence // does not specify a face. A face can either be given by its plane (e.g, XY) // or by the axis that is orthogonal to it (e.g., Z). inline int face_to_int (unsigned int face_id) { switch (face_id) { case 1: return 0; case 2: return 1; case 4: return 2; case 3: return 2; case 5: return 1; case 6: return 0; case 9: return 3; case 10: return 4; case 12: return 5; case 11: return 5; case 13: return 4; case 14: return 3; default: return -1; } } inline int int_to_face (unsigned id) { switch (id) { case 0: return Box3D::YZ ^ Box3D::FRONT; case 1: return Box3D::XZ ^ Box3D::FRONT; case 2: return Box3D::XY ^ Box3D::FRONT; case 3: return Box3D::YZ ^ Box3D::REAR; case 4: return Box3D::XZ ^ Box3D::REAR; case 5: return Box3D::XY ^ Box3D::REAR; } return Box3D::NONE; // should not be reached } inline bool is_face_id (unsigned int face_id) { return !((face_id & 0x7) == 0x7); } /** inline gint opposite_face (guint face_id) { return face_id + (((face_id % 2) == 0) ? 1 : -1); } **/ inline unsigned int number_of_axis_directions (Box3D::Axis axis) { unsigned int num = 0; if (axis & Box3D::X) num++; if (axis & Box3D::Y) num++; if (axis & Box3D::Z) num++; return num; } inline bool is_plane (Box3D::Axis plane) { return (number_of_axis_directions (plane) == 2); } inline bool is_single_axis_direction (Box3D::Axis dir) { // tests whether dir is nonzero and a power of 2 return (!(dir & (dir - 1)) && dir); } /** * Given two axis directions out of {X, Y, Z} or the corresponding plane, return the remaining one * We don't check if 'plane' really specifies a plane (i.e., if it consists of precisely two directions). */ inline Box3D::Axis third_axis_direction (Box3D::Axis dir1, Box3D::Axis dir2) { return (Box3D::Axis) ((dir1 + dir2) ^ 0x7); } inline Box3D::Axis third_axis_direction (Box3D::Axis plane) { return (Box3D::Axis) (plane ^ 0x7); } /* returns the first/second axis direction occurring in the (possibly compound) expression 'dirs' */ inline Box3D::Axis extract_first_axis_direction (Box3D::Axis dirs) { if (dirs & Box3D::X) return Box3D::X; if (dirs & Box3D::Y) return Box3D::Y; if (dirs & Box3D::Z) return Box3D::Z; return Box3D::NONE; } inline Box3D::Axis extract_second_axis_direction (Box3D::Axis dirs) { return extract_first_axis_direction ((Box3D::Axis) (dirs ^ extract_first_axis_direction(dirs))); } inline Box3D::Axis orth_plane_or_axis (Box3D::Axis axis) { return (Box3D::Axis) (Box3D::XYZ ^ axis); } /* returns an axis direction perpendicular to the ones occurring in the (possibly compound) expression 'dirs' */ inline Box3D::Axis get_perpendicular_axis_direction (Box3D::Axis dirs) { if (!(dirs & Box3D::X)) return Box3D::X; if (!(dirs & Box3D::Y)) return Box3D::Y; if (!(dirs & Box3D::Z)) return Box3D::Z; return Box3D::NONE; } Glib::ustring string_from_axes (Box3D::Axis axis); std::pair get_remaining_axes (Axis axis); } // namespace Box3D #endif /* !SEEN_AXIS_MANIP_H */ /* Local Variables: mode:c++ c-file-style:"stroustrup" c-file-offsets:((innamespace . 0)(inline-open . 0)) indent-tabs-mode:nil fill-column:99 End: */ // vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4 :