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/*
* Vanishing point for 3D perspectives
*
* Authors:
* Maximilian Albert <Anhalter42@gmx.de>
*
* Copyright (C) 2007 authors
*
* Released under GNU GPL, read the file 'COPYING' for more information
*/
#ifndef SEEN_VANISHING_POINT_H
#define SEEN_VANISHING_POINT_H
#include "libnr/nr-point.h"
#include "line-geometry.h"
namespace Box3D {
enum VPState {
VP_FINITE = 0, // perspective lines meet in the VP
VP_INFINITE // perspective lines are parallel
};
// 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
};
extern Axis axes[3];
extern Axis planes[3];
extern FrontOrRear face_positions [2];
// 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 gint face_to_int (guint face_id) {
switch (face_id) {
case 1: return 0;
case 2: return 2;
case 4: return 4;
case 3: return 4;
case 5: return 2;
case 6: return 0;
case 9: return 1;
case 10: return 3;
case 12: return 5;
case 11: return 5;
case 13: return 3;
case 14: return 1;
default: return -1;
}
}
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 occuring 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 (Box3D::Axis axis) {
return (Box3D::Axis) (Box3D::XYZ ^ axis);
}
/* returns an axis direction perpendicular to the ones occuring 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;
}
inline gchar * string_from_axes (Box3D::Axis axes) {
GString *pstring = g_string_new("");
if (axes & Box3D::X) g_string_append_printf (pstring, "X");
if (axes & Box3D::Y) g_string_append_printf (pstring, "Y");
if (axes & Box3D::Z) g_string_append_printf (pstring, "Z");
return pstring->str;
}
// FIXME: Store the Axis of the VP inside the class
class VanishingPoint : public NR::Point {
public:
inline VanishingPoint() : NR::Point() {};
/***
inline VanishingPoint(NR::Point const &pt, NR::Point const &ref = NR::Point(0,0))
: NR::Point (pt),
ref_pt (ref),
v_dir (pt[NR::X] - ref[NR::X], pt[NR::Y] - ref[NR::Y]) {}
inline VanishingPoint(NR::Coord x, NR::Coord y, NR::Point const &ref = NR::Point(0,0))
: NR::Point (x, y),
ref_pt (ref),
v_dir (x - ref[NR::X], y - ref[NR::Y]) {}
***/
VanishingPoint(NR::Point const &pt, NR::Point const &inf_dir, VPState st);
VanishingPoint(NR::Point const &pt);
VanishingPoint(NR::Point const &dir, VPState const state);
VanishingPoint(NR::Point const &pt, NR::Point const &direction);
VanishingPoint(NR::Coord x, NR::Coord y);
VanishingPoint(NR::Coord x, NR::Coord y, VPState const state);
VanishingPoint(NR::Coord x, NR::Coord y, NR::Coord dir_x, NR::Coord dir_y);
VanishingPoint(VanishingPoint const &rhs);
bool is_finite();
VPState toggle_parallel();
void draw(Box3D::Axis const axis); // Draws a point on the canvas if state == VP_FINITE
//inline VPState state() { return state; }
VPState state;
//NR::Point ref_pt; // point of reference to compute the direction of parallel lines
NR::Point v_dir; // direction of perslective lines if the VP has state == VP_INFINITE
private:
};
} // namespace Box3D
/** A function to print out the VanishingPoint (prints the coordinates) **/
/***
inline std::ostream &operator<< (std::ostream &out_file, const VanishingPoint &vp) {
out_file << vp;
return out_file;
}
***/
#endif /* !SEEN_VANISHING_POINT_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 :
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