inkscape/src/perspective3d.cpp

	perspective3d.cpp revision d81a973b81c26fcef48f46fc665eef88d386af07
#define __PERSPECTIVE3D_C__

/*
 * Class modelling a 3D perspective
 *
 * Authors:
 *   Maximilian Albert <Anhalter42@gmx.de>
 *
 * Copyright (C) 2007 authors
 *
 * Released under GNU GPL, read the file 'COPYING' for more information
 */

#include "box3d-context.h"
#include "perspective-line.h"
#include <iostream>
#include "desktop.h"

// can probably be removed later
#include "inkscape.h"

namespace Box3D {

Perspective3D *
get_persp_of_box (const SP3DBox *box)
{
    SPDesktop *desktop = inkscape_active_desktop(); // Should we pass the desktop as an argument?
    for (GSList *p = desktop->perspectives; p != NULL; p = p->next) {
        if (((Perspective3D *) p->data)->has_box (box))
            return (Perspective3D *) p->data;
    }
    g_warning ("Stray 3D box!\n");
    g_assert_not_reached();
}

/**
 * Computes the intersection of the two perspective lines from pt1 and pt2 to the respective
 * vanishing points in the given directions.
 */
// FIXME: This has been moved to a virtual method inside PerspectiveLine; can probably be purged
NR::Point
perspective_intersection (NR::Point pt1, Box3D::Axis dir1, NR::Point pt2, Box3D::Axis dir2, Perspective3D *persp)
{
    VanishingPoint const *vp1 = persp->get_vanishing_point(dir1);
    VanishingPoint const *vp2 = persp->get_vanishing_point(dir2);
    NR::Maybe<NR::Point> meet = Line(pt1, *vp1).intersect(Line(pt2, *vp2));
    // FIXME: How to handle parallel lines (also depends on the type of the VPs)?
    if (!meet) { meet = NR::Point (0.0, 0.0); }
    return *meet;
}

/**
 * Find the point on the perspective line from line_pt to the
 * vanishing point in direction dir that is closest to ext_pt.
 */
NR::Point
perspective_line_snap (NR::Point line_pt, Box3D::Axis dir, NR::Point ext_pt, Perspective3D *persp)
{
    return PerspectiveLine(line_pt, dir, persp).closest_to(ext_pt);
}

Perspective3D::Perspective3D (VanishingPoint const &pt_x, VanishingPoint const &pt_y, VanishingPoint const &pt_z)
    : desktop (NULL),
      vp_x (pt_x),
      vp_y (pt_y),
      vp_z (pt_z),
      boxes (NULL)
{
}

Perspective3D::~Perspective3D ()
{
    g_assert (desktop != NULL);
    desktop->remove_perspective (this);

    g_slist_free (boxes);
}


VanishingPoint *Perspective3D::get_vanishing_point (Box3D::Axis const dir)
{
    // FIXME: Also handle value 'NONE' in switch
    switch (dir) {
        case X:
            return &vp_x;
            break;
        case Y:
            return &vp_y;
            break;
        case Z:
            return &vp_z;
            break;
    }
}

void Perspective3D::set_vanishing_point (Box3D::Axis const dir, VanishingPoint const &pt)
{
    switch (dir) {
        case X:
            vp_x = pt;
            break;
        case Y:
            vp_y = pt;
            break;
        case Z:
            vp_z = pt;
            break;
        case NONE:
            // no vanishing point to set
            break;
    }
}

void
Perspective3D::add_box (SP3DBox *box)
{
    if (g_slist_find (this->boxes, box) != NULL) {
        // Don't add the same box twice
        g_warning ("Box already uses the current perspective. We don't add it again.\n");
        return;
    }
    this->boxes = g_slist_append (this->boxes, box);
}

void
Perspective3D::remove_box (const SP3DBox *box)
{
    if (!g_slist_find (this->boxes, box)) {
        g_warning ("Could not find box that is to be removed in the current perspective.\n");
    }
    this->boxes = g_slist_remove (this->boxes, box);
}

bool
Perspective3D::has_box (const SP3DBox *box)
{
    return (g_slist_find (this->boxes, box) != NULL);
}

} // namespace Box3D

/*
  Local Variables:
  mode:c++
  c-file-style:"stroustrup"
  c-file-offsets:((innamespace . 0)(inline-open . 0)(case-label . +))
  indent-tabs-mode:nil
  fill-column:99
  End:
*/
// vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4:encoding=utf-8:textwidth=99 :